Improved whipped silk creams and methods of making and using the same

Abstract

A host of new silk material formats are disclosed, all prepared from an initial liquid composition including silk fibroin, a plasticizer, and xanthan gum and / or alginate. In some cases, particularly preferred material properties are achieved by the addition of glycerol and / or multi-valent metal ions. These various formats include liquids, whipped silk creams, silk meringues, and compressed / heat-compressed meringues. Among the useful end-uses for these materials is a silk leather, which mimics the feel of conventional leather. Other uses include thermal insulation, absorption / gas sensing, biological scaffolding, and the like. A material that has material properties unexpectedly similar to mycelium is also disclosed.

Description

IMPROVED WHIPPED SILK CREAMS AND METHODS OF MAKING AND USING THE SAMECROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims priority to and the benefit of U.S. Provisional Application No 63 / 658,745 filed in the U.S. Patent and Trademark Office on June 11, 2024, and U.S. Provisional Application No. 63 / 638,698 filed April 25, 2024. The foregoing patent applications are incorporated herein by reference in their entireties for all purposes.BACKGROUND

[0002] Sustainability in materials is an area of increasing interest. One material that is sustainable in a certain sense is leather, in that it can be reproduced and grown from animals. However, this material is not sustainable when it comes to humane treatment of animals. Alternatives to leather have been pursued for decades, but those alternatives have primarily been non-sustainable alternatives.

[0003] A need exists for alternatives to conventional leather as a material for use across the spectrum of applications where conventional leather is used.SUMMARY

[0004] In aspects, the disclosure herein relates to a liquid composition including a mixture of silk fibroin, a polysaccharide, and a plasticizer, wherein the liquid composition optionally has a water content of between 89% and 99%.

[0005] In aspects, the disclosure herein relates to whipped silk cream including silk fibroin, a polysaccharide, and a plasticizer, wherein the whipped silk cream optionally has a water content of between 50% and 95%.

[0006] In aspects, the disclosure herein relates to silk meringue including silk fibroin, a polysaccharide, and a plasticizer, wherein the silk meringue optionally has a water content of between 5% and 70%.

[0007] In aspects, the disclosure herein relates to compressed silk meringue including silk fibroin, a polysaccharide, and a plasticizer, wherein the compressed silk meringue optionally has a water content of between 2% and 50%.

[0008] In aspects, the disclosure herein relates to hot-pressed silk meringue including silk fibroin, a polysaccharide, and a plasticizer, wherein the hot-pressed silk meringue optionally has a water content of between 2% and 50%.

[0009] In aspects, the disclosure herein relates to a method of making a composition, the method including whipping a liquid composition including a mixture of silk fibroin, a polysaccharide, and a plasticizer for a predetermined whipping time to form a whipped silk cream. Optionally, the silk fibroin and the polysaccharide are whipped together before addition of the plasticizer; the silk fibroin and theplasticizer are whipped together before addition of the polysaccharide; or the polysaccharide and the plasticizer are whipped together before addition of the silk fibroin.BRIEF DESCRIPTION OF THE FIGURES

[0010] The disclosure and the following detailed description of certain aspects thereof may be understood by reference to the following figures:

[0011] Figs. 1 A and IB depict silk leather of the disclosure.

[0012] Fig. 1C depicts a CO2 sensing reaction.

[0013] Fig. 2 depicts a mechanical comparison between Mycelium and Mysilkium.

[0014] Fig. 3 depicts mechanical properties of composite mysilkium and relative textile.

[0015] Fig. 4 depicts cream density.

[0016] Fig. 5 depicts cream water content.

[0017] Fig. 6 depicts meringue density.

[0018] Fig. 7 shows the solid compositions of the meringues obtained by varying the mass of SF and assuming a total removal of water from the cooking process.

[0019] Fig. 8 provides data regarding various compositions and the ratio of SF. Gly, and XG in each composition.

[0020] Fig. 9A depicts the cream density for the compositions identified in Fig. 8.

[0021] Fig. 9B depicts the cream water content for the compositions identified in Fig. 8.

[0022] Fig. 10A depicts the syneresis (%) for the compositions identified in Fig. 8 and Fig. 10B depicts the relationship of density, water content, and syneresis to solid content.

[0023] Fig. 11 A depicts density variation of the cream as a function of whipping time.

[0024] Fig. 1 IB depicts the mechanical properties of the cream and their variation with whipping time through resistance toward compression (firmness).

[0025] Fig. 12 depicts overrun of the creams measured at different whipping times and using different plasticizers.

[0026] Fig. 13 depicts that the density of the cream reduces and can be controlled through whipping time.

[0027] Fig. 14 depicts the transition from random coils to P-sheet structure upon whipping.

[0028] Fig. 15 depicts the relationship of bubble size and overrun.

[0029] Fig. 16A depicts a photograph of SF:XG:Gly dried foam; Fig. 16B depicts densities; Fig. 16C depicts compressive strength; and Fig. 16D depicts the yield point using different ratios for SF:XG:Gly dried foams.

[0030] Fig. 17 A depicts a comparison of the mechanical performance of xanthan and alginate-based silk foams; Fig. 17B depicts a comparison of the firmness of xanthan and alginate-containing silkcreams; Fig. 17C depicts an experimental setup; and Fig. 17D depicts a temperature vs time plot of alginate foam vs. polystyrene.

[0031] Fig. 18 depicts photographs (A) and densities (B) of SF:XG:Gly 20:20:60 foams at different minutes of whipping.

[0032] Fig. 19A depicts photographs with the detail of the surface morphology of the foam and Fig. 19B depicts its internal structure as a function of the whipping time obtained through fluorescent staining with rhodamine 6G.

[0033] Fig. 20 depicts foams fluorescent staining (ThT) to analyze the internal foam structure.

[0034] Fig. 21 A depicts spectral features for ThT free in solution when excited at 365 nm and Fig. 21B depicts spectral features for ThT bound to a [3-sheet structure when excited at 365 nm.

[0035] Fig. 22 depicts the emission of foams excited at 365 nm displaying a color shift during the initial whipping phases.

[0036] Figs. 23 A, 23B, and 23C depict foam materials as a substrate for algal growth.

[0037] Fig. 24 depicts Alg foams with CaCh in Alg:CaCh different ratios: a) 1:200; b) 1:80; c) 1 :20; d) 1: 16.

[0038] Fig. 25 depicts silk foams with CaCh before (a) and after 20 minutes of immersion in water (b). Fig. 25 d depicts foams after drying and Fig. 25e depicts mass loss after drying.

[0039] Fig. 26 depicts silk foams formulated with Ca(OH)2, CaCCh. CuCh, and ZnCh.

[0040] Fig. 27 shows photos of foams with multivalent ions incorporated: ZnCh (left), CuCh (middle), and CaCOs (right), before immersion (top), after immersion (middle), and after drying (bottom).

[0041] Fig. 28 shows average mass loss of foams with multivalent ions after immersion in water.

[0042] Fig. 29 shows foams formulated with different multivalent ions. Top row, left to right: 20 mg CaCh, 50 mg CaCh, CaCOa, and ZnCh. Bottom row, left to right: 200 mg CaCh, 250 mg CaCh, and CuCh.

[0043] Fig. 30 shows mass loss of various formulations of silk foams after water immersion.

[0044] Fig. 31 A shows a foam (top) and leather (bottom) with SF2o:Alg2o:Glyeo composition and 2 g of shellac added as powder.

[0045] Fig. 3 IB shows silk leathers with shellac before immersion (top), after immersion (middle), and after drying (bottom).

[0046] Fig. 31C shows silk foams with shellac added as an emulsion with a low alginate content (left) or high alginate content (right).

[0047] Fig. 3 ID shows photographs of the water immersion test.

[0048] Fig. 32A shows a control silk leather with silk fibroin, alginate, glycerol, and a food dye.

[0049] Fig. 32B shows shellac dissolved in ethanol at varying concentrations and leathers made using the shellac solutions.

[0050] Fig. 33A shows various shellac-containing silk leathers before swelling.

[0051] Fig. 33B shows various shellac-containing silk leathers after swelling.

[0052] Fig. 33C shows UV-Vis spectra of various shellac-containing silk leathers.

[0053] Fig. 34 shows photographs of silk foams and leathers with differing amounts of latex.

[0054] Fig. 35 A shows latex silk foams before (top) and after (bottom) water immersion and drying.

[0055] Fig. 35B shows latex silk leathers before (top) and after (bottom) water immersion and drying.

[0056] Fig. 36A shows mass loss of different formulations of latex silk leathers.

[0057] Fig. 36B shows UV-Vis of latex silk leathers.

[0058] Fig. 36C shows flexibility of latex silk leathers.

[0059] Fig. 37 A shows xanthan gum creams without Ca2+creams.

[0060] Fig. 37B shows overrun of xanthan gum creams with and without Ca2+.

[0061] Fig. 37C shows xanthan gum creams with Ca2+.

[0062] Fig. 37D shows densities of xanthan gum creams with and without Ca2+.

[0063] Fig. 38 shows alg / XG creams density profile as a function of the whipping time.

[0064] Fig. 39A shows side and top view photographs of foams and corresponding density values and whipping times for a) Alg:XG 100:0; b) Alg:XG 75:25; c) Alg:XG 50:50; d) 25:75; and e) Alg:XG 0:100.

[0065] Fig. 40A shows the appearance of foams produced with different Alg:XG ratios.

[0066] Fig. 40B shows the surface characteristics of foams with different Alg:XG ratios after heat pressing.

[0067] Fig. 41 A shows baking and pressing of 100% Alg foam at different overruns.

[0068] Fig. 41B shows baking and pressing of Alg:XG 50:50 at different overruns.

[0069] Fig. 42A shows low magnification photographs of Alg:XG 80:20 leathers at different whipping times.

[0070] Fig. 42B shows high magnification photographs of Alg:XG 80:20 leathers at different whipping times.

[0071] Fig. 42C shows photographs of foams before (top) and after (bottom) compression testing.

[0072] Fig. 42D shows stress-displacement profiles for all whipping times.

[0073] Fig. 42E shows stress-displacement profile comparison with pure XG and pure Alg foams.

[0074] Fig. 43A shows density variation as a function of Wt for foams made with Alg, LBG, and their combination.

[0075] Fig. 43B shows photographs of the surface morphology of Alg / LBG derived leathers.

[0076] Fig. 43C shows side views of foams indicating different Wt values.

[0077] Fig. 43D shows stress displacement profiles for Alg / LBG foams at different Wt values.

[0078] Fig. 43E shows detailed comparison of the linear and plateau regions of the stress displacement curves across different Wt values.

[0079] Fig. 43F shows comparative stress displacement profiles of XG, Alg, LBG, and Alg / LBG foams at their respective minimum densities.

[0080] Fig. 44A shows density measurements of creams prepared using different alginate types, compared to XG and standard Alg from Sigma-Aldrich®.

[0081] Fig. 44B shows density measurements of foams prepared using different alginate types, compared to XG and standard Alg from Sigma-Aldrich®.

[0082] Fig. 45 shows top and side views of baked foams using a) IL-2 alginate; b) LZ-2 alginate; c) LVC alginate; and d) HVC alginate.

[0083] Fig. 46 shows foams before and after compression testing using a) IL-2 alginate; b) LZ-2 alginate; c) LVC alginate; and d) HVC alginate.

[0084] Fig. 47 shows micrographs of compressed foams as a function of whipping time obtained from a) IL-2 alginate; b) LZ-2 alginate; c) LVC alginate; and d) HVC alginate.

[0085] Fig. 48 shows stress-strain compression profiles of foams obtained using a) IL-2; b) LZ-2; c) LVC; and d) HVC for every Wt; and e) comparison of foams at their minimum density.

[0086] Fig. 49 shows physical properties of xanthan gum-based creams. A) cream pictures and b) their densities for SF:XG:Gly foams at 20:20:60 mass ratio at different whipping times. C) overrun of the cream during the whipping phase and D) change in firmness and density with whipping time.

[0087] Fig. 50 shows physical properties of xanthan gum-based foams. A) photographs of foams after baking at different whipping times. B) density, C) compressive strength, and D) modulus of SF:XG:Gly foams at 20:20:60 mass ratio at different whipping times.

[0088] Fig. 51 shows schematics of the main components for silk leather processing and their influence on material properties.

[0089] Fig. 52A shows a representation of the stand mixer model primarily used for cream preparation.

[0090] Fig. 52C shows overrun of SF2o:XG2o:Gly6o composition whipped at two different speeds using the stand mixer setup.

[0091] Fig. 52D shows an axial stirrer schematic.

[0092] Fig. 52E shows overrun comparison of SF2o:XG2o:Glyeo at two different speeds using the axial stirrer.

[0093] Fig. 52F (left) shows a photograph highlighting the unmixed cream volume with the axial stirrer and (right) is an illustration of the 6- wire whisk movement in a stand mixer, with both rotational and revolutionary motions.

[0094] Fig. 53 shows a comparison between whipping silk powder vs silk solution. Photographs of creams at different whipping times from a) powder and b) solution. Comparison of c) overrun, d) creams and e) foams density between SF powder and solution. Compression profile for creams obtained from SF f) powder or g) solution and h) their firmness value at the plateau phase.

[0095] Fig. 54 shows the relationship between whipping time and water stability. A) foams and b) leathers of alg-based composition obtained at different Wt and their appearance c) before and d) after being immersed in water for 10 minutes. E) photographs of the samples after drying and f) the measured mass loss.

[0096] Fig. 55 shows a) cream appearance (top) after 5 minutes of whipping at pH 4 and the corresponding baked foam (bottom). B) cream appearance (top) after 5 minutes of whipping at pH 10 and the corresponding baked foam (below). C) firmness of alginate-based creams whipped at different pH values.

[0097] Fig. 56 shows a) foam of SF7.5Alg32.sGly6o. b) foam of SFg sAlgv.sGlyeo. c) leather of SF7.5Alg32.5Gly60. d) leather of SF3.5Alg7.5Gly60.

[0098] Fig. 57 shows water stability at different SF / Alg ratios. A) shows top and side view of the swelling behavior of standard, SF7.5Alg32.5Gly60, SF3.5Alg7.5Gly6o compositions. B) shows photographs of each composition after drying and their mass loss as a bar graph.

[0099] Fig. 58 shows effect of SF MW on XG-Based Foams. A) shows a comparison of overrun values for XG creams prepared using SF with molecular weights of low MW and high MW. B) shows corresponding density measurements of the creams at different whipping times. c,d) show photographs of the resulting baked foams prepared with low MW and high MW SF, respectively, e) shows bulk foam samples obtained from the two formulations, f) cross-sectional views of the foams, highlighting structural differences based on SF MW.

[0100] Fig. 59 shows overrun comparison of alginate-based creams using different SF MWs and total solid concentrations (a) and their corresponding densities (b). c) photographs of baked foams at different whipping times using SF high MW, 5% total solid concentrations, d) SF low MW, 10% total solid concentrations, e) SF low MW, 5% total solid concentrations, f) SF low MW, 10% total solid concentrations.

[0101] Fig. 60 compares alginate and xanthan gum creams and foams, a) Overrun and b) density comparison as function of Wt. c) Firmness of 5 minute whipped creams, d) Foams densities as functionof Wt. e) compressive strength and yield point comparison, f) compressive-strain profile comparison for 5 minute whipped foams and complete stress-displacement plots for at all Wt for g) XG and h) alg.

[0102] Fig. 61 shows silk leather material properties, a) Young’s modulus andb) elongation at break of different foam compositions, c) ultimate tensile stress comparison between XG- and Alg- based formulations, d) photographs of final material examples, featuring bulk dyeing (left) and surface embossing (right).

[0103] Fig. 62 shows water dyed with a food color dropped on control leather (left) and ketene dimer- treated leather (right).DETAILED DESCRIPTION

[0104] Before the present invention is described in further detail, it is to be understood that the invention is not limited to the particular embodiments described. It is also understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting. The scope of the present invention will be limited only by the claims. As used herein, the singular forms "a", "an", and "the" include plural embodiments unless the context clearly dictates otherwise.

[0105] It should be apparent to those skilled in the art that many additional modifications beside those already described are possible without departing from the inventive concepts. In interpreting this disclosure, all terms should be interpreted in the broadest possible manner consistent with the context. Variations of the term "comprising" should be interpreted as referring to elements, components, or steps in a non-exclusive manner, so the referenced elements, components, or steps may be combined with other elements, components, or steps that are not expressly referenced. Embodiments referenced as "comprising" certain elements are also contemplated as "consisting essentially of" and "consisting of" those elements. When two or more ranges for a particular value are recited, this disclosure contemplates all combinations of the upper and lower bounds of those ranges that are not explicitly recited. For example, recitation of a value of between 1 and 10 or between 2 and 9 also contemplates a value of between 1 and 9 or between 2 and 10.Definitions

[0106] As used herein, "low molecular weight" silk fibroin refers to silk fibroin that has been subjected to boiling during degumming or another processing step for a length of time of at least 30 minutes, thereby reducing the average molecular weight of the protein fragments. Examples of low molecular weight silk fibroin can be found at WO 2014 / 145002, which is incorporated herein in its entirety by reference.

[0107] As used herein, mysilkium refers to a material that is composed of at least 20% silk fibroin and which has one or more material properties (e.g., compressive modulus, tensile strength, etc.) falling within 50%, within 25%, within 20%, within 15%, or within 10% of a native mycelium.

[0108] As used herein, "silk fibroin" refers to silk fibroin protein whether produced by silkworm, spider, or other insect, or otherwise generated (Lucas et al., Adv. Protein Chem., 13: 107-242 (1958)). Any type of silk fibroin can be used in different embodiments described herein. Silk fibroin produced by silkworms, such as Bombyx mori, is the most common and represents an earth-friendly, renewable resource. For instance, silk fibroin used in a silk film may be attained by extracting sericin from the cocoons of B. mori. Organic silkworm cocoons are also commercially available. There are many different silks, however, including spider silk (e.g., obtained from Nephila clavipes), transgenic silks, genetically engineered silks, such as silks from bacteria, yeast, mammalian cells, transgenic animals, or transgenic plants, and variants thereof, that can be used. See, e.g., WO 97 / 08315 and U.S. Pat. No. 5,245,012, each of which is incorporated herein by reference in their entireties.Liquid Compositions

[0109] The present disclosure provides a liquid composition. Compositions disclosed herein may include a protein, at least one polysaccharide, and a plasticizer. In embodiments, the protein may be silk fibroin. In embodiments, the polysaccharide may be xanthan gum, an alginate, or another high molecular weight sugar, cellulose derivative (e.g., microcrystalline cellulose, hydroxypropyl cellulose, carboxymethyl cellulose), combinations thereof, or the like. In embodiments, the polysaccharide may be a thickening agent. In embodiments, the polysaccharide may be carrageenan. Liquid compositions containing xanthan gum may be superior at obtaining silk leathers. It should be understood, however, that examples and embodiments throughout this Specification that reference xanthan gum as a component may comprise a different polysaccharide in place of, or in addition to, xanthan gum, such as an alginate. In some embodiments, selection of the particular polysaccharide or combination of polysaccharides used in the liquid composition may depend on the ultimate material properties desired. For example, in some aspects, alginate may be preferred if a free-standing leather material is desired. It is expressly contemplated that certain applications may require a combination of different polysaccharides within the same composition, such as a specific application requiring a whipped silk cream including silk fibroin, glycerol, xanthan gum, and alginate as the principal components.

[0110] In some aspects, the weight ratio of silk fibroin, polysaccharide, and plasticizer may have an impact on one or more of a mechanical property, a density, or a water content of a resulting material made from the composition. Without wishing to be bound by any particular theory, variations of the weight of the plasticizer may preferentially impact mechanical properties, variations of the weight ofthe polysaccharide or combination of polysaccharides may preferentially impact density, and variations of the weight of the silk fibroin may preferentially impact water content.

[0111] In some embodiments, the liquid composition includes a mixture of silk fibroin and xanthan gum. In some aspects, the liquid composition includes a mixture of silk fibroin, xanthan gum, and a plasticizer. In some aspects, the liquid composition includes a mixture of silk fibroin, xanthan gum, and glycerol. In some aspects, the liquid composition includes a mixture of silk fibroin, xanthan gum, and a functionalizing agent. In some aspects, the liquid composition includes a mixture of silk fibroin, xanthan gum, a plasticizer, and a functionalizing agent. In some aspects, the liquid composition includes a mixture of silk fibroin, xanthan gum, glycerol, and a functionalizing agent. In some aspects, the liquid composition includes a mixture of silk fibroin and a high molecular weight sugar (e.g., such as xanthan gum), and may optionally further include at least one of a plasticizer (e.g., such as glycerol) or a functionalizing agent.

[0112] The liquid composition can include other components that a skilled artisan will recognize are valuable in certain contexts. In certain cases, the liquid composition can further include glycerol. In certain cases, the liquid composition can further include a sensing agent. In certain case, the liquid composition can further include a therapeutically active agent. In certain cases, the liquid composition can include an aroma-providing compound.

[0113] The mixture of silk fibroin and polysaccharide (e.g., xanthan gum, alginate, etc.) includes a weight ratio of silk fibroin to polysaccharide of between 1:4 and 20:1 or between 1 :2 and 10:1. For example, the mixture of silk fibroin and polysaccharide can include a weight ratio of silk fibroin to polysaccharide of at least 1:4, at least 1:3, or at least 1:2. For example, mixture of silk fibroin and polysaccharide can include a weight ratio of silk fibroin to polysaccharide of at most 20:1, at most 19:1, at most 18:1, at most 16:1, at most 15:1, at most 14:1, at most 12:1, at most 11 :1, or at most 10:1.

[0114] The silk fibroin can be present in the liquid composition in an amount by weight of between 1% and 10% or between 3% and 7%. Without wishing to be bound by any particular theory, it is believed that the concentration of silk fibroin can impact the structural integrity of a resulting product. If the concentration is too low, the resulting product may not coalesce into a single physical structure, thereby failing to make an article at all. If the concentration is too high, the resulting product may form in a fashion with visible defects, cracks, and other imperfections. For example, the silk fibroin can be present in the liquid composition in an amount by weight of at least 1%, at least 2%, at least 3%, at least 4%, at least 5%, or at least 6%. For example, the silk fibroin can be present in the liquid composition in an amount by weight of at most 10%, at most 9%, at most 8%, at most 7%, at most 6%, or at most 5%.

[0115] The polysaccharide can be present in the liquid composition in an amount by weight of between 0.1% and 10.0%. For example, the polysaccharide can be present in the liquid composition in an amount by weight of at least 0.1%, at least 0.3%, at least 0.5%, at least 1.0%, at least 1.5%, at least 2.0%, at least 2.5%, at least 3.0%, at least 3.5%, at least 4.0%, at least 4.5%, at least 5.0%, at least5.5%, at least 6.0%, at least 6.5%, at least 7.0%, at least 7.5%, at least 8.0%, at least 8.5%, at least9.0%, or at least 9.5%. For example, the polysaccharide can be present in the liquid composition in an amount by weight of at most 10.0%, at most 9.5%, at most 9.0%, at most 8.5%, at most 8.0%, at most7.5%, at most 7.0%, at most 6.5%, at most 6.0%, at most 5.5%, at most 5.0%, at most 4.5%, at most4.0%, at most 3.5%, at most 3.0%, at most 2.5%, at most 2.0%, at most 1.5%, or at most 1.0%.

[0116] The plasticizer can be present in the liquid composition in an amount by weight of between 0.5% and 20.0%. For example, the plasticizer can be present in the liquid composition in an amount by weight of at least 0.5%, at least 1.0%, at least 1.5%, at least 2.0%, at least 2.5%, at least 3.0%, at least 3.5%, at least 4.0%, at least 4.5%, at least 5.0%, at least 5.5%, at least 6.0%, at least 6.5%, at least 7.0%, at least 7.5%, at least 8.0%, at least 8.5%, at least 9.0%, at least 9.5%, at least 10.0%, at least 12.0%, or at least 15.0%. For example, the plasticizer can be present in the liquid composition in an amount by weight of at most 20.0%, at most 18.5%, at most 17.5%, at most 16.0%, at most 15.0%, at most 14.0%, at most 13.0%, at most 12.5%, at most 11.0%, at most 10.0%, at most 8.0%, or at most 5.0%.

[0117] The plasticizer can be present in the liquid composition in an amount by weight of between 20.0% and 75.0%. For example, the plasticizer can be present in the liquid composition in an amount by weight of at least 20.0%, at least 25.0%, at least 30.0%, at least 35.0%, at least 40.0%, at least 45.0%, at least 50.0%, at least 55.0%, at least 60.0%, at least 65.0%, or at least 70.0%. For example, the plasticizer can be present in the liquid composition in an amount by weight of at most 75.0%, at most 70.0%, at most 65.0%, at most 60.0%, at most 55.0%, at most 50.0%, at most 45.0%, at most 40.0%, at most 35.0%, at most 30.0%, at most 25.0%, or at most 20.0%.

[0118] Plasticizers can include at least one of polyols, esters, phthalates, terephthalates, trimellitates, adipates, sebacates, organophosphates, ethanolamines, waxes, resins, or glycerols. The plasticizer can be selected from the group consisting of glycerol, 1,2 pentanediol, 1,5 pentanediol, 1,2,6 hexanetriol, and mixtures thereof. In some cases, the plasticizer is glycerol. In some cases, the plasticizer is 1,2 pentanediol. In some cases, the plasticizer is 1,5 pentanediol. In some cases, the plasticizer is 1,2,6 hexanetriol. In some cases, the plasticizer is at least one of xylitol, alditol, 1,2-pentanediol, 1,5- pentanediol, 1,2,6-hexanetriol, oleoyl-glycerol, cottonseed oil, di(ethylene glycol), tri(ethylene glycol), di(propylene glycol), tri(propylene glycol), or a vegetable oil.

[0119] Without wishing to be bound by any particular theory, it is believed that the number or and / or separation between -OH substituents can strongly impact the material properties of the resulting composition. In some cases, the plasticizer comprises at least one -OH substituent. In some cases, the plasticizer comprises at least two -OH substituents, at least 3 -OH substituents, or more -OH substituents. In some cases, the at least two -OH substituents, the at least 3 -OH substituents, or the more -OH substituents are separated from one another on the plasticizer by at least 2 carbon atoms, at least 3 carbon atoms, or at least 4 carbon atoms.

[0120] In some cases, the plasticizer can be partly or wholly evaporated off during processing. In some cases, the plasticizer remains within the composition during processing.

[0121] The sensing agent can be present in an amount that is selected by the nature of the sensing agent and the nature of the desired sensing performance. Similarly, a therapeutically active agent can be present in an amount that is selected by the nature of the therapeutically active agent and the nature of the desired therapeutic outcome. Similarly, a colorant can be present in an amount that is selected by the nature of the coloring ability of the colorant and the nature of the desired coloring. Similarly, an aroma-providing compound can be present in an amount that is selected by the nature of the aromaproviding ability of the compound and the nature of the desired aroma performance. A skilled artisan will recognize that there will be differing lower and upper boundaries for the amount of sensing agent, therapeutically active agent, colorant, and / or aroma-providing compound that will be present based on the nature of the agent. The aforementioned additives, agents, colorants, etc. can optionally be foodsafe versions, which are identified as generally recognized as safe according to the US Food and Drug Administration. The additive can be inorganic, with uses such as fluorescent materials, lasing materials / media, absorbing / light responsive materials, temperature- sensitive materials, electrochemical materials, or combinations thereof.

[0122] In some aspects of the liquid composition or any of the downstream products or articles of manufacture disclosed herein, between 3% and 72% of the total weight of the silk fibroin, the polysaccharide, and the plasticizer is the silk fibroin. In some aspects of the liquid composition or any of the downstream products or articles of manufacture disclosed herein, between 3% and 72% of the total weight of the silk fibroin, the polysaccharide, and the plasticizer is the polysaccharide. In an example, the polysaccharide is present in an amount by weight of between 10% and 32% of the total weight of the silk fibroin, the polysaccharide, and the plasticizer, wherein the polysaccharide is optionally an alginate. In some aspects of the liquid composition or any of the downstream products or articles of manufacture disclosed herein, between 25% and 94% of the total weight of the silk fibroin, the polysaccharide, and the plasticizer is the plasticizer. In some examples, the plasticizer is present in an amount by weight of between 5% and 80% of the total weight of the silk fibroin, thepolysaccharide, and the plasticizer. In some aspects of the liquid composition or any of the downstream products or articles of manufacture disclosed herein, between 3% and 72% of the total weight of the silk fibroin, the polysaccharide, and the plasticizer is the polysaccharide, and between 25% and 94% of the total weight of the silk fibroin, the polysaccharide, and the plasticizer is the plasticizer.

[0123] In some aspects of the liquid composition or any of the downstream products or articles of manufacture disclosed herein, between 15% and 25% of the total weight of the silk fibroin, the polysaccharide, and the plasticizer is the silk fibroin, between 50% and 70% of the total weight of the silk fibroin, the polysaccharide, and the plasticizer is the plasticizer, and between 15% and 25% of the total weight of the silk fibroin, the polysaccharide, and the plasticizer is the polysaccharide.

[0124] In some aspects of the liquid composition or any of the downstream products or articles of manufacture disclosed herein, between 15% and 25% of the total weight of the silk fibroin and the plasticizer is the silk fibroin, and between 75% and 85% of the total weight of the silk fibroin and the plasticizer is the plasticizer.

[0125] In some aspects of the liquid composition or any of the downstream products or articles of manufacture disclosed herein, between 30% and 35% of the total weight of the silk fibroin, the polysaccharide, and the plasticizer is the silk fibroin, between 30% and 35% of the total weight of the silk fibroin, the polysaccharide, and the plasticizer is the plasticizer, and between 30% and 35% of the total weight of the silk fibroin, the polysaccharide, and the plasticizer is the polysaccharide.

[0126] In some aspects of the liquid composition or any of the downstream products or articles of manufacture disclosed herein, between 35% and 45% of the total weight of the silk fibroin, the polysaccharide, and the plasticizer is the silk fibroin, between 15% and 25% of the total weight of the silk fibroin, the polysaccharide, and the plasticizer is the plasticizer, and between 35% and 45% of the total weight of the silk fibroin, the polysaccharide, and the plasticizer is the polysaccharide.

[0127] In some aspects of the liquid composition or any of the downstream products or articles of manufacture disclosed herein, between 15% and 25% of the total weight of the silk fibroin, the polysaccharide, and the plasticizer is the silk fibroin, between 35% and 45% of the total weight of the silk fibroin, the polysaccharide, and the plasticizer is the plasticizer, and between 35% and 45% of the total weight of the silk fibroin, the polysaccharide, and the plasticizer is the polysaccharide.

[0128] In some aspects of the liquid composition or any of the downstream products or articles of manufacture disclosed herein, between 35% and 45% of the total weight of the silk fibroin, the polysaccharide, and the plasticizer is the silk fibroin, between 35% and 45% of the total weight of the silk fibroin, the polysaccharide, and the plasticizer is the plasticizer, and between 15% and 25% of the total weight of the silk fibroin, the polysaccharide, and the plasticizer is the polysaccharide.

[0129] In some aspects of the liquid composition or any of the downstream products or articles of manufacture disclosed herein, between 45% and 85% of the total weight of the silk fibroin and the polysaccharide is the silk fibroin, and between 15% and 55% of the total weight of the silk fibroin and the polysaccharide is the polysaccharide.

[0130] In some aspects of the liquid composition or any of the downstream products or articles of manufacture disclosed herein, between 45% and 55% of the total weight of the silk fibroin and the polysaccharide is the silk fibroin, and between 45% and 55% of the total weight of the silk fibroin and the polysaccharide is the polysaccharide.

[0131] In some aspects of the liquid composition or any of the downstream products or articles of manufacture disclosed herein, between 55% and 65% of the total weight of the silk fibroin and the polysaccharide is the silk fibroin, and between 35% and 45% of the total weight of the silk fibroin and the polysaccharide is the polysaccharide.

[0132] In some aspects of the liquid composition or any of the downstream products or articles of manufacture disclosed herein, between 65% and 75% of the total weight of the silk fibroin and the polysaccharide is the silk fibroin, and between 25% and 35% of the total weight of the silk fibroin and the polysaccharide is the polysaccharide.

