Polymer fibers having a backbone having a positively charged component including a zwitterionic moiety

Abstract

The present application relates to fibers of one or more biocompatible polymers having a diameter of 1 nm to 10,000 nm, wherein the polymer has a main chain including a positively charged component from a zwitterionic portion. In addition, the present application discloses an implantable therapeutic delivery system and a method for forming the same, the implantable therapeutic delivery system comprising a shell defining a chamber, wherein the shell is porous and is formed by the fibers. The interior of the shell includes a cell preparation that releases a therapeutic agent from the chamber. The implantable therapeutic delivery system can be used to treat diabetes.

Description

[0001] This application claims priority to U.S. Provisional Application No. 62 / 840,827, filed on April 30, 2019, which is incorporated herein by reference in its entirety.

[0002] This invention was made with government support under Grant No. 1R01DK105967-01A1 awarded by the National Institutes of Health. The government has certain rights in this invention. Field of the Invention

[0003] The present application relates to polymer fibers having a backbone with a positively charged component including a zwitterionic moiety, and their use in implantable therapeutic delivery systems. Background Art

[0004] Type 1 diabetes (T1D) affects millions of people worldwide. It is an autoimmune disease in which the pancreatic β cells that produce insulin are mistakenly destroyed by the body's immune system (Atkinson et al., "Type 1 Diabetes", The Lancet 383(9911): 69-82 (2014); Katsarou et al., "Type 1 Diabetes Mellitus", Nature Reviews Disease Primers 3(1): 1-17 (2017)). Despite decades of progress in chemical modification and drug delivery strategies, insulin remains an imperfect and painful therapy. Donor islet transplantation has shown promise in some patients (Desai and Shea, “Advances in Islet Encapsulation Technologies,” Nature Reviews Drug Discovery 16(5):338-350 (2017); Yu et al., “Glucose-responsive Insulin Patch for the Regulation of Blood Glucose in Mice and Minipigs,” Nature Biomedical Engineering 1-8 (2020); Facklam et al., “Biomaterials for Personalized Cell Therapy,” Advanced Materials 1902005 (2019); Weaver et al., “Design of a Vascularized Synthetic Poly(Ethylene Glycol) Macroencapsulation Device for Islet Transplantation”). Glycol) Macroencapsulation Device for Islet Transplantation”, Biomaterials, 172:54-65 (2018);Mahou et al., “Injectable and Inherently Vascularizing Semi-interpenetrating Polymer Network for Delivering Cells to the Subcutaneous Space,” Biomaterials 131:27-35 (2017); Orive et al., “Cell Encapsulation: Promise and Progress,” Nature Medicine 9(1):104-107 (2003); Pedraza et al., “Preventing Hypoxia-induced Cell Death in Beta Cells and Islets ViaHydrolytically Activated, Oxygen-generating Biomaterials,” Proceedings of the National Academy of Sciences =Insulin release is a promising approach to treat T1D, but its widespread application in the larger T1D population has been hampered by a shortage of donor islets and the need for long-term immunosuppression to prevent immune rejection. More recently, the development of human embryonic stem cell (hESC)-derived islet technology has the potential to provide an unlimited supply of β cells for transplantation (Pagliuca et al., "Generation of Functional Human Pancreatic β Cells In Vitro", Cell 159(2):428-439 (2014);Hogrebe et al., "Targeting the Cytoskeleton to Direct Pancreatic Differentiation of Human Pluripotent Stem Cells", Nature Biotechnology, 1-11 (2020). However, teratoma formation is a risk and safety issue in transplantation. Therefore, there is an urgent need for an immunoprotective encapsulation device that is both safe, does not allow cell escape / penetration or device rupture, and is functional, supports long-term cell function, has a low foreign body response, and has high mass diffusion. ;

[0005] Currently, there are two main types of encapsulation devices: microscopic devices and macroscopic devices (Ernst et al., “Islet Encapsulation,” Journal of Materials Chemistry B 6(42): 6705-6722 (2018)). For microscopic devices, alginate microcapsules probably represent the most studied islet encapsulation platform (Veiseh et al., "Size-and Shape-dependent Foreign Body Immune Response to Materials Implanted in Rodents and Non-human Primates," Nature Materials 14(6):643-651 (2015); Calafiore and Basta, "Clinical Application of Microencapsulated Islets: Actual Prospectives on Progress and Challenges," Advanced Drug Delivery Reviews 67:84-92 (2014)). Microencapsulation with large surface area can provide sufficient mass transfer to maintain adequate islet survival and function. However, microscopic devices are limited in terms of intact graft retrieval, posing safety concerns and risks for clinical applications.Macroscopic devices such as long fibers, sheets, and diffusion chambers have been developed as alternative strategies for islet transport (An et al., “Designing a Retrievable and Scalable Cell Encapsulation Device for Potential Treatment of Type 1 Diabetes,” Proceedings of the National Academy of Sciences of the United States of America 115(2):E263-E272 (2018); Ludwig et al., “Transplantation of Human Islets Without Immunosuppression,” Proceedings of the National Academy of Sciences of the United States of America 110(47):19054-19058 (2013); Bose et al., “A Retrievable Implant for the Long-term Encapsulation and Survival of Therapeutic Xenogeneic Cells,” Nature Biomedical Engineering 1-13 (2020)). Although macroscopic devices based on hydrogels such as alginate and polyethylene glycol (PEG) have been shown to have biocompatibility and high diffusivity (Mahou et al., “Injectable and Intrinsically Vascularized Semiinterpenetrating Polymer Networks for Cell Delivery into the Subcutaneous Space,” Biomaterials 131:27-35 (2017); An et al., “Design of Retrievable and Scalable Cell Encapsulation Devices for Potential Treatment of Type 1 Diabetes,” Proceedings of the National Academy of Sciences of the United States of America 115(2):E263-E272 (2018); Zhang et al., “Rapid and Long-Term Glycemic Regulation with a Balanced Charged Immune-Evasive Hydrogelin T1DM Mice,” Advanced Functional Materials 29(19):1900140 (2019)), they often have relatively low mechanical strength. In addition, the inherent softness of hydrogels facilitates cell entry and escape.Some hydrophobic macrodevices made of hydrophobic polytetrafluoroethylene (PTFE) or polycaprolactone (PCL) are mechanically robust and are thought to prevent cell escape to some extent (Neufeld et al., "The Efficacy of an Immunoisolating Membrane System for Islet Xenotransplantation in Minipigs", PLoS One 8(8) (2013); Ludwig et al., "Favorable Outcome of Experimental Islet Xenotransplantation Without Immunosuppression in a Nonhuman Primate Model of Diabetes". Diabetes”, Proc. Natl. Acad. Sci. USA, 114(44):11745-11750 (2017); Nyitray et al., “Polycaprolactone Thin-film Micro-and Nanoporous Cell-encapsulation Devices”, ACS Nano, 9(6):5675-5682 (2015). However, fibrotic growth around the device is a significant problem because it prevents mass delivery across the device and makes device retrieval difficult.

[0006] Polyurethane (PU), an important biomaterial, has been previously applied to islet encapsulation, but PU has diffusion constraints (i.e., glucose and insulin into and out of the islets) due to its hydrophobicity (Ward et al., "Development of a Hybrid Artificial Pancreas With a Dense Polyurethane Membrane," ASAIO Journal (American Society for Artificial Internal Organs): 1992) 39(3): M261-7 (1993); Zondervan et al., "Design of a Polyurethane Membrane for the Encapsulation of Islets of Langerhans" Langerhans, Biomaterials, 13(3):136-144 (1992). Zwitterionic polymers have recently attracted increasing attention for cell encapsulation due to their superhydrophilicity and excellent biocompatibility (Chien et al., "Direct Cell Encapsulation in Biodegradable and Functionalizable Carboxybetaine Hydrogels", Biomaterials, 33(23):5706-5712 (2012); Bai et al., "Expansion of Primitive Human Hematopoietic Stem Cells by Culture in a Zwitterionic Hydrogel", Nature Medicine, 25(10):1566-1575 (2019); Dong et al., "In situ 'clickable' zwitterionic starch-based hydrogels for 3D cell encapsulation" situ "Clickable" Zwitterionic Starch-based Hydrogel for 3D Cell Encapsulation)", "ACS Applied Materials & Interfaces", 8(7): 4442-4455 (2016).Previously, zwitterion-modified alginate and triazole-zwitterion hydrogels were reported to effectively reduce fibrotic deposition and were applied to islet encapsulation (Liu et al., "Developing Mechanically Robust, Triazole-zwitterionic Hydrogels to Mitigate Foreign Body Response (FBR) for Islet Encapsulation", Biomaterials 230: 119640 (2020); Liu et al., "Zwitterionically Modified Alginates Mitigate Cellular Overgrowth for Cell Encapsulation", Nature Communications 10(1): 1-14 (2019)). Nevertheless, the low mechanical strength of hydrogel materials severely limits their practical use.

[0007] The present application is directed to overcoming these and other deficiencies in the art. Summary of the invention

[0008] A first aspect of the present application relates to a fiber of one or more biocompatible polymers having a diameter of 1 nm to 10,000 nm, wherein the polymer has a backbone with a positively charged component including a zwitterionic moiety.

[0009] A second aspect of the present application relates to an implantable therapeutic delivery system comprising a housing defining a chamber, wherein the housing is porous and formed from fibers of one or more biocompatible polymers having a diameter of 1 nm to 10,000 nm, wherein the polymer has a backbone having a positively charged component including a zwitterionic moiety.

[0010] Another aspect of the present application relates to a method for preparing an implantable therapeutic delivery system. The method includes providing a fiber of one or more biocompatible polymers having a diameter of 1nm to 10,000nm, wherein the polymer has a main chain of a positively charged component including a zwitterionic portion. The fiber is then applied around the model to produce an elongated porous tube. The elongated porous tube is then removed from the model to produce an elongated hollow porous tube, which defines a chamber therein and extends between a first open end and a second open end. The first end of the elongated hollow porous tube is then sealed to close the first end, while the second end remains open. The hydrogel is then inserted into the chamber through the open second end. The hydrogel is then cross-linked to the fiber of the elongated hollow porous tube, and the second end of the elongated hollow porous tube is sealed.

[0011] Another aspect of the present application relates to a method for treating diabetes, which comprises selecting a subject suffering from diabetes, and implanting the implantable therapeutic delivery system of the present application containing pancreatic islet cells in a chamber into the selected subject.

[0012] Another aspect of the present application relates to a method of delivering a therapeutic agent to a subject. The method comprises implanting the implantable therapeutic delivery system of the present application containing pancreatic islet cells in a chamber into the subject.

[0013] Another aspect of the present application relates to a zwitterionic sulfobetaine-based nylon polymer of formula (II)

[0014]

[0015] in

[0016] R 1 C 1-10 alkyl;

[0017] R 2 SO3 - 、CO2 - , phosphate or

[0018] a, b, c, d, e and f are independently selected from integers from 1 to 20;

[0019] g and h are integers independently selected from 1 to 10,000,000; and

[0020] Represents a connection point.