[0133] In some aspects of the liquid composition or any of the downstream products or articles of manufacture disclosed herein, between 15% and 25% of the total weight of the silk fibroin, the polysaccharide, and the plasticizer is the silk fibroin, between 15% and 25% of the total weight of the silk fibroin, the polysaccharide, and the plasticizer is the plasticizer, and between 55% and 65% of the total weight of the silk fibroin, the polysaccharide, and the plasticizer is the polysaccharide.

[0134] The liquid composition has a high water content. In some cases, the liquid composition has a water content of between 89% and 99%.

[0135] In some aspects, the liquid composition or any of the downstream products or articles of manufacture disclosed herein may further include multi-valent metal ions, such as calcium or copper. Where the polysaccharide is an alginate, the multi-valent metal ions may be present in a concentration of at least 10 mmol of the multi-valent metal ion per gram of the alginate and at most 250 mmol of the multi-valent metal ion per gram of the alginate, including but not limited to, at least 20 mmol, at least 30 mmol, at least 40 mmol, or at least 50 mmol, and at most 240 mmol, at most 225 mmol, at most 210 mmol, at most 200 mmol, at most 175 mmol, or at most 150 mmol. In some cases, the multi-valent metal ions are introduced in the form of CuCh. In some cases, the multi-valent metal ions are introduced in the form of CaCC , which can reduce yellowing in downstream compositions. The multivalent metal ions may have a counterion which is optionally chloride or carbonate.

[0136] In some aspects, the liquid composition or any of the downstream products or articles of manufacture disclosed herein may further include a salt, such as a chloride salt. The salt may be present in a concentration of at least 10 mmol per gram of non-water component (e.g., all non-water ingredients - non-water component can be replaced with a dry solids basis, as would be appreciated by a skilled artisan, if other solvents are used) and at most 500 mmol per gram of non-water component, including but not limited to, at least 25 mmol, at least 50 mmol, or at least 100 mmol, and at most 450 mmol, at most 400 mmol, at most 300 mmol, or at most 250 mmol.

[0137] In some aspects, the liquid composition or any of the downstream products or articles of manufacture disclosed herein may further include shellac, such as in an amount by weight of between 0.1% and 50%.

[0138] In some aspects, the liquid composition or any of the downstream products or articles of manufacture disclosed herein may further include a natural wax, such as in an amount by weight of between 0.1% and 50.

[0139] In some aspects, the liquid composition or any of the downstream products or articles of manufacture disclosed herein may further include lycopodium powder, such as in an amount by weight of between 0.1% and 50%.

[0140] In some aspects, the liquid composition or any of the downstream products or articles of manufacture disclosed herein may further include at least one of a conductive additive, a non- conductive additive, or a thermally-conductive additive (e.g., electrically insulating).Whipped Silk Creams

[0141] Much like dairy milk can be whipped into a cream because of the emulsion- forming capacity of its high fat content, unexpectedly, silk fibroin solutions can be whipped up to a foam in the presence of high molecular weight sugars, such as xanthan gum or alginates. Foams obtained this way may be brittle and may display higher wettability towards organic solvents. Adding plasticizers to the composition may remove the brittleness and makes the foams more hydrophilic and encourages sponge-like behavior in water environments.

[0142] The present disclosure provides a whipped silk cream comprising silk fibroin and xanthan gum. In some aspects, the whipped silk cream comprises silk fibroin, xanthan gum, and a plasticizer. In some aspects, the whipped silk cream comprises silk fibroin, xanthan gum, and glycerol. In some aspects, the whipped silk cream comprises silk fibroin, xanthan gum, a plasticizer, and a functionalizing agent. In some aspects, the whipped silk cream comprises silk fibroin, xanthan gum, glycerol, and a functionalizing agent. In some aspects, the whipped silk cream comprises silk fibroin, xanthan gum, and a functionalizing agent. In some aspects, the whipped silk cream comprises a mixtureof silk fibroin and a high molecular weight sugar (e.g., such as xanthan gum), and may optionally further include at least one of a plasticizer (e.g., such as glycerol) or a functionalizing agent.

[0143] Compositionally, the whipped silk cream can contain the same components in the same amounts as the liquid composition, with the liquid composition being transformed by the whipping process into a whipped silk cream.

[0144] The whipped silk cream can have an irregular porosity.

[0145] In some cases, the whipped silk cream can have an overrun that is comparable to the overrun of dairy whipped cream. Certain properties of the whipped silk cream may be associated with particular overrun values. In some aspects, the properties of the whipped silk cream at a particular overrun value may be variable based on if the particular overrun value is achieved before or after achieving a maximum overrun value. Maximum overrun values may depend on at least one of: the components included in the liquid composition, the weight ratio of one or more components in the liquid composition, the weight % of one or more components in the liquid composition, the amount of whipping time, or the temperature during whipping. In one example, liquid compositions including plasticizers may exhibit greater overrun relative to compositions lacking or having reduced amounts of plasticizers.

[0146] The whipped silk cream may exhibit an overrun of between 10% and 550%, between 20% and 550%, between 50% and 300%, between 10% and 100%, between 10% and 150%, between 10% and 300%, or between 100% and 300%. The whipped silk cream may exhibit an overrun of at least 10%, at least 50%, at least 100%, at least 200%, at least 300%, at least 400%, or at least 500%.

[0147] Given that the whipped silk cream is a downstream product from the liquid composition, the whipped silk cream can include any component or feature of the liquid composition, unless the context clearly dictates otherwise (e.g., if the feature relates specifically to being a liquid and not whipped).

[0148] The whipped silk cream has a water content that can be tailored for specific uses. In some cases, the water content of the whipped silk cream is between 50% and 95%, including but not limited to, between 75% and 93%, between 87% and 92%, or between 88.5% and 91%, including non-recited combinations of the upper and lower limits of those ranges (e.g., between 88.5% and 95%, etc.).Silk Meringue

[0149] The present disclosure provides a silk meringue comprising silk fibroin and xanthan gum. In some aspects, the silk meringue comprises silk fibroin, xanthan gum, and a plasticizer. In some aspects, the silk meringue comprises silk fibroin, xanthan gum, and glycerol. In some aspects, the silk meringue comprises silk fibroin, xanthan gum, a plasticizer, and a functionalizing agent. In some aspects, the silk meringue comprises silk fibroin, xanthan gum, glycerol, and a functionalizing agent. In some aspects, the silk meringue comprises silk fibroin, xanthan gum, and a functionalizing agent. In someaspects, the silk meringue comprises a mixture of silk fibroin and a high molecular weight sugar (e.g., such as xanthan gum), and may optionally further include at least one of a plasticizer (e.g., such as glycerol) or a functionalizing agent.

[0150] The silk meringue is a baked whipped silk cream. The silk meringue may be alternatively described as a foam herein. Compositionally, the silk meringue can contain the same components in the same amounts as the liquid composition and the whipped silk cream, with significantly less water / moisture content. Without wishing to be bound by any particular theory, it is believed that the whipping process and baking process can both give distinct characteristics to the silk meringue disclosed herein, with unique pore structure and size being generated by varying compositional and / or processing parameters.

[0151] Given that the silk meringue is a downstream product from the whipped silk cream, the silk meringue can include any component or feature of the whipped silk cream, unless the context clearly dictates otherwise (e.g., the water content is much lower in silk meringues). Similarly, as both the silk meringue and the whipped silk cream derive from the liquid composition, the silk meringue can include any component or feature of the liquid composition, unless the context clearly dictates otherwise.

[0152] The silk meringue has a water content that can be tailored for specific uses. The silk meringue can have a water content of between 5% and 70%. In some cases, the silk meringue has a water content of at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, or at least 50%. In some cases, the silk meringue has a water content of at most 75%, at most 65%, at most 60%, at most 50%, at most 40%, or al most 25%.Compressed Silk Meringue

[0153] The present disclosure provides a compressed silk meringue comprising silk fibroin and xanthan gum and, in many cases, glycerol. In some aspects, the compressed silk meringue comprises silk fibroin, xanthan gum, and a plasticizer. In some aspects, the compressed silk meringue comprises silk fibroin, xanthan gum, and glycerol. In some aspects, the compressed silk meringue comprises silk fibroin, xanthan gum, a plasticizer, and a functionalizing agent. In some aspects, the compressed silk meringue comprises silk fibroin, xanthan gum, glycerol, and a functionalizing agent. In some aspects, the compressed silk meringue comprises silk fibroin, xanthan gum, and a functionalizing agent. In some aspects, the compressed silk meringue comprises a mixture of silk fibroin and a high molecular weight sugar (e.g., such as xanthan gum), and may optionally further include at least one of a plasticizer (e.g., such as glycerol) or a functionalizing agent.

[0154] Compositionally, the compressed silk meringue is generally the same as the silk meringue. Structurally, the compressed silk meringue has a reduced and / or compressed and / or damaged pore structure when compared with the silk meringue.

[0155] Many of the most preferred compressed silk meringues include glycerol, as its inclusion provides an impressive malleability, thereby allowing compression with the retention of the general material and pore structure of the silk meringue. Specifically, in some cases where glycerol is present, the compressed silk meringue is a mysilkium material. Specifically, in some cases where glycerol is present, the compressed silk meringue can be or can form a part of (e.g., one or two layers adhered to a fabric substrate) a silk leather. In an embodiment, meringues disclosed herein can be used as an alternative to polyurethane foams employed for artificial leathers.

[0156] Given that the compressed silk meringue is a downstream product from the silk meringue, the compressed silk meringue can include any component or feature of the silk meringue, unless the context clearly dictates otherwise (e.g., the porosity is reduced in the compressed silk meringue). Similarly, as all of the compressed silk meringue, the silk meringue, and the whipped silk cream derive from upstream entities, the compressed silk meringue can include any component or feature of the silk meringue, the whipped silk cream, or the liquid composition, unless the context clearly dictates otherwise.

[0157] The compressed silk meringue has a water content that can be tailored for specific uses. The compressed silk meringue has a water content of between 2% and 50%. In some cases, the compressed silk meringue has a water content of at least 2%, at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, or at least 30%. In some cases, the compressed silk meringue has a water content of at most 50%, at most 45%, at most 40%, at most 35%, at most 30%, or at most 25%.Hot-Pressed Silk Meringue

[0158] The present disclosure provides a hot-pressed silk meringue comprising silk fibroin and xanthan gum and, in many cases, glycerol. In some aspects, the hot-pressed silk meringue comprises silk fibroin, xanthan gum, and glycerol. In some aspects, the hot-pressed silk meringue comprises silk fibroin, xanthan gum, and a plasticizer. In some aspects, the hot-pressed silk meringue comprises silk fibroin, xanthan gum, and glycerol. In some aspects, the hot-pressed silk meringue comprises silk fibroin, xanthan gum, a plasticizer, and a functionalizing agent. In some aspects, the hot-pressed silk meringue comprises silk fibroin, xanthan gum, glycerol, and a functionalizing agent. In some aspects, the hot-pressed silk meringue comprises silk fibroin, xanthan gum, and a functionalizing agent. In some aspects, the hot-pressed silk meringue comprises a mixture of silk fibroin and a high molecular weight sugar (e.g., such as xanthan gum), and may optionally further include at least one of a plasticizer (e.g., such as glycerol) or a functionalizing agent.

[0159] Compositionally, the hot-pressed silk meringue is generally the same as the silk meringue. Structurally, the hot-pressed silk meringue has a reduced and / or compressed and / or damaged pore structure when compared with the silk meringue.

[0160] Many of the most preferred hot-pressed silk meringues include glycerol, as its inclusion provides an impressive malleability, thereby allowing compression with the retention of the general material and pore structure of the silk meringue. Specifically, in some cases where glycerol is present, the hot-pressed silk meringue is a mysilkium material. Specifically, in some cases where glycerol is present, the hot-pressed silk meringue can be or can form a part of (e.g., one or two layers adhered to a fabric substrate) a silk leather. In an embodiment, meringues disclosed herein can be used as an alternative to polyurethane foams employed for artificial leathers.

[0161] Without wishing to be bound by any particular theory, it is believed that the most effective bonding between layers of material disclosed herein involves interlinking with mechanical structures (e.g., fibers in a woven fabric)

[0162] In some cases, the hot-pressed silk meringue (or other material format disclosed herein) can be interlinked with fabric, but in other cases the hot-pressed silk meringue is interlinked with a metal mesh, a conducting mesh, an electronic component, an active interface, an insulating interface, or a simple coating.

[0163] Given that the hot-pressed silk meringue is a downstream product from the silk meringue, the hot-pressed silk meringue can include any component or feature of the silk meringue, unless the context clearly dictates otherwise (e.g., the porosity is reduced in the hot-pressed silk meringue). Similarly, as all of the hot-pressed silk meringue, the silk meringue, and the whipped silk cream derive from upstream entities, the hot-pressed silk meringue can include any component or feature of the silk meringue, the whipped silk cream, or the liquid composition, unless the context clearly dictates otherwise.

[0164] The hot-pressed silk meringue has a water content that can be tailored for specific uses. The hot-pressed silk meringue has a water content of between 2% and 50%. In some cases, the hot-pressed silk meringue has a water content of at least 2%, at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, or at least 30%. In some cases, the hot-pressed silk meringue has a water content of at most 50%, at most 45%, at most 40%, at most 35%, at most 30%, or at most 25%.Methods of Making

[0165] The present disclosure provides methods of making the various compositions, materials, and articles described herein.

[0166] In one case, the present disclosure provides a method of making a composition, such as a whipped silk cream. A method of making a whipped silk cream can include whipping a liquid comprising silk fibroin and xanthan gum (and, in many cases, plasticizer or functionalizing agent) for a predetermined whipping time to form the whipped silk cream. The predetermined whipping time can be between 5 minutes and 30 minutes, including but not limited to, at least 5 minutes, at least 6 minutes,at least 7 minutes, at least 8 minutes, at least 9 minutes, or at least 10 minutes and at most 30 minutes, at most 25 minutes, at most 20 minutes, at most 15 minutes, or at most 10 minutes.

[0167] The whipping can be achieved with mechanical agitation action that is associated with the integration of air, as would typically be understood from the context of food preparation involving various dairy and egg products, among other things. In some cases, the whipping is performed with a whisk. The whipping can optionally be performed manually, though there may be advantages to automated whipping, such as increased speed, endurance, and the like. The whipping can be performed using conventional whipping equipment or machines, such as a stand mixer. The whisk itself can be composed of metal or the whisk can be non-metal (or a metal whisk coated with a non-metal material, in some cases). The whipping can be done within a mixing bowl, such as a metal mixing bowl, for example a stainless steel mixing bowl.

[0168] In one specific case, the whipping involves whipping of a heterogenous solution, in which water and glycerol are the liquid phase and the silk fibroin and xanthan gum are in powder form.

[0169] In some cases, the temperature of the whipping is maintained at room temperature or lower, including refrigerated temperatures of between 1 °C and 25 °C.

[0170] In another case, the present disclosure provides a method of making a composition, such as a silk meringue. A method of making a silk meringue can include baking the whipped silk cream (optionally along with any method steps involved in preparing the whipped silk cream itself) at a temperature of between 25 °C and 150 °C, between 30 °C and 120 °C, or between 50 °C and 80 °C for a length of time of between 2 hours and 24 hours to form the silk meringue. In an example, the baking is performed at a temperature of between 40 °C and 150 °C for a length of time of between 5 minutes and 24 hours.

[0171] In some cases, the present disclosure provides a method of making an article, such as a compressed silk meringue. A method of making a compressed silk meringue can include compressing the silk meringue with a force of between 0.25 MPa and 25 MPa for a length of time of between 15 minutes and 6 hours. In some cases, the compressing can be heat-compressing that is performed at an elevated temperature of between 80 °C and 200 °C. In some cases, the compressing can be performed with a calendar press. A method of making a compressed silk meringue can include compressing the silk meringue with a force of between 0.25 MPa and 25 MPa for a length of time of between 5 minutes and 6 hours.

[0172] In some cases, the methods disclosed herein can further include embossing an article. The embossed article, such as an embossed silk leather, can have an appearance strikingly similar to embossed conventional leather.

[0173] The properties of silk creams, silk meringues, silk foams (baked silk creams), and articles of manufacture made from or including the silk creams, meringues, and or foams can be tuned by selection of weight ratios of starting materials, identity of starting materials, conditions of making the creams, meringues, and foams, and the like.

[0174] In some aspects, a method of making a whipped silk cream having a desired whipped silk cream morphology, a silk meringue having a desired silk meringue morphology, a compressed silk meringue having a desired compressed silk meringue morphology, or a hot-pressed silk meringue having a desired hot-pressed silk meringue morphology may include selecting a silk concentration, a silk molecular weight distribution, a polysaccharide species, a polysaccharide concentration, a plasticizer species, a plasticizer concentration, a whipping speed, optionally a silk meringue baking temperature, optionally a compressed silk meringue compressing force, optionally a hot-pressed silk meringue hot-pressing force and temperature. The method may further include making the whipped silk cream, the silk meringue, the compressed silk meringue, or the hot-pressed silk meringue using the silk concentration, the silk molecular weight distribution, the polysaccharide species, the polysaccharide concentration, the plasticizer species, the plasticizer concentration, the whipping speed, optionally the silk meringue baking temperature, optionally the compressed silk meringue compressing force, and optionally the hot-pressed silk meringue hot-pressing force and temperature.

[0175] For example, the density, water content, and syneresis of the creams can be varied based on the selected weight ratio of silk fibroin, polysaccharide, and plasticizer in the composition. For example, compositions to be used in food or pharmaceutical industries may be tuned to exhibit low syneresis, while compositions to be used in dried foams where mechanical stability is favored may be tuned to exhibit a higher amount of syneresis. In certain aspects, the polysaccharide may have the greatest impact on overall density, the silk fibroin may have the greatest impact on water content, and the plasticizer may have the greatest impact on syneresis. The discovery of these differential impacts enables the tuning of the composition in accordance with the desired application or the desired performance.

[0176] In another example, the properties of density, firmness, and overrun of the cream may vary with whipping time. For example, depending on the application, greater or less firmness may be desired, and whipping time may be used to tune the cream for the desired application.

[0177] In another example, the properties of a cream’ s density or overrun may be tuned by selection of a particular plasticizer species. In an aspect, higher numbers of -OH groups of a plasticizer, such as glycerol and 1-3-6 hexanetriol, reduces the whipping time to overrun plateau by efficiently facilitating a hydrogen bonding network between the silk fibroin and the polysaccharide. In another aspect, the distance of -OH groups in a plasticizer influences the air capacity of the foam - plasticizers such asdiols (e.g., 1,2 and 1,5 pentanediol) exhibit slower cream growth with a significantly higher overrun when the OH groups are at a greater distance.

[0178] In some aspects, the properties of silk foams made from creams and / or meringues may also be tuned via the composition ratio. For example, varying the amount of plasticizer may have an effect on the foam’s compressive strength and / or yield point. In another example, varying the polysaccharide species or combination of polysaccharides may be useful in tuning the foam for certain applications. For example, xanthan gum may be useful for applications where the foam is compressed (e.g., silk leather) where alginate may be more useful for foams being used in their expanded state.

[0179] In some aspects, the properties of silk foams made from creams and / or meringues may also be impacted by additives, such as borate ions which improve mechanical properties while providing flame retardant and anti-fungal properties.

[0180] In some aspects, varying the whipping time may have an effect on the resultant dried foam, such as due to the distribution of bubble sizes or the open / closed cell morphology. For example, longer whipping times may result in denser foams. As whipping time increases, cell structure may transition from a closed cell structure to an open cell structure. Variation in internal structure of foams may have an impact on performance in certain applications, such as in leather applications.

[0181] In an example method of making a composition, a liquid composition including a mixture of silk fibroin, a polysaccharide, and a plasticizer is whipped for a predetermined whipping time to form a whipped silk cream. In a further optional aspect of the example, the silk fibroin and the polysaccharide are whipped together before addition of the plasticizer. In another optional aspect of the example, the silk fibroin and the plasticizer are whipped together before addition of the polysaccharide. In still another optional aspect of the example, the polysaccharide and the plasticizer are whipped together before addition of the silk fibroin.

[0182] In certain cases the order of addition may be important, for example where highly hydrophobic compounds are used (e.g., fatty acids or oils). In these cases, the methods may include whipping a liquid composition including the silk fibroin and the polysaccharide for a first length of time before adding the highly hydrophobic compounds (optionally a plasticizer) and continuing the whipping.Articles of Manufacture

[0183] The present disclosure provides articles of manufactures that include or are made from one or more of the liquid compositions, whipped silk creams, silk meringues, compressed silk meringues, or hot-pressed silk meringues disclosed herein.Silk Leather

[0184] The present disclosure provides a silk leather. The silk leather is a layered structure comprising a first fabric layer and a second material layer disposed adjacent to the first fabric layer. The second material layer comprises the compressed silk meringue or the hot-pressed silk meringue disclosed herein. The silk leather optionally includes a third material layer disposed adjacent to the first fabric layer on a surface opposing the surface to which the second material layer is adjacent. The third material layer comprises the compressed silk meringue or the hot-pressed silk meringue disclosed herein. In effect, the compressed or hot-pressed silk meringues form a "sandwich" around the first fabric layer. Referring to Fig. 1, the silk leather 100 comprises a first fabric layer 102 and a second material layer 104 disposed adjacent to the first fabric layer 102 (See Fig. 1 A) . In aspects, a silk leather 108 optionally includes a third material layer 110 disposed adjacent to the first fabric layer 102 on a surface opposing the surface to which the second material layer 104 is adjacent (See Fig. IB).

[0185] The first fabric layer can be composed of cotton fabric, including but not limited to, cotton jersey, cotton canvas, and the like; silk fabric; synthetic fabric, including but not limited to, polyester fabric, rayon fabric, nylon fabric, and the like; linen; organza; the like; and combinations thereof. In some examples, the first fabric layer may be treated with tannic acid.

[0186] In the aspects described herein, a unitary portion of silk leather may homogenously exhibit a property or functionality throughout the silk leather, or it may heterogeneously include various portions exhibiting one or more properties or functionalities (e.g., conductive, magnetic, colored, scented, tanned, patterned / embossed / textured, sensing / responsive (e.g., gas, humidity, thermochromic, pH), absorbing, thermal insulator, biological scaffold, electronics, semiconductor device-embedded, haptic, impact-resistant, heat-resistant, cold-resistant, or the like).

[0187] The silk leather can be colored to mimic non-colored natural leather. In some cases, the silk leather can be colored to mimic artificially colored natural leather. In one specific case, an artificial leather color can be produced by polymerizing phloroglucinol.

[0188] In some cases, using very cold water in making the whipped silk cream from which a silk leather is made can cause a thin "skin" to form on the surface, which can provide a wrinkled texture that mimics the texture of leather.

[0189] The present disclosure provides a thermal insulator. The thermal insulator comprises, consists essentially of, or consists of the silk meringue disclosed herein. The thermal insulator can be made by any of the methods disclosed herein. In aspects, thermally-insulating silk leather may have a thermochromic reporting property throughout a bulk interior volume.

[0190] The present disclosure provides a sorbent and / or gas sensing material. The sorbent and / or gas sensing material can comprise, consist essentially of, or consist of the silk meringue described herein.The sorbent and / or gas sensing material can further include a sensing agent that undergoes a measurable change upon exposure to a gas of interest. The sorbent and / or gas sensing material can include as a sensing agent a dye that changes color upon exposure to the gas of interest. The sorbent and / or gas-sensing material can be made by any of the methods disclosed herein.

[0191] The present disclosure provides a biological scaffold. In general, the biological scaffold is intended for the purpose of receiving a population of cells for one or more of growth, proliferation, differentiation, carbon dioxide capture, biomineralization, biosynthesis, fermentation, the like, and combinations thereof.

[0192] In one specific case, the biological scaffolds disclosed herein are particularly excellent for algae growth. Specifically, both marine and freshwater algae were seeded and successfully grown on scaffolds for at least a month at 90% relative humidity and under adequate lighting conditions.

[0193] In one particular case, the present disclosure provides a mysilkium material with material properties that closely mimic the material properties of mycelium. The mysilkium material can be used in applications where mycelium is currently used.Functionalizing / Active Agents

[0194] The compositions described herein can include a functionalizing agent, an active agent, a therapeutic agent, or a combination thereof.

[0195] According to various embodiments, a variety of functionalizing agents may be used with the silk-containing embodiments described herein (e.g., liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, silk leather, etc.). It should be understood that the examples herein may recite one or a few silk-containing embodiments but are applicable to any silk-containing embodiment, as applicable. In some embodiments, a functionalizing agent may be any compound or molecule that facilitates the attachment to and / or development (e.g., growth) of one or more endothelial cells on a silk membrane. In some embodiments, a functionalizing agent may be any compound or molecule that facilitates the attachment and / or development (e.g., growth) of one or more megakaryocytes and / or hematopoietic progenitor cells on a silk matrix and / or silk membrane. In some embodiments, a functionalizing agent may be or comprise an agent suitable for facilitating the production of one or more of white blood cells and red blood cells.

[0196] In some embodiments, a functionalizing agent may be or comprise a cell attachment mediator and / or an extracellular matrix protein, for example: collagen (e.g., collagen type I, collagen type III, collagen type IV or collagen type VI), elastin, fibronectin, vitronectin, laminin, fibrinogen, von Willebrand factor, proteoglycans, decorin, perlecan, nidogen, hyaluronan, and / or peptides containing known integrin binding domains e.g. “RGD” integrin binding sequence, or variations thereof, that are known to affect cellular attachment.

[0197] In some embodiments, a functionalizing agent may be any soluble molecule produced by endothelial cells. Non-limiting examples include fibroblast growth factor- 1 (FGF1) and vascular endothelial growth factors (VEGF).

[0198] According to some embodiments, a plurality of functionalizing agents may be used. For example, in some embodiments wherein production of platelets is desired, provided compositions may comprise the use of laminin, fibronectin and / or fibrinogen, and type IV collagen in order to facilitate the attachment and growth of endothelial cells on a silk membrane (e.g., a porous silk membrane) and / or attachment of megakaryocytes to a silk matrix.

[0199] In some embodiments, a functionalizing agent may be embedded or otherwise associated with a silk membrane and / or silk matrix such that at least a portion of the functionalizing agent is surrounded by a silk membrane and / or silk matrix as contrasted to a functionalizing agent simply being positioned along the surface of a silk membrane and / or silk matrix. In some embodiments, a functionalizing agent is distributed along and / or incorporated in substantially the entire surface area of a silk membrane / silk wall. In some embodiments, a functionalizing agent is distributed and / or incorporated only at one or more discrete portions of a silk membrane / wall and / or silk matrix. In some embodiments, a functionalizing agent is distributed in and / or along at least one of the lumen-facing side of a silk wall and the matrix-facing side of a silk wall.

[0200] According to various embodiments, any application-appropriate amount of one or more functionalizing agents may be used. In some embodiments, the amount of an individual functionalizing agent may be between about 1 pg / ml and 1,000 pg / ml (e.g., between about 2 and 1,000, 5 and 1,000, 10 and 1,000, 10 and 500, 10 and 100 pg / ml). In some embodiments, the amount of an individual functionalizing agent may be at least 1 pg / ml (e.g., at least 5, 10, 15, 20 25, 50, 100, 200, 300 400, 500, 600, 700, 800, or 900 pg / ml ). In some embodiments, the amount of an individual functionalizing agent is at most 1,000 pg / ml (e.g., 900, 800, 700, 600, 500, 400, 300 200, 100, 90, 80, 70, 60, 50, 40, 30, 20, 10, or 5 pg / ml ).

[0201] In some aspects, the composition comprises one or more sensing agents, such as a sensing dye. The sensing agents / sensing dyes are environmentally sensitive and produce a measurable response to one or more environmental factors. In some aspects, the environmentally- sensitive agent or dye may be present in the composition in an effective amount to alter the composition from a first chemical -physical state to a second chemical -physical state in response to an environmental parameter (e.g., a change in pH, light intensity or exposure, temperature, pressure or strain, voltage, physiological parameter of a subject, and / or concentration of chemical species in the surrounding environment) or an externally applied stimulus (e.g., optical interrogation, acoustic interrogation, and / or applied heat). In some cases, the sensing dye is present to provide one optical appearance under one given set ofenvironmental conditions and a second, different optical appearance under a different given set of environmental conditions. Suitable concentrations for the sensing agents described herein can be the concentrations for the colorants and additives described elsewhere herein. A person having ordinary skill in the chemical sensing arts can determine a concentration that is appropriate for use in a sensing application of the inks described herein.

[0202] In some aspects, the first and second chemical-physical state may be a physical property of the composition, such as mechanical property, a chemical property, an acoustical property, an electrical property, a magnetic property, an optical property, a thermal property, a radiological property, or an organoleptic property. Exemplar}' sensing dyes or agents include, but are not limited to, a pH sensitive agent, a thermal sensitive agent, a pressure or strain sensitive agent, a light sensitive agent, or a potentiometric agent.

[0203] Exemplary pH sensitive dyes or agents include, but are not limited to, cresol red, methyl violet, crystal violet, ethyl violet, malachite green, methyl green, 2-(p- dimethylaminophenylazo) pyridine, paramethyl red, metanil yellow, 4-phenylazodiphenylamine, thymol blue, metacresol purple, orange IV, 4-o-Tolylazo-o-toluindine, quinaldine red, 2,4- dinitrophenol, erythrosine disodium salt, benzopurpurine 4B, N,N-dimethyl-p-(m-tolylazo) aniline, p-dimethylaminoazobenene, 4,4’-bis(2- amino-l-naphthylazo)-2,2’-stilbenedisulfonic acid, tetrabromophenolphthalein ethyl ester, bromophenol blue, Congo red, methyl orange, ethyl orange, 4-(4-dimethylamino-l-naphylazo)-3- methoxybenesulfonic acid, bromocresol green, resazurin, 4- phenylazo-l-napthylamine, ethyl red 2- (1-dimethylaminophenyazo) pyridine, 4-(p- ethoxypehnylazo)-m-phenylene-diamine monohydrochloride, resorcin blue, alizarin red S, methyl red, propyl red, bromocresol purple, chlorophenol red, p-nitrophenol, alizarin 2-(2,4- dinitrophenylazo) l-napthol-3,6-disulfonic acid, bromothymol blue, 6,8-dinitro-2,4-(lH) quinazolinedione, brilliant yellow, phenol red, neutral red, m- nitrophenol, cresol red, turmeric, metacresol purple, 4,4'-bis(3-amino-l-naphthylazo)-2,2’- stilbenedisulfonic acid, thymol blue, p- naphtholbenzein, phenolphthalein, o-cresolphthalein, ethyl bis(2,4-dimethylphenyl) ethanoate, thymolphthalein, nitrazine yellow, alizarin yellow R, alizarin, p- (2,4-dihydroxyphenylazo) benzenesulfonic acid, 5,5'-indigodisulfonic acid, 2,4,6-trinitrotoluene, 1,3,5-trinitrobenezne, and clayton yellow.

[0204] Exemplary light responsive dyes or agents include, but are not limited to, photochromic compounds or agents, such as triarylmethanes, stilbenes, azasilbenes, nitrones, fulgides, spiropyrans, napthopyrans, spiro-oxzines, quinones, derivatives and combinations thereof.

[0205] Exemplary potentiometric dyes include, but are not limited to, substituted amiononaphthylehenylpridinium (ANEP) dyes, such as di-4-ANEPPS, di-8-ANEPPS, and N-(4- Sulfobutyl)-4-(6-(4-(Dibutylamino)phenyl)hexatrienyl)Pyridinium (RH237).

[0206] Exemplary temperature sensitive dyes or agents include, but are not limited to, thermochromic compounds or agents, such as thermochromic liquid crystals, leuco dyes, fluoran dyes, octadecylphosphonic acid.

[0207] Exemplary pressure or strain sensitive dyes or agents include, but are not limited to, spiropyran compounds and agents.

[0208] Exemplary chemi- sensitive dyes or agents include, but are not limited to, antibodies such as immunoglobulin G (IgG) which may change color from blue to red in response to bacterial contamination.