[0021] The last aspect of the present application relates to a polydimethylsiloxane polymer based on zwitterionic sulfobetaine of formula (III)

[0022]

[0023] in

[0024] X and Y are independently selected from substituted or unsubstituted C 1-20 Alkylene;

[0025] Q is O or NH;

[0026] Z is polydimethylsiloxane;

[0027] R 1 H or C 1-10 alkyl;

[0028] R 2 SO3 - 、CO2 - or phosphate;

[0029] a, b and c are integers independently selected from 1 to 20; and

[0030] d and e are integers independently selected from 1 to 10,000,000.

[0031] Applicants have found that encapsulation devices made of zwitterionic polyurethane polymers are suitable for islet encapsulation in therapy. The zwitterionic portion of the polymer helps improve the polyurethane's hydrophilicity, mass delivery, antifouling properties and biocompatibility. The polyurethane backbone ensures mechanical robustness. To date, research on zwitterionic polyurethanes has been extremely limited and has primarily focused on in vitro studies (Wang et al., “Zwitterionic Polyurethanes with Tunable Surface and Bulk Properties,” ACS Appl Materials & Interfaces 10(43):37609-37617 (2018); Chen et al., “Development of Zwitterionic Polyurethanes With Multi-shape Memory Effects and Self-healing Properties,” Journal of Materials Chemistry A 3(6):2924-2933 (2015); Hong et al., “Synthesis, Characterization, and Paclitaxel Release From a Biodegradable, Elastomeric, Poly(Ester)urea with Phosphocholine Groups for Thrombosis Reduction” Urethane)Urea Bearing Phosphorylcholine Groups for ReducedThrombogenicity", "Biomacromolecules" 13(11):3686-3694(2012)).

[0032] A series of zwitterionic polyurethane (ZPU) polymers have been developed, wherein the mechanical properties, hydrophilicity, antifouling properties and biocompatibility of the resulting polymers are finely adjusted by adjusting the zwitterionic sulfobetaine (SB) content used in the synthesis. The ZPU polymer is electrospun to manufacture a nanofiber encapsulation device that incorporates various attractive properties for islet transport. First, in contrast to conventional PU devices, the ZPU nanofiber membrane as the device wall is hydrophilic. Water droplets and in vitro glucose-stimulated insulin secretion tests confirm that this thick and hydrophilic wall allows sufficient mass delivery. At the same time, the ZPU film can maintain mechanical stability, wherein the fracture strain>1.5 and the tensile stress>10MPa. Secondly, the ZPU film exhibits excellent antifouling properties (i.e., low nonspecific protein or cell attachment and macrophage activation). In addition, the ZPU device is able to prevent cell entry and escape, wherein the size of the electrospun fiber is less than 281nm. More importantly, the ZPU device induced minimal cell deposition in the intraperitoneal space of immunocompetent mice at different implantation time points up to 6 months, reproducibly less than about 10 μm, while the thickness of cell deposition on the PU device was 3 times higher relative to the ZPU device. Finally, the ZPU device was demonstrated to be safe, biocompatible, and long-term functional, enabling diabetes correction in chemically induced diabetic C57BL / 6 mice using encapsulated rat islets for up to 3 months. The ZPU device of the present application represents a promising candidate for the development of cell encapsulation therapy for T1D. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figures 1A-1D is a reaction scheme for forming the polydimethylsiloxane variant of the polymers of the present application.

[0034] Figures 2A-2J Shown is the design and fabrication of a zwitterionic polyurethane (ZPU) device and its material characterization. Figure 2A is the chemical structure of an exemplary ZPU polymer of the present application. Figure 2B is a schematic diagram of the ZPU device encapsulating pancreatic islets. Figure 2C Shown are electrospinning ZPU devices with various sizes. Figure 2D is a scanning electron micrograph of the electrospinning ZPU device. Figure 2E are the XPS spectra of PU and ZPU-2 devices. Figure 2F are the N1s XPS spectra of the PU and ZPU-2 devices. Figure 2G are FT-IR spectra of PU and ZPU-2 devices. Figure 2H is a graph (stress-strain curve) of tensile tests of various ZPU devices. Fig.2I Here are images of the water drop test on the ZPU and PU devices. Figure 2JShown are H&E stained images of ZPU-2 and ZPU-3 devices retrieved 1 month after intraperitoneal implantation in C57BL / 6J mice (n=4).

[0035] Figures 3A-3D In vitro characterization of the ZPU device is shown. Figure 3A Depicted are fluorescent images showing the adsorption of FITC-labeled fibrinogen on the surfaces of PU and ZPU membranes quantified by ImageJ, and graphical representations. Figure 3B Fluorescence microscopic images of NIH / 3T3 cells cultured on TCPS, PU, ​​and ZPU membranes after 3 days, and graphical representations. Figure 3C is a graph showing the quantification of TNF-α secretion from macrophages cultured on different surfaces. Mean±SEM; n=6; *P<0.05. Figure 3D Graphs showing in vitro GSIS of rat islets encapsulated in ZPU devices compared to free islets after 1 day of culture, mean ± SEM (n=4).

[0036] Figures 4A-4D Evaluation of cell penetration of the ZPU device is shown. Figure 4A are SEM images of ZPU devices made with different polymer concentrations (from left to right: 10%, 15%, and 20%). Figure 4B is a graph of fiber size as a function of ZPU polymer concentration during electrospinning. Figure 4C Shown are H&E stained images of ZPU devices (from left to right: 10%, 15%, and 20% ZPU) retrieved 1 month after intraperitoneal implantation in C57BL / 6J mice (n=3-4). Figure 4D is a graph showing the quantification of cell penetration of various ZPU devices.

[0037] Figure 5A -B shows that the ZPU device alleviates cell overgrowth in mice. Figure 5A are representative H&E staining images of blank PU and ZPU devices at different implantation time points. Figure 5B is a graph showing analysis of the thickness of cell overgrowth around the device measured from H&E staining images, mean ± SEM (n=3-4).

[0038] Figures 6A-6L Demonstrating the therapeutic potential of the ZPU device using rat pancreatic islets. Fig. 6A is a graph of blood glucose concentrations in non-fasting mice (n=17). Figure 6B is a graph of intraperitoneal glucose tolerance test (IPGTT) before retrieval on day 60 (n=4 per group). Figure 6C The graphs are of ex vivo GSIS of rat islets retrieved from ZPU on day 60, n=3, mean±SEM, *P<0.05. Fig.6Dis a graph of IPGTT before retrieval on day 90 (n=3 per group). Fig. 6E The graphs are of ex vivo GSIS of rat islets retrieved from ZPU on day 90, n=3, mean±SEM, *P<0.05. Fig. 6F is a graph of the measurement of total insulin content of the pancreas in the different groups on day 60. (n=4-5). Figure 6G Bright-field image of encapsulated rat islets after retrieval on day 60. Scale bar, 500 μm. Figure 6H This is an H&E-stained cross-sectional image of a ZPU device containing islets retrieved after membrane stripping on day 60. Scale bar, 1000 μm. Fig.6I This is an H&E-stained cross-sectional image of a ZPU device containing islets retrieved on day 60. Scale bar, 100 μm. Figure 6J Immunohistochemical staining of rat islets in the ZPU device retrieved on day 60 (scale bar: 50 μm). Figure 6K This is an H&E-stained cross-sectional image of a ZPU device containing islets retrieved on day 90. Scale bar, 200 μm. Figure 6L Immunohistochemical staining of rat islets in the ZPU device retrieved on day 90 (scale bar: 50 μm). DETAILED DESCRIPTION

[0039] A first aspect of the present application relates to a fiber of one or more biocompatible polymers having a diameter of 1 nm to 10,000 nm, wherein the polymer has a backbone with a positively charged component including a zwitterionic moiety.

[0040] As used above, and throughout the description herein, unless otherwise indicated, the following terms shall be understood to have the following meanings. Unless otherwise defined herein, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the technology belongs. Unless otherwise indicated, in the case where a term herein has multiple definitions, the definitions in this section shall prevail.

[0041] As used herein, the term "zwitterion" refers to a moiety that includes both positively and negatively charged groups in the same molecule. Without being bound by any theory, it is believed that zwitterionic functional groups can provide improved hydrophilicity and biocompatibility.

[0042] The term "copolymer" refers to a polymer derived from more than one monomeric species.

[0043] The term “random copolymer” or “random polymer” refers to a copolymer in which the sequence of the different building blocks has no defined order (—M1M2M1M1M2M1M2M2—, wherein M1 and M2 represent different monomers).

[0044] The term "block copolymer" or "block polymer" refers to a macromolecule composed of a long sequence of different repeating units. Exemplary block polymers include, but are not limited to, AnBm, AnBmAm, AnBmCk, or AnBmCkAn, where A, B, and C represent different monomers, and n, m, and k are the number of monomers present in each block.

[0045] The term "alkyl" means an aliphatic hydrocarbon group which may be straight or branched. When not otherwise limited, the term refers to an alkyl group of 20 or fewer carbon atoms. Branched means that one or more lower alkyl groups (such as methyl, ethyl or propyl) are attached to a linear alkyl chain. Exemplary alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, n-pentyl, 3-pentyl, and the like.

[0046] The term "aryl" means an aromatic monocyclic or multicyclic / polycyclic ring system of 6 to about 19 carbon atoms or 6 to about 10 carbon atoms, and includes aralkyl groups. The ring system of the aryl group may be optionally substituted. Representative aryl groups include, but are not limited to, groups such as phenyl, naphthyl, azulenyl, phenanthrenyl, anthracenyl, fluorenyl, pyrenyl, triphenylene, chrysene, and tetraphenylene.

[0047] An "unsubstituted" atom carries all of the hydrogen atoms determined by its valence.

[0048] The term "optionally substituted" is used to indicate that a group may have one substituent at each substitutable atom of the group (including more than one substituent on a single atom), provided that the normal valence of the designated atom is not exceeded and the identity of each substituent is independent of the other atoms. Up to three H atoms in each residue are replaced by alkyl, halogen, haloalkyl, hydroxy, lower alkoxy, carboxyl, carboalkoxy (also known as alkoxycarbonyl), carboxamido (also known as alkylaminocarbonyl), cyano, carbonyl, nitro, amino, alkylamino, dialkylamino, sulfhydryl, alkylthio, sulfoxide, sulfone, amido, amidino, phenyl, benzyl, heteroaryl, phenoxy, benzyloxy or heteroaryloxy. When the substituent is keto (i.e., =0), then two hydrogens on the atom are replaced. Combinations of substituents and / or variables are permissible only if such combinations result in stable compounds. "Stable compound" means a compound that is sufficiently robust to survive isolation from a reaction mixture to a useful degree of purity and formulation into an effective therapeutic agent.

[0049] As used herein, the term "pendant functional group" refers to a functional group that is a pendant branch from the backbone of the copolymer. In one embodiment, the pendant functional group provides a location where additional functional groups can be attached to the backbone of the polymer.

[0050] As used herein, the term "backbone" or "backbone chain" refers to a linear chain relative to which all other chains (long or short or both) can be considered as pendant. The backbone chain or main chain of a polymer can be a series of covalently bonded atoms that together produce a continuous chain of molecules.

[0051] As used herein, the term "biocompatible" refers to a material that is inert when introduced into a biological system. A biocompatible material will not be broken down (biodegradable) and will not cause a reaction in a biological system into which it is introduced.