[0209] In some aspects, the compositions comprise one or more additive, dopant, or biologically active agent suitable for a desired intended purpose. In some aspects, the additive or dopant may be present in the composition in an amount effective to impart an optical or organoleptic property to the composition. Exemplary additives or dopants that impart optical or organoleptic properties include, but are not limited to, dyes / pigments, flavorants, aroma compounds, granular or fibrous fillers.

[0210] Additionally or alternatively, the additive, dopant, or biologically active agent may be present in the composition in an amount effective to "functionalize" the composition to impart a desired mechanical property or added functionality to the composition. Exemplary additive, dopants, or biologically active agent that impart the desired mechanical property or added functionality include, but are not limited to: environmentally sensitive / sensing dyes; active biomolecules; conductive or metallic particles; inorganic particles drugs (e.g., antibiotics, small molecules or low molecular weight organic compounds); proteins and fragments or complexes thereof (e.g., enzymes, antigens, antibodies and antigen-binding fragments thereof); cells and fractions thereof (viruses and viral particles; prokaryotic cells such as bacteria; eukaryotic cells such as mammalian cells and plant cells; fungi).

[0211] In some aspects, the additive or dopant comprises a flavoring agent or flavorant.

[0212] Exemplary flavorants include ester flavorants, amino acid flavorants, nucleic acid flavorants, organic acid flavorants, and inorganic acid flavorants, such as, but not limited to, diacetyl, acetylpropionyl, acetoin, isoamyl acetate, benzaldehyde, cinnamaldehyde, ethyl propionate, methyl anthranilate, limonene, ethyl decadienoate, allyl hexanoate, ethyl maltol, ethylvanillin, methyl salicylate, manzanate, glutamic acid salts, glycine salts, guanylic acids salts, inosinic acid salts, acetic acid, ascorbic acid, citric acid, fumaric acid, lactic acid, malic acid, phosphoric acid, tartaric acid, derivatives, and mixtures thereof.

[0213] In some aspects, the additive or dopant comprises an aroma compound. Exemplary aroma compounds include ester aroma compounds, terpene aroma compounds, cyclic terpenes, and aromatic aroma compounds, such as, but not limited to, geranyl acetate, methyl formate, metyl acetate, methyl propionate, methyl butyrate, ethyl acetate, ethyl butyrate, isoamyl acetate, pentyl butrate, pentylpentanoate, octyl acetate, benzyl acetate, methyl anthranilate, myrecene, geraniol, nerol, citral, cironellal, cironellol, linalool, nerolidol, limonene, camphor, menthol, carone, terpineol, alpha-lonone, thujone, eucalyptol, benzaldehyde, eugenol, cinnamaldehyde, ethyl maltol, vanillin, anisole, anethole, estragole, thymol.

[0214] In some aspects, the additive or dopant comprises a colorant, such as a dye or pigment. In some aspects, the dye or pigment imparts a color or grayscale to the composition. The colorant can be different than the sensing agents and / or sensing dyes below. Any organic and / or inorganic pigments and dyes can be included in the inks. Exemplary pigments suitable for use in the present disclosure include International Color Index or C.I. Pigment Black Numbers 1 , 7, 1 1 and 31 , C.I. Pigment Blue Numbers 15, 15 : 1 , 15 :2, 15 :3, 15 :4, 15 :6, 16, 27, 29, 61 and 62, C.I. Pigment Green Numbers 7, 17, 18 and 36, C.I. Pigment Orange Numbers 5, 13, 16, 34 and 36, C.I. Pigment Violet Numbers 3, 19, 23 and 27, C.I. Pigment Red Numbers 3, 17, 22, 23, 48: 1 , 48:2, 57: 1 , 81 : 1 , 81 :2, 81 :3, 81 :5, 101 , 1 14, 122, 144, 146, 170, 176, 179, 181 , 185, 188, 202, 206, 207, 210 and 249, C.I. Pigment Yellow Numbers 1 , 2, 3, 12, 13, 14, 17, 42, 65, 73, 74, 75, 83, 30, 93, 109, 1 10, 128, 138, 139, 147, 142, 151 , 154 and 180, D&C Red No. 7, D&C Red No. 6 and D&C Red No. 34, carbon black pigment (such as Regal 330, Cabot Corporation), quinacridone pigments (Quinacridone Magenta (228-0122), available from Sun Chemical Corporation, Fort Lee, N.J.), diarylide yellow pigment (such as AAOT Yellow (274- 1788) available from Sun Chemical Corporation); and phthalocyanine blue pigment (such as Blue 15 :3 (294-1298) available from Sun Chemical Corporation). The classes of dyes suitable for use in present invention can be selected from acid dyes, natural dyes, direct dyes (either cationic or anionic), basic dyes, and reactive dyes. The acid dyes, also regarded as anionic dyes, are soluble in water and mainly insoluble in organic solvents and are selected, from yellow acid dyes, orange acid dyes, red acid dyes, violet acid dyes, blue acid dyes, green acid dyes, and black acid dyes. European Patent 0745651 , incorporated herein by reference, describes a number of acid dyes that are suitable for use in the present disclosure. Exemplary yellow acid dyes include Acid Yellow 1 International Color Index or C.I. 10316); Acid Yellow 7 (C.I. 56295); Acid Yellow 17 (C.I. 18965); Acid Yellow 23 (C.I. 19140); Acid Yellow 29 (C.I. 18900); Acid Yellow 36 (C.I. 13065); Acid Yellow 42 (C.I. 22910); Acid Yellow 73 (C.I. 45350); Acid Yellow 99 (C.I. 13908); Acid Yellow 194; and Food Yellow 3 (C.I. 15985). Exemplary orange acid dyes include Acid Orange 1 (C.I. 13090 / 1); Acid Orange 10 (C.I. 16230); Acid Orange 20 (C.I. 14603); Acid Orange 76 (C.I. 18870); Acid Orange 142; Food Orange 2 (C.I. 15980); and Orange B.

[0215] Exemplary red acid dyes include Acid Red 1. (C.I. 18050); Acid Red 4 (C.I. 14710); Acid Red 18 (C.I. 16255), Acid Red 26 (C.I. 16150); Acid Red 2.7 (C.I. as Acid Red 51 (C.I. 45430, available from BASF Corporation, Mt. Olive, N.J.) Acid Red 52 (C.I. 45100); Acid Red 73 (C.I.27290); Acid Red 87 (C. I. 45380); Acid Red 94 (C.I. 45440) Acid Red 194; and Food Red 1 (C.I. 14700). Exemplary violet acid dyes include Acid Violet 7 (C.I. 18055); and Acid Violet 49 (C.I. 42640). Exemplary blue acid dyes include Acid Blue 1 (C.I. 42045); Acid Blue 9 (C.I. 42090); Acid Blue 22 (C.I. 42755); Acid Blue 74 (C.I. 73015); Acid Blue 93 (C.I. 42780); and Acid Blue 158A (C.I. 15050). Exemplary green acid dyes include Acid Green 1 (C.I. 10028); Acid Green 3 (C.I. 42085); Acid Green 5 (C.I. 42095); Acid Green 26 (C.I. 44025); and Food Green 3 (C.I. 42053). Exemplary black acid dyes include Acid Black 1 (C.I. 20470); Acid Black 194 (Basantol® X80, available from BASF Corporation, an azo / 1 :2 CR-complex.

[0216] Exemplary direct dyes for use in the present disclosure include Direct Blue 86 (C.I. 74180); Direct Blue 199; Direct Black 168; Direct Red 253; and Direct Yellow 107 / 132 (C.I. Not Assigned).

[0217] Exemplary natural dyes for use in the present disclosure include Alkanet (C.I. 75520,75530); Annatto (C.I. 75120); Carotene (C.I. 75130); Chestnut; Cochineal (C.I.75470); Cutch (C.I. 75250, 75260); Divi-Divi; Fustic (C.I. 75240); Hypemic (C.I. 75280); Logwood (C.I. 75200); Osage Orange (C.I. 75660); Paprika; Quercitron (C.I. 75720); Sanrou (C.I. 75100) ; Sandal Wood (C.I. 75510, 75540, 75550, 75560); Sumac; and Tumeric (C.I. 75300). Exemplary reactive dyes for use in the present disclosure include Reactive Yellow 37 (monoazo dye); Reactive Black 31 (disazo dye); Reactive Blue 77 (phthalo cyanine dye) and Reactive Red 180 and Reactive Red 108 dyes. Suitable also are the colorants described in The Printing Ink Manual (5th ed., Leach et al. eds. (2007), pages 289-299. Other organic and inorganic pigments and dyes and combinations thereof can be used to achieve the colors desired.

[0218] In addition to or in place of visible colorants, compositions provided herein can contain ETV fluorophores that are excited in the ETV range and emit light at a higher wavelength (typically 400 nm and above). Examples of ETV fluorophores include but are not limited to materials from the coumarin, benzoxazole, rhodamine, napthalimide, perylene, benzanthrones, benzoxanthones or benzothiaxanthones families. The addition of a UV fluorophore (such as an optical brightener for instance) can help maintain maximum visible light transmission. The amount of colorant, when present, generally is between 0.05% to 5% or between 0.1% and 1% based on the weight of the composition.

[0219] For non- white compositions, the amount of pigment / dye generally is present in an amount of from at or about 0.1 wt% to at or about 20 wt% based on the weight of the composition. In some applications, a non- white ink can include 15 wt% or less pigment / dye, or 10 wt% or less pigment / dye or 5 wt% pigment / dye, or 1 wt% pigment / dye based on the weight of the composition. In some applications, a non-white ink can include 1 wt% to 10 wt%, or 5 wt% to 15 wt%, or 10 wt% to 20 wt% pigment / dye based on the weight of the composition. In some applications, a non-white ink can contain an amount of dye / pigment that is 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15%, 16 wt%, 17 wt%, 18 wt%, 19 wt% or 20 wt% based on the weight of the composition.

[0220] For white compositions, the amount of white pigment generally is present in an amount of from at or about 1 wt% to at or about 60 wt% based on the weight of the composition. In some applications, greater than 60 wt% white pigment can be present. Preferred white pigments include titanium dioxide (anatase and rutile), zinc oxide, lithopone (calcined coprecipitate of barium sulfate and zinc sulfide), zinc sulfide, blanc fixe and alumina hydrate and combinations thereof, although any of these can be combined with calcium carbonate. In some applications, a white ink can include 60 wt% or less white pigment, or 55 wt% or less white pigment, or 50 wt% white pigment, or 45 wt% white pigment, or 40 wt% white pigment, or 35 wt% white pigment, or 30 wt% white pigment, or 25 wt% white pigment, or 20 wt% white pigment, or 15 wt% white pigment, or 10 wt% white pigment, based on the weight of the composition. In some applications, a white ink can include 5 wt% to 60 wt%, or 5 wt% to 55 wt%, or 10 wt% to 50 wt%, or 10 wt% to 25 wt%, or 25 wt% to 50 wt%, or 5 wt% to 15 wt%, or 40 wt% to 60 wt% white pigment based on the weight of the composition. In some applications, a non-white ink can an amount of dye / pigment that is 5%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15%, 16 wt%, 17 wt%, 18 wt%, 19 wt%, 20 wt%, 21 wt%, 22 wt%, 23 wt%, 24 wt%, 25%, 26 wt%, 27 wt%, 28 wt%, 29 wt%, 30 wt%, 31 wt%, 32 wt%, 33 wt%, 34 wt%, 35%, 36 wt%, 37 wt%, 38 wt%, 39 wt%, 40 wt%, 41 wt%, 42 wt%, 43 wt%, 44 wt%, 45%, 46 wt%, 47 wt%, 48 wt%, 49 wt%, 50 wt%, 51 wt%, 52 wt%, 53 wt%, 54 wt%, 55%, 56 wt%, 57 wt%, 58 wt%, 59 wt% or 60 wt% based on the weight of the composition.

[0221] In some aspects, the additive or dopant comprises a conductive additive. Exemplary conductive additives include, but are not limited to graphite, graphite powder, carbon nanotubes, and metallic particles or nanoparticles, such as gold nanoparticles. In some aspects, the conductive additive is biocompatible and non-toxic.

[0222] In some aspects, the additive is a biologically active agent. The term “biologically active agent” as used herein refers to any molecule which exerts at least one biological effect in vivo. For example, the biologically active agent can be a therapeutic agent to treat or prevent a disease state or condition in a subject. Biologically active agents include, without limitation, organic molecules, inorganic materials, proteins, peptides, nucleic acids (e.g., genes, gene fragments, gene regulatory sequences, and antisense molecules), nucleoproteins, polysaccharides, glycoproteins, and lipoproteins. Classes of biologically active compounds that can be incorporated into the composition provided herein include, without limitation, anticancer agents, antibiotics, analgesics, anti-inflammatory agents, immunosuppressants, enzyme inhibitors, antihistamines, anti-convulsants, hormones, musclerelaxants, antispasmodics, ophthalmic agents, prostaglandins, anti-depressants, anti-psychotic substances, trophic factors, osteoinductive proteins, growth factors, and vaccines.

[0223] The term “active agent” may also be used herein to refer to a biological sample (e.g., a sample of tissue or fluid, such as for instance blood) or a component thereof, and / or to a biologically active entity or compound, and / or to a structurally or functionally labile entity.

[0224] Exemplary active agents include, but are not limited to, therapeutic agents, diagnostic agents (e.g., contrast agents), and any combinations thereof. In some embodiments, the active agent present in a silk matrix (e.g., a silk microsphere), composition, or the like can include a labile active agent, e.g., an agent that can undergo chemical, physical, or biological change, degradation and / or deactivation after exposure to a specified condition, e.g., high temperatures, high humidity, light exposure, and any combinations thereof. In some embodiments, the active agent present in the silk matrix (e.g., a silk microsphere), composition, or the like can include a temperature-sensitive active agent, e.g., an active agent that will lose at least about 30% or more, of its original activity or bioactivity, upon exposure to a temperature of at least about 10° C. or above, including at least about 15° C. or above, at least about room temperature or above, or at least about body temperature (e.g., about 37° C.) or above.

[0225] The active agent can be generally present in the silk matrix (e.g., a silk microsphere), composition, or the like in an amount of about 0.01% (w / w) to about 70% (w / w), or about 0.1% (w / w) to about 50% (w / w), or about 1% (w / w) to about 30% (w / w). The active agent can be present on a surface of the silk matrix (e.g., a silk microsphere), composition, or the like and / or encapsulated and dispersed in the silk matrix (e.g., a silk microsphere), composition, or the like homogeneously or heterogeneously or in a gradient. In some embodiments, the active agent can be added into the silk solution, which is then subjected to the methods described herein for preparing a silk matrix (e.g., a silk microsphere), composition, or the like. In some embodiments, the active agent can be coated on a surface of the silk matrix (e.g., a silk microsphere), composition, or the like. In some embodiments, the active agent can be loaded in a silk matrix (e.g., a silk microsphere), composition, or the like by incubating the silk microsphere in a solution of the active agent for a period of time, during which an amount of the active agent can diffuse into the silk matrix (e.g., a silk microsphere), composition, or the like, and thus distribute within the silk matrix (e.g., a silk microsphere), composition, or the like.

[0226] In some aspects, the additive is a therapeutic agent. As used herein, the term “therapeutic agent” means a molecule, group of molecules, complex or substance administered to an organism for diagnostic, therapeutic, preventative medical, or veterinary purposes. As used herein, the term “therapeutic agent” includes a “drug” or a “vaccine.” This term include externally and internally administered topical, localized and systemic human and animal pharmaceuticals, treatments, remedies,nutraceuticals, cosmeceuticals, biologicals, devices, diagnostics and contraceptives, including preparations useful in clinical and veterinary screening, prevention, prophylaxis, healing, wellness, detection, imaging, diagnosis, therapy, surgery, monitoring, cosmetics, prosthetics, forensics and the like. This term can also be used in reference to agriceutical, workplace, military, industrial and environmental therapeutics or remedies comprising selected molecules or selected nucleic acid sequences capable of recognizing cellular receptors, membrane receptors, hormone receptors, therapeutic receptors, microbes, viruses or selected targets comprising or capable of contacting plants, animals and / or humans. This term can also specifically include nucleic acids and compounds comprising nucleic acids that produce a therapeutic effect, for example deoxyribonucleic acid (DNA), ribonucleic acid (RNA), nucleic acid analogues (e.g., locked nucleic acid (LNA), peptide nucleic acid (PNA), xeno nucleic acid (XNA)), or mixtures or combinations thereof, including, for example, DNA nanoplexes, siRNA, microRNA, shRNA, aptamers, ribozymes, decoy nucleic acids, antisense nucleic acids, RNA activators, and the like. Generally, any therapeutic agent can be included in the composition provided herein.

[0227] The term “therapeutic agent” also includes an agent that is capable of providing a local or systemic biological, physiological, or therapeutic effect in the biological system to which it is applied. For example, the therapeutic agent can act to control infection or inflammation, enhance cell growth and tissue regeneration, control tumor growth, act as an analgesic, promote anti-cell attachment, and enhance bone growth, among other functions. Other suitable therapeutic agents can include anti-viral agents, hormones, antibodies, or therapeutic proteins. Other therapeutic agents include prodrugs, which are agents that are not biologically active when administered but, upon administration to a subject are converted to biologically active agents through metabolism or some other mechanism. Additionally, a silk-based drug delivery composition can contain one therapeutic agent or combinations of two or more therapeutic agents.

[0228] A therapeutic agent can include a wide variety of different compounds, including chemical compounds and mixtures of chemical compounds, e.g., small organic or inorganic molecules; saccharines; oligosaccharides; polysaccharides; biological macromolecules, e.g., peptides, proteins, and peptide analogs and derivatives; peptidomimetics; antibodies and antigen binding fragments thereof; nucleic acids; nucleic acid analogs and derivatives; an extract made from biological materials such as bacteria, plants, fungi, or animal cells; animal tissues; naturally occurring or synthetic compositions; and any combinations thereof. In some aspects, the therapeutic agent is a small molecule.

[0229] The term “bioactivity,” as used herein in reference to an active agent, generally refers to the ability of an active agent to interact with a biological target and / or to produce an effect on a biologicaltarget. For example, bioactivity can include, without limitation, elicitation of a stimulatory, inhibitory, regulatory, toxic or lethal response in a biological target. The biological target can be a molecule or a cell. For example, a bioactivity can refer to the ability of an active agent to modulate the effect / activity of an enzyme, block a receptor, stimulate a receptor, modulate the expression level of one or more genes, modulate cell proliferation, modulate cell division, modulate cell morphology, or any combination thereof. In some instances, a bioactivity can refer to the ability of a compound to produce a toxic effect in a cell. Exemplary cellular responses include, but are not limited to, lysis, apoptosis, growth inhibition, and growth promotion; production, secretion, and surface expression of a protein or other molecule of interest by the cell; membrane surface molecule activation including receptor activation; transmembrane ion transports; transcriptional regulations; changes in viability of the cell; changes in cell morphology; changes in presence or expression of an intracellular component of the cell; changes in gene expression or transcripts; changes in the activity of an enzyme produced within the cell; and changes in the presence or expression of a ligand and / or receptor (e.g., protein expression and / or binding activity). Methods for assaying different cellular responses are well known to one of skill in the art, e.g., western blot for determining changes in presence or expression of an endogenous protein of the cell, or microscopy for monitoring the cell morphology in response to the active agent, or FISH and / or qPCR for the detection and quantification of changes in nucleic acids. Bioactivity can be determined in some embodiments, for example, by assaying a cellular response.

[0230] In reference to an antibody, the term “bioactivity” includes, but is not limited to, epitope or antigen binding affinity, the in vivo and / or in vitro stability of the antibody, the immunogenic properties of the antibody, e.g., when administered to a human subject, and / or the ability to neutralize or antagonize the bioactivity of a target molecule in vivo or in vitro. The aforementioned properties or characteristics can be observed or measured using art-recognized techniques including, but not limited to, scintillation proximity assays, ELISA, ORIGEN immunoassay (IGEN), fluorescence quenching, fluorescence ELISA, competitive ELISA, SPR analysis including, but not limited to, SPR analysis using a BIAcore biosensor, in vitro and in vivo neutralization assays (see, for example, International Publication No. WO 2006 / 062685), receptor binding, and immunohistochemistry with tissue sections from different sources including human, primate, or any other source as needed. In reference to an immunogen, the “bioactivity” includes immunogenicity, the definition of which is discussed in detail later. In reference to a virus, the “bioactivity” includes infectivity, the definition of which is discussed in detail later. In reference to a contrast agent, e.g., a dye, the “bioactivity” refers to the ability of a contrast agent when administered to a subject to enhance the contrast of structures or fluids within the subject's body. The bioactivity of a contrast agent also includes, but is not limited to, its ability tointeract with a biological environment and / or influence the response of another molecule under certain conditions.

[0231] As used herein, the term “small molecule” can refer to compounds that are “natural productlike,” however, the term “small molecule” is not limited to “natural product-like” compounds. Rather, a small molecule is typically characterized in that it contains several carbon — carbon bonds, and has a molecular weight of less than 5000 Daltons (5 kDa), preferably less than 3 kDa, still more preferably less than 2 kDa, and most preferably less than 1 kDa. In some cases it is preferred that a small molecule have a molecular weight equal to or less than 700 Daltons.

[0232] Exemplary therapeutic agents include, but are not limited to, those found in Harrison’s Principles of Internal Medicine, 13th Edition, Eds. T.R. Harrison et al. McGraw-Hill N.Y., NY; Physicians’ Desk Reference, 50th Edition, 1997, Oradell New Jersey, Medical Economics Co.; Pharmacological Basis of Therapeutics, 8th Edition, Goodman and Gilman, 1990; United States Pharmacopeia, The National Formulary, ETSP XII NF XVII, 1990, the complete contents of all of which are incorporated herein by reference.

[0233] Therapeutic agents include the herein disclosed categories and specific examples. It is not intended that the category be limited by the specific examples. Those of ordinary skill in the art will recognize also numerous other compounds that fall within the categories and that are useful according to the present disclosure. Examples include a radiosensitizer, a steroid, a xanthine, a beta-2-agonist bronchodilator, an anti-inflammatory agent, an analgesic agent, a calcium antagonist, an angiotensinconverting enzyme inhibitors, a beta-blocker, a centrally active alpha- agonist, an alpha- 1 -antagonist, an anticholinergic / antispasmodic agent, a vasopressin analogue, an anti arrhythmic agent, an antiparkinsonian agent, an antiangina / antihypertensive agent, an anticoagulant agent, an antiplatelet agent, a sedative, an ansiolytic agent, a peptidic agent, a biopolymeric agent, an antineoplastic agent, a laxative, an antidiarrheal agent, an antimicrobial agent, an antifungal agent, a vaccine, a protein, or a nucleic acid. In a further aspect, the pharmaceutically active agent can be coumarin, albumin, steroids such as betamethasone, dexamethasone, methylprednisolone, prednisolone, prednisone, triamcinolone, budesonide, hydrocortisone, and pharmaceutically acceptable hydrocortisone derivatives; xanthines such as theophylline and doxophylline; beta-2-agonist bronchodilators such as salbutamol, fenterol, clenbuterol, bambuterol, salmeterol, fenoterol; antiinflammatory agents, including antiasthmatic anti-inflammatory agents, antiarthritis antiinflammatory agents, and nonsteroidal antiinflammatory agents, examples of which include but are not limited to sulfides, mesalamine, budesonide, salazopyrin, diclofenac, pharmaceutically acceptable diclofenac salts, nimesulide, naproxene, acetaminophen, ibuprofen, ketoprofen and piroxicam; analgesic agents such as salicylates; calcium channel blockers such as nifedipine, amlodipine, and nicardipine; angiotensinconverting enzyme inhibitors such as captopril, benazepril hydrochloride, fosinopril sodium, trandolapril, ramipril, lisinopril, enalapril, quinapril hydrochloride, and moexipril hydrochloride; betablockers (i.e., beta adrenergic blocking agents) such as sotalol hydrochloride, timolol maleate, esmolol hydrochloride, carteolol, propanolol hydrochloride, betaxolol hydrochloride, penbutolol sulfate, metoprolol tartrate, metoprolol succinate, acebutolol hydrochloride, atenolol, pindolol, and bisoprolol fumarate; centrally active alpha-2-agonists such as clonidine; alpha- 1 -antagonists such as doxazosin and prazosin; anticholinergic / antispasmodic agents such as dicyclomine hydrochloride, scopolamine hydrobromide, glycopyrrolate, clidinium bromide, flavoxate, and oxybutynin; vasopressin analogues such as vasopressin and desmopressin; antiarrhythmic agents such as quinidine, lidocaine, tocainide hydrochloride, mexiletine hydrochloride, digoxin, verapamil hydrochloride, propafenone hydrochloride, flecainide acetate, procainamide hydrochloride, moricizine hydrochloride, and disopyramide phosphate; antiparkinsonian agents, such as dopamine, L-Dopa / Carbidopa, selegiline, dihydroergocryptine, pergolide, lisuride, apomorphine, and bromocryptine; antiangina agents and antihypertensive agents such as isosorbide mononitrate, isosorbide dinitrate, propranolol, atenolol and verapamil; anticoagulant and antiplatelet agents such as Coumadin, warfarin, acetylsalicylic acid, and ticlopidine; sedatives such as benzodiazapines and barbiturates; ansiolytic agents such as lorazepam, bromazepam, and diazepam; peptidic and biopolymeric agents such as calcitonin, leuprolide and other LHRH agonists, hirudin, cyclosporin, insulin, somatostatin, protirelin, interferon, desmopressin, somatotropin, thymopentin, pidotimod, erythropoietin, interleukins, melatonin, granulocyte / macrophage-CSF, and heparin; antineoplastic agents such as etoposide, etoposide phosphate, cyclophosphamide, methotrexate, 5 -fluorouracil, vincristine, doxorubicin, cisplatin, hydroxyurea, leucovorin calcium, tamoxifen, flutamide, asparaginase, altretamine, mitotane, and procarbazine hydrochloride; laxatives such as senna concentrate, casanthranol, bisacodyl, and sodium picosulphate; antidiarrheal agents such as difenoxine hydrochloride, loperamide hydrochloride, furazolidone, diphenoxylate hdyrochloride, and microorganisms; vaccines such as bacterial and viral vaccines; antimicrobial agents such as penicillins, cephalosporins, and macrolides, antifungal agents such as imidazolic and triazolic derivatives; and nucleic acids such as DNA sequences encoding for biological proteins, and antisense oligonucleotides.

[0234] Anti-cancer agents include alkylating agents, platinum agents, antimetabolites, topoisomerase inhibitors, antitumor antibiotics, antimitotic agents, aromatase inhibitors, thymidylate synthase inhibitors, DNA antagonists, farnesyltransferase inhibitors, pump inhibitors, histone acetyltransferase inhibitors, metalloproteinase inhibitors, ribonucleoside reductase inhibitors, TNF alpha agonists / antagonists, endothelinA receptor antagonists, retinoic acid receptor agonists, immunomodulators, hormonal and antihormonal agents, photodynamic agents, and tyrosine kinase inhibitors.

[0235] Antibiotics include aminoglycosides (e.g., gentamicin, tobramycin, netilmicin, streptomycin, amikacin, neomycin), bacitracin, corbapenems (e.g., imipenem / cislastatin), cephalosporins, colistin, methenamine, monobactams (e.g., aztreonam), penicillins (e.g., penicillin G, penicillinV, methicillin, natcillin, oxacillin, cloxacillin, dicloxacillin, ampicillin, amoxicillin, carbenicillin, ticarcillin, piperacillin, mezlocillin, azlocillin), polymyxin B, quinolones, and vancomycin; and bacteriostatic agents such as chloramphenicol, clindanyan, macrolides (e.g., erythromycin, azithromycin, clarithromycin), lincomyan, nitrofurantoin, sulfonamides, tetracyclines (e.g., tetracycline, doxycycline, minocycline, demeclocyline), and trimethoprim. Also included are metronidazole, fluoroquinolones, and ritampin.

[0236] Enzyme inhibitors are substances which inhibit an enzymatic reaction. Examples of enzyme inhibitors include edrophonium chloride, N-methylphysostigmine, neostigmine bromide, physostigmine sulfate, tacrine, tacrine, 1 -hydroxy maleate, iodotubercidin, p- bromotetramiisole, 10- (alpha-diethylaminopropionyl)-phenothiazine hydrochloride, calmidazolium chloride, hemicholinium-3,3,5-dinitrocatechol, diacylglycerol kinase inhibitor I, diacylglycerol kinase inhibitor II, 3 -phenylpropargylamine, N°-monomethyl-Larginine acetate, carbidopa, 3- hydroxybenzylhydrazine, hydralazine, cl orgyline, deprenyl, hydroxylamine, iproniazid phosphate, 6- MeO-tetrahydro-9H-pyrido-indole, nialamide, pargyline, quinacrine, semi carb azide, tranylcypromine, N,N-diethylaminoethyl-2,2-diphenylvalerate hydrochloride, 3 - isobutyl- 1- methylxanthne, papaverine, indomethacind, 2-cyclooctyl-2 -hydroxy ethylamine hydrochloride, 2,3- dichloro-a-methylbenzylamine (DCMB), 8,9-dichloro-2,3,4, 5 -tetrahydro- lH-2-benzazepine hydrochloride, p-amino glutethimide, p-aminoglutethimide tartrate, 3- iodotyrosine, alphamethyltyrosine, acetazolamide, dichlorphenamide, 6-hydroxy-2- benzothiazolesulfonamide, and allopurinol.

[0237] Antihistamines include pyrilamine, chlorpheniramine, and tetrahydrazoline, among others.

[0238] Anti-inflammatory agents include corticosteroids, nonsteroidal anti-inflammatory drugs (e.g., aspirin, phenylbutazone, indomethacin, sulindac, tolmetin, ibuprofen, piroxicam, and fenamates), acetaminophen, phenacetin, gold salts, chloroquine, D-Penicillamine, methotrexate colchicine, allopurinol, probenecid, and sulfinpyrazone.

[0239] Muscle relaxants include mephenesin, methocarbomal, cyclobenzaprine hydrochloride, trihexylphenidyl hydrochloride, levodopa / carbidopa, and biperiden.

[0240] Anti-spasmodics include atropine, scopolamine, oxyphenonium, and papaverine.

[0241] Analgesics include aspirin, phenybutazone, idomethacin, sulindac, tolmetic, ibuprofen, piroxicam, fenamates, acetaminophen, phenacetin, morphine sulfate, codeine sulfate, meperidine, nalorphine, opioids (e.g., codeine sulfate, fentanyl citrate, hydrocodone bitartrate, loperamide,morphine sulfate, noscapine, norcodeine, normorphine, thebaine, nor- binaltorphimine, buprenorphine, chlomaltrexamine, funaltrexamione, nalbuphine, nalorphine, naloxone, naloxonazine, naltrexone, and naltrindole), procaine, lidocain, tetracaine and dibucaine.

[0121] Ophthalmic agents include sodium fluorescein, rose bengal, methacholine, adrenaline, cocaine, atropine, alphachymotrypsin, hyaluronidase, betaxalol, pilocarpine, timolol, timolol salts, and combinations thereof.

[0242] Prostaglandins are art recognized and are a class of naturally occurring chemically related long-chain hydroxy fatty acids that have a variety of biological effects.

[0243] Anti-depressants are substances capable of preventing or relieving depression.

[0244] Examples of anti-depressants include imipramine, amitriptyline, nortriptyline, protriptyline, desipramine, amoxapine, doxepin, maprotiline, tranylcypromine, phenelzine, and isocarboxazide.

[0245] Trophic factors are factors whose continued presence improves the viability or longevity of a cell trophic factors include, without limitation, platelet-derived growth factor (PDGP), neutrophilactivating protein, monocyte chemoattractant protein, macrophage- inflammatory protein, platelet factor, platelet basic protein, and melanoma growth stimulating activity; epidermal growth factor, transforming growth factor (alpha), fibroblast growth factor, platelet- derived endothelial cell growth factor, insulin-like growth factor, glial derived growth neurotrophic factor, ciliary neurotrophic factor, nerve growth factor, bone growth / cartilage- inducing factor (alpha and beta), bone morphogenetic proteins, interleukins (e.g., interleukin inhibitors or interleukin receptors, including interleukin 1 through interleukin 10), interferons (e.g., interferon alpha, beta and gamma), hematopoietic factors, including erythropoietin, granulocyte colony stimulating factor, macrophage colony stimulating factor and granulocyte- macrophage colony stimulating factor; tumor necrosis factors, and transforming growth factors (beta), including beta-1, beta-2, beta-3, inhibin, and activin.

[0246] Hormones include estrogens (e.g., estradiol, estrone, estriol, diethylstibestrol, quinestrol, chlorotrianisene, ethinyl estradiol, mestranol), anti-estrogens (e.g., clomiphene, tamoxifen), progestins (e.g., medroxyprogesterone, norethindrone, hydroxyprogesterone, norgestrel), antiprogestin (mifepristone), androgens (e.g, testosterone cypionate, fluoxymesterone, danazol, testolactone), antiandrogens (e.g., cyproterone acetate, flutamide), thyroid hormones (e.g., triiodothyronne, thyroxine, propylthiouracil, methimazole, and iodixode), and pituitary hormones (e.g., corticotropin, sumutotropin, oxytocin, and vasopressin). Hormones are commonly employed in hormone replacement therapy and / or for purposes of birth control. Steroid hormones, such as prednisone, are also used as immunosuppressants and anti-inflammatories. In some aspects, the additive is an agent that stimulates tissue formation, and / or healing and regrowth of natural tissues, and any combinations thereof. Agents that increase formation of new tissues and / or stimulates healing or regrowth of native tissue at the site of injection can include, but are not limited to, fibroblast growth factor (FGF),transforming growth factor-beta (TGF-beta, platelet-derived growth factor (PDGF), epidermal growth factors (EGFs), connective tissue activated peptides (CTAPs), osteogenic factors including bone morphogenic proteins, heparin, angiotensin II (A-II) and fragments thereof, insulin- like growth factors, tumor necrosis factors, interleukins, colony stimulating factors, erythropoietin, nerve growth factors, interferons, biologically active analogs, fragments, and derivatives of such growth factors, and any combinations thereof.

[0247] In some aspects, the silk composition can further comprise at least one additional material for soft tissue augmentation, e.g., dermal filler materials, including, but not limited to, poly(methyl methacrylate) microspheres, hydroxylapatite, poly(L-lactic acid), collagen, elastin, and glycosaminoglycans, hyaluronic acid, commercial dermal filler products such as BOTOX® (from Allergan), DYSPORT®, COSMODERM®, EVOLENCE®, RADIESSE®,RESTYLANE®, JUVEDERM® (from Allergan), SCULPTRA®, PERLANE®, and CAPTIQEIE®, and any combinations thereof.

[0248] In some aspects, the additive is a wound healing agent. As used herein, a “wound healing agent" is a compound or composition that actively promotes wound healing process.

[0249] Exemplary wound healing agents include, but are not limited to dexpanthenol; growth factors; enzymes, hormones; povidon-iodide; fatty acids; anti-inflammatory agents; antibiotics; antimicrobials; antiseptics; cytokines; thrombin; angalgesics; opioids; aminoxyls; furoxans; nitrosothiols; nitrates and anthocyanins; nucleosides, such as adenosine; and nucleotides, such as adenosine diphosphate (ADP) and adenosine triphosphate (ATP); neutotransmitter / neuromodulators, such as acetylcholine and 5 -hydroxy tryptamine (serotonin / 5- HT); histamine and catecholamines, such as adrenalin and noradrenalin; lipid molecules, such as 5 sphingosine-1 -phosphate and lysophosphatidic acid; amino acids, such as arginine and lysine; peptides such as the bradykinins, substance P and calcium gene-related peptide (CGRP); nitric oxide; and any combinations thereof.

[0250] In certain aspects, the active agents provided herein are immunogens. In one aspect, the immunogen is a vaccine. Most vaccines are sensitive to environmental conditions under which they are stored and / or transported. For example, freezing may increase reactogenicity (e.g., capability of causing an immunological reaction) and / or loss of potency for some vaccines (e.g., HepB, and DTaP / IPV / FQB), or cause hairline cracks in the container, leading to contamination. Further, some vaccines (e.g., BCG, Varicella, and MMR) are sensitive to heat. Many vaccines (e.g., BCG, MMR, Varicella, Meningococcal C Conjugate, and most DTaP-containing vaccines) are light sensitive. See, e.g., Galazka et ak, Thermostability of vaccines, in Global Programme for Vaccines & Immunization (World Health Organization, Geneva, 1998); Peetermans et ak, Stability of freeze-dried rubella virus vaccine (Cendehill strain) at various temperatures, 1 J. Biological Standardization 179 (1973). Thus,the compositions and methods provided herein also provide for stabilization of vaccines regardless of the cold chain and / or other environmental conditions.

[0251] In some aspects, the additive is a cell, e.g., a biological cell. Cells useful for incorporation into the composition can come from any source, e.g., mammalian, insect, plant, etc. In some aspects, the cell can be a human, rat or mouse cell. In general, cells to be used with the compositions provided herein can be any types of cells. In general, the cells should be viable when encapsulated within compositions. In some aspects, cells that can be used with the composition include, but are not limited to, mammalian cells (e.g. human cells, primate cells, mammalian cells, rodent cells, etc.), avian cells, fish cells, insect cells, plant cells, fungal cells, spore cells, bacterial cells, and hybrid cells. In some aspects, exemplary cells that can be used with the compositions include platelets, activated platelets, stem cells, totipotent cells, pluripotent cells, and / or embryonic stem cells. In some aspects, exemplary cells that can be encapsulated within compositions include, but are not limited to, primary cells and / or cell lines from any tissue. For example, cardiomyocytes, myocytes, hepatocytes, keratinocytes, melanocytes, neurons, astrocytes, embryonic stem cells, adult stem cells, hematopoietic stem cells, hematopoietic cells (e.g. monocytes, neutrophils, macrophages, etc.), ameloblasts, fibroblasts, chondrocytes, osteoblasts, osteoclasts, neurons, sperm cells, egg cells, liver cells, epithelial cells from lung, epithelial cells from gut, epithelial cells from intestine, liver, epithelial cells from skin, etc., and / or hybrids thereof, can be included in the silk / platelet compositions disclosed herein. Those skilled in the art will recognize that the cells listed herein represent an exemplary, not comprehensive, list of cells. Cells can be obtained from donors (allogenic) or from recipients (autologous). Cells can be obtained, as a non-limiting example, by biopsy or other surgical means known to those skilled in the art.

[0252] In some aspects, the cell can be a genetically modified cell. A cell can be genetically modified to express and secrete a desired compound, e.g. a bioactive agent, a growth factor, differentiation factor, cytokines, and the like. Methods of genetically modifying cells for expressing and secreting compounds of interest are known in the art and easily adaptable by one of skill in the art.

[0253] Differentiated cells that have been reprogrammed into stem cells can also be used.

[0254] For example, human skin cells reprogrammed into embryonic stem cells by the transduction of Oct3 / 4, Sox2, c-Myc and Klf4 (Junying Yu, et. ah, Science , 2007, 318 , 1917-1920 and Takahashi K. et. ah, Cell , 2007, 131 , 1-12).

[0255] For the avoidance of doubt, the components listed in this section are combinable with all forms of composition described herein, including liquid composition, whipped silk cream, any form of silk meringue, silk leather, or a combination thereof.Conductive Silk Leather

[0256] The present disclosure provides a conductive silk leather. Conductive silk leathers may be used to power embedded lights, for central processing for distributed sensors, and as a component of circuitry. In aspects, a unitary portion of silk leather may include portions that are conductive and portions that are not conductive.

[0257] Conductive silk leathers can be used with any other product or article of manufacture described herein. For example, the conductive silk leather can further include sorbent and / or gas sensing material, such as for example to provide a safety garment for a hazardous environment with embedded, powered lights and gas sensing capabilities. In another example, conductive silk leathers can be used with magnetic silk leathers, described elsewhere herein, to form a multi-functional item with magnetic and conductive properties. In some aspects, the conductive silk leather may also include materials, such as magnetic particles or chromium oxide, to render it both conductive and magnetic. Conductive silk leathers can be used with or include a thermal insulator to provide items with conductive and thermal insulation properties.

[0258] The conductive silk leather can comprise, consist essentially of, or consist of any of the silk meringues described herein. In aspects, at least one of a plurality of graphite flakes or a graphene powder is distributed within the compressed silk meringue or the hot-pressed silk meringue of the conductive silk leather. The graphite flakes or graphene powder may be added before or during the whipping process, or after whipping. In one example, graphite flakes or graphene powder are added when the whipped silk cream reaches a particular overrun value. The graphite flakes or graphene powder may be added before or during meringue formation or may be added before or during compression or hot-pressing the meringue.

[0259] In some aspects, the conductive silk leather includes a conductive ink. For example, the conductive ink is printed on a surface of the compressed silk meringue or the hot-pressed silk meringue. In another example, the conductive ink is printed between layers of the compressed silk meringue or the hot-pressed silk meringue or printed and subsequently embedded within the compressed silk meringue or the hot-pressed silk meringue. In yet another example, the conductive ink is printed between the compressed silk meringue or the hot-pressed silk meringue and a fabric layer. The conductivity is patterned into an electronic circuit. The resistivity of the conductive silk leather is at most IkQ, at most 0.7kQ, at most 0.5kQ, or at most O.lkQ.

[0260] For the avoidance of doubt, the conductive silk leathers described herein can wholly include or include features of the silk leathers disclosed elsewhere here. Similarly, the conductive silk leathers described herein can be made from, comprise, wholly include, or include features from the liquidcompositions, whipped silk creams, silk meringues, compressed silk meringues, hot-pressed silk meringues, or methods disclosed elsewhere herein.Magnetic Silk Leather

[0261] The present disclosure provides a magnetic silk leather. The magnetic silk leather can comprise, consist essentially of, or consist of any of the silk meringues described herein. In aspects, at least one of a plurality of magnetic particles or a plurality of chromium oxide particles is distributed within the compressed silk meringue or the hot-pressed silk meringue. The plurality of magnetic particles or plurality of chromium oxide particles may be added before or during the whipping process, or after whipping. In one example, plurality of magnetic particles or plurality of chromium oxide particles are added when the whipped silk cream reaches a particular overrun value. The plurality of magnetic particles or plurality of chromium oxide particles may be added before or during meringue formation or may be added before or during compression or hot-pressing the meringue. In an aspect, a magnetic field may be applied at any point during the processing of the liquid composition to a silk whipped cream and silk meringues. Magnetic silk leathers can block RFID signals or be a building block for products such as robots, games, home organizing / decor, or the like.

[0262] The magnetic silk leather can be tailored to have a specific polarity at a surface of the magnetic silk leather. In some cases, the polarity is North. In some cases, the polarity is South.

[0263] In some cases, the magnetic material may be manipulated prior to curing, such that a specific magnetic configuration is locked into the magnetic silk leather. Conceptually, applications involving ferrofluids such as generating different patterns could be applied to creation of magnetic silk foams / meringues / leathers. In general, a magnetic field could be applied at any step of the methods disclosed herein with the intention of manipulating magnetic particles located within one or more of the compositions disclosed herein.

[0264] In some cases, the magnetic silk leather can be used as an external surface for a robot (e.g., a “robot skin”).

[0265] For the avoidance of doubt, the magnetic silk leathers described herein can wholly include or include features of the silk leathers disclosed elsewhere here. Similarly, the magnetic silk leathers described herein can be made from, comprise, wholly include, or include features from the liquid compositions, whipped silk creams, silk meringues, compressed silk meringues, hot-pressed silk meringues, or methods disclosed elsewhere herein.Scented Silk Leather

[0266] The present disclosure provides a scented silk leather. The scented silk leather can comprise, consist essentially of, or consist of any of the silk meringues described herein. In aspects, a pluralityof aromatic compounds are distributed throughout the compressed silk meringue or the hot-pressed silk meringue of the scented silk leather.

[0267] The aromatic compounds may include emulsions, oils, alcohols, scented powder, or the like. The character of the aromatic compounds can impact the processing and the methods disclosed herein may afford different processing requirements. Both oil and alcohols can be freely incorporated into creams during the whipping, especially if the fragrance is concentrated (e.g., such as if the oil / alcohol is less than 5% of total volume). For adsorbing the fragrance on a dry material (e.g., meringue or leather), both oils and alcohols may be useful, but the permeability of the material would be controlled by the nature and content of the plasticizer. For example, foams with no glycerol (e.g., pure silk fibroin and xanthan gum) display a higher oil sorption capacity.

[0268] Applying an additional volume of the aromatic compound to a surface of the scented silk leather, such as by spraying, wiping, submerging, or other application method, may at least partly recharge the scented silk leather, thereby extending the lifetime of aroma release. In some cases, alcohol-based aroma compounds can be particularly effective at recharging scented silk leathers.

[0269] The aromatic compounds may be added before or during the whipping process, or after whipping. In one example, aromatic compounds are added when the whipped silk cream reaches a particular overrun value. The aromatic compounds may be added before or during meringue formation or may be added before or during compression or hot-pressing the meringue.

[0270] The silk foam can exhibit heterogeneous domains of scent such that scent intensity can be distributed based on foam particles. Through compression, gradients of scent may be generated. In one aspect, the scented silk leather exhibits pressure-sensitive aroma release.

[0271] The ability of a silk leather to become scented, maintain scent, release / dispense / disperse scent, and / or recharge scent may depend on factors such as the components of the liquid composition, the density, the water content, the presence of other agents / additives in the silk leather, or the like. Likewise, the release profile of scents may depend on similar factors.

[0272] For the avoidance of doubt, the scented silk leathers described herein can wholly include or include features of the silk leathers disclosed elsewhere here. Similarly, the scented silk leathers described herein can be made from, comprise, wholly include, or include features from the liquid compositions, whipped silk creams, silk meringues, compressed silk meringues, hot-pressed silk meringues, or methods disclosed elsewhere herein. pH Responsive Silk Leather

[0273] The present disclosure provides a pH-responsive silk leather. The pH-responsive silk leather can comprise, consist essentially of, or consist of any of the silk meringues described herein. In aspects, a pH-responsive chemical is distributed throughout the compressed silk meringue or the hot-pressedsilk meringue of the pH-responsive silk leather. The pH-responsive chemical may be added before or during the whipping process, or after whipping. In one example, a pH-responsive chemical is added when the whipped silk cream reaches a particular overrun value. The pH-responsive chemical may be added before or during meringue formation or may be added before or during compression or hot- pressing the meringue. pH-responsive silk leather may be useful in worn garments such as to alert a wearer of certain ambient or precipitating pollutants.

[0274] For the avoidance of doubt, the pH-responsive silk leathers described herein can wholly include or include features of the silk leathers disclosed elsewhere here. Similarly, the pH-responsive silk leathers described herein can be made from, comprise, wholly include, or include features from the liquid compositions, whipped silk creams, silk meringues, compressed silk meringues, hot-pressed silk meringues, or methods disclosed elsewhere herein.Humidity Sensing Silk Leather

[0275] The present disclosure provides a humidity sensing silk leather. The humidity sensing silk leather can comprise, consist essentially of, or consist of any of the silk meringues described herein. In aspects, a pH responsive chemical (e.g., o-cresolphtalein) and a pH altering agent (e.g., sodium carbonate) are distributed throughout the compressed silk meringue or the hot-pressed silk meringue of the humidity sensing silk leather. In aspects, measurable amounts of humidity solubilize at least a portion of the pH altering agent, thereby lowering the pH, thereby providing a measurable report of humidity. At least one of the pH responsive chemical or the pH altering agent may be added before or during the whipping process, or after whipping. In one example, at least one of the pH responsive chemical or the pH altering agent are added when the whipped silk cream reaches a particular overrun value. At least one of the pH responsive chemical or the pH altering agent may be added before or during meringue formation or may be added before or during compression or hot-pressing the meringue. Humidity sensing silk leathers may be useful, for example, as a component of a humidor box.

[0276] For the avoidance of doubt, the humidity sensing silk leathers described herein can wholly include or include features of the silk leathers disclosed elsewhere here. Similarly, the humidity sensing silk leathers described herein can be made from, comprise, wholly include, or include features from the liquid compositions, whipped silk creams, silk meringues, compressed silk meringues, hot- pressed silk meringues, or methods disclosed elsewhere herein.Patterned Silk Leather

[0277] The present disclosure provides a patterned silk leather. The patterned silk leather can comprise, consist essentially of, or consist of any of the silk meringues described herein. Patterned silk leathers may exhibit any pattern or texture, such as for example to mimic reptile skin in appearanceand / or feeling. Certain patterns or textures may provide an aesthetic quality and / or a function / property to silk leather, such as improved grip, anti-bacterial, anti-fouling, water-repellent, waterproof, dustrepellent, or the like. The dimensions of the patterns may be nano-, micro-, or macro-scale.

[0278] Examples of suitable surface patterns include, but are not limited to: leather mimicking patterns, which mimics a variety of different leathers, including alligator leather, crocodile leather, snake leather, cow leather, stingray leather, ostrich leather; a water-resistant or water-proof pattern; tessellating patterns; optically-active patterns, such as diffraction patterns; plant patterns, geometric patterns, letters and numbers, or the like.

[0279] For the avoidance of doubt, the patterned silk leathers described herein can wholly include or include features of the silk leathers disclosed elsewhere here. Similarly, the patterned silk leathers described herein can be made from, comprise, wholly include, or include features from the liquid compositions, whipped silk creams, silk meringues, compressed silk meringues, hot-pressed silk meringues, or methods disclosed elsewhere herein.Electronic Embedded Silk Leather

[0280] The present disclosure provides an electronic silk leather having an electronic component embedded therein. The electronic silk leather can comprise, consist essentially of, or consist of any of the silk meringues described herein. In aspects, the electronic component or a second electronic component is embedded between the silk layer and the fabric layer in the electronic silk leather. In aspects, the electronic component or a third electronic component is embedded within the silk layer in the electronic silk leather. In aspects, the electronic silk leather further comprises a power supply coupled to the electronic component. For example, the power supply may be a rechargeable battery, a wired disposable battery holder, fiber-shaped solar cells (e.g., perovskite solar cells), or a combination thereof. In aspects, the electronic component comprises an RFID tag. In aspects, the electronic component comprises wiring. The present disclosure also provides a silk cream or silk meringue having electronics distributed throughout. In aspects, the silk cream or silk meringue may be a variable density filler material having electronic functionalization. In embodiments, electronic components may include light emitting devices such as LEDs or electroluminescent wires. Such components may be useful in fashion and design applications as well as for powering sensing applications.

[0281] For the avoidance of doubt, the electronic silk leathers described herein can wholly include or include features of the silk leathers disclosed elsewhere here. Similarly, the electronic silk leathers described herein can be made from, comprise, wholly include, or include features from the liquid compositions, whipped silk creams, silk meringues, compressed silk meringues, hot-pressed silk meringues, or methods disclosed elsewhere herein.Semiconductor Device Embedded Silk Leather

[0282] The present disclosure provides a semiconductor device-embedded silk leather having a semiconductor device embedded therein. The semiconductor device-embedded silk leather can comprise, consist essentially of, or consist of any of the silk meringues described herein. The semiconductor device or a second semiconductor device may be embedded at a surface of the compressed silk meringue or the hot-pressed silk meringue. The semiconductor device or a third semiconductor device may be embedded within the compressed silk meringue or the hot-pressed silk meringue. The semiconductor device or a fourth semiconductor device may be embedded between the first fabric layer and the compressed silk meringue or the hot-pressed silk meringue. In aspects, the semiconductor device-embedded silk further comprises a power supply, as described elsewhere herein, coupled to the semiconductor devices. In aspects, the semiconductor device may be in communication with one or more electronic components in the silk leather.

[0283] For the avoidance of doubt, the semiconductor device-embedded silk leathers described herein can wholly include or include features of the silk leathers disclosed elsewhere here. Similarly, the semiconductor device-embedded silk leathers described herein can be made from, comprise, wholly include, or include features from the liquid compositions, whipped silk creams, silk meringues, compressed silk meringues, hot-pressed silk meringues, or methods disclosed elsewhere herein.Haptic Silk Leather

[0284] The present disclosure provides a haptic silk leather having a haptic switch embedded therein. The haptic silk leather can comprise, consist essentially of, or consist of any of the silk meringues described herein. The haptic switch or a second haptic switch may be embedded at a surface of the silk leather. The haptic switch or a third haptic switch may be embedded within the compressed silk meringue or the hot-pressed silk meringue. The haptic switch or a fourth haptic switch may be embedded between the first fabric layer and the compressed silk meringue or the hot-pressed silk meringue. In aspects, the haptic silk further comprises a power supply, as described elsewhere herein, coupled to the haptic switch. In aspects, the haptic switch may be in communication with one or more electronic components or semiconductor devices in the silk leather.

[0285] For the avoidance of doubt, the haptic silk leathers described herein can wholly include or include features of the silk leathers disclosed elsewhere here. Similarly, the haptic silk leathers described herein can be made from, comprise, wholly include, or include features from the liquid compositions, whipped silk creams, silk meringues, compressed silk meringues, hot-pressed silk meringues, or methods disclosed elsewhere herein.Tanned Silk Leather

[0286] The present disclosure provides a tanned silk leather. The tanned silk leather can comprise, consist essentially of, or consist of any of the silk meringues described herein. The tanned silk leather may have a bulk volume of a compressed silk meringue or hot-compressed silk meringue and a surface layer of the compressed silk meringue or hot-pressed silk meringue. The surface layer may be formed from the same chemical composition as the bulk volume but includes at least one differing structural, mechanical, or chemical feature relative to the bulk volume. In an aspect, the surface layer includes a dye.

[0287] In an aspect, the surface layer comprises a material, such as a precursor material, that may mimic tanning products (e.g., absorb aniline / dyes). In some examples, the precursor reacts to form the surface layer. In aspects, the surface layer may be modified / re-shaped relative to the bulk volume, such as by surface patterning, to provide a material difference to the surface layer. Silk leathers subjected to processes akin to tanning (e.g., chemical treatment with aniline) may result in a relatively stiff material which may, for example, be relatively more processable for fashion industries.

[0288] For the avoidance of doubt, the tanned silk leathers described herein can wholly include or include features of the silk leathers disclosed elsewhere here. Similarly, the tanned silk leathers described herein can be made from, comprise, wholly include, or include features from the liquid compositions, whipped silk creams, silk meringues, compressed silk meringues, hot-pressed silk meringues, or methods disclosed elsewhere herein.Fiber Fortified Silk Cream / Meringue

[0289] The present disclosure provides a silk cream or silk meringue having fibers distributed throughout, such as fibers / textiles described herein. In aspects, woven fabrics may be penetrated with the liquid composition or any of the downstream products described herein.

[0290] For the avoidance of doubt, the fiber fortified silk cream / meringue can wholly include or include features of the whipped silk creams or silk meringues disclosed elsewhere herein. Similarly, the fortified creams / meringues described herein can be made from, comprise, wholly include, or include features from the liquid compositions, whipped silk creams, silk meringues, compressed silk meringues, hot-pressed silk meringues, or methods disclosed elsewhere herein.Ultra- Lightweight Silk Down Alternative

[0291] The present disclosure provides an ultra-lightweight silk down alternative comprising, consisting essentially of, or consisting of any of the silk meringues described herein. The ultralightweight silk down alternative is made from a regenerated silk fibroin solution made from a recycled regenerated silk fibroin article or a waste silk fabric. The ultra-lightweight silk down alternative may further include a plurality of heat-reflective particles and / or have a thermochromic reporting capability.Impact Distributing Foam

[0292] The present disclosure provides an impact-distributing foam comprising a silk meringue. The impact-distributing foam has one or more impact and / or strain sensors positioned within the impactdistributing foam. The one or more impact and / or strain sensors are selected from the group consisting of a PDA sensor, an accelerometer, a piezoelectric sensor, a vibration sensor, a piezoresistive sensor, or a strain gauge sensor. The impact-distributing foam has one or more strain sensors positioned within the impact-distributing foam. The density of the foam may be between 0.1 g / cm3and 0.2 g / cm3, or between 0.01 g / cm3and 0.05 g / cm3, r between 0.05 g / cm3and 0.25 g / cm3. For example, the density of the foam is at least 0.01 g / cm3, at least 0.05 g / cm3, at least 0.1 g / cm3, at least 0.2 g / cm3, or at least 0.25 g / cm3. The density of the foam may be tuned by one or more factors such as the components included in the liquid composition, the weight ratio of one or more components in the liquid composition, the weight % of one or more components in the liquid composition, the amount of whipping time, or the temperature during whipping.

[0293] The foams described herein serve two related but distinct functional purposes at the same time. On the one hand, the foam protects an underlying item from impact. On the other hand, the foam protects embedded sensors from the environment. In this way, a variety of different impact sensors may be usable, which otherwise would not be due to stability.Protected Item

[0294] The present disclosure provides a protected item comprising: an item to be protected; and protective shell comprising a silk meringue, a cured silk meringue, a compressed silk meringue, or a hot-compressed silk meringue. The protective shell is formed by surrounding and contacting the item to be protected with a precursor to the protective shell and curing the precursor to form the protective shell, wherein surrounding comprises fully encapsulating or encapsulating against a surface. For example, the item to be protected may be at least one of an electronics component, an aerospace component, a semiconductor chip, a semiconductor device, or a three-dimensional printed structure.

[0295] The protective shell renders the item to be protected resistant to an impact of between 100 Newtons (N) and 25,000N, between 200N and 15,000N, between 500N and 10,000N, or between 1 ,000N and 5,000N. The level of impact resistance of the protective shell may be tuned by one or more factors such as the components included in the liquid composition, the weight ratio of one or more components in the liquid composition, the weight % of one or more components in the liquid composition, the amount of whipping time, or the temperature during whipping. The level of impact resistance of the protective shell may be tuned to provide a protective shell that is substantially resistant to impact, a protective shell that is moderately resistant to impact (e.g., the protective shell sustains damage while the item does not sustain damage, an outer portion of the protective shell sustains severedamage while an inner portion sustains less damage and the item sustains no damage), or a protective shell is minimally resistant to impact.

[0296] The item to be protected is resistant to a temperature of between 80°F and 500°F, between 100°F and 400°F, or between 150°F and 300°F. The item to be protected is resistant to a temperature of between 0°F and -500°F, between -50°F and -400°F, or between -150°F and -300°F.

[0297] For certain items, the nature of the material when it is applied may be relevant, such as a water content for applications involving electronics.

[0298] In cases where moisture sensitivity is an issue, the whipped silk cream or silk meringue that is applied to the item can have a water content below a threshold value. In cases where low moisture is an issue, the whipped silk cream or silk meringue that is applied to the item can have a water content above a threshold value.

[0299] In some cases, the protective shell, the silk meringue, the compressed silk meringue, or the hot-pressed silk meringue can have one or more impact sensors distributed throughout for reporting impacts that exceed a given threshold. In some cases, the impact sensors and / or strain sensors are polydiacetylene (PDA) based sensors.Open Cell Silk Foam

[0300] The present disclosure provides an open-cell silk foam. The inventors discovered that controlling the whipping during the making of the silk cream can control the nature of the pores that are created in eventual silk foams / meringues. If the whipping falls within a given window of whipping (i.e., exceeds a first whipping threshold, but does not exceed a second whipping threshold), an opencell pore structure is formed in the whipped silk cream, resulting in an open-cell silk foam / meringue when baked. The open cell foams are generally lighter, more white and reflective, and more permeable to organic solvents. In some embodiments, open cell foams may be preferable for fragrance release or other applications that include loading of the baked foam. Open cell foams may be useful for sensor applications where sensors have to interact with the environment, such as gas, humidity or pH sensors.Closed Cell Silk Foam

[0301] The present disclosure provides a closed-cell silk foam. The inventors discovered that controlling the whipping during the making of the silk cream can control the nature of the pores that are created in eventual silk foams / meringues. If the whipping falls outside a given window of whipping (i.e., does not exceed a first whipping threshold or does exceed a second, higher whipping threshold), a closed-cell pore structure is formed in the whipped silk cream, resulting in a closed-cell silk foam / meringue when baked. A closed cell morphology may be useful for applications in which anelement is added to the foam during whipping and it is desired to preserve the element (e.g., living organisms or mechanical / thermal sensors).Multi- valent Ions

[0302] The present disclosure provides compositions that include multi-valent ions. The inventors discovered that addition of multi- valent ions alters the mechanical properties of the leather resulting in greater mechanical strength. Addition of multi-valent ions also improves homogeneity of the foam after whipping which is evidenced by fewer clots in the whipped silk creams. Dissolution of alginate is also facilitated, which reduces yellowing of the silk foams. Without wishing to be bound by any particular theory, it is believed that addition of multi-valent ions crosslinks the alginate present in the silk compositions.

[0303] Multi-valent ions may include cupric ions, calcium salts, chloride salts, or the like. Cupric ions may include CuCh. Calcium salts may include Ca(OH)2, CaCCh, and / or CaCh. Chloride salts may include CuCh, CaCh, or ZnCh.

[0304] In some embodiments, adding CaCh before whipping may reduce clot formation. There may be a decrease in overrun dependent on multi-valent ion concentration. Addition of multi-valent ions may influence the material’s appearance, including color and feeling to the touch, as well as mechanical properties. Addition of multi-valent ions may result in swelling of up to 100%, up to 200%, up to 300%, or higher. Swelling may increase with increasing multi-valent ion concentration. Swelling of silk leathers with multi-valent ions may persist after drying. Addition of multi-valent ions may decrease mass loss after water immersion and / or reduce foam dissolution in water. Mass loss may decrease after water immersion proportional to multi-valent ion concentration. Addition of multivalent ions may induce formation of alginate films on the bottom of the foam.

[0305] In some embodiments, multi-valent ions may be added in 10 mmol to 250 mmol of salt per gram of added alginate or 10 mmol to 500 mmol of salt per gram of added alginate.High Alginate

[0306] The present disclosure provides formulations with high ratios of alginate relative to the usual 20:20:60 alginate-based ratio. The inventors discovered that adjusting the silk fibroin: alginate ratio changed both the mechanical properties and swelling behavior of the corresponding foams and leathers in water. While high alginate foams collapsed after baking, they also demonstrated increased sturdiness. The high SF ratio foams were smoother and softer to the touch which could lead to increased surface damage.Types of Alginate

[0307] The present disclosure provides different viscosities of alginates for formulations. High viscosity alginates may have a viscosity above 500 mPa*s. For example, high viscosity alginates mayhave a viscosity of at least 500 mPa*s, at least 700 mPa*s, at least 900 mPa*s, at least 1100 mPa*s, or at least 1250 mPa*s. Low viscosity alginates may have a viscosity below 500 mPa*s. For example, low viscosity alginates may have a viscosity of at most 500 mPa*s, at most 400 mPa*s, at most 300 mPa*s, at most 200 mPa*s, at most 100 mPa*s, at most 50 mPa^s, or at most 30 mPa*s. The alginates may be modified with propylene glycol or other compounds or polymers.Whipping Time

[0308] The present disclosure provides a variety of different whipping times (Wts) in the processing of the liquid compositions described herein. Wt may be at least 2.5 min, at least 5 min, at least 7.5 min, at least 10 min, at least 12.5 min, at least 15 min, at least 17.5 min, at least 20 min, at least 22.5 min, at least 25 min, or at least 30 min. pH

[0309] The present disclosure provides different pHs of liquid compositions for whipping. For example, the pH may be at least 4, at least 8, at least 10, or at least 11, or at most 11, at most 9, at most 8, or at most 5.SF Molecular Weight

[0310] In some aspects, low molecular weight silk fibroin may have a molecular weight between 10 kDa and 100 kDa, including, but not limited to, at least 10 kDa, at least 30 kDa, at least 50 kDa, or at least 70 kDa, and at most 80 kDa, at most 60 kDa, at most 40 kDa, or at most 20 kDa.