[0052] The term "derivative thereof" refers to a salt thereof, an ester thereof, a free acid form thereof, a free base form thereof, a solvate thereof, a deuterated derivative thereof, a hydrate thereof, an N-oxide thereof, a polymorph thereof, a stereoisomer thereof, a geometric isomer thereof, a tautomer thereof, a mixture of tautomers thereof, an enantiomer thereof, a diastereomer thereof, a racemate thereof, a mixture of stereoisomers thereof, an isotope thereof (e.g., tritium, deuterium), or a combination thereof.

[0053] The fibers of the present application can be used in surgical sutures and vascular stents, such as tubular stents for vascular regeneration.

[0054] In one embodiment of the fiber of the present application, the fiber comprises a zwitterionic sulfobetaine-based polyurethane polymer of formula (I):

[0055]

[0056] in

[0057] X is substituted or unsubstituted C 1-20 Alkylene, or

[0058] Y is C 1-20 Alkylene,

[0059] Z is independently selected at each occurrence from C 1-6 Alkylene and dimethylsilyl;

[0060] Q is

[0061] R 1 C 1-10 alkyl;

[0062] R 2 SO3 - 、CO2 - , phosphate or

[0063] a, b, c, d and n are independently selected from integers from 1 to 20;

[0064] e and f are independently integers selected from 1 to 10,000,000;

[0065] g is an integer selected from 0 to 10,000,000; and

[0066] Represents a connection point.

[0067] Polyurethane resins are generally produced by the reaction between a polyisocyanate component and a polyol component, and are widely used in various industrial fields, for example, as elastomers, lenses, synthetic leather, slush powders, elastic moldings, RIM moldings, paints, adhesives, sealing materials or foams. In the present application, isocyanates react with zwitterionic monomers to produce polyurethane polymers, wherein zwitterions are incorporated into the main chain of the polymer.

[0068] In the preparation of the zwitterionic polyurethane polymer of the present application, polyisocyanates, for example, diisocyanates such as alicyclic diisocyanates, aliphatic diisocyanates, aralkyl diisocyanates and aromatic diisocyanates may be used as long as the properties of the polyurethane resin of the present application are not impaired.

[0069] Examples of alicyclic diisocyanates include 1,3-cyclopentane diisocyanate, 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (also known as isophorone diisocyanate), 4,4′-methylene-bis(cyclohexyl isocyanate), methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, 1,3-bis(isocyanatoethyl)cyclohexane, 1,4-bis(isocyanatoethyl)cyclohexane and 2,5- or 2,6-bis(isocyanatomethyl)norbornane (NBDI), and mixtures thereof.

[0070] Examples of the aliphatic diisocyanate include trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, 1,2-propylene diisocyanate, 1,2-butylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, 2,4,4- or 2,2,4-trimethylhexamethylene diisocyanate, and 2,6-diisocyanatomethyl hexanoate.

[0071] Examples of the aralkyl diisocyanate include 1,3- or 1,4-xylene diisocyanate or a mixture thereof, 1,3- or 1,4-tetramethylxylene diisocyanate or a mixture thereof, and ω,ω′-diisocyanato-1,4-diethylbenzene.

[0072] Examples of the aromatic diisocyanate include 2,4-toluene diisocyanate and 2,6-toluene diisocyanate, and isomeric mixtures of these toluene diisocyanates; 4,4′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate and 2,2′-diphenylmethane diisocyanate, and any isomeric mixtures of these diphenylmethane diisocyanates; toluene diisocyanate, p-phenylene diisocyanate, and naphthalene diisocyanate.

[0073] Derivatives of these diisocyanates may be used in combination. More specifically, polymers (dimers or trimers (eg, isocyanurate-modified products)) of these diisocyanates may also be used in combination.

[0074] In one embodiment of the zwitterionic polyurethane polymer of the present application, the polyisocyanate is selected from the group consisting of hexamethylene diisocyanate, poly(hexamethylene diisocyanate), dicyclohexylmethane 4,4'-diisocyanate, isophorone diisocyanate, 4,4'-diphenylmethane diisocyanate, toluene diisocyanate, ethylene diisocyanate and p-phenylene diisocyanate.

[0075] In another embodiment of the fiber of the present application, the fiber comprises a zwitterionic sulfobetaine-based nylon polymer of formula (II):

[0076]

[0077] in

[0078] R 1 for a C 1-10 alkyl;

[0079] R 2 SO3 - 、CO2 - , phosphate or

[0080] a, b, c, d, e and f are independently selected from integers from 1 to 20;

[0081] g and h are integers selected from 1 to 10,000,000; and

[0082] Represents a connection point.

[0083] Nylon is a generic name for a series of polyamide polymers characterized by the presence of an amide group -CONH in the main chain. The polyamide of the present application may comprise a polycondensation product (or residue) of a zwitterionic diamine component and a dicarboxylic acid (or diacyl chloride) component, and / or be obtained by ring-opening polymerization of a lactam. When used to refer to the components of the polyamide of the present application, "residue" refers to a portion of a resulting product or subsequent formulation or chemical product as a chemical species in a specific reaction scheme, regardless of whether the portion is actually obtained from a chemical species.

[0084] Polyamides are generally prepared by methods well known in the art. Examples of methods for the synthesis of polyamides that may be suitable for use in the present application are disclosed in U.S. Pat. No. 2,130,523 to Carothers; U.S. Pat. No. 6,737,464 to Bagrodia et al.; U.S. Pat. No. 8,057,732 to Bersted et al.; U.S. Pat. No. 6,531,529 to Bersted et al.; U.S. Pat. No. 6,359,055 to Delannoy et al.; and U.S. Pat. No. 5,665,815 to Vankan et al., all of which are incorporated herein by reference in their entirety.

[0085] In one embodiment of the fiber of the present application, the zwitterionic polymer may include polydimethylsiloxane groups in the backbone of the polymer.

[0086] In another embodiment of the fiber of the present application, the fiber comprises a zwitterionic sulfobetaine-based polydimethylsiloxane polymer of formula (III)

[0087]

[0088] in

[0089] X and Y are independently selected from substituted or unsubstituted C 1-20 Alkylene;

[0090] Q is O or NH;

[0091] Z is polydimethylsiloxane;

[0092] R 1 H or C 1-10 alkyl;

[0093] R 2 SO3 - 、CO2 - or phosphate;

[0094] a, b and c are integers independently selected from 1 to 20; and

[0095] d and e are independently integers selected from 1 to 10,000,000.

[0096] Figures 1A-1D A possible reaction scheme for forming exemplary polymers of the present application is shown. These polymers have polydimethylsiloxane in the backbone and are formed by reacting diols and diamines with diisocyanates. The zwitterionic portion is then formed by reacting the polymer with trifluoroacetic acid.

[0097] In one embodiment, the biocompatible zwitterionic polymers of the present application can be formed by any of the following techniques, but not limited to: reversible addition-fragmentation chain transfer (RAFT) polymerization, atom transfer radical polymerization (ATRP), nitroxide-mediated polymerization (NMP), cyano-mediated free radical polymerization, conventional free radical polymerization, ring-opening polymerization (ROP), emulsion polymerization, suspension polymerization, etc. All of these methods should be known to those skilled in the art. Nitroxide-mediated free radical polymerization refers to a free radical polymerization method that utilizes alkoxyamine initiators to produce polymers with good stereochemical control and very low polydispersity index. Ring-opening polymerization refers to a form of chain growth polymerization in which the ends of the polymer chain act as reactive centers where other cyclic monomers can react by opening their ring systems and form longer polymer chains. The growth center can be a free radical, anion, or cation. Anionic ring-opening polymerization or "AROP" refers to a ring-opening polymerization involving a nucleophile as an initiator. Ring opening can be triggered by a nucleophilic attack on carbon by the initiator, forming a new species that will act as a nucleophile. The sequence can be repeated until a polymer is formed. A typical example of anionic ROP is the ROP of ε-caprolactone, initiated by an alkoxide functional group.

[0098] The zwitterionic polymer of the present application may further include a polyol. Suitable polyols suitable for forming the zwitterionic polymer of the present application include, but are not limited to, ethylene glycol, propylene glycol, polycaprolactone diol, dipropylene glycol, 1,2,4-butanetriol, 1,7-heptanediol, glycerol, polycaprolactone diol, poly(tetrahydrofuran), isosorbide, polyethylene glycol, butylene glycol, polyethylene oxide, panaxatriol, panaxynetriol, talose, balsaminol B, momordol, erythritol, enterodiol, xylitol, miglitol, sorbitol, mannitol, galactitol, isomalt and maltitol. Suitable polyols may also include sugars such as aldohexose, aldopentose, tetraose, aldotose, aldotose, allose, altrose, arabinose, amylopectin, amylose, dextrose, erythrose, fructose, galactose, glucose, gulose, hexose, idose, ketohexose, ketose, lactose, lyxose, maltose, mannose, pentose, ribose, saccharose / sucrose, talose, tetrose, triose, xylose, and their corresponding stereoisomers. The diols may be polymers of different molecular weights, or mixtures containing molecular weights.

[0099] In the formation of the zwitterionic polyurethane polymer of the present application, the catalyst is selected from the group consisting of dibutyltin dilaurate, triethylamine, triethylenediamine, N-methylmorpholine, tetramethyltin, tetraoctyltin, dimethyldioctyltin and triethyltin chloride.

[0100] Additional methods of forming polyurethane polymers that may be suitable for use in the present application are disclosed in U.S. Pat. Nos. 8,722,752 to Kuwamura et al.; 4,826,944 to Hoefer et al.; 4,742,087 to Kluth et al.; 2,833,730 to Barthel; and 8,492,433 to Selifonov, each of which is incorporated herein by reference in its entirety.

[0101] Suitable dicarboxylic acids for forming the zwitterionic nylon polymers of the present application include aliphatic dicarboxylic acids, such as oxalic acid, succinic acid, adipic acid, or sebacic acid. Other types of dicarboxylic acids can also be used in the nylons of the present application, including alicyclic dicarboxylic acids, such as cyclobutane dicarboxylic acid, hexahydroterephthalic acid, or hexahydroisophthalic acid; aromatic dicarboxylic acids, such as phthalic acid, isophthalic acid, terephthalic acid, methyl terephthalic acid, naphthalene-2,6-dicarboxylic acid, or naphthalene-2,7-dicarboxylic acid; carboxylic acids, such as diphenyl ether dicarboxylic acid, diphenyl sulfone dicarboxylic acid, diphenoxyethane dicarboxylic acid, or sodium 3,5-dicarboxybenzene sulfonate, and hydroxycarboxylic acids, such as glycolic acid, p-hydroxybenzoic acid, or p-B-hydroxyethoxybenzoic acid.

[0102] In the formation of the zwitterionic nylon polymers of the present application, the use of a catalyst may or may not be necessary. The use of a catalyst will depend on the monomers selected. In some embodiments, the zwitterionic nylon polymers may require the use of an acid or base catalyst, the selection of which will be apparent to those skilled in the art.