[0311] In other aspects, high molecular weight silk fibroin may have a molecular weight between 100 kDa and 200 kDa, including, but not limited to, at least 110 kDa, at least 130 kDa, at least 150 kDa, or at least 170 kDa, and at most 180 kDa, at most 160 kDa, at most 140 kDa, or at most 120 kDa.Blended Polysaccharides

[0312] In some aspects, a blend of alginate and xanthan gum can be used as the polysaccharide. The alginate can be between 10% and 90% of the blend of alginate and xanthan gum, including, but not limited to, at least 10%, at least 30%, at least 50%, or at least 70%, and at most 80%, at most 60%, at most 40%, or at most 20%. The xanthan gum can be between 10% and 90% of the blend of alginate and xanthan gum, including, but not limited to, at least 10%, at least 30%, at least 50%, or at least 70%, and at most 80%, at most 60%, at most 40%, or at most 20%.

[0313] In other aspects, a blend of alginate and locust bean gum can be used as the polysaccharide. The alginate can be between 10% and 90% of the blend of alginate and xanthan gum, including, but not limited to, at least 10%, at least 30%, at least 50%, or at least 70%, and at most 80%, at most 60%, at most 40%, or at most 20%. The locust bean gum can be between 10% and 90% of the blend of alginate and xanthan gum, including, but not limited to, at least 10%, at least 30%, at least 50%, or at least 70%, and at most 80%, at most 60%, at most 40%, or at most 20%.

[0314] It should be appreciated that there are a host of end uses for the materials described herein. Examples include, but are not limited to, bio-responsive seating, body monitors, leather bracelets as health indicators, enzymatic bracelets, scented bracelets, sensing sofas, fluorescent foams, microelectronic heat dissipators, fuel cell electrode matrices, food flavoring, water purifiers, pool purifiers, ocean oil capture, an ultralight insulator alternative (e.g., alternative to goose down), a leather- like impact monitor, gas sensing personal protective equipment (PPE), and the like.EXAMPLES

[0315] Example 1. 4mL of silk solution (boiled 30-180 minutes) at a concentration of 3-7% was mixed with lOOmg of xanthan gum and whipped with a whisk for about ten minutes to obtain a silk cream that can be cooked at 600C overnight to obtain a foam. The foam has an irregular porosity, is brittle, has excellent buoyancy, low hydrophilicity and high affinity for organic solvents. The foams can be useful for several applications such as thermal insulators, substrates for gas sensing and biological scaffolds. As proof of the concept, a sponge was used to remove an organic phase (hexane) colored with a dye (oil red O) from a stirred aqueous phase. The sponge was tested as a substrate for gas sensing. In 1 mL chloroform, 2mg of the pH sensor of bromothymol blue and triethanolamine were dissolved in different ratios to make a sensor for CO2. The sponges were dried and placed in a desiccator filled with gaseous CO2. After a short time (e.g., minutes), a color change was appreciated on the sponges whose speed depends on the quantity of triethanolamine (TEA). The reversible CO2 sensing reaction is depicted in Fig. 1C. Furthermore, the sensor is also reversible since, exposed to air, it partially returns to its original color. Different porosity in the SF:XG foam could modulate the sensitivity / responsiveness. Further, the amount of TEA may affect both the speed of color change and its partial recovery.

[0316] Example 2. Artificial Leathers: By adding glycerol to the composition and following the same process (e.g., a process as detailed in Example 1), the foam obtained after cooking results in a soft material. By hot pressing the foam (0.5-3 Mpa at 1500C for 30 minutes), a material whose properties are reminiscent of mycelium is obtained, therefore, this material is referred to as "mysilkium". Under these conditions, the foam also exhibits self-healing capabilities since sheets can be made from isolated foam fragments. The foam was subjected to mechanical tests comparing its properties to those of the mycelium. In some examples, polyphenols were added to the composition, but these do not cause significant changes in mechanical properties using these conditions. Young's modulus and tensile strength of the mycelium are at least an order of magnitude higher than those of the Mysilkium, while the elongation is roughly the same (Fig. 2).

[0317] To increase the mechanical properties of the mysilkium, a composite material was made by making "layered cakes" by adding a fabric between two layers of cream before cooking it. Thecomposite foam was then pressed and heated as described previously. With this strategy, materials have been created that aesthetically and to the touch recall the mycelium or artificial skin, but whose mechanical properties are similar to the added fabric / tissue (Fig. 3).

[0318] Example 3. Additional Characterization

[0319] Cream and meringue densities: In 35mL of bidistilled water, 3 mL of glycerol (gly), 1 gram of xanthan gum (XG) and 250mg, 1.25g, 2.5g and 3.75 of silk fibroin (SF) powder (220 minute boiled) were added. Controls were also prepared with only XG (1g) and gly (3mL), and only SF (1g) and gly (3mL). All the samples were whipped for 12 minutes to obtain the “cream”. The cream was used to fill 7.5mL petri dishes and, after weighting the density of the cream was measured (Fig. 4).

[0320] Control with XG alone does not whip to cream but forms a sticky slime. Whip only SF and Gly forms a not very consistent cream with a density between 0.1-0.15 g / cm3. The addition of XG increases the density of the creams obtained to around 0.3g / cm3. Variations in the density of the creams could be more influenced by the amount of water used for whipping or by the whipping time.

[0321] The creams were subsequently baked at 60° C overnight and the weight was measured again. This allowed to estimate the water content of the different creams assuming that the glycerol (boiling point 290°C) is not lost during the baking process while all the water in the cream is removed.

[0322] The silk cream has the highest water content (73%) while the addition of XG reduces the water content (46-58%) (Fig. 5). This is likely due to a higher porosity obtained with XG. By increasing the amount of silk compared to XG, the water content of the cream slightly increases.

[0323] In general, after cooking overnight the cream to meringue, density is reduced by a factor of 10. The density of meringues made of SF is very low (below 0.02g / cm3). With the combinations of SF and XG the density of the meringues increases around 0.05g / cm3for meringues with solid silk contents lower than 34% and reaches 0.06g / cm3for meringue with solid SF contents of 44% (see Fig. 7). Fig. 7 shows the solid compositions of the meringues obtained by varying the mass of SF and assuming a total removal of water from the cooking process. From all compositions except the XG control, a cream has been obtained that can be cooked in meringue, and then processed using a hot press (150°C for 30minutes) at “mysilkium”

[0324] As the SF content increases, the meringues become gradually stiffer and the same goes for the mysilkium obtained. The tactile perception of the material is comparable to an artificial leather. From a qualitative point of view, the mysilkium obtained with the composition SF21 : Gly63: XG17 had the best tactile properties in terms of softness, flexibility, elasticity and homogeneity. Samples with SF 34% and higher content tend to deform over time after being pressed to mysilkium, while with SF <34% content, they remain flat indefinitely.

[0325] Example 4: Alternatives to silk or xanthan gum

[0326] The ingredients used to prepare the foams were changed while maintaining a solid ratio of protein20:glycerol60:gum20. Silk Alternatives: Compositions were mixed, baked, and pressed following the same aforementioned process. A “mysilkium” with gelatin, soy protein, casein as protein alternatives and pluronics and PEG (65kDa) as synthetic alternative was obtained. Gelatin failed to form a cream. Soy protein formed a very liquid film that displayed high water content and stickiness after the hot-pressing process. Casein was the only protein alternative able to form a material similar to mysilkium although the homogeneity, softness and aesthetics were much lower compared to silk. PEG failed to form a cream. With pluronics (65KDa), a “mysilkium” was formed, but still with homogeneity, softness and aesthetics greatly inferior to those obtained with silk. Pluronic was chosen as an alternative because, like SF, is a polymer organized in an alternation of hydrophobic and hydrophilic domains.

[0327] Gum alternatives: Xanthan gum was substituted with pine rosin gum, Arabic gum and tragacanth gum. None of these where suitable to obtain a cream or meringue with similar properties to mysilkium. Guar gum may be used as an alternative to xanthan gum, though it showed inferior performance for the specific applications that were pursued in this disclosure (e.g., to obtain a silk cream that is compressible into other interesting material formats, like silk leather) when compared to xanthan gum.

[0328] Example 5. Properties related to composition: The density, water content and syneresis of the whipped creams using different compositions with tunability on some parameters has been characterized. Fig. 8 provides data regarding various compositions and the varying weight ratio of SF, Gly, and XG in each composition. Fig. 9a depicts the cream density for the compositions identified in Fig. 8 in g / cm3. Fig. 9b depicts the cream water content for the compositions identified in Fig. 8. Fig. 10a depicts the syneresis (%) for the compositions identified in Fig. 8 and Fig. 10b depicts the correlation of density, water content, and syneresis with the solid content. It is possible to tune the density (important for thermal and mechanical properties, water content (very narrow range, but important for cell cultures) and syneresis which affect cream stability overtime.

[0329] Different combinations of SF, XG, and Gly yield varying densities, water contents, and syneresis, indicating that the components have distinct effects on the overall properties of the mixture.

[0330] The Pearson correlation coefficient for each component and each variable was calculated, revealing that the content of XG (r=0.82) is the component most closely related to the increase in density that can range between 0.09-0.28 g / cm3. The water content exhibits low variability (88.5% < x < 91%) with changes in composition, and SF (r=0.40) is correlated with the water content.

[0331] Syneresis refers to the spontaneous expulsion of water from a colloidal system, resulting in the contraction or shrinkage of the material. As shown in Fig. 10a, the water loss for every compositionis minimal, being less than 3% for each combination. This low syneresis ensures stability and consistency, making this material particularly interesting for the food or pharmaceutical industries.

[0332] Lastly, Gly is the component most strongly correlated with syneresis. While high syneresis negatively impacts foam stability, creams with low glycerol content might initially appear more desirable. However, it's important to note that glycerol content is important for the mechanical performance of the dried foams, as disclosed herein.

[0333] Example 6: Cream firmness (20:60:20): The mechanical properties of the cream (compression) were measured as a function of whipping time. Figs. I la and l ib depicts an increase of firmness as the air content increases.

[0334] Example 7: Overrun and Baked Cream characterization: The composition 20:20:60 (SF:XG:Gly) exhibited the lowest density, so a detailed analysis of the whipping time was conducted. The properties were investigated by whipping at 200 rpm using a 6-wire whip over a duration ranging from 0 to 25 minutes. In Fig. 11A, the density variation of the cream is illustrated as a function of whipping time. The density fluctuation is a result of the varying amount of air incorporated into the foam during the whipping phase.

[0335] Additionally, the mechanical properties of the cream and their variation with whipping time through resistance toward compression (firmness) (Fig. 13) was measured. The findings indicate an increase in firmness as the density decreases or as the air content increases. The firmness of a cream, often indicative of its texture or consistency, holds significance not only in food applications but also in various industries. This quality is particularly relevant in sectors such as cosmetics and personal care products, pharmaceuticals, textile and fabric treatments, as well as art and craft supplies. With firmness controlled through whipping time, the silk cream exhibits a range of values spanning between 94 and 211 Pa, making it an appealing substrate for applications in cosmetics, pharmaceuticals, food, textiles, and fabrics. Given the mechanical properties of this silk foam, incorporating the silk cream into 3D printer materials was evaluated. The application of customized 3D food printing, for example, has gained attention in the culinary world for crafting intricate food designs and decorations. To indirectly gauge the air content of the cream, the overrun was evaluated, representing the increase in volume when air is incorporated during whipping. For the 20:20:60 composition, the volume increases up to 133% in 5 minutes (resulting in lower density) and then starts decreasing after 10 minutes due to excessive whipping. Similar to common whipped cream, over-whipping can lead to the separation of fat from the liquid, resulting in butter and buttermilk instead of whipped cream. This implies a parallel role played by silk in this process.

[0336] An additional method for controlling the cream's density / overrun involves using plasticizers other than glycerol. Overrun was measured using plasticizers with varying numbers or distances of -OH groups. The results show that the number of -OH groups affect the whipping time, while their distance influences the air capacity of the foam (Figure 12). This phenomenon occurs because a hydrogen bonding network is formed between the protein and sugars during the whipping process, and plasticizers aid in bridging these interactions. As a result, a higher number of -OH functionalities (such as glycerol and 1-3-6 hexanetriol) lead to faster interactions, reaching the overrun plateau in just a few minutes. On the other hand, diols (1,2 and 1,5 pentanediol) exhibit slower cream growth (15-20 minutes) with a significantly higher overrun when the -OH groups are at a greater distance (150% vs. 500%).

[0337] Example 8: Foams FTIR characterization: Unwhipped foams display a considerable amount of random coils, but after few minutes of whipping (e.g., 2.5 min), silk turns to [3-sheet structure with no further variation for longer whipping times, as seen in Fig. 14. This is attributable to silk’s shear thinning behavior.

[0338] Example 9: Foams optical characterization: The average bubble size decreases in the initial phase (5-10 min) corresponding to the highest overrun value, and then increases again and remains relatively stable during prolonged whipping (20-25min), as depicted in Fig. 15.

[0339] Example 10: Foam physical characterization: Composition related analyses: Tests were conducted on the physical and mechanical properties of the foams (baked creams, Figure 16 A) obtained with different composition ratios. The density decreased by a factor of 10 compared to its wet state (Figure 16B). Regarding the mechanical properties, the foam's compressive strength and yield point (Figure 16C, D) were assessed and found to be primarily influenced by the glycerol content.

[0340] In general, foams obtained with SF, XG, and glycerol are very soft and deformable, especially the 20:20:60 composition, making it ideal for a compressed material (the silk-leather). However, it may be less suitable for using the foam in its expanded state, as silk and xanthan gum foam tend to self-collapse within a few days.

[0341] To enhance the mechanical properties of the dried foam for potential applications in their expanded state, alternative sugars may be considered. For instance, using alginate instead of xanthan gum significantly increases the mechanical performance of both dried foams (Figure 17A) and creams (Figure 17B). There may be additional applications of alginate-based foams in their expanded state, such as thermal insulation. In Figure 17C, a setup for measuring the thermal conductivity of foam materials is presented. Briefly, two thermocouples are placed — one in contact with a hot plate with a surface temperature of 60°C and the other at a 2cm height with either the 20:20:60 silk-alginate foam or polystyrene in between — and the temperature is recorded in a time-resolved experiment. As shown in Figure 17D, the silk-alginate foam displays a very similar trend to polystyrene, which is known tohave a thermal conductivity between 0.034 and 0.038 W / mK. Additives such as borate ions may further increase mechanical properties while providing flame retardant and anti-fungal properties.

[0342] Example 11 : Whipping time related analysis: The creams with various compositions, including the 20:20:60 composition obtained at different whipping times, were subsequently baked at 60°C overnight and further characterized in their dried state. As depicted in Figure 18A, the dried foams exhibit varying whiteness depending on the whipping time. This difference is likely attributed to the distribution of bubble sizes or the open / closed cell morphology, which may vary based on the whipping time (see Figure 19). The density, once again, is one-tenth of the density in the wet state and can be adjusted by the whipping time, ranging from 0.009 to 0.048 g / cm3(Figure 18B). This value is notably low compared to other protein-based foams.

[0343] In Figure 19A, schematics and pictures illustrating the surface detail are presented, showing the proposed change in the internal architecture of the foam at different whipping times. As previously mentioned, the whiteness and the reflective and scattering properties of the foams change with whipping time. This aspect may be significant for leather applications as it may influence the tactile sensation of the compressed material.

[0344] In Figure 19B, the foam's internal structure was analyzed using fluorescent staining. It can be observed that the bubble size is polydisperse, but the average diameter ranges between millimeters and micrometers depending on the whipping duration, with variations in the internal structure corresponding to the overrun trend (the overrun value remains stable between 5 and 10 minutes, and so does the foam's internal structure). The smallest bubbles (around 100 pm) are obtained with a 7.5- minute whipping, and the cell structure transitions from a closed cell structure at 2.5 minutes to an open cell structure after 5 minutes of whipping.

[0345] Example 12: Foams fluorescent staining (ThT): To better understand the internal foam structure, a fluorescent dye (ThT) was added (100 mM) during the whipping phase and the dried foams were analyzed in reflection with BF and FITC filter (Fig. 20). ThT was chosen because is a staining agent for P-amyloids and shows different spectral features if it is free in solution or bound to a 0-sheet structure when excited at 365 nm (Fig. 21 A and 2 IB).

[0346] The emission of foams excited at 365nm display a color shift during the initial whipping phases (Fig. 22). This is probably due to a different binding of the dye to the increasing 0-sheet content in silk (due to its shear thinning behavior) and this is in accordance with the FTIR of baked foams.

[0347] Example 13: Algal growth: Foam materials in their wet state (cream) may be used as a substrate for algal growth as shown in figure 23. Two algal strains from fresh water (chlorella) (figure 23A) and marine (coccolithophores) (figure 23B) environments were used to inoculate the cream. The creams were stored in a greenhouse at 90% of relative humidity and sunlight illumination for 9 daysvisibly observing cellular growth for both cases. Global photosynthesis consumes ten times more CO2 than net anthropogenic emissions, and microalgae account for nearly half of this consumption. The high efficiency of algal photosynthesis relies on a mechanism concentrating CO2, which enhances its fixation at a rate of 10-50 times higher than terrestrial plants. This high rate allows algae to convert up to 2.7 tons of CO2 per acre per day, making them a good candidate for use in agriculture as a carbonnegative process that can also produce products. However, despite the potential benefits, the annual production of commercialized microalgal biomass (13,600 1) is low compared to worldwide CO2 emissions(~40 Gt year-1).Therefore, new technologies need to be developed to increase productivity and make it economically viable. It has been reported that carbon dioxide fixation by microalgae might become economically viable when production costs fall below $500 t-1ha-1year-1. A key factor in achieving this is improving the photosynthetic conversion efficiency, which is currently between 1.5% and 6%. Increasing this efficiency would allow for higher productivity and lower costs.

[0348] Microalgae have a wide range of diversity, and developing a substance to enhance their growth could help with the development of new technologies for different purposes such as direct carbon capture, hydrogen production, biofuels, food for humans or livestock, and biodegradation / bioremediation, each requiring a specific algal strain. For instance, coccolithophores are an interesting option for carbon capture applications. Coccolithophores are single-celled algae that have calcareous plates called coccoliths. These plates are formed through a biomineralization process where CO2 is trapped as calcium carbonate, providing a permanent sink for carbon emissions. This makes them important in the marine carbon cycle and helps to mitigate the effects of greenhouse gas emissions. Other algae species fix CO2 into organic polymers that are converted back into CO2 in a short period, but coccolithophores provide a long-term solution for carbon storage. In order to improve the algal economy and overcome current technological limitations, a foam substrate for algal culturing may be used. This substrate has several advantages that can enhance algal growth (Fig 23C). The structural material of the foam can be consumed by the algae, providing them with nutrients and other biomolecules. The porous structure of the foam can also help to distribute light and gas more uniformly, which are currently limiting factors in algal culturing techniques. Additionally, the photosynthesis process can be enhanced by adding artificial antennas (fluorophores) to the foam structure, which fill the chlorophyll's orange gap and increase the available solar spectrum. This approach could also allow for out-of-water cultivation, as it only requires a humid environment or a greenhouse, potentially expanding the possibilities for a broader bio-based economy.

[0349] Example 14: Multivalent ions

[0350] In an example, Fig. 24 shows the effects of incorporating CaCh during whipping in different ratios: Fig. 24a) 1:200, Fig. 24b) 1 :80, Fig. 24c) 1 :20, and Fig. 24d) 1 :16. Incorporating the CaCbreduced clot formation and revealed a concentration dependent overrun decrease. The amount of CaCh also influenced the material’s aesthetics, namely color and feeling to the touch, and mechanical properties. Alginate-based leathers were prepared with varying CaCh concentrations of 20 mg, 50 mg, 200 mg, and 250 mg, corresponding to 0.18, 0.45, 1.8, and 2.25 mmol Ca2+, respectively, per 4 g of alginate (equivalent to 1.2 mmol of polymer). Higher CaCh concentrations resulted in a more viscous and difficult-to-whip cream, leading to reduced spreadability in containers and increased resistance to compression. As shown in Figure 24, the final leathers exhibited increased thickness despite being produced from foams of the same initial volume.

[0351] The amount of swelling in water is also dependent on amount of CaCh in the silk foams, as shown in Fig. 25 a (before) and Fig.25b (after 20 minutes of immersion). Increasing amounts of CaCh increases water absorption with the swelling persisting after drying. Increasing amounts of CaCh also reduces foam dissolution in water and induces yellowing of the foams. The CaCh foams also formed alginate films on the bottom of the silk foams after swelling. Although the mechanical performance of both the creams and foams improved due to the crosslinking effect of Ca2+, water stability decreased with increasing Ca2+content. Figure 25a and Fig. 25b illustrate the accelerated swelling behavior at higher Ca2+concentrations, where the material absorbed more water and expanded significantly. Fig. 25d depicts after drying, and Fig. 25e depicts mass loss after drying. After drying (Figure 25d), all samples became increasingly brittle, particularly at the surface, and a noticeable yellowing effect correlated with Ca2+content was observed. Interestingly, mass loss after water immersion decreased from 20% for 20 mg of CaCh to only 5% for 250 mg, suggesting that Ca2+effectively retained alginate within the composition and prevented its leaching upon immersion. However, the materials also exhibited increased swelling behavior, functioning more like a hydrogel sponge. This process compromised the internal bubble architecture responsible for mechanical properties and whiteness, leading to irreversible structural alterations upon drying, as seen in Figure 25d.

[0352] Other multivalent ions were also incorporated into the silk foams. Fig. 26 shows foams formulated with Ca(OH)2, CaCO3, CuCh, and ZnCh. Fig. 27 shows photographs of the effects of immersion on silk foams formulated with ZnCh, CuCh, and CaCO3 and Fig. 28 quantifies the mass loss of various multivalent ion foams after immersion. CaCh decreases mass loss after water immersion. CuCh has similar effects on mass loss but alters the color of the foam, as seen in Fig. 27. Increasing the amount of chloride seems to decrease the amount of mass loss with water immersion.

[0353] Inclusion of multivalent ions also affects flexibility of the foams dried after water immersion. Figure 29 depicts the flexibility of foams with multivalent ions. All multivalent ion foams displayed flexibility with CaCh being superior. CaCCh silk foam with 200 mg to 300 mg of salt incorporatedalso showed good flexibility. Overall, a silk leather with 30% silk fibroin, 30% alginate, 40% glycerol, and 250 mg of CaCO showed promise.

[0354] Example 15: Mass Loss

[0355] Different formulations of silk foams and leathers were explored to reduce mass loss after water immersion. The data, seen in Fig. 30, reveals that reduction in glycerol reduces mass loss after water immersion. An increase in alginate also reduces mass loss, but higher amounts of alginate caused a worse appearance and worse flexibility. Adding a textile layer to the silk foam or leather did not affect mass loss.

[0356] Example 16: Shellac

[0357] Shellac, a natural resin secreted by Kerria lacca, is commonly processed into flakes or dissolved in alcohol to form liquid shellac. Composed of esters, fatty acids, and waxes, it is known for its thermoplasticity, water resistance, and non-toxicity. Two approaches were tested to integrate shellac into the foams: dry mixing the powder with other components during the whipping process and emulsifying it in ethanol (EtOH) at 20% w / v before adding it to the mixture. The dry mixing method aimed to leverage shellac’s thermoplastic properties, assuming that heat pressing would enhance water resistance, while the emulsion method sought to improve its integration within the foam matrix.

[0358] In the dry mixing approach, the resulting foams and leathers resembled those made with pure alginate in terms of homogeneity and color (Fig. 31 A). The emulsification approach, when tested in a low-alginate formulation, led to complete foam collapse during baking, whereas maintaining an alginate content of approximately 20% produced a stable foam that could be pressed into a leather-like material (Fig. 31C).

[0359] Water immersion testing showed that shellac-containing formulations exhibited reduced swelling compared to pure alginate-based materials and remained partially intact and flexible after drying (Fig. 31B, Fig. 31D). However, yellowing persisted after the wetting-drying process. Attempts to apply shellac as a posttreatment coating by dipping compressed leathers into EtOH-shellac solutions at concentrations between 25 and 200 mg / mL resulted in increased swelling, pronounced yellowing, and surface cracking after immersion and drying (Fig. 32A, Fig. 32B, Fig. 33A, Fig. 33B, Fig. 33C). While integrating shellac in bulk improved water resistance, further optimizations are needed to prevent color alteration and surface degradation.

[0360] Example 17: Latex

[0361] Latex is a stable emulsion of polymer microparticles in water, primarily composed of cis- 1,4-polyisoprene, proteins, lipids, and organic compounds. Due to its natural origin, high elasticity, flexibility, and water-resistant properties, latex was tested as an additive in some formulations. An initial attempt involved completely replacing alginate with latex (Figure 34). Although a cream wassuccessfully formed through the whipping process, baking resulted in severe material shrinkage. Subsequent formulations using various alginate-to-latex ratios were evaluated, and a 1 : 1 alg / latex ratio was found to produce more stable foams. However, as shown in Fig. 36A (foams) and Fig. 36B (leathers), the appearance and homogeneity of both foams and leathers deteriorated with latex incorporation. The materials exhibited increased yellowing, presence of clots, and rubbery texture.

[0362] These formulations were further tested for water immersion resistance. Fig. 36B (top: preimmersion samples; bottom: post-drying samples) demonstrates that none of the tested formulations showed significant improvements in water resistance. However, Fig. 37A summarizes the decrease in mass loss with increasing latex. UV-Vis of the samples, shown in Fig. 37B, reveals yellowing of the latex silk leather samples. Flexibility of the latex silk leathers was best in the sample on the far left of Fig. 37C. Overall, the silk leather comprising 17% silk fibroin, 17% alginate, 13% latex, and 52% glycerol showed promise.

[0363] Example 18: CaCb Additives

[0364] Calcium ions (Ca2+) are known to stabilize protein structures, particularly extracellular proteins, and are also strong crosslinkers for biopolymers such as alginate, xanthan gum, and carrageenan, forming hydrogels with tunable mechanical properties. To investigate their effect, CaCb was introduced into the formulation at a concentration of 500 mg per 4 g of SF, 4 g of XG, and 12 g of glycerol.

[0365] Fig. 37 presents a comparison of overrun and density measurements for XG-based creams and foams with and without CaCE. As shown in Fig. 37B, the overrun remained largely unaffected by the addition of Ca2+, and no significant differences were observed in cream or foam densities (Fig. 37D). However, as illustrated in Fig. 37A and 37C, the foams containing CaCE exhibited greater structural integrity after baking, with reduced tendency to collapse at both low and high whipping times. This suggests that, while Ca2+does not impact the foaming process directly (in XG-based compositions), it plays a role in improving foam stability post-baking.

[0366] The incorporation of CaCE into alginate-based formulations resulted in significant changes in material properties. This effect is attributed to the well-documented ability of alginate to form strong crosslinks with Ca2+ions through the formation of egg-box junctions within polyglucuronate blocks. According to literature, complete saturation of alginate polymers with Ca2+occurs at a molar ratio of 1:2.

[0367] Example 18: Xanthan Gum / Alginate and Alginate / LBG Combinations

[0368] Previous analyses demonstrated that bulk mechanical properties of foams can be significantly altered by varying the polysaccharide component. To further investigate this effect, foams wereproduced using different Alg:XG mass ratios while maintaining the overall 20:20:60 composition. The tested ratios included 100 / 0, 75 / 25, 50 / 50, 25 / 75, and 0 / 100 (Alg / XG).

[0369] Fig. 38 presents the relationship between cream density and whipping time for each composition. The pure alginate and pure xanthan formulations define the upper and lower density boundaries, while intermediate combinations exhibit densities falling between those of the pure components. The highlighted region in the graph corresponds to foams that did not undergo severe collapse during baking. Table 1 illustrates the minimum cream density achieved for each composition, along with its corresponding whipping time. The data indicate a progressive decrease in density as the xanthan gum content increases, suggesting an improved ability to incorporate air into the structure when xanthan is present in higher proportions.Table 1: Minimum Cream Density at 540 rpm

[0370] Fig. 39A-E presents detailed density values, representative photographs, and highlighted whipping time (Wt) regions where foams remained structurally stable after baking in petri dishes. It is important to note that the instability of the cream during baking occurs precisely when its density begins to increase again due to overwhipping, a trend observed across all tested compositions. Moreover, the data indicate that even the addition of small amounts of xanthan gum (XG) significantly improves foam stability, preventing collapse and cracking that were observed in pure alginate-based foams at low Wt. This suggests that xanthan gum enhances structural integrity during the drying process, likely by modulating the foam’s ability to retain its internal air structure.

[0371] Figure 40 presents the appearance of foams produced with different Alg:XG ratios (Fig. 40A) and their surface characteristics after heat pressing (Fig. 40B). All foams were obtained by baking creams whipped for 5 minutes. Intermediate compositions (70:30, 60:40, 50:50, 30:70) exhibited slight collapsing during baking, with thicker samples (5 cm) showing a higher tendency for deformation compared to thinner (2.5 cm) ones.

[0372] Fig. 40B highlights the differences between the top surface, which was exposed to air during baking, and the bottom surface, which was in contact with the tray. The air-exposed surface generally appears shinier, whereas compositions containing higher XG content exhibit a slight surface shrinkage upon drying, resulting in a corrugated texture resembling natural skin (e.g., 90:10 composition).

[0373] Fig. 41 illustrates the impact of overwhipping on foam integrity during baking. Overwhipped foams exhibit a higher tendency to collapse, leading to inconsistencies in structural integrity. While collapsed foams can still undergo heat pressing, they often result in aesthetic defects, including localized browning (Fig. 41A, Fig. 41B).

[0374] The propensity for collapse is not solely dependent on foam density. For example, an overwhipped alginate foam (9 min) with a density of 0.14 g / cm3and a 50:50 Alg:XG foam (2 min) with a similar density of 0.12 g / cm3displayed different outcomes after pressing, with only the former exhibiting noticeable defects (*the 50:50 Alg:XG sample appears cracked due to insufficient drying before baking).

[0375] Observations indicate that each composition has a specific whipping time window where the cream retains its internal structure throughout baking. As previously shown in Figure 39, this optimal window generally corresponds to the final phase of decreasing density during whipping and ends when density begins to increase.

[0376] Additional experiments were conducted on the Alg:XG 80 / 20 composition, focusing on the morphological analysis of leathers and the compressive behavior of foams at different whipping times with higher resolution (0.5 min), as shown in Figure 42. As previously indicated in Figure 39, the 75 / 25 composition remained structurally stable during baking within a Wt window between 3 and 6 minutes. Therefore, creams were whipped with a 6-wired whisk at 440 rpm for durations ranging from 1 to 6 minutes.

[0377] Fig. 42A presents the surface texture of the compressed foams, highlighting a reduction in roughness occurring at a faster rate. Surface defects are attributed to the compressive test rather than inherent material flaws. This suggests that leathers containing XG are generally softer and more susceptible to surface scratches. Fig. 42B provides a higher-magnification view of the same surfaces, confirming a reduction in average bubble size during the initial 4 minutes of whipping, followed by a consistent internal structure at longer Wt.

[0378] Fig. 42C displays photographs of the baked foams before (top) and after compression (bottom). Compared to locust bean gum foams, the 80 / 20 foam exhibited a greater tendency to selfbend and curl post-compression. This suggests the presence of internal forces specific to XG- containing compositions, likely contributing to the corrugated, skin-like texture observed in Figure 40.

[0379] Fig. 42D illustrates the compressive behavior at various Wt, indicating the highest resistance to compression at 3.5 minutes of whipping. When compared to the compressive behavior of pure Alg and pure XG foams (Fig. 42E), the 80 / 20 composition closely follows the mechanical response of pure Alg.

[0380] A composition incorporating Alg:LBG in a 50 / 50 mass ratio, while maintaining the overall formulation at 20:20:60, was tested, with the results presented in Figure 43. Fig. 43A illustrates the changes in cream density at different Wt for Alg, XG, LBG, and Alg / LBG. As demonstrated in Figure 38, pure Alg and XG yield creams with the highest and lowest densities, respectively, and combining these two components results in density values falling between these extremes. Similarly, Alg / LBG exhibited intermediate density values compared to pure Alg or pure LBG.

[0381] In previous analyses, LBG foams demonstrated significant resistance to collapsing after baking. However, as shown in Fig. 43C, Alg / LBG foams exhibited collapse at Wt > 7 min. It is noteworthy that at 7 min, the Alg / LBG composition begins to increase in density, whereas pure LBG continues to display a slow but steady decrease. Across multiple experiments conducted in this study, compositions exhibiting a sharp increase in density at a specific Wt have consistently shown a tendency to collapse during baking.

[0382] Fig. 43B presents the surface morphology of leathers derived from the Alg / LBG composition. Samples displaying a smoother appearance were obtained at Wt values between 6 and 7 min. This Wt range also correlates with the highest resistance to compression among the tested conditions, as depicted in Fig. 43D. Fig. 23E provides a detailed view of the stress-displacement behavior across different Wt values, revealing variations in the linear and plateau regions (as described in the overview section). At the lowest density, the linear region is extended, indicating a more elastic response.

[0383] Finally, Fig. 43F compares the stress -displacement profiles for XG, Alg, LBG, and Alg / LBG foams at their respective minimum density points. The mechanical performance of Alg / LBG closely resembles that of pure Alg, similar to the behavior observed in the Alg:XG 80 / 20 composition (Fig. 42E). This suggests that even with a 50% Alg content, the resulting mechanical properties remain predominantly influenced by Alg, aligning with those of the pure Alg formulation.

[0384] Example 19: Alginate Screening

[0385] Further studies were conducted on different types of alginates selected from commercial products supplied by KIMICA®. The alginate candidates for this study included IL-2 and LZ-2, representing standard low- and high- viscosity alginates, respectively, as well as LVC and HVC, which are low and high-viscosity propylene glycol-modified alginates. The primary characteristics of these four polysaccharides, as reported by the manufacturer, are summarized in Table 2.Table 2: Alginates Tested

[0386] The densities of the creams and foams obtained from these alternative alginates were measured and compared to the commonly used alginate (Alg) and xanthan gum (XG) from Sigma Aldrich, as shown in Fig. 44A and Fig. 44B. XG consistently produced the lowest densities across all relevant whipping times, while IL-2, a standard low-viscosity alginate, exhibited significantly lower densities compared to the other alginate types, both in cream and foam formulations. These findings suggest that the selection of alginate type plays a role in determining the final material properties, with lower- viscosity alginates promoting the formation of lighter foams.

[0387] Figure 45 presents top and side views of foams produced using different alginate types at various whipping times (Wt) using IL-2 (Fig. 45 A), LZ-2 (Fig. 45B), LVC (Fig. 45C), and HVC (Fig. 45D). High- viscosity alginates (LZ-2 and HVC) exhibited greater structural stability, showing reduced collapse after baking, particularly at higher Wt.

[0388] Fig. 46 presents photographs of foams produced from different alginates at varying Wt before and after compression testing for IL-2 (Fig. 46A), LZ-2 (Fig. 46B), LVC (Fig. 46C), and HVC (Fig. 46D). The IL-2 composition (standard alginate, low viscosity) primarily exhibited plastic deformation, remaining flat post-compression, similar to pure XG but without the curling effect. In contrast, all other compositions demonstrated more pronounced elastic behavior, expanding after the applied pressure was released. It is important to note that the pressure used in this experiment (250 kPa) is significantly lower than the typical pressure range (1-10 MPa) applied to produce leather- like materials, where elastic recovery and foam expansion are less prominent.

[0389] Fig. 47 presents bright-field reflection images of compressed foams obtained from different alginate types at varying whipping times (Wt) for IL-2 (Fig. 47 A), LZ-2 (Fig. 47B), LVC (Fig. 47C), and HVC (Fig. 47D). The results are consistent with previous imaging analyses of other compositions (see Figures 42 and 43), showing a gradual reduction in average bubble size during the initial minutesof whipping. For standard alginates, bubble sizes ranged between 100-500 pm, whereas for propylene glycol-modified alginates, they ranged from 100-250 pm. IL-2 exhibited larger average bubble sizes compared to LZ-2, which may correlate with its increased tendency to collapse after baking. Minimal differences were observed between LVC and HVC, both of which exhibited similar characteristics to LZ-2.

[0390] Figure 48 presents the stress-strain compression profiles of foams obtained from different alginate types at various Wt. The highest resistance to compression was observed at 5 minutes of Wt for standard alginates and at 8 minutes for propylene glycol-modified alginates (Fig. 48A-D). Fig. 48E compares the compression curves of each alginate composition at the Wt corresponding to their peak resistance. Extracted numerical values from these profiles are summarized in Table 3, including toughness — calculated as the area under the curve representing the total compressive energy applied to each foam — and the maximum strain at 250 kPa of applied pressure. IL-2 exhibited the highest strain, compressing up to 96% of its original thickness, while LZ-2 displayed the lowest strain at 86.5%. Additionally, IL-2 demonstrated the lowest toughness among the samples, whereas the remaining three alginate-based foams exhibited comparable values. Despite differences in viscosity, both PG-modified alginates showed nearly identical stress-strain profiles.Table 3: Toughness and Max Strain Extracted from Fig. 48E

[0391] Example 20: Influence of Whipping Time

[0392] Although variations in cream properties were observed across different compositions, most physical characteristics, including density, were primarily influenced by processing conditions, with whipping time playing a key role.

[0393] To further investigate this effect, a specific composition (SF2o:XG2o:Glyeo) was selected for analysis, and its density, overrun, and firmness were measured at different whipping times.

[0394] Overrun and firmness are commonly used parameters in food product characterization. Overrun was determined using the following formula:(weight of unwhipped cream - weight of whipped cream)Overrun (%) = - - - - — - - - - x 100 weight of whipped cream

[0395] Firmness was evaluated by compressing the cream using a cylindrical pressing plate with a 50 mm diameter, attached to a universal testing machine. The compression was performed at a rate of 10 mm / min, and firmness was determined by measuring the pressure at the plateau phase.

[0396] Fig. 49 A illustrates the transformation of the cream during the whipping process. Initially, the heterogeneous suspension incorporates air, leading to an increase in volume. This process is often accompanied by a change in whiteness, as the average bubble size decreases, enhancing light scattering within the material. However, excessive whipping causes the structure to collapse, reducing the volume and leading to densification, as shown in the density and overrun graphs in Fig. 49B and Fig. 49C, respectively.

[0397] This general behavior has been observed across various combinations of silk, polysaccharides, and plasticizers, found able to successfully form a cream. Modifying the components or their mass ratio affects the timing of expansion and collapse, the duration of each phase, and the minimum / maximum density values achieved.

[0398] Finally, Fig. 49D presents a comparison between cream density and firmness at different whipping times. The two curves appear almost inverse, with the highest resistance to compression coinciding with the lowest density. This suggests that the mechanical properties of the material are more closely related to the internal bubble architecture rather than the chemical composition of the cream.

[0399] The physical properties of the foams as a function of whipping time (Wt) were also evaluated for the 20:20:60 composition, with the general results presented in Figure 50.

[0400] Foams baked after different whipping durations exhibited varying structural resistance to the baking process (Fig. 50A). When the cream reached its minimum density during whipping, its structural features were generally well-preserved, resulting in a soft and homogeneous foam similar to the original cream. Conversely, at very short or excessively long whipping times, the foams tended to collapse at the center during baking, appearing more rigid and yellowish.

[0401] Fig. 50B presents the densities of the foams at different Wt, showing strong consistency with the corresponding cream densities in Fig. 40B. As highlighted in the graph, for the SF2o:XG2o:Glyeo foams, a Wt of 5 minutes at 440 rpm using a six-wire whisk resulted in the lowest foam density of 0.009 g / cm3. For the same composition, this whipping time also yielded the highest compressive strength (Fig. 50C) and yield point (Fig. 50D), emphasizing the correlation between mechanical properties and whipping time.

[0402] Fig. 51 provides a schematic representation of the key components involved in the processing and highlights the variables identified as critical for influencing the final material properties. These variables were systematically analyzed.

[0403] For whipping, the starting materials in powder format (usually 4 g of SF and 4 g of XG) are typically mixed in 200 mL of water containing 10 mL of glycerol. The heterogeneous solution is then whipped until a cream is formed. Various trials with different whipping setups and speeds have been conducted, with results presented in Fig. 52.

[0404] In most experiments, the heterogeneous suspension is mixed using a stand mixer (Ailessom model 6-QT) equipped with a 6-wired whisk. This mixer operates with both rotational and revolutionary movements (Fig. 52A). The model offers 10 power levels, corresponding to the speeds reported in Table 4. Overrun and whipping time results for SF2o:XG2o:Gly6o foams whipped at 340 or 440 rpm are shown in Fig. 52C. The trend observed is consistent with Fig. 49C, where overrun initially increases within the first few minutes and starts declining after 10 minutes of whipping.Table 4: Mixer speeds

[0405] At higher speeds the process is accelerated. At 440 rpm, the overrun peak is reached around 7 minutes, followed by a decline after 9 minutes. At 340 rpm, the peak occurs at 10 minutes, declining after 12 minutes. At the maximum speed of the stand mixer (540 rpm), the peak is reached after just 5 minutes, with a decline occurring after 7 minutes.

[0406] To achieve even higher whipping speeds, an axial stirrer (Fig. 52D) was tested at 440 and 1000 rpm using a 6-wired whisk. The changes in overrun at 440 rpm were similar to those observedwith the stand mixer (Fig. 52E). However, at 1000 rpm, the data was unreliable due to the absence of revolutionary motion, causing steady accumulation of cream on the sides of the bowl (Fig. 52F left).

[0407] For large-scale production, a whipping system that ensures uniform mixing throughout the entire volume — such as those found in commercial stand mixers (Fig. 52F right) — is recommended to achieve consistent results.

[0408] In this process, the SF component can be whipped starting from either a powder or a solution. The differences in the resulting creams and foams obtained via these two methods were systematically evaluated. Fig. 53 A and Fig. 53B display images of the cream at various whipping times for a SF2o:XG2o:Glyeo composition, prepared with SF from powder and solution, respectively. Fig.53C reports the overrun values for the two alternatives, showing that using an SF solution results in a faster process — both in the rising and collapsing phases — with a higher maximum overrun (280%) compared to the powder format ( 132%). This behavior is likely due to the slower release of silk from the powder, which delays each step of the process.

[0409] Fig. 53D and Fig. 53E compare the density values of creams and foams obtained from SF in powder versus solution at different whipping times. For the creams, the density range over 15 minutes of whipping was 0.11 -0.64 g / cm3for the powder and 0.13-0.40 g / cm3for the solution. After baking, the foams exhibited density ranges of 0.010 0.059 g / cm3for the powder and 0.016 0.041 g / cm3for the solution. These trends are similar, with the notable difference that materials produced from the solution displayed slightly higher densities at equivalent whipping times, likely due to more efficient component interactions during mixing.

[0410] The water content of the creams was similar in both cases, as indicated by a ten-fold difference between the cream density and the final product, suggesting an approximate water content of 90% for all specimens.

[0411] Mechanical properties, specifically firmness, were also measured and are presented in Fig. 53F, Fig. 53G, and Fig. 53H. Fig. 53F and Fig. 53G show the force profiles recorded during compression of the creams using a compression plate, for samples prepared from powder and solution, respectively. The bar chart in Fig. 53H compares firmness between the two processes across different whipping times. The firmness trends for both the powder and solution approaches are very similar and consistent with the data presented in Fig. 49C, with the highest firmness observed after 5 minutes of whipping (199 N / m2for powder and 211 N / m2for solution).

[0412] In conclusion, aside from a slight delay in the whipping time when using the powder format, no significant differences in material properties were observed between whipping SF from powder versus solution.

[0413] Beyond the composition of the leather-like material, whipping time (Wt) was also found to be a critical factor influencing water stability. Figure 54 illustrates alginate-based foams (a) and their corresponding compressed leathers (b) obtained with whipping times ranging from 4 to 7 minutes.

[0414] As shown in Fig. 54A, the foam whipped for 7 minutes exhibited partial collapse during baking. Following 10 minutes of water immersion, all samples swelled to a similar extent (Fig. 54B, Fig. 54C).

[0415] However, after drying, the leather produced from the 7-minute whipping time displayed the most severe structural damage (Fig. 54E). This degradation is likely associated with alterations in the internal bubble architecture caused by both excessive whipping and water exposure. Despite the significant differences in material integrity after drying, no substantial variations in mass loss were observed among the samples, as shown in Fig. 54F. Across all whipping times, the mass loss remained approximately 20%, indicating that while overwhipping may weaken the material’s structural stability, it does not necessarily increase the dissolution of components upon water exposure.

[0416] Example 21 : pH

[0417] The transition from a solution to a cream likely involves electrostatic interactions between SF and the polysaccharide. Given the nature of these materials, hydrogen bonding is the most probable and strongest interaction between these two components, owing to their high number of hydroxyl functionalities. Fig. 55A and 55B illustrate the appearance of creams produced from a SF2o:XG2o:Gly6o composition whipped in water and glycerol with the pH adjusted to 4 and 10 by adding HC1 or NaOH, respectively.

[0418] Lowering the pH results in a cream that appears clumsier, while increasing the pH makes the cream more liquid. This can be explained by the fact that a low pH keeps the hydroxyl groups of the biopolymers protonated, thereby enhancing hydrogen bonding, whereas a basic pH may deprotonate these groups, weakening the overall internal structure. In both cases, drying the creams under these conditions proved detrimental to the baking process, as both samples collapsed at the center during baking. Notably, the cream whipped at pH 4 exhibited brittleness, rendering it unsuitable for the subsequent pressing process.

[0419] An additional experiment was conducted at pH values of 8, 10, and 11 using the same composition. The firmness of the resulting creams was measured and is presented in Fig. 55C, which shows a progressive decrease in resistance to compression with increasing pH — from 350 N / m2at pH 8 to 80 N / m2at pH 11.

[0420] Across these experiments, alginate-based foams and creams generally demonstrated stronger mechanical performance and a higher tendency toward clumsiness compared to those prepared with xanthan gum. This behavior may be partially attributed to the intrinsic acidity of alginate polymers,which possess a significantly higher number of carboxyl groups compared to xanthan gum. Consequently, the acidic nature of the polysaccharide should be taken into account when evaluating these systems.

[0421] Example 22: High Alginate

[0422] Since alginate appears to be a primary contributor to the material’s interaction with water, composition variants with high silk fibroin (SF) or high alginate content were tested. Two formulations were prepared: one with a SF32.5:Alg7.5:Gly6o ratio (high SF content) and another with a SF7.5:Alg32.5:Gly60 ratio (high alginate content). The resulting foams and compressed leathers are shown in Figure 56.

[0423] Increasing the alginate content resulted in severe foam collapse after baking, as observed in Fig. 56A. In contrast, the high SF formulation (Fig. 56B) exhibited improved homogeneity, enhanced whiteness — indicative of a more uniform bubble distribution — and greater structural stability during baking. The corresponding compressed materials (Fig. 56C and Fig. 56D) appeared visually similar. However, the high-alginate composition demonstrated increased sturdiness and robustness, while the high-SF variant was smoother and softer, making it more susceptible to tearing or surface damage. Both formulations were subjected to water immersion testing, and their results were compared to the standard 20:20:60 alginate-based composition. The comparative data are presented in Figure 57.

[0424] Adjusting the SF / alginate ratio resulted in notable differences in the swelling behavior of the corresponding compressed materials. This effect is illustrated in Fig. 57A (right), which presents the side view of samples after 10 minutes of water immersion. The high-SF formulation exhibited reduced swelling compared to both the control and high-alginate samples. The high-alginate composition displayed visible defects, including delamination and the formation of internal voids.

[0425] Fig. 57B presents images of the dried samples along with the measured mass loss following immersion. Increasing the alginate content resulted in greater material degradation when exposed to water, affecting whiteness, structural integrity, and post-drying flexibility. The highest mass loss was recorded for the high-SF composition, whereas the high-alginate variant exhibited the lowest mass loss. However, despite the reduced mass loss, the overall material integrity and appearance were superior for the high-SF formulation.

[0426] It is important to note that, as shown in Fig. 57, the high-alginate leather tested was obtained from a foam that had undergone severe collapse during baking (Fig. 57A). Consequently, the observed results may be influenced by the differences in internal foam architecture rather than purely by compositional variations.

[0427] Example 23 : Silk Fibroin Molecular Weight

[0428] The protein constituent of the material, silk fibroin (SF), can be obtained with varying average molecular weights depending on the processing method. In most experiments, a low MW SF has been used for the production of creams and foams. However, some experiments have also been conducted using a high MW SF for both XG and Alg foams, as detailed in this example.

[0429] Fig. 58A and Fig. 58B compare the overruns and densities of XG foams produced with either low MW or high MW SF. While no significant differences were observed in the maximum overrun or cream density values, notable changes in the process were evident. The low MW SF exhibited a slower rising phase and a longer steady state, whereas the high MW creams began to increase in density after 5 minutes of whipping. In contrast, the low MW creams maintained more constant density values throughout the process.

[0430] Fig. 58C and Fig. 58D collapse during baking. However, the creams prepared with high MW SF resulted in foams that were somewhat clumsier and exhibited a less homogeneous appearance after baking. This is further illustrated in the foam squares in Fig. 58E and the cross-sectional images in Fig. 58F, which indicate that the low MW foam possessed better overall homogeneity.

[0431] In summary, while both molecular weights can yield similar maximum overrun and density values, the low MW SF appears to provide a more consistent and homogenous cream and foam structure under the conditions studied.

[0432] The same analysis was conducted on alginate-based foams. Fig. 59A presents the overrun values of alginate foams prepared using either low MW or high MW SF at total solid concentrations of 5% or 10%. The results indicate that low MW SF led to creams that retained air more effectively, maintaining a stable overrun for up to 9 minutes, whereas high MW SF-based creams began collapsing after 6 minutes. No significant differences were observed between 5% and 10% solid concentrations.

[0433] Fig. 59B displays the densities of the creams, where formulations containing high MW SF exhibited higher densities, likely due to increased water retention, as indicated by the generally lower overrun throughout the process.

[0434] Fig. 59C and Fig. 59D show images of baked foams prepared with high MW SF, while Fig. 59E and Fig. 59F show foams obtained using low MW SF. Unlike the trend observed in XG-based foams, higher molecular weight SF (high MW) resulted in greater structural collapse during baking. However, in both cases, foams exhibited a decreasing degree of collapse with increased whipping time, with the low MW SF samples showing greater structural stability.

[0435] Although additional mechanical testing of the compressed materials would be necessary to determine any specific advantages of using high MW SF, the results presented here suggest that low MW SF provides better control over the whipping process and is therefore recommended for achieving more stable foams.

[0436] Example 24: Xanthan Gum vs Alginate Foams

[0437] The two primary polysaccharides used in the preparation of creams, foams, and leathers in this example are alginate (Alg) and xanthan gum (XG). Fig. 60 summarizes the key differences in the materials obtained from these polysaccharides.

[0438] Fig. 60 A compares the overrun values of the two systems, revealing a similar trend. However, XG-based creams achieved a slightly higher maximum overrun (395% after 6 minutes of whipping) compared to Alg-based creams (343% after 10 minutes), indicating a comparable ability to incorporate air but at different rates. Fig. 60B presents the cream densities, with Alg creams ranging from 0.35 to 0.14 g / cm3, whereas XG creams exhibited significantly lower densities, ranging from 0.18 to 0.07 g / cm3. Furthermore, the firmness of the creams, measured at a Wt of 5 minutes, was approximately 200 N / m2for XG and 350 N / m2for Alg.

[0439] The differences in cream densities persist after baking, as shown in Fig. 60D, suggesting that the variations arise from differences in the solid content rather than differences in water retention capacity. Regarding the mechanical properties of the dried foams, Alg-based foams generally exhibited higher resistance to compression and lower strain at a given applied pressure compared to XG foams (Fig. 60E and Fig. 60F). Specifically, the compressive strength and yield strength of XG foams were found to be 0.001 MPa and 0.13 MPa, respectively, whereas Alg foams exhibited higher values of 0.003 MPa and 0.37 MPa. These findings indicate that Alg-based foams form denser, more rigid materials, whereas XG-based foams are softer and more easily compressible into 2D materials.

[0440] This difference in mechanical behavior is further illustrated in Fig. 60F, which presents the stress-strain curves of the two foams at a Wt of 5 minutes. For an applied pressure of 140 kPa, XG foams reached a strain of 90%, whereas Alg foams reached 80%, confirming that XG foams are more deformable under compression. Fig. 60G and Fig. 60H display the full set of compression profiles for both compositions at different Wt. Notably, in both cases, the optimal mechanical performance (i.e., the highest resistance to compression) was achieved at a Wt corresponding to the point where the cream density stabilizes (Fig. 60B).

[0441] Typically, the compression behavior of these types of foams follows a three-stage process: (1) an initial linear-elastic region at low strains, (2) a plateau region where deformation occurs at an almost constant stress, and (3) a densification region where the cell walls collapse. The extent of each region depends on the relative density (p / ps). While elastic, plastic, and brittle foams all exhibit three-stage stress-strain curves, the underlying mechanisms governing the plateau region differ depending on the material structure and composition.

[0442] When foams are subjected to hot pressing within a metal frame, a leather- like material can be obtained. The mold consists of a metal base with four screws, a square frame, a metal cube that fitswithin the frame, and a top plate equipped with threading to apply pressure through the tightening of nuts.

[0443] In the standard procedure, the foam is enclosed within the mold, placed between two sheets of parchment paper to prevent adhesion to the metal. The mold is then tightly closed to achieve a pressure of approximately 1-2 MPa and heated in an oven set to 150°C for 30 minutes. After this process, a two-dimensional leather-like material can be retrieved from the mold.

[0444] Fig. 61 A and Fig. 61 B display the Young’s modulus and elongation at break, respectively, for various compositions of silk fibroin (SF), xanthan gum (XG), and glycerol (Gly). Observing the ultimate tensile strength (UTS) in Fig. 61C, it becomes evident that these materials exhibit low mechanical strength, with UTS values in the kPa range. Even when switching between different compositions, such as alginate- or XG-based formulations, the mechanical performance remains insufficient for leather-related applications.

[0445] Due to these limitations, the final product is envisioned as a composite material, where a textile layer is embedded between two foam layers to provide the necessary tensile strength. In this configuration, the foam functions primarily as a coating for the textile, requiring compatibility in flexibility and elongation with the fabric, robust adhesion to the substrate, and resistance to surface damage such as scratches. Fig. 61D shows examples of final materials obtained through this process.

[0446] Example 25: Surface Treatments

[0447] An objective of these treatments was to improve water resistance. Ketene dimers are reactive organic compounds formed by the dimerization of ketenes (R2C=C=O). They are widely used in industrial applications, particularly in paper sizing, where they react with cellulose hydroxyl groups to enhance hydrophobicity. Their water-repellent properties were tested here to assess their effect on the leather material. Ketene dimers may be alkyl ketene dimers (AKDs) with varying carbon chain lengths — stearyl (Cl 8), palmityl (Cl 6), behenyl (C22), or blended versions of these.

[0448] Glutaraldehyde, a well-known crosslinking agent, is commonly used in gelatin, collagen, and alginate-based biomaterials. It is also employed in leather tanning as an alternative to chromium-based tanning, improving the flexibility and durability of treated materials.

[0449] Each treatment was applied by brushing a 10% solution onto the leather surface, followed by drying at room temperature. The effectiveness of these coatings was qualitatively assessed by placing droplets of a food dye-stained water solution on the treated surfaces to visualize wettability.

[0450] Among the tested coatings, the ketene dimer treatment demonstrated the most effective water repellency, as shown in Fig. 62. In contrast, the glutaraldehyde-treated sample did not exhibit significant improvements in water resistance under the tested conditions. The latex -based treatmentformed a rubbery layer on the surface, significantly altering both the appearance and tactile properties of the material.

[0451] In addition to the features described above and elsewhere herein, the present disclosure also includes the following clauses:

[0452] Clause 1. A liquid composition comprising a mixture of silk fibroin, a blend of an alginate and xanthan gum, and a plasticizer, wherein the liquid composition optionally has a water content of between 89% and 99%.

[0453] Clause 2. A whipped silk cream comprising silk fibroin, a blend of an alginate and xanthan gum, and a plasticizer, wherein the whipped silk cream optionally has a water content of between 50% and 95%.

[0454] Clause 3. A silk meringue comprising silk fibroin, a blend of an alginate and xanthan gum, and a plasticizer, wherein the silk meringue optionally has a water content of between 5% and 70%.

[0455] Clause 4. A compressed silk meringue comprising silk fibroin, a blend of an alginate and xanthan gum, and a plasticizer, wherein the compressed silk meringue optionally has a water content of between 2% and 50%.

[0456] Clause 5. A hot-pressed silk meringue comprising silk fibroin, a blend of an alginate and xanthan gum, and a plasticizer, wherein the hot-pressed silk meringue optionally has a water content of between 2% and 50%.

[0457] Clause 6. A method of making a composition, the method comprising whipping a liquid composition comprising a mixture of silk fibroin, a blend of an alginate and xanthan gum, and a plasticizer for a predetermined whipping time to form a whipped silk cream, wherein optionally: i) the silk fibroin and the blend of alginate and xanthan gum are whipped together before addition of the plasticizer; ii) the silk fibroin and the plasticizer are whipped together before addition of the blend of alginate and xanthan gum; or iii) the blend of alginate and xanthan gum and the plasticizer are whipped together before addition of the silk fibroin.

[0458] Clause 7. A liquid composition comprising a mixture of silk fibroin, a blend of an alginate and locust bean gum (LBG), and a plasticizer, wherein the liquid composition optionally has a water content of between 89% and 99%.

[0459] Clause 8. A whipped silk cream comprising silk fibroin, a blend of an alginate and locust bean gum (LBG), and a plasticizer, wherein the whipped silk cream optionally has a water content of between 50% and 95%.

[0460] Clause 9. A silk meringue comprising silk fibroin, a blend of an alginate and locust bean gum (LBG), and a plasticizer, wherein the silk meringue optionally has a water content of between 5% and 70%.

[0461] Clause 10. A compressed silk meringue comprising silk fibroin, a blend of an alginate and locust bean gum (LBG), and a plasticizer, wherein the compressed silk meringue optionally has a water content of between 2% and 50%.

[0462] Clause 11. A hot-pressed silk meringue comprising silk fibroin, a blend of an alginate and locust bean gum (LBG), and a plasticizer, wherein the hot-pressed silk meringue optionally has a water content of between 2% and 50%.

[0463] Clause 12. A method of making a composition, the method comprising whipping a liquid composition comprising a mixture of silk fibroin, a blend of an alginate and locust bean gum (LBG), and a plasticizer for a predetermined whipping time to form a whipped silk cream, wherein optionally: i) the silk fibroin and the blend of alginate and locust bean gum are whipped together before addition of the plasticizer; ii) the silk fibroin and the plasticizer are whipped together before addition of the blend of alginate and locust bean gum; or iii) the blend of alginate and locust bean gum and the plasticizer are whipped together before addition of the silk fibroin.

[0464] Clause 13. A liquid composition comprising a mixture of low molecular weight silk fibroin, a polysaccharide, and a plasticizer, wherein the liquid composition optionally has a water content of between 89% and 99%.

[0465] Clause 14. A whipped silk cream comprising low molecular weight (MW) silk fibroin (SF), a polysaccharide, and a plasticizer, wherein the whipped silk cream optionally has a water content of between 50% and 95%.

[0466] Clause 15. A silk meringue comprising low molecular weight silk fibroin, a polysaccharide, and a plasticizer, wherein the silk meringue optionally has a water content of between 5% and 70%.

[0467] Clause 16. A compressed silk meringue comprising low molecular weight silk fibroin, a polysaccharide, and a plasticizer, wherein the compressed silk meringue optionally has a water content of between 2% and 50%.

[0468] Clause 17. A hot-pressed silk meringue comprising low molecular weight silk fibroin, a polysaccharide, and a plasticizer, wherein the hot-pressed silk meringue optionally has a water content of between 2% and 50%.

[0469] Clause 18. A method of making a composition, the method comprising whipping a liquid composition comprising a mixture of low molecular weight silk fibroin, a polysaccharide, and a plasticizer for a predetermined whipping time to form a whipped silk cream, wherein optionally: i) the low molecular weight silk fibroin and the polysaccharide are whipped together before addition of the plasticizer; ii) the low molecular weight silk fibroin and the plasticizer are whipped together before addition of the polysaccharide; or iii) the polysaccharide and the plasticizer are whipped together before addition of the low molecular weight silk fibroin.

[0470] Clause 19. A liquid composition comprising a mixture of high molecular weight silk fibroin, a polysaccharide, and a plasticizer, wherein the liquid composition optionally has a water content of between 89% and 99%.

[0471] Clause 20. A whipped silk cream comprising high molecular weight silk fibroin, a polysaccharide, and a plasticizer, wherein the whipped silk cream optionally has a water content of between 50% and 95%.

[0472] Clause 21. A silk meringue comprising high molecular weight silk fibroin, a polysaccharide, and a plasticizer, wherein the silk meringue optionally has a water content of between 5% and 70%.

[0473] Clause 22. A compressed silk meringue comprising high molecular weight silk fibroin, a polysaccharide, and a plasticizer, wherein the compressed silk meringue optionally has a water content of between 2% and 50%.

[0474] Clause 23. A hot-pressed silk meringue comprising high molecular weight silk fibroin, a polysaccharide, and a plasticizer, wherein the hot-pressed silk meringue optionally has a water content of between 2% and 50%.

[0475] Clause 24. A method of making a composition, the method comprising whipping a liquid composition comprising a mixture of high molecular weight silk fibroin, a polysaccharide, and a plasticizer for a predetermined whipping time to form a whipped silk cream, wherein optionally: i) the high molecular weight silk fibroin and the polysaccharide are whipped together before addition of the plasticizer; ii) the high molecular weight silk fibroin and the plasticizer are whipped together before addition of the polysaccharide; or iii) the polysaccharide and the plasticizer are whipped together before addition of the low molecular weight silk fibroin.

[0476] Clause 25. A liquid composition comprising a mixture of silk fibroin, a polysaccharide, and a plasticizer, wherein the liquid composition optionally has a water content of between 89% and 99%.

[0477] Clause 26. A whipped silk cream comprising silk fibroin, a polysaccharide, and a plasticizer, wherein the whipped silk cream optionally has a water content of between 50% and 95%.

[0478] Clause 27. A silk meringue comprising silk fibroin, a polysaccharide, and a plasticizer, wherein the silk meringue optionally has a water content of between 5% and 70%.

[0479] Clause 28. A compressed silk meringue comprising silk fibroin, a polysaccharide, and a plasticizer, wherein the compressed silk meringue optionally has a water content of between 2% and 50%.

[0480] Clause 29. A hot-pressed silk meringue comprising silk fibroin, a polysaccharide, and a plasticizer, wherein the hot-pressed silk meringue optionally has a water content of between 2% and 50%.

[0481] Clause 30. A method of making a composition, the method comprising whipping a liquid composition comprising a mixture of silk fibroin, a polysaccharide, and a plasticizer for a predetermined whipping time to form a whipped silk cream, wherein optionally: i) the silk fibroin and the polysaccharide are whipped together before addition of the plasticizer; ii) the silk fibroin and the plasticizer are whipped together before addition of the polysaccharide; or iii) the polysaccharide and the plasticizer are whipped together before addition of the silk fibroin.

[0482] Clause 31. The method of the immediately preceding clause, the method further comprising baking the whipped silk cream at a temperature of between 30 °C and 150 °C or between 50 °C and 80 °C for a length of time of between 2 hours and 24 hours to form a silk meringue.

[0483] Clause 32. The method of the immediately preceding clause, the method further comprising compressing the silk meringue with a force of between 0.25 MPa and 25 MPa for a length of time of between 15 minutes and 6 hours to form a compressed silk meringue.

[0484] Clause 33. The method of the immediately preceding clause, wherein the compressing is performed at an elevated temperature of between 80 °C and 200 °C and the compressed silk meringue is a hot-pressed silk meringue.