[0103] The polymerization solution used to form the zwitterionic polymer of the present application may also contain an initiator. Suitable initiators depend largely on the details of the polymerization, including the type of monomers used, the type of catalyst system, the solvent system and the reaction conditions. The initiator generates active centers (e.g., free radicals or cations) that react with the monomers in the reaction mixture, thereby starting the polymerization process.

[0104] In some embodiments, the initiator can be a photoinitiator, a thermal initiator, a UV initiator, or another type of initiator.

[0105] The photoinitiator generates free radicals upon irradiation with UV light, which initiate photopolymerization. The initiator can be, for example, 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylbenzophenone, benzoin ether, benzil ketal, α-dialkoxyacetophenone, α-hydroxyphenone, α-amino-alkylphenone, acylphosphine oxide, benzophenone / amine, thioxanthone / amine, azobisisobutyronitrile, lithium phenyl-2,4,6-trimethylbenzoylphosphinate, or a combination thereof. Other examples of suitable photoinitiators include acetophenone; anisole; anthraquinone; anthraquinone-2-sulfonic acid, sodium salt monohydrate; chromium tricarbonyl; benzil; benzoin, sublimed; benzoin ethyl ether; benzoin isobutyl ether; benzoin methyl ether; benzophenone; benzophenone / 1-hydroxycyclohexyl benzophenone, 50 / 50 blend; 3,3',4,4'-benzophenone tetracarboxylic dianhydride; 4-phenylbenzophenone; 2-benzyl-2-(diphenyl)-2-nitrobenzoyl)-1-hydroxycyclohexyl benzophenone; benzophenone tetracarboxylic dianhydride; 4-phenylbenzophenone; 2-benzyl-2-(diphenyl)-1 ...hydroxycyclohexyl benzophenone; benzophenone tetracarboxylic dianhydride; 4-phenylbenzophenone; 2-benzyl-2-(diphenyl)-1-hydroxycyclohexyl benzophenone; 2-benzyl-2-(diphenyl)-1-hydroxycyclohexyl benzophenone; 2-benzyl-2-(diphenyl)-1-hydroxycyclohexyl benzophenone; 2-benzyl-2-(diphenyl)-1-hydroxycyclohexyl benzophenone; 2-benzyl-2-(diphenyl)-1-hydroxycyclohexyl benzophenone; 2-benzyl-2-(diphenyl)-1-hydroxy 4,4'-bis(diethylamino)benzophenone; 4,4'-bis(dimethylamino)benzophenone; camphorquinone; 2-chlorothioxanthen-9-one; (isopropylbenzene)cyclopentadienyliron(II) hexafluorophosphate; dibenzosuberenone; 2,2-diethoxyacetophenone; 4,4'-dihydroxybenzophenone; 2,2-dimethoxy-2-phenylacetophenone; 4-(dimethylamino)diphenyl benzophenone; 4,4'-dimethylbenzil; 2,5-dimethylbenzophenone; 3,4-dimethylbenzophenone; diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide / 2-hydroxy-2-methylpropiophenone, 50 / 50 blend; 4'-ethoxyacetophenone; 2-ethylanthraquinone; ferrocene; 3'-hydroxyacetophenone; 4'-hydroxyacetophenone; 3-hydroxybenzophenone; 4-hydroxybenzophenone; 1-hydroxy cyclohexyl phenyl ketone; 2-hydroxy-2-methylpropiophenone; 2-methylbenzophenone; 3-methylbenzophenone; methylbenzoylformate; 2-methyl-4'-(methylthio)-2-morpholinopropiophenone; phenanthrenequinone; 4'-phenoxyacetophenone; thioxanthen-9-one; triarylsulfonium hexafluoroantimonates, mixed, 50% in propylene carbonate; triarylsulfonium hexafluorophosphates, mixed, 50% in propylene carbonate, or a combination thereof.

[0106] Thermal free radical initiators decompose upon heating into free radical fragments that initiate polymerization. Exemplary thermal free radical initiators include ammonium persulfate; sodium metabisulfite; benzoyl peroxide; di-tert-amyl peroxide; tert-butyl perbenzoate; dicumyl peroxide; azobisisobutyronitrile (AIBN); 1,1'azobis(cyclohexanecarbonitrile) (ABCN); 4,4'-azobis(4-cyanovaleric acid) (ACVA); 2,2'-azobis(2,4-dimethylvaleronitrile); and 2,2'-azobis(cyclohexanecarbonitrile).

[0107] The initiator in the polymerization solution may be in the range of about 0.01 wt % to 10 wt %.

[0108] In addition, the polymerization solution may further include a crosslinking agent. The crosslinking agent interacts with the reactive groups on the zwitterionic polymer, whether part of the backbone or the pendant groups. The crosslinking agent chemically bonds two polymer chains in the reaction mixture together, thereby exponentially increasing the molecular weight of the polymer.

[0109] Suitable classes of crosslinking agents are selected from the group consisting of isocyanates, anhydrides, poly(meth)acrylated crosslinkers, polyacids and acyl halides. The crosslinking agent may be, for example, poly(ethylene glycol) dimethacrylate, tetramethylethylenediamine, carboxybetaine diacrylamide crosslinker, carboxybetaine diacrylate, other difunctional and polyfunctional monomers and macromers, or combinations thereof.

[0110] The crosslinking agent may be a diisocyanate. Exemplary diisocyanates suitable for the present application are disclosed above. Other crosslinking agents that may interact with the residual reactive groups on the zwitterionic polymers of the present application include poly(meth)acylated crosslinking agents such as diethylene glycol dimethacrylate (DEGDMA), diethylene glycol diacrylate, triethylene glycol dimethacrylate (TEGDMA), ethylene glycol dimethacrylate (EGDMA), hexane-1,6-diol diacrylate (HDDA), ethylene glycol diacrylate, ethylene glycol dimethacrylate, poly(ethylene glycol) diacrylate, poly(ethylene glycol) dimethacrylate, tetra(ethylene glycol) diacrylate or triethylene glycol dimethacrylate.

[0111] In addition, crosslinking agents such as polyacids, anhydrides and acyl halides may also be used. Exemplary crosslinking agents of these types include maleic acid, 2-methylmaleic acid, itaconic acid, 2-methylitaconic acid, α,β-methyleneglutaric acid, maleic anhydride, itaconic anhydride, acrylic anhydride, methacrylic anhydride, 1,4-phenylenediacryl chloride, and the like.

[0112] The concentration of zwitterionic monomers (zwitterionic diols and zwitterionic diamines) and isocyanates and / or dicarboxylic acids used in any of the polymerization reactions described herein depends in part on the solubility of the monomers and polymer products and the evaporation temperature of the solvent. The solvent concentration can also affect the gelation of the polymer. Insufficient solvent can cause the polymer to crosslink in a short period of time without achieving a sufficiently high conversion rate. The concentration of the monomer dissolved in the solvent in the reaction can range from 1% to 100% by weight of the monomer. Generally, a monomer concentration of less than 90 wt % is suitable to ensure the solubility of the resulting polymer and to prevent premature crosslinking and gelation. In some examples of the formation of the polymers of the present application, the monomers are preferably soluble in water.

[0113] Based on the solubility of the zwitterionic diol and or diamine monomers, isocyanates and dicarboxylic acids, and the requirements of boiling point and polymerization temperature compatible with the type of polymerization used, suitable solvents for the method of preparing the zwitterionic polymers of the present application are selected. Exemplary solvents suitable for forming the zwitterionic polymers described herein include, but are not limited to, water, methanol, ethanol, dichloromethane, toluene, dioxane, THF, chloroform, cyclohexane, dimethyl sulfoxide, dimethylformamide, acetone, acetonitrile, n-butanol, n-pentanol, chlorobenzene, diethyl ether, tert-butanol, 1,2,-dichloroethylene, diisopropyl ether, ethanol, ethyl acetate, ethyl methyl ketone, heptane, hexane, isopropanol, isopentanol, methanol, pentane, n-propanol, pentachloroethane, 1,1,2,2,-tetrachloroethane, 1,1,1,-trichloroethane, tetrachloroethylene, tetrachloromethane, trichloroethylene, water, xylene, benzene, nitromethane, glycerol, and mixtures thereof.

[0114] The solvent used in the polymerization reaction of the present application may further include a stabilizer, a surfactant or a dispersant. Suitable surfactants include ionic and nonionic surfactants, such as alkyl polyglycol ethers, such as ethoxylated products of lauryl alcohol, oleyl alcohol and stearyl alcohol; alkylphenol polyglycol ethers, such as ethoxylated products of octylphenol or nonylphenol, diisopropylphenol, triisopropylphenol; alkali metal ammonium salts of alkyl, aryl or alkylaryl sulfonates, sulfates, phosphates, etc., including sodium lauryl sulfate, sodium octylphenol glycol ether sulfate, sodium dodecylbenzene sulfonate, sodium lauryl diglycol sulfate and tri-tert-butylphenol ammonium; and pentaethylene glycol and octaethylene glycol sulfonates, sulfosuccinates, such as disodium sulfosuccinic acid ethoxylated nonylphenol half ester, disodium n-octyldecyl sulfosuccinate, dioctyl sodium sulfosuccinate, etc.

[0115] The zwitterionic polymers of the present application may be copolymers, including random or statistical copolymers, or block copolymers. In addition, the zwitterionic polymers of the present application may be mixed together and or formed by copolymerization of different monomers or polymer blocks.

[0116] Inhibitors can be used to prevent excessive polymerization or crosslinking of the zwitterionic polymers of the present application. Exemplary inhibitors include, but are not limited to, phenothiazines, hydroquinones, or antioxidant inhibitors such as ETHANOX TM family (SI Group, Schenectady, NY) (e.g. ETHANOX 330 TM ), IRGANOX (BASF, Florham Park, New Jersey), and STABOXOL (Rhein Chemie, Mannheim, Germany).

[0117] In another embodiment of the fiber of the present application, the diameter of the fiber is 1 nm to 10,000 nm. The fiber can be a nanofiber with a diameter ranging from 1 nm to 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, 160 nm, 170 nm, 180 nm, 190 nm, 200 nm, 210 nm, 220 nm, 230 nm, 240 nm, 250 nm, 260 nm, 270 nm, 280 nm, 290 nm, 300 nm, 310 nm, 320 nm, 330 nm, 340 nm, 350 nm, 360 nm, 370 nm, 380 nm, 390 nm or 400 nm. In another embodiment, the diameter of the fiber is 1 nm to 1000 nm; 1 nm to 10,000 nm; 1 nm to 100,000 nm; or 1 nm to 1,000,000 nm. The fiber can be prepared by extruding a polymer solution through a narrow hole, and the extruded filaments can then be collected as fibers on a rotating spindle by wet spinning, dry spinning, electrospinning, or melt spinning processes. The diameter of the fiber can be controlled based on the concentration of the polymer in the solution and the size of the hole used.

[0118] It is known to produce fine fibers from polymeric solutions by electrostatic spinning (also known as "electrospinning") through an electric field generated by a voltage difference between a collector electrode and a spinning electrode. For example, as shown in U.S. Pat. No. 6,743,273, a polymeric solution is pumped to a spinning electrode in the form of a rotating emitter, where the pump solution is pumped from a reservoir and forced through holes in the emitter. Upon exit, the electrostatic potential between the grid and the emitter imparts an electric charge that causes the liquid to be "spun" into thin, fine fibers, where the fibers collect on a substrate as an efficiency layer. During this process, solvent evaporates from the fine fibers, which reduces the fiber diameter during its flight. Additional electrospinning techniques that can be used to form the fibers of the present application are disclosed in U.S. Pat. No. 4,044,404 to Martin et al.; U.S. Pat. No. 7,086,846 to Kleinmeyer et al.; and U.S. Patent Application Publication No. US2006 / 0290031 to Jirsak et al., all of which are incorporated herein by reference in their entirety.

[0119] Forming fibers by melt spinning is well known in the art and is disclosed in U.S. Pat. Nos. 5,149,517 and 5,156,831 to Fain et al.; U.S. Pat. No. 4,606,872 to Watanabe; U.S. Pat. No. 5,213,677 to Yamamoto et al.; U.S. Pat. No. 4,005,183 to Singer; U.S. Pat. No. 5,037,589 to Iwashita et al.; U.S. Pat. No. 4,628,001 to Sasaki et al.; and U.S. Pat. No. 4,606,808 to Yamada et al., all of which are incorporated herein by reference in their entirety. In general, melt spinning requires heating and melting the polymer of interest in a spinning cylinder having a spinning head. The molten polymer is extruded from the spinning head into filaments by pressurizing with gas or by pressing with a piston, which are wound on a drum rotating at a constant speed to obtain continuous length polymer filaments.

[0120] A second aspect of the present application relates to an implantable therapeutic delivery system comprising a housing defining a chamber, wherein the housing is porous and formed from fibers of one or more biocompatible polymers having a diameter of 1 nm to 10,000 nm, wherein the polymer has a backbone having a positively charged component including a zwitterionic moiety.

[0121] In one embodiment of the implantable therapeutic delivery system of the present application, the biocompatible polymer comprises a zwitterionic sulfobetaine-based polyurethane polymer of formula (I):

[0122]

[0123] in

[0124] X is substituted or unsubstituted C 1-20 Alkylene, or

[0125] Y is C 1-20 Alkylene,

[0126] Z is independently selected at each occurrence from C 1-6 Alkylene and dimethylsilyl;

[0127] Q is

[0128] R 1 C 1-10 alkyl;

[0129] R 2 SO3 - 、CO2 - , phosphate or

[0130] a, b, c, d and n are independently selected from integers from 1 to 20;

[0131] e and f are independently integers selected from 1 to 10,000,000;

[0132] g is an integer selected from 0 to 10,000,000; and

[0133] Represents a connection point.

[0134] In another embodiment of the implantable therapeutic delivery system of the present application, the biocompatible polymer comprises a zwitterionic sulfobetaine-based nylon polymer of formula (II)

[0135]

[0136] in

[0137] R 1 C 1-10 alkyl;

[0138] R 2 SO3 - 、CO2 - , phosphate or

[0139] a, b, c, d, e and f are independently selected from integers from 1 to 20;

[0140] g and h are integers selected from 1 to 10,000,000; and

[0141] Represents a connection point.

[0142] In another embodiment of the implantable therapeutic delivery system of the present application, the biocompatible polymer comprises a zwitterionic sulfobetaine-based polydimethylsiloxane polymer of formula (III)

[0143]

[0144] in

[0145] X and Y are independently selected from substituted or unsubstituted C 1-20 Alkylene;

[0146] Q is O or NH;

[0147] Z is polydimethylsiloxane;

[0148] R 1 H or C 1-10 alkyl;

[0149] R 2 SO3 - 、CO2 - or phosphate;

[0150] a, b and c are integers independently selected from 1 to 20; and

[0151] d and e are independently integers selected from 1 to 10,000,000.

[0152] In another embodiment of the implantable therapeutic delivery system, the housing is an elongated hollow porous tube extending between a first end and a second end, wherein the fibers are wound around the chamber. In another embodiment of the implantable therapeutic delivery system, the porous tube has a sealed first end. In addition, the chamber of the hollow porous tube may contain a hydrogel.

[0153] like Figure 2B As shown in , the implantable therapeutic delivery system 2 includes fibers formed into an elongated hollow porous tube 4. The sealed first end 6 holds the hydrogel in the elongated hollow porous tube 4. The hydrogel may include cells 8. Figure 2C In the implantable therapeutic delivery system 2, the sealed first end 6 and the sealed second end 10 contain cells 8 (in Figure 2C The hydrogel is not visible in FIG.

[0154] The hydrogel comprises a material that can form crosslinks with the polymeric fibers of the shell. Suitable hydrogel materials include natural and synthetic polymeric materials. The composition of the hydrogel can be homopolymeric, copolymeric or polymeric. Suitable hydrogel materials include, but are not limited to, those derived from collagen, hyaluronate, fibrin, alginate, agarose, chitosan, bacterial cellulose, elastin, keratin, MATRIGEL TM (Corning Life Sciences, Tewksbury MA.), DNA (as the actual polymer), and combinations thereof. In other embodiments, suitable hydrogels are synthetic polymers, including hydrogels derived from polyethylene glycol (PEG), poly(acrylic acid) and its derivatives, poly(ethylene oxide) and its copolymers, poly(vinyl alcohol), polyphosphazenes, and combinations thereof.

[0155] In another embodiment of the implantable therapeutic delivery system, the hydrogel comprises alginate. In another embodiment, the hydrogel and the porous fiber tube are cross-linked.

[0156] Exemplary cationic crosslinking agents suitable for crosslinking the porous fiber tube to the hydrogel of the implantable therapeutic delivery system include divalent cations such as Ba 2+, Ca 2+ 、Cd 2+ , Cu 2+ , Fe 2+ Mg 2+ , Mn 2+ 、Ni 2+ , Pb 2+ Sn 2+ , Sr 2+ and Zn 2+ In one embodiment, the divalent crosslinking agent is calcium chloride. Other suitable cationic crosslinking agents include, but are not limited to, Al 3+ and Fe 3+ The crosslinking agent may be present in the hydrogel, the porous fiber tube, or applied as a solution after the hydrogel is added to the porous fiber tube. The concentration of the crosslinking agent needs to be sufficient to crosslink the hydrogel and adhere to the porous fiber tube. Therefore, in some embodiments, the crosslinking agent is present in an excess concentration. Exemplary crosslinking solutions include aqueous solutions of CaCl2, BaCl2.

[0157] In another embodiment of the implantable therapeutic delivery system, the elongated hollow porous tube is sealed at the first end and the second end such that the chamber is closed.

[0158] The implantable therapeutic delivery system may include a cell preparation within a closed chamber that releases a therapeutic agent from the chamber through an elongated hollow porous tube.

[0159] In one embodiment, the therapeutic agent is a biological agent produced and / or secreted or released from a tissue and / or cell preparation encapsulated or present in a hydrogel of an implantable therapeutic delivery system. The cell may comprise a naturally occurring or genetically engineered cell, which may be in the form of a single cell and / or a cell cluster. In one embodiment, the cells in the hydrogel of an implantable therapeutic delivery system secrete one or more biological factors suitable for treating a disease or condition. These factors are secreted from the cells, released from the hydrogel, and delivered to or diffused to surrounding target cells, tissues or organs in need. Suitable cells include, but are not limited to, one or more cell types selected from the group consisting of smooth muscle cells, cardiomyocytes, platelets, epithelial cells, endothelial cells, urothelial cells, fibroblasts, embryonic fibroblasts, myoblasts, chondrocytes, chondroblasts, osteoblasts, osteoclasts, keratinocytes, hepatocytes, bile duct cells, pancreatic islet cells, thyroid cells, parathyroid cells, adrenal cells, hypothalamic cells, pituitary cells, ovarian cells, testicular cells, salivary gland cells, adipocytes, embryonic stem cells, mesenchymal stem cells, neural cells, endothelial progenitor cells, hematopoietic cells, and precursor cells.

[0160] In one embodiment, the cell is an insulin secreting cell, such as a pancreatic islet cell.

[0161] As noted above, suitable cells include progenitor cells and / or stem cells. Suitable stem cells can be pluripotent, multipotent, oligopotent or unipotent cells or cell populations, and include embryonic stem cells, ectoderm cells, primitive ectoderm cells and primordial germ cells. In another embodiment, suitable stem cells also include induced pluripotent stem (iPS) cells, which are pluripotent stem cells derived from non-pluripotent cells. See Zhou et al., Cell Stem Cell 4:381-384 (2009); Yu et al., Science 324(5928):797-801 (2009); Yu et al., Science 318(5858):1917-20 (2007); Takahashi et al., Cell 131:861-72 (2007); and Takahashi and Yamanaka, Cell 126:663-76 (2006), which are incorporated herein by reference in their entirety. According to this embodiment, the hydrogel may further comprise growth and differentiation factors suitable for promoting differentiation of stem cells into a desired cell population capable of producing and releasing a therapeutic agent of interest.

[0162] Cells suitable for use in the implantable therapeutic delivery systems described herein can be derived from any animal capable of producing the desired cells. The animal from which the cells are collected can be a vertebrate or an invertebrate, a mammal or a non-mammal, a human or a non-human. Examples of animal sources include, but are not limited to, primates, rodents, canines, felines, equines, bovines, or porcines. The cells can be obtained from or comprise a primary cell preparation or an immortalized cell preparation. The cells can be isolated from the same species as the implant recipient or a species different from the implant recipient.

[0163] Islet cells are clusters of cells that produce hormones. The density of islet cells is often described by islet equivalent (IEQ). An islet cell aggregate (or entire islet) may contain about 1500-2000 cells per 150 μm diameter aggregate, which is defined as one islet equivalent. In some embodiments, the systems described herein contain about 1×10 3 IEQ islet cells / ml is about 1×10 6The islet cell density of the system is between or greater than IEQ islet cells / mL. In one embodiment, the cell retention capacity of the system is based at least in part on the length of the system. The cells can survive in vivo in an implantable system for at least one month, two months, three months, four months, five months, six months, seven months, eight months, nine months, ten months, eleven months, twelve months or one year or more, and their functions represent at least about 50%, 55%, 60%, 65%, 70%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or more of the functions expressed when the cells are introduced into the system or the cells are fully developed and / or matured in the system (e.g., implanted progenitor cells that need to be further developed or matured into functional cells in vivo). In some embodiments, cells or cell preparations in the system are expanded within the system to increase cell density and / or cell function following implantation of the system in vivo.

[0164] When the hydrogel of the implantable therapeutic delivery system contains cells or cell preparations, additional cell-specific growth and / or differentiation factors can be added to the hydrogel solution to enhance cell growth, differentiation and survival. These factors include supplements (e.g., glutamine, non-essential amino acids), growth factors (e.g., epidermal growth factor, fibroblast growth factor, transforming growth factor / bone morphogenetic protein, platelet-derived growth factor, insulin growth factor, cytokines), extracellular matrix proteins (e.g., fibronectin, laminin, heparin, collagen, glycosaminoglycans, proteoglycans, elastin, chitin derivatives, fibrin and fibrinogen), angiogenic factors (e.g., FGF, bFGF, acidic FGF (aFGF), FGF-2, FGF-4, EGF, PDGF, TGF-β, angiopoietin-1, angiopoietin-2, placental growth factor (PlGF), VEGF and PMA (phorbol 12-myristate 13-acetate)) and signal transduction factors and / or transcription factors.