[0485] Clause 34. The method of any one of clauses 30 to the immediately preceding clause, wherein the predetermined whipping time is between 5 minutes and 30 minutes, including but not limited to, at least 5 minutes, at least 6 minutes, at least 7 minutes, at least 8 minutes, at least 9 minutes, or at least 10 minutes and at most 30 minutes, at most 25 minutes, at most 20 minutes, at most 15 minutes, or at most 10 minutes.

[0486] Clause 35. The method of any one of clauses 30 to the immediately preceding clause, wherein the whipping is performed with a whisk.

[0487] Clause 36. The method of any one of clauses 30 to the immediately preceding clause, wherein the whipping is performed manually.

[0488] Clause 37. The method of any one of clauses 30 to the claim immediately preceding the immediately preceding clause, wherein the whipping is performed by a machine, including but not limited to, a stand mixer.

[0489] Clause 38. The method of any one of clauses 35 to the immediately preceding clause, wherein the whisk is a metal whisk.

[0490] Clause 39. The method of any one of clauses 35 to the claim immediately preceding the immediately preceding clause, wherein the whisk is a non-metal whisk.

[0491] Clause 40. The method of any one of clauses 30 to the immediately preceding clause, wherein the whipping is performed in a mixing bowl.

[0492] Clause 41. The method of the immediately preceding clause, wherein the mixing bowl is a metal mixing bowl, optionally a stainless steel mixing bowl.

[0493] Clause 42. The method of clause 30, the method further comprising baking the whipped silk cream to form a silk meringue.

[0494] Clause 43. The method of the immediately preceding clause, wherein the baking is performed at a temperature of between 25 °C and 1 0 °C for a length of time of between 5 minutes and 24 hours.

[0495] Clause 44. The method of any one of either of the two immediately preceding clauses, the method comprising compressing the silk meringue to form a compressed silk meringue.

[0496] Clause 45. The method of the immediately preceding clause, wherein compressing involves applying a force of between 0.25 MPa and 25 MPa for a length of time of between 5 minutes and 6 hours.

[0497] Clause 46. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of any one of the preceding clauses, wherein the silk fibroin is present in an amount by weight of between 3% and 72% or between 10% and 70% of the total weight of the silk fibroin, the polysaccharide, and the plasticizer.

[0498] Clause 47. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of clause 46, wherein the silk fibroin is present in an amount by weight of between 15% and 25% of the total weight of the silk fibroin, the polysaccharide, and the plasticizer.

[0499] Clause 48. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of any one of the preceding clauses, wherein the polysaccharide is present in an amount by weight of between 3% and 72% of the total weight of the silk fibroin, the polysaccharide, and the plasticizer.

[0500] Clause 49. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of clause 48, wherein the polysaccharide is present in an amount by weight of between 10% and 32% of the total weight of the silk fibroin, the polysaccharide, and the plasticizer, wherein the polysaccharide is optionally an alginate.

[0501] Clause 50. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of clause 48, wherein the polysaccharide is present in an amount by weight of between 15% and 25% of the total weight of the silk fibroin, the polysaccharide, and the plasticizer.

[0502] Clause 51. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of any one of the preceding clauses, wherein theplasticizer is present in an amount by weight of between 5% and 80% of the total weight of the silk fibroin, the polysaccharide, and the plasticizer.

[0503] Clause 52. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of clause 51, wherein the plasticizer is present in an amount by weight of between 50% and 70% of the total weight of the silk fibroin, the polysaccharide, and the plasticizer.

[0504] Clause 53. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of any one of the preceding clauses, wherein the silk fibroin is present in an amount by weight of between 15% and 25% of the total weight of the silk fibroin, the polysaccharide, and the plasticizer, wherein the polysaccharide is present in an amount by weight of between 15% and 25% of the total weight of the silk fibroin, the polysaccharide, and the plasticizer, and wherein the plasticizer is present in an amount by weight of between 50% and 70% of the total weight of the silk fibroin, the polysaccharide, and the plasticizer.

[0505] Clause 54. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of any one of clauses 1 to 45, wherein the silk fibroin is present in an amount by weight of between 15% and 25% of the total weight of the silk fibroin and the plasticizer.

[0506] Clause 55. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of any one of clauses 1 to 45, wherein the plasticizer is present in an amount by weight of between 75% and 85% of the total weight of the silk fibroin and the plasticizer.

[0507] Clause 56. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of any one of clauses 1 to 45, wherein the silk fibroin is present in an amount by weight of between 15% and 25% of the total weight of the silk fibroin and the plasticizer, and wherein the plasticizer is present in an amount by weight of between 75% and 85% of the total weight of the silk fibroin and the plasticizer.

[0508] Clause 57. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of any one of clauses 1 to 45, wherein the silk fibroin is present in an amount by weight of between 45% and 85% of the total weight of the silk fibroin and the polysaccharide.

[0509] Clause 58. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of clause 57, wherein the silk fibroin is present in an amount by weight of between 45% and 55% of the total weight of the silk fibroin and the polysaccharide.

[0510] Clause 59. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of clause 57, wherein the silk fibroin is present in an amount by weight of between 55% and 65% of the total weight of the silk fibroin and the polysaccharide.

[0511] Clause 60. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of clause 57, wherein the silk fibroin is present in an amount by weight of between 65% and 75% of the total weight of the silk fibroin and the polysaccharide.

[0512] Clause 61. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of clause 57, wherein the silk fibroin is present in an amount by weight of between 75% and 85% of the total weight of the silk fibroin and the polysaccharide.

[0513] Clause 62. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of any one of clauses 1 to 45, wherein the polysaccharide is present in an amount by weight of between 15% and 55% of the total weight of the silk fibroin and the polysaccharide.

[0514] Clause 63. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of clause 62, wherein the polysaccharide is present in an amount by weight of between 45% and 55% of the total weight of the silk fibroin and the polysaccharide.

[0515] Clause 64. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of clause 62, wherein the polysaccharide is present in an amount by weight of between 35% and 45% of the total weight of the silk fibroin and the polysaccharide.

[0516] Clause 65. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of clause 62, wherein the polysaccharide is present in an amount by weight of between 25% and 35% of the total weight of the silk fibroin and the polysaccharide.

[0517] Clause 66. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of clause 62, wherein the polysaccharide is present in an amount by weight of between 15% and 25% of the total weight of the silk fibroin and the polysaccharide.

[0518] Clause 67. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of any one of clauses 1 to 45, wherein the silkfibroin is present in an amount by weight of between 45% and 85% of the total weight of the silk fibroin and the polysaccharide, and wherein the polysaccharide is present in an amount by weight of between 15% and 55% of the total weight of the silk fibroin and the polysaccharide.

[0519] Clause 68. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of any one of the preceding clauses, wherein the silk fibroin and polysaccharide are present in a weight ratio of between 1:4 and 20:1 or between 1 :2 and 10:1, including but not limited to, at least 1:4, at least 1:3, or at least 1:2, and at most 20: 1, at most 19:1, at most 18:1, at most 16:1, at most 15:1, at most 14:1, at most 12:1, at most 11 :1, or at most 10:1.

[0520] Clause 69. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of any one of the preceding clauses, wherein the silk fibroin is low molecular weight silk fibroin.

[0521] Clause 70. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of any one of the preceding clauses, wherein the polysaccharide is a polysaccharide having a molecular weight of at least 10 kDa, at least 20 kDa, at least 30 kDa, at least 40 kDa, or at least 50 kDa.

[0522] Clause 71. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of any one of the preceding clauses, wherein the polysaccharide is a thickening agent.

[0523] Clause 72. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of any one of clauses 1 to 71, wherein the polysaccharide is xanthan gum.

[0524] Clause 73. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of any one of clauses 1 to 71, wherein the polysaccharide is an alginate.

[0525] Clause 74. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of the immediately preceding clause, wherein the alginate is sodium alginate.

[0526] Clause 75. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of any one of clauses 1 to 71, wherein the polysaccharide is carrageenan.

[0527] Clause 76. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of any one of clauses 1 to 71, wherein the polysaccharide is a cellulose derivative (e.g., microcrystalline cellulose, hydroxypropyl cellulose, carboxymethyl cellulose).

[0528] Clause 77. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of the immediately preceding clause, wherein the polysaccharide is carboxymethyl cellulose.

[0529] Clause 78. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of any one of the preceding clauses, wherein the plasticizer is selected from the group consisting of hydrophobic fatty acid compounds, oils, polyols, esters, phthalates, terephthalates, trimellitates, adipates, sebacates, organophosphates, ethanolamines, glycerols, waxes, resins, and combinations thereof.

[0530] Clause 79. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of any one of the preceding clauses, wherein the plasticizer comprises at least one -OH substituent.

[0531] Clause 80. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of the immediately preceding clause, wherein the plasticizer comprises at least two -OH substituents, at least 3 -OH substituents, or more -OH substituents.

[0532] Clause 81. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of the immediately preceding clause, wherein the at least two -OH substituents, the at least 3 -OH substituents, or the more -OH substituents are separated from one another on the plasticizer by at least 2 carbon atoms, at least 3 carbon atoms, or at least 4 carbon atoms.

[0533] Clause 82. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of any one of clauses 1 to 81, wherein the plasticizer is glycerol.

[0534] Clause 83. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of any one of clauses 1 to 81, wherein the plasticizer is xylitol.

[0535] Clause 84. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of any one of clauses 1 to 81, wherein the plasticizer is alditol.

[0536] Clause 85. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of any one of clauses 1 to 81, wherein the plasticizer is 1,2-pentanediol.

[0537] Clause 86. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of any one of clauses 1 to 81, wherein the plasticizer is 1,5-pentanediol.

[0538] Clause 87. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of any one of clauses 1 to 81, wherein the plasticizer is 1,2,6-hexanetriol.

[0539] Clause 88. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of any one of clauses 1 to 81, wherein the plasticizer is oleoyl-glycerol.

[0540] Clause 89. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of any one of clauses 1 to 81, wherein the plasticizer is cottonseed oil.

[0541] Clause 90. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of any one of clauses 1 to 81, wherein the plasticizer is a di(ethylene glycol).

[0542] Clause 91. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of any one of clauses 1 to 81, wherein the plasticizer is a tri (ethylene glycol).

[0543] Clause 92. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of any one of clauses 1 to 81, wherein the plasticizer is a di(propylene glycol).

[0544] Clause 93. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of any one of clauses 1 to 81, wherein the plasticizer is a tri(propylene glycol).

[0545] Clause 94. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of any one of clauses 1 to 81, wherein the plasticizer is a triethanolamine.

[0546] Clause 95. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of any one of clauses 1 to 81, wherein the plasticizer is a vegetable oil.

[0547] Clause 96. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of any one of the preceding clauses, the liquid composition, whipped silk cream, silk meringue, compressed silk meringue, or hot-pressed silk meringue further comprising multi- valent metal ions.

[0548] Clause 97. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of clause 96, wherein the multi- valent metal ions include calcium.

[0549] Clause 98. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of clause 96, wherein the multi- valent metal ions include copper.

[0550] Clause 99. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of any one of clauses 96 to the immediately preceding clause, wherein the polysaccharide is an alginate, wherein the polysaccharide is optionally sodium alginate.

[0551] Clause 100. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of the immediately preceding clause, wherein the multi- valent metal ions are present in a concentration of at least 10 mmol of the multi-valent metal ion per gram of the alginate and at most 250 mmol of the multi-valent metal ion per gram of the alginate, including but not limited to, at least 20 mmol, at least 30 mmol, at least 40 mmol, or at least 50 mmol, and at most 240 mmol, at most 225 mmol, at most 210 mmol, at most 200 mmol, at most 175 mmol, or at most 150 mmol.

[0552] Clause 101. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of any one of the preceding clauses, the liquid composition, whipped silk cream, silk meringue, compressed silk meringue, or hot-pressed silk meringue further comprising a salt.

[0553] Clause 102. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of the immediately preceding clause, wherein the salt is a chloride salt.

[0554] Clause 103. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of either of the two immediately preceding clauses, wherein the salt is present in a concentration of at least 10 mmol per gram of non- water component (e.g., all non-water ingredients - non-water component can be replaced with a dry solids basis, as would be appreciated by a skilled artisan, if other solvents are used) and at most 500 mmol per gram of non- water component, including but not limited to, at least 25 mmol, at least 50 mmol, or at least 100 mmol, and at most 450 mmol, at most 400 mmol, at most 300 mmol, or at most 250 mmol.

[0555] Clause 104. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of any one of the preceding clauses, the liquidcomposition, whipped silk cream, silk meringue, compressed silk meringue, or hot-pressed silk meringue further comprising shellac.

[0556] Clause 105. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of the immediately preceding clause, wherein the shellac is present in an amount by weight of between 0.1% and 50%.

[0557] Clause 106. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of any one of the preceding clauses, the liquid composition, whipped silk cream, silk meringue, compressed silk meringue, or hot-pressed silk meringue further comprising a natural wax.

[0558] Clause 107. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of the immediately preceding clause, wherein the natural wax is present in an amount by weight of between 0.1% and 50%.

[0559] Clause 108. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of any one of the preceding clauses, the liquid composition, whipped silk cream, silk meringue, compressed silk meringue, or hot-pressed silk meringue further comprising lycopodium powder.

[0560] Clause 109. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of the immediately preceding clause, wherein the lycopodium powder is present in an amount by weight of between 0.1% and 50%.

[0561] Clause 110. The whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or method of any one of the preceding clauses, wherein the whipped silk cream, silk meringue, compressed silk meringue, and / or hot-pressed silk meringue has irregular porosity.

[0562] Clause 111. The whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or method of any one of the preceding clauses, wherein the whipped silk cream, silk meringue, compressed silk meringue, and / or hot-pressed silk meringue further comprises a conductive additive.

[0563] Clause 112. The whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or method of any one clauses 1 to the claim immediately preceding the immediately preceding clause, wherein the whipped silk cream, silk meringue, compressed silk meringue, and / or hot-pressed silk meringue further comprises a non-conductive additive.

[0564] Clause 113. The whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or method of any one of the preceding clauses, wherein the whipped silk cream, silk meringue, compressed silk meringue, and / or hot-pressed silk meringue further comprises a thermally - conductive additive.

[0565] Clause 114. The whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or method of the immediately preceding clause, wherein the thermally-conductive additive is electrically insulating.

[0566] Clause 115. The whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or method of any one of the preceding clauses, wherein the whipped silk cream, silk meringue, compressed silk meringue, and / or hot-pressed silk meringue further comprises a magnetic additive.

[0567] Clause 116. The whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or method of any one of the preceding clauses, wherein the whipped silk cream, silk meringue, compressed silk meringue, and / or hot-pressed silk meringue further comprises a sensing agent.

[0568] Clause 117. The whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or method of the immediately preceding clause, wherein the sensing agent is a pH sensitive agent, a thermal sensitive agent, a pressure or strain sensitive agent, a light sensitive agent, or a potentiometric agent.

[0569] Clause 118. The whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or method of any one of the preceding clauses, wherein the whipped silk cream, silk meringue, compressed silk meringue, and / or hot-pressed silk meringue further comprises a functionalizing agent.

[0570] Clause 119. The whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or method of the immediately preceding clause, wherein the functionalizing agent is or comprises a cell attachment mediator and / or an extracellular matrix protein.

[0571] Clause 120. The whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or method of any one of the preceding clauses, wherein the whipped silk cream, silk meringue, compressed silk meringue, and / or hot-pressed silk meringue further comprises an active agent.

[0572] Clause 121. The whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or method of either of the two immediately preceding clauses, wherein the active agent is selected from the group consisting of anticancer agents, antibiotics, analgesics, anti-inflammatory agents, immunosuppressants, enzyme inhibitors, antihistamines, anti-convulsants, hormones, muscle relaxants, antispasmodics, ophthalmic agents, prostaglandins, anti-depressants, anti-psychotic substances, trophic factors, osteoinductive proteins, growth factors, vaccines, and combinations thereof.

[0573] Clause 122. The whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or method of the immediately preceding clause, wherein the active agent is a biologically active agent.

[0574] Clause 123. The whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or method of any one of the preceding clauses, wherein the whipped silk cream, silk meringue, compressed silk meringue, and / or hot-pressed silk meringue further comprises a therapeutic agent.

[0575] Clause 124. The whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or method of the immediately preceding clause, wherein the therapeutic agent comprises: small organic or inorganic molecules; saccharines; oligosaccharides; polysaccharides; biological macromolecules, e.g., peptides, proteins, and peptide analogs and derivatives; peptidomimetics; antibodies and antigen binding fragments thereof; nucleic acids; nucleic acid analogs and derivatives; an extract made from biological materials such as bacteria, plants, fungi, or animal cells; animal tissues; naturally occurring or synthetic compositions; and any combinations thereof.

[0576] Clause 125. The whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or method of any one of the preceding clauses, wherein the whipped silk cream, silk meringue, compressed silk meringue, and / or hot-pressed silk meringue further comprises an aromaproviding compound.

[0577] Clause 126. The whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or method of any one of the preceding clauses, wherein the whipped silk cream, silk meringue, compressed silk meringue, and / or hot-pressed silk meringue further comprises a colorant.

[0578] Clause 127. The whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or method of any one of the preceding clauses, wherein the whipped silk cream, silk meringue, compressed silk meringue, and / or hot-pressed silk meringue further comprises an electronic component and / or an electronic device.

[0579] Clause 128. The whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or method of any one of the preceding clauses, wherein the whipped silk cream, silk meringue, compressed silk meringue, and / or hot-pressed silk meringue further comprises a semiconductor component and / or a semiconductor device.

[0580] Clause 129. The whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or method of any one of the preceding clauses, wherein the whipped silk cream, silk meringue, compressed silk meringue, and / or hot-pressed silk meringue further comprises a haptic switch embedded therein.

[0581] Clause 130. The whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or method of any one of the preceding clauses, wherein the whipped silk cream, silk meringue, compressed silk meringue, and / or hot-pressed silk meringue further comprises fibers distributed throughout.

[0582] Clause 131. A silk leather that is a layered structure comprising a first fabric layer and a second material layer disposed adjacent to the first fabric layer, the second material layer comprising the compressed silk meringue or the hot-pressed silk meringue of or made by the method of any one of clauses 4, 5, 10, 11, 16, 17, 22, 23, 28, 29, and 32 to 130.

[0583] Clause 132. The silk leather of the immediately preceding clause, further comprising a third material layer disposed adjacent to the first fabric layer on a surface opposing the surface to which the second material layer is adjacent, the third material layer comprising the compressed silk meringue or the hot-pressed silk meringue of or made by the method of any one clauses 4, 5, 10, 11, 16, 17, 22, 23, 28, 29, and 32 to 130.

[0584] Clause 133. The silk leather of either of the two immediately preceding clauses, wherein the first fabric layer is composed of cotton fabric, including but not limited to, cotton jersey, cotton canvas, and the like; silk fabric; synthetic fabric, including but not limited to, polyester fabric, rayon fabric, nylon fabric, and the like; linen; organza; the like; and combinations thereof.

[0585] Clause 134. The silk leather of any one of the three immediately preceding clauses, wherein the first fabric layer is treated with tannic acid.

[0586] Clause 135. A conductive silk leather comprising a compressed silk meringue or a hot-pressed silk meringue.

[0587] Clause 136. The conductive silk leather of clause 135, wherein a plurality of graphite flakes is distributed within the compressed silk meringue or the hot-pressed silk meringue.

[0588] Clause 137. The conductive silk leather of clause 135, wherein a graphene powder is distributed within the compressed silk meringue of the hot-pressed silk meringue.

[0589] Clause 138. The conductive silk leather of clause 135, wherein a conductive ink is printed on a surface of the compressed silk meringue or the hot-pressed silk meringue.

[0590] Clause 139. The conductive silk leather of clause 135, wherein a conductive ink is printed between layers of the compressed silk meringue or the hot-pressed silk meringue or printed and subsequently embedded within the compressed silk meringue or the hot-pressed silk meringue.

[0591] Clause 140. The conductive silk leather of clause 135, wherein a conductive ink is printed between the compressed silk meringue or the hot-pressed silk meringue and the fabric layer.

[0592] Clause 141. The conductive silk leather of any one of clauses 135 to the immediately preceding clause, wherein the conductivity is patterned into an electronic circuit.

[0593] Clause 142. The conductive silk leather of any one of clauses 135 to the immediately preceding clause, wherein a resistivity of the conductive silk leather is at most 1 kQ, at most 0.7 kQ, at most 0.5 k , or at most 0.1 kQ.

[0594] Clause 143. The conductive silk leather of any one of clauses 135 to the immediately preceding clause, wherein the conductive silk leather is made from the liquid composition of any one of claims 1, 7, 13, 19, 25, and 46 to 130.

[0595] Clause 144. The conductive silk leather of any one of clauses 135 to the immediately preceding clause, wherein the conductive silk leather is made from the whipped silk cream of or made by the method of any one of claims 2, 8, 14, 20, 24, 26, and 30 to 130.

[0596] Clause 145. The conductive silk leather of any one of clauses 135 to the immediately preceding clause, wherein the conductive silk leather comprises or is made from the silk meringue of or made by the method of any one of claims 3, 9, 15, 21, 27 and 31 to 130.

[0597] Clause 146. The conductive silk leather of any one of clauses 135 to the immediately preceding clause, wherein the conductive silk leather comprises or is made from the compressed silk meringue of any one of claims 4, 10, 16, 22, 28, and 32 to 130.

[0598] Clause 147. The conductive silk leather of any one of clauses 135 to the immediately preceding clause, wherein the conductive silk leather comprises or is made from the hot-pressed silk meringue of any one of claims 5, 11, 17, 23, 29, and 33 to 130.

[0599] Clause 148. The conductive silk leather of any one of clauses 135 to the immediately preceding clause, the conductive silk leather comprising the silk leather of any one of claims 131 to 134.

[0600] Clause 149. A magnetic silk leather comprising a compressed silk meringue or a hot-pressed silk meringue.

[0601] Clause 150. The magnetic silk leather of clause 149, wherein a plurality of magnetic particles is distributed within the compressed silk meringue or the hot-pressed silk meringue.

[0602] Clause 151. The magnetic silk leather of any one of clauses 149 to the immediately preceding clause, wherein a plurality of chromium oxide particles is distributed within the compressed silk meringue or the hot-pressed silk meringue.

[0603] Clause 152. The magnetic silk leather of any one of clauses 149 to the immediately preceding clause, wherein the magnetic silk leather blocks RFID signals.

[0604] Clause 153. The magnetic silk leather of any one of clauses 149 to the immediately preceding clause, wherein the magnetic silk leather is made from the liquid composition of any one of 1, 7, 13, 19, 25, and 46 to 130.

[0605] Clause 154. The magnetic silk leather of any one of clauses 149 to the immediately preceding clause, wherein the magnetic silk leather is made from the whipped silk cream of or made by the method of any one of claims 2, 8, 14, 20, 24, 26, and 30 to 130.

[0606] Clause 155. The magnetic silk leather of any one of clauses 149 to the immediately preceding clause, wherein the magnetic silk leather comprises or is made from the silk meringue of or made by the method of any one of claims 3, 9, 15, 21, 27 and 31 to 130.

[0607] Clause 156. The magnetic silk leather of any one of clauses 149 to the immediately preceding clause, wherein the magnetic silk leather comprises or is made from the compressed silk meringue of any one of claims 4, 10, 16, 22, 28, and 32 to 130.

[0608] Clause 157. The magnetic silk leather of any one of clauses 149 to the immediately preceding clause, wherein the magnetic silk leather comprises or is made from the hot-pressed silk meringue of any one of claims 5, 11, 17, 23, 29, and 33 to 130.

[0609] Clause 158. The magnetic silk leather of any one of clauses 149 to the immediately preceding clause, the magnetic silk leather comprising the silk leather of any one of claims 131 to 134.

[0610] Clause 159. A scented silk leather comprising a compressed silk meringue or a hot-pressed silk meringue.

[0611] Clause 160. The scented silk leather of clause 159, wherein a plurality of aromatic compounds are distributed throughout the compressed silk meringue or the hot-pressed silk meringue of the scented silk leather.

[0612] Clause 161. The scented silk leather of any one of clauses 159 to the immediately preceding clause, wherein applying an additional volume of the aromatic compound to a surface of the scented silk leather at least partly recharges the scented silk leather, thereby extending the lifetime of aroma release.

[0613] Clause 162. The scented silk leather of any one of clauses 159 to the immediately preceding clause, wherein the scented silk leather is made from the liquid composition of any one of 1, 7, 13, 19, 25, and 46 to 130.

[0614] Clause 163. The scented silk leather of any one of clauses 159 to the immediately preceding clause, wherein the scented silk leather is made from the whipped silk cream of or made by the method of any one of claims 2, 8, 14, 20, 24, 26, and 30 to 130.

[0615] Clause 164. The scented silk leather of any one of clauses 159 to the immediately preceding clause, wherein the scented silk leather comprises or is made from the silk meringue of or made by the method of any one of claims 3, 9, 15, 21, 27 and 31 to 130.

[0616] Clause 165. The scented silk leather of any one of clauses 159 to the immediately preceding clause, wherein the scented silk leather comprises or is made from the compressed silk meringue of any one of claims 4, 10, 16, 22, 28, and 32 to 130.

[0617] Clause 166. The scented silk leather of any one of clauses 159 to the immediately preceding clause, wherein the scented silk leather comprises or is made from the hot-pressed silk meringue of any one of claims 5, 11, 17, 23, 29, and 33 to 130.

[0618] Clause 167. The scented silk leather of any one of clauses 159 to the immediately preceding clause, the scented silk leather comprising the silk leather of any one of claims 131 to 134.

[0619] Clause 168. A thermally-insulating silk leather having thermochromic reporting property throughout a bulk interior volume, the thermally-insulating silk leather comprising a compressed silk meringue or a hot-pressed silk meringue.

[0620] Clause 169. The thermally-insulating silk leather of clause 168, wherein the thermally- insulating silk leather is made from the liquid composition of any one of claims 1, 7, 13, 19, 25, and 46 to 130.

[0621] Clause 170. The thermally-insulating silk leather of any one of clauses 168 to the immediately preceding clause, wherein the thermally-insulating silk leather is made from the whipped silk cream of or made by the method of any one of claims 2, 8, 14, 20, 24, 26, and 30 to 130.

[0622] Clause 171. The thermally-insulating silk leather of any one of clauses 168 to the immediately preceding clause, wherein the thermally-insulating silk leather comprises or is made from the silk meringue of or made by the method of any one of claims 3, 9, 15, 21, 27 and 31 to 130.

[0623] Clause 172. The thermally-insulating silk leather of any one of clauses 168 to the immediately preceding clause, wherein the thermally-insulating silk leather comprises or is made from the compressed silk meringue of any one of claims 4, 10, 16, 22, 28, and 32 to 130.

[0624] Clause 173. The thermally-insulating silk leather of any one of clauses 168 to the immediately preceding clause, wherein the thermally-insulating silk leather comprises or is made from the hot- pressed silk meringue of any one of claims 5, 11, 17, 23, 29, and 33 to 130.

[0625] Clause 174. The thermally-insulating silk leather of any one of clauses 168 to the immediately preceding clause, the thermally-insulating silk leather comprising the silk leather of any one of claims 131 to 134.

[0626] Clause 175. A pH responsive leather comprising a compressed silk meringue or a hot-pressed silk meringue having a pH responsive chemical distributed therein.

[0627] Clause 176. The pH responsive leather of clause 175, wherein the pH responsive silk leather is made from the liquid composition of any one of claims 1, 7, 13, 19, 25, and 46 to 130.

[0628] Clause 177. The pH responsive leather of any one of clauses 175 to the immediately preceding clause, wherein the pH responsive silk leather is made from the whipped silk cream of or made by the method of any one of claims 2, 8, 14, 20, 24, 26, and 30 to 130.

[0629] Clause 178. The pH responsive leather of any one of clauses 175 to the immediately preceding clause, wherein the pH responsive silk leather comprises or is made from the silk meringue of or made by the method of any one of claims 3, 9, 15, 21, 27 and 31 to 130.

[0630] Clause 179. The pH responsive leather of any one of clauses 175 to the immediately preceding clause, wherein the compressed silk meringue comprises or is made from the compressed silk meringue of any one of claims 4, 10, 16, 22, 28, and 32 to 130.

[0631] Clause 180. The pH responsive leather of any one of clauses 175 to the immediately preceding clause, wherein the hot-pressed silk meringue comprises or is made from the hot-pressed silk meringue of any one of claims 5, 11, 17, 23, 29, and 33 to 130.

[0632] Clause 181. The pH responsive leather of any one of clauses 175 to the immediately preceding clause, the pH responsive silk leather comprising the silk leather of any one of claims 131 to 134.

[0633] Clause 182. A humidity sensing leather comprising a pH responsive chemical and a pH altering agent distributed throughout the compressed silk meringue or the hot-pressed silk meringue of the pH responsive leather, wherein measurable amounts of humidity solubilize at least a portion of the pH altering agent, thereby lowering the pH, thereby providing a measurable report of humidity.

[0634] Clause 183. The humidity sensing silk leather of clause 182, wherein the humidity sensing silk leather is made from the liquid composition of any one of claim 1, 7, 13, 19, 25, and 46 to 130.

[0635] Clause 184. The humidity sensing silk leather of any one of clauses 182 to the immediately preceding clause, wherein the humidity sensing silk leather is made from the whipped silk cream of or made by the method of any one of claim 2, 8, 14, 20, 24, 26, and 30 to 130.

[0636] Clause 185. The humidity sensing silk leather of any one of clauses 182 to the immediately preceding clause, wherein the humidity sensing silk leather comprises or is made from the silk meringue of or made by the method of any one of claim 3, 9, 15, 21, 27 and 31 to 130.

[0637] Clause 186. The humidity sensing silk leather of any one of clauses 182 to the immediately preceding clause, wherein the compressed silk meringue comprises or is made from the compressed silk meringue of any one of claim 4, 10, 16, 22, 28, and 32 to 130.

[0638] Clause 187. The humidity sensing silk leather of any one of clauses 182 to the immediately preceding clause, wherein the hot-pressed silk meringue comprises or is made from the hot-pressed silk meringue of any one of claims 5, 11, 17, 23, 29, and 33 to 130.

[0639] Clause 188. The humidity sensing silk leather of any one of clauses 182 to the immediately preceding clause, the humidity sensing silk leather comprising the silk leather of any one of claims 131 to 134.

[0640] Clause 189. A patterned silk leather.

[0641] Clause 190. The patterned silk leather of clause 189 comprising a surface pattern selected from the group consisting of: a leather mimicking pattern; a water-resistant or water-proof pattern; a tessellating pattern; an optically active pattern; and combinations thereof.

[0642] Clause 191. The patterned silk leather of any one of clauses 189 to the immediately preceding clause, wherein the patterned leather is made from the liquid composition of any one of claims 1, 7, 13, 19, 25, and 46 to 130.

[0643] Clause 192. The patterned silk leather of any one of clauses 189 to the immediately preceding clause, wherein the patterned silk leather is made from the whipped silk cream of or made by the method of any one of claims 2, 8, 14, 20, 24, 26, and 30 to 130.

[0644] Clause 193. The patterned silk leather of any one of clauses 189 to the immediately preceding clause, wherein the patterned silk leather comprises or is made from the silk meringue of or made by the method of any one of claims 3, 9, 15, 21, 27 and 31 to 130.

[0645] Clause 194. The patterned silk leather of any one of clauses 189 to the immediately preceding clause, wherein the patterned silk leather comprises or is made from the compressed silk meringue of or made by the method of any one of claims 4, 10, 16, 22, 28, and 32 to 130.

[0646] Clause 195. The patterned silk leather of any one of clauses 189 to the immediately preceding clause, wherein the patterned silk leather comprises or is made from the hot-pressed silk meringue of or made by the method of any one of claims 5, 11, 17, 23, 29, and 33 to 130.

[0647] Clause 196. The patterned silk leather of any one of clauses 189 to the immediately preceding clause, wherein the patterned silk leather comprises the silk leather of any one of claims 131 to 134.