[0165] In another embodiment of the implantable therapeutic delivery system of the present application, the elongated hollow porous tube has pores with a diameter of 10nm to 1mm. Ideally, the pores of the system are large enough to allow the therapeutic agent to flow out of the system into the subject, but not too large to allow cells to migrate out of the implantable therapeutic delivery system.

[0166] The tensile strength of the elongated hollow porous tube of the implantable therapeutic delivery system may range from 0.01 MPa to 100 MPa.

[0167] The diameter of the implantable system is generally in the range of micrometers to centimeters. In one embodiment, the diameter of the chamber of the elongated hollow porous tube is 0.1 mm to 10 cm. For example, the diameter of the implantable system can be 0.1 mm, 0.5 mm, 1 mm, 5 mm, 10 mm, 20 mm, 30 mm, 40 mm, 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, or 100 mm.

[0168] The wall thickness of the elongated hollow porous tube may be from 10 μm to 1 cm. In addition, the length of the elongated hollow porous tube may be from 1 cm to 10 m.

[0169] Another aspect of the present application relates to a method for preparing an implantable therapeutic delivery system. The method includes providing a fiber of one or more biocompatible polymers having a diameter of 1nm to 10,000nm, wherein the polymer has a main chain of a positively charged component including a zwitterionic portion. The fiber is then applied around the model to produce an elongated porous tube. The elongated porous tube is then removed from the model to produce an elongated hollow porous tube, which defines a chamber therein and extends between a first open end and a second open end. The first end of the elongated hollow porous tube is then sealed to close the first end, while the second end remains open. The hydrogel is then inserted into the chamber through the open second end. The hydrogel is then cross-linked to the fiber of the elongated hollow porous tube, and the second end of the elongated hollow porous tube is sealed.

[0170] In another embodiment of the method of making an implantable therapeutic delivery system, applying the fibers around the former to create an elongated porous tube is achieved by electrospinning. During the electrospinning process, the electrospun polymeric fibers can be directly wrapped around the cylindrical former.

[0171] In another embodiment of the method of forming the implantable therapeutic delivery system of the present application, crosslinking requires exposing the implantable therapeutic delivery system to a crosslinking agent. Suitable crosslinking agents are discussed above. In addition, as discussed above, the hydrogel may include a cell preparation, and these cells may be pancreatic islet cells.

[0172] In another embodiment of the method of preparing the implantable therapeutic delivery system of the present application, the polymer of the fiber comprises a zwitterionic sulfobetaine-based polyurethane polymer of formula (I):

[0173]

[0174] in

[0175] X is substituted or unsubstituted C 1-20 Alkylene, or Y is C 1-20 Alkylene,

[0176] Z is independently selected at each occurrence from C 1-6 Alkylene and dimethylsilyl;

[0177] Q is R 1 C 1-10 alkyl;

[0178] R 2 SO3 - 、CO2 - , phosphate or a, b, c, d and n are independently selected from integers from 1 to 20;

[0179] e and f are independently integers selected from 1 to 10,000,000;

[0180] g is an integer selected from 0 to 10,000,000; and

[0181] Represents a connection point.

[0182] In another embodiment of the method for preparing the implantable therapeutic delivery system of the present application, the polymer of the fiber comprises a zwitterionic sulfobetaine-based nylon polymer of formula (II)

[0183]

[0184] in

[0185] R 1 C 1-10 alkyl;

[0186] R 2 SO3 - 、CO2 - , phosphate or

[0187] a, b, c, d, e and f are independently selected from integers from 1 to 20;

[0188] g and h are integers selected from 1 to 10,000,000; and

[0189] Represents a connection point.

[0190] In another embodiment of the method for preparing the implantable therapeutic delivery system of the present application, the polymer of the fiber comprises a zwitterionic sulfobetaine-based polydimethylsiloxane polymer of formula (III)

[0191]

[0192] in

[0193] X and Y are independently selected from substituted or unsubstituted C 1-20 Alkylene;

[0194] Q is O or NH;

[0195] Z is polydimethylsiloxane;

[0196] R 1 H or C 1-10 alkyl;

[0197] R 2 SO3 - 、CO2 - or phosphate;

[0198] a, b and c are integers independently selected from 1 to 20; and

[0199] d and e are independently integers selected from 1 to 10,000,000.

[0200] Another aspect of the present application relates to a method for treating diabetes, which comprises selecting a subject suffering from diabetes, and implanting the implantable therapeutic delivery system of the present application into the selected subject.

[0201] Diabetes can be divided into two major types of diseases: type I (T1D) and type II (T2D). The term "diabetes" herein also refers to a group of metabolic diseases in which patients have high blood sugar levels, including type I diabetes (T1D), type II diabetes (T2D), gestational diabetes, congenital diabetes, maturity-onset diabetes (MODY), cystic fibrosis-related diabetes, hemochromatosis-related diabetes, drug-induced diabetes (e.g., steroid diabetes), and several forms of monogenic diabetes.

[0202] Thus, in one embodiment, the subject has been diagnosed with one or more of type 1 diabetes (T1D), type 2 diabetes (T2D), gestational diabetes, congenital diabetes, maturity-onset diabetes (MODY), cystic fibrosis-related diabetes, hemochromatosis-related diabetes, drug-induced diabetes, or monogenic diabetes.

[0203] Another aspect of the present application relates to a method for delivering a therapeutic agent to a subject. The method comprises implanting the implantable therapeutic delivery system of the present application into the subject.

[0204] Conditions or diseases suitable for treatment using an implantable therapeutic delivery system include chronic diseases or disease states that require, inter alia, repeated administration of a therapeutic agent over a long period of time. In one embodiment, the condition is diabetes requiring ongoing insulin therapy.

[0205] The implantable therapeutic delivery system described herein can be used to treat a variety of diseases and conditions that require continuous supply of bioactive substances to an organism. The system may contain a homogeneous or heterogeneous mixture of bioactive agents and / or cells or cells that produce one or more bioactive substances of interest. Bioactive agents and / or cells are completely encapsulated in an elongated porous tube. This semipermeable outer layer allows the encapsulated bioactive substances of interest (e.g., insulin, glucagon, pancreatic polypeptide, etc., in the case of treating diabetes) to come out of the system, so that the active substances can be used for target cells outside the system and in the body of the recipient. In one embodiment, the semipermeable elongated porous tube allows the nutrients naturally present in the subject to provide the necessary nutrients to the cells present in the hydrogel through the membrane. At the same time, this semipermeable membrane can prevent the cells of the recipient subject, more specifically, its immune system cells pass through and enter the implantable system to harm the cells in the system. For example, in the case of diabetes, this method can allow glucose and oxygen (e.g., contained in the body) to stimulate the cells that produce insulin in the implanted system to release insulin in real time as needed by the body, while preventing the host immune system cells from recognizing and destroying the implanted cells.

[0206] The implantable therapeutic delivery system can be surgically implanted into a subject. In one embodiment, the system uses minimally invasive surgical techniques, such as laparoscopic implantation. Depending on the therapeutic agent delivered, the condition to be treated, and the tissue or organ as the delivery target, the system can be implanted percutaneously, subcutaneously, intraperitoneally, intrathoracically, intramuscularly, intraarticularly, intraocularly, or intracranially.

[0207] In one embodiment, the implantable therapeutic delivery system is anchored or fixed (e.g., by suturing) at the implantation site to maintain the system and / or the released therapeutic agent at or near the implantation site. In one embodiment, the anchoring point is in or close to the tissue or organ that is the focus of treatment. In another embodiment where the delivery of therapeutic agents from the system is not position-dependent and the biodistribution of the reagent depends on the vascular system or body fluids of the subject, the system is implantable and anchored at a remote location. In one embodiment, the implantable delivery system is percutaneously or subcutaneously implanted under the skin of the abdomen, forearm, flank, back, buttocks, legs, etc., where the system is retained until the time when it is necessary to remove it.

[0208] In another embodiment, the implantable therapeutic delivery system can be retrieved after implantation. As described above, the anchoring or fixing system prevents the system from migrating, moving or traversing within the patient and facilitates easy retrieval. According to this embodiment, the system may further include a tether that facilitates retrieval. Retrieval is required when the cells stop releasing a sufficient amount of therapeutic agent. After retrieval, the retrieved system can be replaced by another system to maintain therapeutic agent delivery in the subject. A second or subsequent implant system can be implanted in the same or different position.

[0209] The implantable therapeutic delivery system described herein provides several advantages over other cell encapsulation technologies developed for delivering insulin-secreting cells for the treatment of diabetes. The main advantage is that the cell dispersion in the hydrogel of the implantable system produces a short diffusion distance, which provides rapid glucose responsiveness. The short diffusion distance also enhances the delivery of nutrients and oxygen to the islet cells in the system, thereby greatly improving long-term islet cell survival and function.

[0210] Implantable therapeutic delivery systems containing cells that produce and secrete insulin (e.g., pancreatic islet cells) are suitable for treating subjects with type I (juvenile diabetes) or type II diabetes. Suitable subjects include children, adults, and elderly subjects with insulin deficiency.

[0211] According to one embodiment, an implantable therapeutic delivery system containing cells that produce insulin is implanted laparoscopically into the abdominal or thoracic cavity. Diabetic patients can significantly reduce the need to monitor blood sugar levels using an implantable system and can completely eliminate the need for insulin injections. The implant system can be monitored regularly (e.g., monthly or bimonthly) to ensure that the cells of the implant are fully functional.

[0212] According to aspects of the present application relating to the treatment of diabetes, the implantable therapeutic delivery system comprises cells that produce insulin. Suitable insulin-secreting cells include pancreatic islet cells. Since the cells in the implantable system described herein are protected from the influence of the host immune system, the pancreatic islet cells can be derived from any suitable source, that is, human or non-human. Examples of suitable animal sources include, but are not limited to, primates, pigs, bovines, equines, felines, canines, and rodents. In one embodiment, the pancreatic islet cells are stem cells or progenitor cells, including induced pluripotent stem cells that differentiate into pancreatic islet cells that produce insulin.Suitable insulin-secreting cell populations and methods for producing such populations are known in the art, see, for example, but not limited to, U.S. Pat. No. 8,425,928 to Martinson et al.; U.S. Pat. Nos. 5,773,255 and 5,712,159 to Fiore; U.S. Pat. No. 6,642,003 to Perfetti et al.; Rezania et al., “Reversal of Diabetes with Insulin-Producing Cells Derived In vitro from Human Pluripotent Stem Cells,” Nature Biotechnology 32: 1121-1133 (2014); Kuo et al., “Stem Cell Therapy: Differentiation Potential of Insulin Producing Cells from Human Adipose Derived Stem Cells and Umbilical Cord MSCs,” Nature Biotechnology 32: 1121-1133 (2014); MSCs), "Int'l. J. Clin. Med. 1(1):21-25 (2014); Thakkar et al., "Insulin-secreting Adipose-derived Mesenchymal Stromal Cells with Bone Marrow-derived Hematopoietic Stem Cells from Autologous and Allogenic Sources for Type I Diabetes Mellitus", "Cytotherapy", doi.org / 10.1016 / j.jcyt.2015.03.608 (published online in April 2015), which are incorporated herein by reference in their entirety.