[0648] Clause 197. An electronic leather having an electronic component embedded therein.

[0649] Clause 198. The electronic silk leather of clause 197, wherein the electronic component or a second electronic component is embedded between the silk layer and the fabric layer in the electronic silk leather.

[0650] Clause 199. The electronic silk leather of any one of clauses 197 to the immediately preceding clause, wherein the electronic component or a third electronic component is embedded within the silk layer in the electronic silk leather.

[0651] Clause 200. The electronic silk leather of any one of clauses 197 to the immediately preceding clause, wherein the electronic silk leather further comprises a power supply coupled to the electronic component.

[0652] Clause 201. The electronic silk leather of the immediately preceding clause, wherein the power supply is a rechargeable battery, a wired disposable battery holder, or a combination thereof.

[0653] Clause 202. The electronic silk leather of any one of clauses 197 to the immediately preceding clause, wherein the electronic component comprises an RFID tag.

[0654] Clause 203. The electronic silk leather of any one of clauses 197 to the immediately preceding clause, wherein the electronic component comprises wiring.

[0655] Clause 204. The electronic silk leather of any one of clauses 197 to the immediately preceding clause, wherein the electronic leather is made from the liquid composition of any one of claims 1 , 7, 13, 19, 25, and 46 to 130.

[0656] Clause 205. The electronic silk leather of any one of clauses 197 to the immediately preceding clause, wherein the electronic silk leather is made from the whipped silk cream of or made by the method of any one of claims 2, 8, 14, 20, 24, 26, and 30 to 130.

[0657] Clause 206. The electronic silk leather of any one of clauses 197 to the immediately preceding clause, wherein the electronic silk leather comprises or is made from the silk meringue of or made by the method of any one of claims 3, 9, 15, 21, 27 and 31 to 130.

[0658] Clause 207. The electronic silk leather of any one of clauses 197 to the immediately preceding clause, wherein the electronic silk leather comprises or is made from the compressed silk meringue of or made by the method of any one of claims 4, 10, 16, 22, 28, and 32 to 130.

[0659] Clause 208. The electronic silk leather of any one of clauses 197 to the immediately preceding clause, wherein the electronic silk leather comprises or is made from the hot-pressed silk meringue of or made by the method of any one of claims 5, 11, 17, 23, 29, and 33 to 130.

[0660] Clause 209. The electronic silk leather of any one of clauses 197 to the immediately preceding clause, wherein the electronic silk leather comprises the silk leather of any one of claims 131 to 134.

[0661] Clause 210. A semiconductor device-embedded silk leather having a semiconductor device embedded therein.

[0662] Clause 211. The semiconductor device-embedded silk leather of clause 210, wherein the semiconductor device or a second semiconductor device is embedded at a surface of the compressed silk meringue or the hot-pressed silk meringue.

[0663] Clause 212. The semiconductor device-embedded silk leather of any one of clauses 210 to the immediately preceding clause, wherein the semiconductor device or a third semiconductor device is embedded within the compressed silk meringue or the hot-pressed silk meringue.

[0664] Clause 213. The semiconductor device-embedded silk leather of any one of clauses 210 to the immediately preceding clause, wherein the semiconductor device or a fourth semiconductor device isembedded between the first fabric layer and the compressed silk meringue or the hot-pressed silk meringue.

[0665] Clause 214. The semiconductor device-embedded silk leather of any one of clauses 210 to the immediately preceding clause, wherein the semiconductor device-embedded silk leather is made from the liquid composition of any one of claims 1, 7, 13, 19, 25, and 46 to 130.

[0666] Clause 215. The semiconductor device-embedded silk leather of any one of clauses 210 to the immediately preceding clause, wherein the semiconductor device-embedded silk leather is made from the whipped silk cream of or made by the method of any one of claims 2, 8, 14, 20, 24, 26, and 30 to 130.

[0667] Clause 216. The semiconductor device-embedded silk leather of any one of clauses 210 to the immediately preceding clause, wherein the semiconductor device-embedded silk leather comprises or is made from the silk meringue of or made by the method of any one of claims 3, 9, 15, 21, 27 and 31 to 130.

[0668] Clause 217. The semiconductor device-embedded silk leather of any one of clauses 210 to the immediately preceding clause, wherein the semiconductor device-embedded silk leather comprises or is made from the compressed silk meringue of or made by the method of any one of claims 4, 10, 16,22, 28, and 32 to 130.

[0669] Clause 218. The semiconductor device-embedded silk leather of any one of clauses 210 to the immediately preceding clause, wherein the semiconductor device-embedded silk leather comprises or is made from the hot-pressed silk meringue of or made by the method of any one of claims 5, 11, 17,23, 29, and 33 to 130.

[0670] Clause 219. The semiconductor device-embedded silk leather of any one of clauses 210 to the immediately preceding clause, wherein the semiconductor device-embedded silk leather comprises the silk leather of any one of claims 131 to 134.

[0671] Clause 220. A haptic silk leather having a haptic switch embedded therein.

[0672] Clause 221. The haptic silk leather of clause 220, wherein the haptic switch or a second haptic switch is embedded at a surface of the silk leather.

[0673] Clause 222. The haptic silk leather of any one of clauses 220 to the immediately preceding clause, wherein the haptic switch or a third haptic switch is embedded within a compressed silk meringue or a hot-pressed silk meringue of the haptic silk leather.

[0674] Clause 223. The haptic silk leather of any one of clauses 220 to the immediately preceding clause, wherein the haptic switch or a fourth haptic switch is embedded adjacent to a first fabric layer of the haptic silk leather.

[0675] Clause 224. The haptic silk leather of any one of clauses 220 to the immediately preceding clause, wherein the haptic silk leather is made from the liquid composition of any one of claims 1, 7, 13, 19, 25, and 46 to 130.

[0676] Clause 225. The haptic silk leather of any one of clauses 220 to the immediately preceding clause, wherein the haptic silk leather is made from the whipped silk cream of or made by the method of any one of claims 2, 8, 14, 20, 24, 26, and 30 to 130.

[0677] Clause 226. The haptic silk leather of any one of clauses 220 to the immediately preceding clause, wherein the haptic silk leather comprises or is made from the silk meringue of or made by the method of any one of claims 3, 9, 15, 21, 27 and 31 to 130.

[0678] Clause 227. The haptic silk leather of any one of clauses 220 to the immediately preceding clause, wherein the haptic silk leather comprises or is made from the compressed silk meringue of or made by the method of any one of claims 4, 10, 16, 22, 28, and 32 to 130.

[0679] Clause 228. The haptic silk leather of any one of clauses 220 to the immediately preceding clause, wherein the haptic silk leather comprises the hot-pressed silk meringue of or made by the method of any one of claims 5, 11, 17, 23, 29, and 33 to 130.

[0680] Clause 229. The haptic silk leather of any one of clauses 220 to the immediately preceding clause, wherein the haptic silk leather comprises the silk leather of any one of claims 131 to 134.

[0681] Clause 230. A tanned silk leather, the tanned silk leather having a bulk volume of a compressed silk meringue or hot-compressed silk meringue and a surface layer of the compressed silk meringue or hot-pressed silk meringue, wherein the surface layer is formed from the same chemical composition as the bulk volume but includes at least one differing structural, mechanical, or chemical feature relative to the bulk volume.

[0682] Clause 231. The tanned silk leather of clause 230, wherein the surface layer includes a dye.

[0683] Clause 232. The tanned silk leather of either of the immediately preceding clauses, wherein the surface layer comprises a precursor that reacts to form the surface layer.

[0684] Clause 233. The tanned silk leather of any one of clauses 230 to the immediately preceding clause, wherein the surface layer is patterned.

[0685] Clause 234. The tanned silk leather of any one of clauses 230 to the immediately preceding clause, wherein the compressed silk meringue or the hot-pressed silk meringue is made from the liquid composition of any one of claims 1, 7, 13, 19, 25, and 46 to 130.

[0686] Clause 235. The tanned silk leather of any one of clauses 230 to the immediately preceding clause, wherein the compressed silk meringue or the hot-pressed silk meringue is made from the whipped silk cream of or made by the method of any one of claims 4, 5, 10, 11, 16, 17, 22, 23, 28, 29, and 32 to 130.

[0687] Clause 236. The tanned silk leather of any one of clauses 230 to the immediately preceding clause, wherein the compressed silk meringue or the hot-pressed silk meringue is made from the silk meringue of or made by the method of any one of claims 3, 9, 15, 21, 27 and 31 to 130.

[0688] Clause 237. The tanned silk leather of any one of clauses 230 to the immediately preceding clause, wherein the compressed silk meringue or the hot-pressed silk meringue is or is made from the compressed silk meringue of or made by the method of any one of claims 4, 5, 10, 11, 16, 17, 22, 23, 28, 29, and 32 to 130.

[0689] Clause 238. The tanned silk leather of any one of clauses 230 to the immediately preceding clause, wherein the hot-pressed silk meringue is the hot-pressed silk meringue of or made by the method of any one of claims 5, 11, 17, 23, 29 and 33 to 130.

[0690] Clause 239. The tanned silk leather of any one of clauses 230 to the immediately preceding clause, wherein the tanned silk leather comprises the silk leather of any one of claims 131 to 134.

[0691] Clause 240. An ultra- lightweight silk down alternative comprising silk meringue.

[0692] Clause 241. The ultra-lightweight silk down alternative of clause 240, wherein the silk meringue is made from a regenerated silk fibroin solution made from a recycled regenerated silk fibroin article or a waste silk fabric.

[0693] Clause 242. The ultra-lightweight silk down alternative of any one of clauses 240 to the immediately preceding clause, further comprising a plurality of heat-reflective particles distributed throughout the silk meringue.

[0694] Clause 243. The ultra- lightweight silk down alternative of any one of clauses 240 to the immediately preceding clause, wherein the silk meringue is made from the liquid composition of any one of claims 1, 7, 13, 19, 25, and 46 to 130.

[0695] Clause 244. The ultra-lightweight silk down alternative of any one of clauses 240 to the immediately preceding clause, wherein the silk meringue is made from the whipped silk cream of or made by the method of any one of claims 2, 8, 14, 20, 24, 26, and 30 to 130.

[0696] Clause 245. The ultra- lightweight silk down alternative of any one of clauses 240 to the immediately preceding clause, wherein the silk meringue is the silk meringue of or made by the method of any one of claims 4, 10, 16, 22, 28, and 32 to 130.

[0697] Clause 246. An impact-distributing foam comprising a silk meringue.

[0698] Clause 247. The impact-distributing foam of clause 246, wherein the impact-distributing foam has one or more impact sensors positioned within the impact-distributing foam.

[0699] Clause 248. The impact distributing foam of clause 246, wherein the one or more impact sensors include a PDA impact sensor.

[0700] Clause 249. The impact-distributing foam of any one of clauses 246 to the immediately preceding clause, wherein the impact-distributing foam has one or more strain sensors positioned within the impact-distributing foam.

[0701] Clause 250. The impact-distributing foam of any one of clauses 246 to the immediately preceding clause, wherein the impact-distributing foam is made from the liquid composition of any one of claims 1, 7, 13, 19, 25, and 46 to 130.

[0702] Clause 251. The impact-distributing foam of any one of clauses 246 to the immediately preceding clause, wherein the impact-distributing foam is made from the whipped silk cream of or made by the method of any one of claims 2, 8, 14, 20, 24, 26, and 30 to 130.

[0703] Clause 252. The impact-distributing foam of any one of clauses 246 to the immediately preceding clause, wherein the impact-distributing foam is or is made from the silk meringue of or made by the method of any one of claims 3, 9, 15, 21, 27 and 31 to 130.

[0704] Clause 253. The impact-distributing foam of any one of clauses 246 to the immediately preceding clause, wherein the impact-distributing foam is or is made from the compressed silk meringue of or made by the method of any one of claims 4, 10, 16, 22, 28, and 32 to 130.

[0705] Clause 254. The impact-distributing foam of any one of clauses 246 to the immediately preceding clause, wherein the impact-distributing foam is the hot-pressed silk meringue of or made by the method of any one of claims 5, 11, 17, 23, 29, and 33 to 130.

[0706] Clause 255. A protected item comprising: an item to be protected; and a protective shell comprising a silk meringue, a cured silk meringue, a compressed silk meringue, or a hot-pressed silk meringue, wherein the protective shell is formed by surrounding and contacting the item to be protected with a precursor to the protective shell and curing the precursor to form the protective shell, wherein surrounding comprises fully encapsulating or encapsulating against a surface.

[0707] Clause 256. The protected item of clause 255, wherein the item to be protected is an electronics component.

[0708] Clause 257. The protected item of clause 255, wherein the item to be protected is an aerospace component.

[0709] Clause 258. The protected item of clause 255, wherein the item to be protected is a semiconductor chip.

[0710] Clause 259. The protected item of clause 255, wherein the item to be protected is a semiconductor device.

[0711] Clause 260. The protected item of clause 255, wherein the item to be protected is a three- dimensional printed structure.

[0712] Clause 261. The protected item of any one of clauses 255 to the immediately preceding clause, wherein the item to be protected is resistant to an impact of between F 100 Newtons (N) and 25,000N.

[0713] Clause 262. The protected item of any one of clauses 255 to the immediately preceding clause, wherein the item to be protected is resistant to a temperature of between 80 °F and 500 °F.

[0714] Clause 263. The protected item of any one of clauses 255 to the immediately preceding clause, wherein the silk meringue, the cured silk meringue, the compressed silk meringue, or the hot-pressed silk meringue is made from a liquid composition comprising silk fibroin in an amount by weight of between 1.0% and 5.0%.

[0715] Clause 264. The protected item of any one of clauses 255 to the claim immediately preceding the immediately preceding clause, wherein the silk meringue, the cured silk meringue, the compressed silk meringue, or the hot-pressed silk meringue is made from a liquid composition comprising silk fibroin in an amount by weight of between 5.0% and 10.0%.

[0716] Clause 265. The protected item of any one of clauses 255 to the immediately preceding clause, wherein the silk meringue, the cured silk meringue, the compressed silk meringue, or the hot-pressed silk meringue is made from the liquid composition of any one of claims 1, 7, 13, 19, 25, and 46 to 130.

[0717] Clause 266. The protected item of any one of clauses 255 to the immediately preceding clause, wherein the silk meringue, the cured silk meringue, the compressed silk meringue, or the hot-pressed silk meringue is made from the whipped silk cream of or made by the method of any one of claims 2, 8, 14, 20, 24, 26, and 30 to 130.

[0718] Clause 267. The protected item of any one of clauses 255 to the immediately preceding clause, wherein the silk meringue, the cured silk meringue, the compressed silk meringue, or the hot-pressed silk meringue is or is made from the silk meringue of or made by the method of any one of claims 3, 9, 15, 21, 27 and 31 to 130.

[0719] Clause 268. The protected item of any one of clauses 255 to the immediately preceding clause, wherein the compressed silk meringue is the compressed silk meringue of or made by the method of any one of claims 4, 10, 16, 22, 28, and 32 to 130.

[0720] Clause 269. The protected item of any one of clauses 255 to the immediately preceding clause, wherein the hot-pressed silk meringue is the hot-pressed silk meringue of or made by the method of any one of claims 5, 11, 17, 23, 29, and 33 to 130.

[0721] Clause 270. A sorbent and / or gas sensing material comprising, consisting essentially of, or consisting of the silk meringue of or made by the method of any one of clauses 3, 9, 15, 21, 27 and 31 to 130.

[0722] Clause 271. The sorbent and / or gas sensing material of the immediately preceding clause, further comprising a sensing agent that undergoes a measurable change upon exposure to a gas of interest.

[0723] Clause 272. The sorbent and / or gas sensing material of the immediately preceding clause, wherein the sensing agent is a dye that changes color upon exposure to the gas of interest.

[0724] Clause 273. A biological scaffold for receiving a population of cells for one or more of growth, proliferation, differentiation, carbon dioxide capture, biomineralization, biosynthesis, fermentation, the like, and combinations thereof, the biological scaffold comprising, consisting essentially of, consisting of, or made from the liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or made by the method of any one of clauses 1 to 130.

[0725] Clause 274. A mysilkium material comprising, consisting essentially of, consisting of, or made from the liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot- pressed silk meringue, or made by the method of any one of clauses 1 to 130.

[0726] Clause 275. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of clause 49, wherein the alginate comprises at least one of a low-viscosity alginate, a high-viscosity alginate, a low-viscosity propylene glycol- modified alginate, or a high- viscosity propylene glycol-modified alginate.

[0727] Clause 276. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of clause 99, wherein the alginate comprises at least one of a low-viscosity alginate, a high-viscosity alginate, a low-viscosity propylene glycol- modified alginate, or a high- viscosity propylene glycol-modified alginate.

[0728] Clause 277. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of clause 96, wherein the multi- valent metal ions include chloride.

[0729] Clause 278. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot-pressed silk meringue, or the method of clause 96, wherein the multi- valent metal ions include zinc.

[0730] Clause 279. A ketene-treated silk leather with improved water resistance, the ketene- treated silk leather having at least a portion of at least one surface treated with a ketene surface treatment, wherein the ketene surface treatment comprises a ketene compound.

[0731] Clause 280. A method of improving water resistance of silk leather with a ketene surface treatment, the method comprising applying a ketene surface treatment to a silk leather to form a ketene- treated silk leather.

[0732] Clause 281. The method of the immediately preceding clause, further comprising drying the ketene-treated silk leather to form a dried ketene-treated silk leather.

[0733] Clause 282. The ketene-treated silk leather of any one of clauses 279 to the immediately preceding clause, wherein the ketene compound is a ketene dimer.

[0734] Clause 283. The ketene-treated silk leather of any one of clauses 279 to the immediately preceding clause, wherein a hydrophobicity of the ketene-treated silk leather is improved relative to a comparison hydrophobicity for a comparison silk leather that lacks the ketene surface treatment.

[0735] Clause 284. A glutaraldehyde-treated silk leather, the glutaraldehyde-treated silk leather having at least a portion of at least one surface treated with a glutaraldehyde surface treatment, wherein the glutaraldehyde surface treatment comprises: water; and glutaraldehyde.

[0736] Clause 285. A method of treating silk leather with a glutaraldehyde surface treatment, the method comprising applying a glutaraldehyde surface treatment to an untreated silk leather to form a glutaraldehyde-treated silk leather.

[0737] Clause 286. The glutaraldehyde-treated silk leather of any clauses 284 to the immediately preceding clause, wherein the glutaraldehyde surface treatment comprises a 10% glutaraldehyde solution.

[0738] Clause 287. The glutaraldehyde-treated silk leather of any of clauses 284 to the immediately preceding clause, wherein the glutaraldehyde surface treatment is applied via and / or wherein the applying an ionic surface treatment comprises at least one of dipping, soaking, brushing, rinsing, immersing, or dripping.

[0739] Clause 288. The glutaraldehyde-treated silk leather of any clauses 284 to the immediately preceding clause, wherein the glutaraldehyde surface treatment is applied at least one time, at least two times, or at least three times, optionally drying the glutaraldehyde-treated silk leather after each application.

[0740] Clause 289. The whipped silk cream of clause 14, wherein a stability of the whipped silk cream is improved relative to a comparison whipped silk cream that lacks the low MW SF and includes an equal proportion of high MW SF.

[0741] Clause 290. The silk meringue of clause 15, wherein a stability of the silk meringue is improved relative to a comparison silk meringue that lacks the low MW SF and includes an equal proportion of high MW SF.

[0742] Clause 291. The compressed silk meringue of clause 16, wherein a stability of the compressed silk meringue is improved relative to a comparison compressed silk meringue that lacks the low MW SF and includes an equal proportion of high MW SF.

[0743] Clause 292. The hot-pressed silk meringue of clause 17, wherein a stability of the hot-pressed silk meringue is improved relative to a comparison hot-pressed silk meringue that lacks the low MW SF and includes an equal proportion of high MW SF.

[0744] Clause 293. The whipped silk cream of clause 14, wherein a consistency of the whipped silk cream is improved relative to a comparison whipped silk cream that lacks the low MW SF and includes an equal proportion of high MW SF.

[0745] Clause 294. The silk meringue of clause 15, wherein a consistency of the silk meringue is improved relative to a comparison silk meringue that lacks the low MW SF and includes an equal proportion of high MW SF.

[0746] Clause 295. The compressed silk meringue of clause 16, wherein a consistency of the compressed silk meringue is improved relative to a comparison compressed silk meringue that lacks the low MW SF and includes an equal proportion of high MW SF.

[0747] Clause 296. The hot-pressed silk meringue of clause 17, wherein a consistency of the hot- pressed silk meringue is improved relative to a comparison hot-pressed silk meringue that lacks the low MW SF and includes an equal proportion of high MW SF.

[0748] Clause 297. The whipped silk cream of clause 20, wherein a density of the whipped silk cream is improved relative to a comparison whipped silk cream that lacks the high MW SF and includes an equal proportion of low MW SF.

[0749] Clause 298. The silk meringue of clause 21 , wherein a density of the silk meringue is improved relative to a comparison silk meringue that lacks the high MW SF and includes an equal proportion of low MW SF.

[0750] Clause 299. The compressed silk meringue of clause 22, wherein a density of the compressed silk meringue is improved relative to a comparison compressed silk meringue that lacks the high MW SF and includes an equal proportion of low MW SF.

[0751] Clause 300. The hot-pressed silk meringue of clause 23, wherein a density of the hot-pressed silk meringue is improved relative to a comparison hot-pressed silk meringue that lacks the high MW SF and includes an equal proportion of low MW SF.

[0752] Clause 301. The whipped silk cream of clause 275, wherein the alginate is the low- viscosity alginate or the low- viscosity propylene glycol-modified alginate, and wherein a density of the whipped silk cream is lower relative to a comparison whipped silk cream that lacks the low- viscosity alginate or the low- viscosity propylene glycol-modified alginate, and includes an equal proportion of the high- viscosity alginate or the high- viscosity propylene glycol-modified alginate.

[0753] Clause 302. The silk meringue of clause 275, wherein the alginate is the low-viscosity alginate or the low- viscosity propylene glycol-modified alginate, and wherein a density of the silk meringue islower relative to a comparison silk meringue that lacks the low- viscosity alginate or the low-viscosity propylene glycol-modified alginate, and includes an equal proportion of the high- viscosity alginate or the high-viscosity propylene glycol-modified alginate.

[0754] Clause 303. The compressed silk meringue of clause 275, wherein the alginate is the low- viscosity alginate or the low- viscosity propylene glycol-modified alginate, and wherein a density of the compressed silk meringue is lower relative to a comparison compressed silk meringue that lacks the low- viscosity alginate or the low- viscosity propylene glycol-modified alginate, and includes an equal proportion of the high-viscosity alginate or the high-viscosity propylene glycol-modified alginate.

[0755] Clause 304. The hot-pressed silk meringue of clause 275, wherein the alginate is the low- viscosity alginate or the low- viscosity propylene glycol-modified alginate, and wherein a density of the hot-pressed silk meringue is lower relative to a comparison hot-pressed silk meringue that lacks the low- viscosity alginate or the low- viscosity propylene glycol-modified alginate, and includes an equal proportion of the high-viscosity alginate or the high-viscosity propylene glycol-modified alginate.

[0756] Clause 305. The whipped silk cream of clause 276, wherein the alginate is the low- viscosity alginate or the low- viscosity propylene glycol-modified alginate, and wherein a density of the whipped silk cream is lower relative to a comparison whipped silk cream that lacks the low- viscosity alginate or the low- viscosity propylene glycol-modified alginate, and includes an equal proportion of the high- viscosity alginate or the high- viscosity propylene glycol-modified alginate.

[0757] Clause 306. The silk meringue of clause 276, wherein the alginate is the low-viscosity alginate or the low- viscosity propylene glycol-modified alginate, and wherein a density of the silk meringue is lower relative to a comparison silk meringue that lacks the low- viscosity alginate or the low-viscosity propylene glycol-modified alginate, and includes an equal proportion of the high- viscosity alginate or the high-viscosity propylene glycol-modified alginate.

[0758] Clause 307. The compressed silk meringue of clause 276, wherein the alginate is the low- viscosity alginate or the low- viscosity propylene glycol-modified alginate, and wherein a density of the compressed silk meringue is lower relative to a comparison compressed silk meringue that lacks the low- viscosity alginate or the low- viscosity propylene glycol-modified alginate, and includes an equal proportion of the high-viscosity alginate or the high-viscosity propylene glycol-modified alginate.

[0759] Clause 308. The hot-pressed silk meringue of clause 276, wherein the alginate is the low- viscosity alginate or the low- viscosity propylene glycol-modified alginate, and wherein a density of the hot-pressed silk meringue is lower relative to a comparison hot-pressed silk meringue that lacksthe low-viscosity alginate or the low- viscosity propylene glycol-modified alginate, and includes an equal proportion of the high-viscosity alginate or the high-viscosity propylene glycol-modified alginate.

Claims

What is claimed:I / we claim:

1. A liquid composition comprising a mixture of silk fibroin, a blend of an alginate and xanthan gum, and a plasticizer, wherein the liquid composition optionally has a water content of between 89% and 99%.

2. A whipped silk cream comprising silk fibroin, a blend of an alginate and xanthan gum, and a plasticizer, wherein the whipped silk cream optionally has a water content of between 50% and 95%.

3. A silk meringue comprising silk fibroin, a blend of an alginate and xanthan gum, and a plasticizer, wherein the silk meringue optionally has a water content of between 5% and 70%.

4. A compressed silk meringue comprising silk fibroin, a blend of an alginate and xanthan gum, and a plasticizer, wherein the compressed silk meringue optionally has a water content of between 2% and 50%.

5. A hot-pressed silk meringue comprising silk fibroin, a blend of an alginate and xanthan gum, and a plasticizer, wherein the hot-pressed silk meringue optionally has a water content of between 2% and 50%.

6. A method of making a composition, the method comprising whipping a liquid composition comprising a mixture of silk fibroin, a blend of an alginate and xanthan gum, and a plasticizer for a predetermined whipping time to form a whipped silk cream, wherein optionally: i) the silk fibroin and the blend of alginate and xanthan gum are whipped together before addition of the plasticizer; ii) the silk fibroin and the plasticizer are whipped together before addition of the blend of alginate and xanthan gum; or iii) the blend of alginate and xanthan gum and the plasticizer are whipped together before addition of the silk fibroin.

7. A liquid composition comprising a mixture of silk fibroin, a blend of an alginate and locust bean gum (LBG), and a plasticizer, wherein the liquid composition optionally has a water content of between 89% and 99%.

8. A whipped silk cream comprising silk fibroin, a blend of an alginate and locust bean gum (LBG), and a plasticizer, wherein the whipped silk cream optionally has a water content of between 50% and 95%.

9. A silk meringue comprising silk fibroin, a blend of an alginate and locust bean gum (LBG), and a plasticizer, wherein the silk meringue optionally has a water content of between 5% and 70%.

10. A compressed silk meringue comprising silk fibroin, a blend of an alginate and locust bean gum (LBG), and a plasticizer, wherein the compressed silk meringue optionally has a water content of between 2% and 50%.

11. A hot-pressed silk meringue comprising silk fibroin, a blend of an alginate and locust bean gum (LBG), and a plasticizer, wherein the hot-pressed silk meringue optionally has a water content of between 2% and 50%.

12. A method of making a composition, the method comprising whipping a liquid composition comprising a mixture of silk fibroin, a blend of an alginate and locust bean gum (LBG), and a plasticizer for a predetermined whipping time to form a whipped silk cream, wherein optionally: i) the silk fibroin and the blend of alginate and locust bean gum are whipped together before addition of the plasticizer; ii) the silk fibroin and the plasticizer are whipped together before addition of the blend of alginate and locust bean gum; or iii) the blend of alginate and locust bean gum and the plasticizer are whipped together before addition of the silk fibroin.

13. A liquid composition comprising a mixture of low molecular weight silk fibroin, a polysaccharide, and a plasticizer, wherein the liquid composition optionally has a water content of between 89% and 99%.

14. A whipped silk cream comprising low molecular weight (MW) silk fibroin (SF), a polysaccharide, and a plasticizer, wherein the whipped silk cream optionally has a water content of between 50% and 95%.

15. A silk meringue comprising low molecular weight silk fibroin, a polysaccharide, and a plasticizer, wherein the silk meringue optionally has a water content of between 5% and 70%.

16. A compressed silk meringue comprising low molecular weight silk fibroin, a polysaccharide, and a plasticizer, wherein the compressed silk meringue optionally has a water content of between 2% and 50%.

17. A hot-pressed silk meringue comprising low molecular weight silk fibroin, a polysaccharide, and a plasticizer, wherein the hot-pressed silk meringue optionally has a water content of between 2% and 50%.

18. A method of making a composition, the method comprising whipping a liquid composition comprising a mixture of low molecular weight silk fibroin, a polysaccharide, and a plasticizer for a predetermined whipping time to form a whipped silk cream, wherein optionally: i) the low molecular weight silk fibroin and the polysaccharide are whipped together before addition of the plasticizer; ii) the low molecular weight silk fibroin and the plasticizer are whipped together before addition of the polysaccharide; or iii) the polysaccharide and the plasticizer are whipped together before addition of the low molecular weight silk fibroin.

19. A liquid composition comprising a mixture of high molecular weight silk fibroin, a polysaccharide, and a plasticizer, wherein the liquid composition optionally has a water content of between 89% and 99%.

20. A whipped silk cream comprising high molecular weight silk fibroin, a polysaccharide, and a plasticizer, wherein the whipped silk cream optionally has a water content of between 50% and 95%.

21. A silk meringue comprising high molecular weight silk fibroin, a polysaccharide, and a plasticizer, wherein the silk meringue optionally has a water content of between 5% and 70%.

22. A compressed silk meringue comprising high molecular weight silk fibroin, a polysaccharide, and a plasticizer, wherein the compressed silk meringue optionally has a water content of between 2% and 50%.

23. A hot-pressed silk meringue comprising high molecular weight silk fibroin, a polysaccharide, and a plasticizer, wherein the hot-pressed silk meringue optionally has a water content of between 2% and 50%.

24. A method of making a composition, the method comprising whipping a liquid composition comprising a mixture of high molecular weight silk fibroin, a polysaccharide, and a plasticizer for a predetermined whipping time to form a whipped silk cream, wherein optionally: i) the high molecular weight silk fibroin and the polysaccharide are whipped together before addition of the plasticizer; ii) the high molecular weight silk fibroin and the plasticizer are whipped together before addition of the polysaccharide; or iii) the polysaccharide and the plasticizer are whipped together before addition of the high molecular weight silk fibroin.

25. A liquid composition comprising a mixture of silk fibroin, a polysaccharide, a plasticizer, and multi- valent metal ions.

26. A whipped silk cream comprising silk fibroin, a polysaccharide, a plasticizer, and multivalent metal ions.

27. A silk meringue comprising silk fibroin, a polysaccharide, a plasticizer, and multi- valent metal ions.

28. A compressed silk meringue comprising silk fibroin, a polysaccharide, a plasticizer, and multi- valent metal ions.

29. A hot-pressed silk meringue comprising silk fibroin, a polysaccharide, a plasticizer, and multi- valent metal ions.

30. A method of making a composition, the method comprising whipping a liquid composition comprising a mixture of silk fibroin, a polysaccharide, a plasticizer, and multi- valent metal ions for a predetermined whipping time to form a whipped silk cream, wherein optionally: i) the silk fibroin and the polysaccharide are whipped together before addition of the plasticizer; ii) the silk fibroin andthe plasticizer are whipped together before addition of the polysaccharide; or iii) the polysaccharide and the plasticizer are whipped together before addition of the silk fibroin.

31. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot- pressed silk meringue, or the method of any one of claims 25 to 30, wherein the multi-valent metal ions include calcium.

32. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot- pressed silk meringue, or the method of any one of claims 25 to 30, wherein the multi-valent metal ions include copper.

33. The liquid composition, whipped silk cream, silk meringue, compressed silk meringue, hot- pressed silk meringue, or the method of any one of claims 25 to 30, wherein a counterion to the multi-valent metal ion is chloride.

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