[0213] In addition, implantable therapeutic delivery systems can be used to treat conditions associated with insufficient levels of insulin secretion. These are conditions in which the subject produces plasma levels of insulin that are lower than the levels required to maintain normal glucose levels in the blood, causing the subject with the condition associated with insufficient insulin secretion to become hyperglycemic. In such conditions, the level of insulin secreted by the pancreatic β cells of the diseased subject is insufficient to maintain normal concentrations of glucose in the blood (i.e., normal blood sugar).

[0214] One of the conditions associated with insufficient insulin secretion levels is insulin resistance. Insulin resistance is a condition in which the cells of a subject become less sensitive to the glucose-lowering effects of insulin. Insulin resistance in muscle and adipocytes reduces glucose uptake (and therefore, glucose is locally stored in the form of glycogen and triglycerides), while insulin resistance in hepatocytes causes reduced glycogen synthesis and storage and is unable to inhibit glucose production and release into the blood. Insulin resistance generally refers to a reduction in the glucose-lowering effect of insulin. However, other functions of insulin may also be affected. For example, insulin resistance in adipocytes reduces the normal effects of insulin on lipids, and causes a reduction in the uptake of circulating lipids and an increase in the hydrolysis of stored triglycerides. The increased mobilization of lipids stored in these cells increases free fatty acids in plasma. Increased blood fatty acid concentrations, reduced muscle glucose uptake, and increased liver glucose production all contribute to increased blood sugar levels. If there is insulin resistance, the pancreas needs to secrete more insulin. If this compensatory increase does not occur, blood sugar concentrations increase and type II diabetes occurs.

[0215] Another condition associated with insufficient insulin secretion levels is metabolic syndrome. Metabolic syndrome is generally used to define a series of abnormalities associated with an increased risk of developing type II diabetes and atherosclerotic vascular disease. Related conditions and symptoms include, but are not limited to, fasting hyperglycemia (impaired fasting glucose in type II diabetes, impaired glucose tolerance, or insulin resistance), high blood pressure; central obesity (also known as visceral, male-type, or apple-shaped obesity), meaning overweight and fat deposited primarily around the waist; decreased HDL cholesterol; and elevated triglycerides.

[0216] Other conditions that may be associated with inadequate levels of insulin secretion include, but are not limited to, hyperuricemia, fatty liver (especially in concurrent obesity) progressing to non-alcoholic fatty liver disease, polycystic ovary syndrome (in women), and acanthosis nigricans.

[0217] Another aspect of the present application relates to a zwitterionic sulfobetaine-based nylon polymer of formula (II)

[0218]

[0219] in

[0220] R1 C 1-10 alkyl;

[0221] R 2 SO3 - 、CO2 - , phosphate or

[0222] a, b, c, d, e and f are independently selected from integers from 1 to 20;

[0223] g and h are integers selected from 1 to 10,000,000; and

[0224] Represents a connection point.

[0225] In one embodiment of the zwitterionic sulfobetaine based nylon polymer, the nylon polymer has a molar ratio of g:h ranging from 0.01:0.99 to 0.99:0.01. The nylon polymer may have a number average molecular weight of 1000 to 1000000 g / mole polymer and a glass transition point of -60°C to 300°C.

[0226] The last aspect of the present application relates to a polydimethylsiloxane polymer based on zwitterionic sulfobetaine of formula (III)

[0227]

[0228] in

[0229] X and Y are independently selected from substituted or unsubstituted C 1-20 Alkylene;

[0230] Q is O or NH;

[0231] Z is polydimethylsiloxane;

[0232] R 1 H or C 1-10 alkyl;

[0233] R 2 SO3 - 、CO2 - or phosphate;

[0234] a, b and c are integers independently selected from 1 to 20; and

[0235] d and e are independently integers selected from 1 to 10,000,000.

[0236] In one embodiment of the zwitterionic sulfobetaine based polydimethylsiloxane polymer, the polymer has a d:e molar ratio ranging from 0.01:0.99 to 0.99:0.01. The polydimethylsiloxane based polymer may have a number average molecular weight of 1000 to 1000000 g / mole of polymer and a glass transition point of -60°C to 300°C.

[0237] Unless the context dictates otherwise, preferences and options for a given aspect, feature, implementation, or parameter of the techniques described herein should be considered to have been disclosed along with any and all preferences and options for all other aspects, features, implementations, and parameters of the techniques described.

[0238] The following examples are presented to illustrate various aspects of the present application, but are not intended to limit the scope of the claimed application.

[0239] Example

[0240] The following examples are intended to illustrate the practice of embodiments of the present invention, but are in no way intended to limit the scope of the present disclosure.

[0241] Materials and methods

[0242] Materials / Reagents

[0243] Poly(tetramethylene ether) glycol (number average molecular weight 2000, PTMG, Sigma-Aldrich) was dried in a vacuum oven before synthesis. 1,4-Diaminobutane, stannous octoate (Sn(Oct)2), anhydrous dimethyl sulfoxide (DMSO), dichloromethane, ether, and 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) were obtained from Sigma-Aldrich. 1,6-Diisocyanatohexane (HDI), 1,3-propane sultone, and N-butyldiethanolamine were purchased from Alfa Aesar. Calcium chloride (CaCl2) and barium chloride (BaCl2) were purchased from EMD Millipore. Sterile sodium alginate (SLG100, 200-300 kDa MW) was purchased from FMC BioPolymer Co. (Philadelphia, PA). Rabbit anti-insulin antibody (Catalog No. ab63820) was purchased from Abcam, and anti-glucagon antibody raised in mouse (Catalog No. SAB4200685) was purchased from Sigma-Aldrich. Alexa Fluor™594 donkey anti-rabbit antibody (Catalog No. A-21207) and Alexa Fluor™488 goat anti-mouse antibody (Catalog No. A-11001) were purchased from Invitrogen.

[0244] animal

[0245] Male C57BL / 6 mice aged 8 weeks with immune competence were purchased from The Jackson Laboratory, and Sprague-Dawley rats were purchased from Charles River Laboratories (Wilmington, MA). All animal procedures were approved by the Cornell Institutional Animal Care and Use Committee.

[0246] Statistical analysis

[0247] In these experiments, data are expressed as mean ± SEM. Paired Student's t-test was used to compare the two sets of quantitative data from macrophage activation studies, studies on FBR of various PU devices and ex vivo GSIS experiments, with P < 0.05 considered statistically significant.

[0248] Example 1 - Synthesis of 3-(butylbis(2-hydroxyethyl)ammonio)propane-1-sulfonate (SB-diol); 4-(bis(2-aminoethyl)(methyl)ammonio)butyrate (SB-diamine); 3-((bis(2-hydroxyethyl)amino)methyl)-5,5-dimethylimidazolidine-2,4-dione (haloamine-diol); and tert-butyl 3-(bis(2-hydroxyethyl)amino)propionate (THAP) monomers

[0249] SB-diol monomer

[0250] N-butyldiethanolamine (16.1 g, 0.1 mol), 1,3-propanesultone (13.4 g, 0.11 mmol) and dichloromethane (300 mL) were added to a 500 mL round-bottom flask. The mixture was stirred at 40 ° C for 24 hours under a nitrogen atmosphere. After the reaction, a rotary evaporator was used to remove the solvent. The product was precipitated by ether and then washed three times with ether to obtain a white powder. The chemical structure of the product (SB-diol) was confirmed by proton nuclear magnetic resonance. 1 H NMR (D2O, 400MHz, ppm): δ3.97(t,4H),3.54(m,6H),3.4(t,2H),2.91(t,2H),2.15(m,2H),1.68(m,2H),1.34(m,2H),0.90(t,3H).

[0251] SB-Diamine Monomer

[0252] At 0 ° C, di-tert-butyl dicarbonate (50 g, 229 mmol) and triethylamine (38.3 mL, 275 mmol) were added dropwise to a solution of N, N-dimethylethylenediamine (6.71 g, 57.25 mmol) in anhydrous ethanol (150 mL) over 0.5 hours. The mixture was stirred at 0 ° C for 1 hour and then at 50 ° C for 18 hours. The solvent was removed using a rotary evaporator. The residue was dissolved in dichloromethane (150 mL), and the solution was washed with water in sequence. The organic layer was dried over anhydrous sodium sulfate and evaporated to give the product N, N'-((methylazanediyl)bis(ethane-2,1-diyl))bis(2,2-dimethylpropionamide). 1 NMR (CDCl3, 400MHz): δ4.92(s,2H),3.19(t,4H),2.45(t,4H),2.22(s,3H),1.42(s,18H).

[0253] N,N'-((methylazanediyl)bis(ethane-2,1-diyl))bis(2,2-dimethylpropionamide) (2.85 g, 10.0 mmol), 1,3-propanesultone (2.45 g, 20.0 mmol) and anhydrous dichloromethane (30 mL) were added to a 150 mL round-bottom flask. The mixture was stirred at 40 °C for 48 hours under a nitrogen atmosphere. After the reaction, the solvent was removed using a rotary evaporator. The product was precipitated with anhydrous ether and washed with anhydrous ether to obtain a white powder. 1 NMR (D2O, 400MHz): δ3.39-3.65(m,10H),3.15(s,3H),2.94(t,2H),2.21(m,2H),1.40(s,18H).

[0254] Finally, 3.0 g of the obtained product was treated with a mixture of 12 mL of trifluoroacetic acid (TFA) and 12 mL of dichloromethane at room temperature overnight, concentrated with a rotary evaporator, and precipitated in anhydrous ether to obtain a white powder (sulfobetaine-diamine monomer). 1 NMR (D2O, 400MHz): δ3.81 (m, 4H), 3.67 (m, 2H), 3.57 (m, 4H), 3.30 (s, 3H), 3.00 (t, 2H), 2.26 (s, 2H).

[0255] Halamine-diol monomers

[0256] 5,5-dimethylhydantoin (13.21 g, 100 mmol), diethanolamine (10.6 g, 100 mmol), 8.1 g (100 mmol) of 37% formaldehyde solution and 100 mL of methanol were added to a 250 mL round-bottom flask. The mixture was stirred at room temperature for 4 hours. The solvent was removed from the reaction mixture using a rotary evaporator. The resulting viscous residue was then dissolved in ethyl acetate, and anhydrous sodium sulfate was added for further drying. After removing sodium sulfate, the resulting solution was stored in a refrigerator. After 12 hours, a white solid product precipitated from the ethyl acetate solution was obtained after filtering using a cold solution. The structure of the halamine-diol monomer is shown by H 1 NMR (DMSO-d6, 400 MHz) confirmed the peaks: δ 8.27 (s, 1H), 4.37 (t, 2H), 4.30 (s, 2H), 3.42 (m, 4H), 2.64 (t, 2H), 1.28 (s, 6H).

[0257] THAP monomer

[0258] THAP was synthesized using a Michael-type reaction. Diethanolamine (10.5 g, 0.1 mol) was added to tert-butyl acrylate (12.8 g, 0.1 mol), and the reaction solution was stirred overnight at 35 ° C. under a nitrogen atmosphere, and protected from light during the reaction. The resulting solution was removed using a rotary evaporator to remove any unreacted material, and the product was subsequently purified by flash chromatography using dichloromethane and methanol (4:1) to give THAP as a colorless oil with a yield of 87%. 1 NMR (400MHz, CDCl3, ppm): 3.55 (t, 4H), 3.17 (s, 2H), 2.75 (t, 2H), 2.58 (m, 4H), 2.35 (t, 2H), 1.40 (s, 9H).

[0259] Example 2 - Synthesis of Zwitterionic Polyurethane (ZPU) and Zwitterionic Nylon (ZN)

[0260] Zwitterionic polyurethane

[0261]

[0262] Scheme 1. Reaction route of zwitterionic polyurethane

[0263] The synthetic route of ZPU is shown in Scheme 1. In this study, SB-diol / PTMG was blended in various molar ratios of 0:1, 1:1, 2:1 and 3:1 (forming PU, ZPU-1, ZPU-2, ZPU-3, respectively) and dissolved in DMSO solvent at 80°C under a nitrogen atmosphere. HDI was then added dropwise to the flask after adding two small drops of Sn(Oct)2 catalyst. The mixture was vigorously stirred for 1 hour at 80°C. If the viscosity of the reaction solution increased significantly, DMSO was added. 1,4-diaminobutane, which acts as a chain extender, was added dropwise to the solution and stirred overnight at 80°C under nitrogen protection. The molar ratio of (SB-diol+PTMG):HDI:1,4-diaminobutane was set to 1:2:1. After the reaction, the polymer solution was precipitated in diethyl ether and then washed three times with diethyl ether. The resulting white powder was then washed three times with DI water and placed in a vacuum oven at 70°C for 24 hours to remove residual solvent. To prepare the ZPU polymer films, the ZPU powders were each dissolved in HFIP at 50°C, then cast into a poly(tetrafluoroethylene) dish and placed in a vacuum oven at 60°C for 1 day.

[0264] Zwitterionic Nylon

[0265]

[0266] Scheme 2. Reaction route of carboxybetaine-based nylon

[0267] An exemplary synthetic route for forming ZN is shown in Scheme 2. SB-diamine and hexamethylenediamine are blended in various molar ratios and then dissolved in anhydrous DMSO in a nitrogen-filled 500 mL three-necked flask at 0°C. Anhydrous triethylamine is then added to the solution. Adipoyl chloride is added dropwise to the mixture over 30 minutes. The mixture is stirred at 0°C for 1 hour and then at 50°C for 18 hours. The polymer is then precipitated in ether and washed several times with ether. The resulting polymer is washed several times with water and dried in a vacuum oven. The (SB-diamine+hexamethylenediamine):trimethylamine:adipoyl chloride molar ratio is set to 1:2:1.

[0268] An exemplary synthetic scheme for polydimethylsiloxane-based zwitterionic polymers can be found in Figures 1A-1D These polymers have polydimethylsiloxane in the backbone and are formed by reacting a diol and a diamine with a diisocyanate. Using a tin catalyst, the diisocyanate reacts with the diamine and diol to form a precursor monomer. The monomer is then reacted with the diamine to form a polymer, which is then treated with an acid to form the zwitterionic portion.

[0269] Example 3 - Fabrication of ZPU Devices by Electrospinning

[0270] The ZPU polymer is first dissolved in HFIP solvent by sufficient stirring at room temperature. The polymer solution is loaded into a 10mL plastic syringe (BD Biosciences) and fed with 1.2mL / hour by a syringe pump (Harvard Apparatus, USA). The nanofiber is spun at 15kV, with a 22G blunt needle as a spinning head. The distance between the needle tip and the collector is set to 12cm. A rotating aluminum rod (McMaster-Carr) with different sizes is placed in the path of the polymer solution jet and used to collect the electrospun fibers. The rod rotates at a speed of 400-450rpm. After 40 minutes of electrospinning, the nanofiber tube is immersed in a DI water bath with the rod overnight. The tube is then carefully removed from the rod and dried in a vacuum oven at 40°C for 1 day. The end of the tube is heat-sealed using a manual pulse sealer (Impulse Sealer Supply, California (CA)). Finally, the tube is placed in a 70% ethanol solution and sterilized with UV light for future use.

[0271] Example 4 - ZPU Device Characterization

[0272] Scanning electron microscope (SEM) (LEO 1550FESEM) was used to observe the morphology of ZPU nanofiber tubes. ImageJ software was used to analyze and quantify the fiber diameter. The tensile test of ZPU nanofiber tubes was carried out on TA instruments DMA Q800 dynamic mechanical thermal analysis (DMTA). All samples were mounted between holders, separated by a distance of about 2 cm. The samples were stretched at a rate of 5 mm / min until failure. In order to verify the polymer chemical structure, ZPU nanofiber tubes were analyzed by FT-IR (Fourier transform infrared spectroscopy, Bruker Vertex V80V vacuum FT-IR system). The wave number was between 400 and 4000 cm -1 The range was 64 scans. The Scienta Omicron ESCA-2SR was used to scan the -9 XPS analysis was performed at an operating pressure of 100 mbar. Electron kinetic energy was determined using a hemispherical analyzer, using a pass energy of 200 eV for wide / survey scans and a pass energy of 50 eV for high resolution scans. Binding energy (BE) scaling was performed using C at a BE of 284.6 eV. 1s The elemental composition was calculated by CasaXPS software based on the C 1s 、N 1s , O 1s and S 2p The water absorption rate of ZPU nanofiber tubes was tested by gravity method. The ZPU nanofiber tubes were dried and weighed to obtain dry weight (m干 The tubes were immersed in 0.9% saline solution and weighed to obtain wet weight (m 湿 ). The water absorption rate is calculated as (m 湿 -m 干 ) / m 干 ×100%.

[0273] Example 5 - Protein adsorption analysis

[0274] Protein adsorption on ZPU membrane was evaluated using fluorescence method. Briefly, ZPU membrane was cut into small discs (6 mm in diameter and 1 mm in thickness) with a biopsy punch. The above discs were placed in FITC-labeled fibrinogen solution (0.1 mg / mL in PBS solution) for 1 hour at room temperature. After this period, the membrane was gently washed three times with PBS buffer to remove loosely adsorbed proteins. Fluorescence images of ZPU membrane surfaces were taken with a fluorescence microscope with a 10× lens at a fixed exposure time. ImageJ software was used to analyze and quantify the fluorescence intensity of each sample.

[0275] Example 6 - Cell Adhesion Assay

[0276] NIH / 3T3 cells were maintained in a humidified incubator at 37°C with 5% CO2 before use. The cell culture medium consisted of Dulbecco's modified Eagle medium (DMEM), 10% fetal bovine serum (FBS) and 2% penicillin-streptomycin. The nanofiber ZPU membrane (6 mm × 6 mm) was washed three times with sterile PBS and placed in each well of a 12-well plate. 2 ml was added at 10 5 Cell suspension at 100 cells / ml was added to each well and incubated for 3 days with the sample. After incubation, the membrane was gently washed with PBS and transferred to a new 12-well plate. Live / dead (LIVE / DEAD) assay kit was added to each well and incubated for 30 minutes. Finally, EVOS AMF4300 imaging system was used to obtain fluorescent images.

[0277] Example 7 - Cytokine Secretion

[0278] Murine bone marrow derived macrophages (BMDM) for cytokine secretion analysis were collected from the femur or tibia of 6-8 week old C57BL / 6J mice (Jackson Laboratory). The cells were treated with ACK lysis buffer (Invitrogen), centrifuged, and resuspended in a medium consisting of Dulbecco's modified Eagle's medium (DMEM), 10% FBS, 1% penicillin-streptomycin, and 15% macrophage colony stimulating factor (MCSF) for macrophage differentiation. After one week of culture, BMDM were isolated using a cell scraper and were plated at 10 °C for 24 h. 5The density of each cell / well was inoculated in the culture medium on the tissue culture plate. The cells were allowed to attach for 6 hours, and the culture medium was changed and IFNγ (20ng / mL) / LPS (25ng / mL) and samples were added. The samples were incubated for 12 hours, and the supernatant was collected and followed the manufacturer's instructions (Thermofisher), and TNF-α secretion was analyzed by enzyme-linked immunosorbent assay (ELISA).

[0279] Example 8 - Rat Islet Isolation and Purification

[0280] Male Spurge-Dolly rats from Charles River Laboratories are used as islet donors. Briefly, the rat bile duct is cannulated, and the pancreas is expanded by injecting cold 0.15% liberase (Liberase) (research grade, Roche) RPMI 1640 culture medium solution. The pancreas is digested in a 37°C water bath for 30 minutes. Islets are purified using discontinuous Histopaque 1077 (Sigma) gradient density and collected from the interface. These islets are further purified by a series of six gravity sedimentations. Finally, the purified islets are hand-picked under a microscope and washed with sterile saline solution. Subsequently, islets are cultured overnight in RPMI 1640 culture medium containing 10% heat-inactivated fetal bovine serum (HIFBS) and 1% penicillin / streptomycin for further use.

[0281] Example 9 - Islet Encapsulation

[0282] Before islet encapsulation, a sterile ZPU tube (diameter: 1.0 mm; length: 2.5 cm) was prepared. One end of the device was heat-sealed by a manual impulse sealer (Impulse Sealer Supply, California). The cultured islets were centrifuged at 562 RCF for 1 minute and washed with 0.9% saline solution. After washing, approximately 250 IEQ islets were resuspended in 2% SLG100 alginate solution. The alginate solution containing islets was loaded into the device and placed in a cross-linking buffer containing 100 mM CaCl2 and 5 mM BaCl2 for 10 minutes. After cross-linking, the device with encapsulated islets was washed 5 times with 0.9% saline solution to remove residual cross-linking buffer. Before implantation, the other end of the device was heat-sealed.

[0283] Example 10 - Implantation and Retrieval of the Device

[0284] Male C57BL / 6 mice with immune competence are used for implantation. Diabetic mice are produced by intraperitoneal injection of streptozotocin (130mg / kg body weight) solution (13mg / mL of 5mM sodium citrate buffer solution). Mice with non-fasting blood glucose levels exceeding 300mg / dL are considered as diabetes for two consecutive measurements. Mice are anesthetized with 3% isoflurane / oxygen and maintained at the same ratio throughout the procedure. After shaving and disinfection of the abdomen, a 1mm incision is made along the midline of the abdomen, and the peritoneal lining is exposed using blunt dissection. The peritoneal wall is then clamped with forceps, and a 1mm incision is made using a scalpel. Two devices with a total of 500-600IEQ islets are implanted in the peritoneal cavity through the incision. The incision is closed by surgical suture. For empty device implantation, the same procedure is followed.

[0285] The transplanted mice remained alive for a predetermined time after device retrieval. BG levels were monitored after retrieval to further confirm the functionality of the implanted device. If no other characterization was performed, such as ex vivo GSIS analysis or imaging, the retrieved devices were fixed in 10% neutral buffered formalin for staining.

[0286] Example 11 - Blood Glucose Monitoring

[0287] A small drop of blood was collected from the tail vein using a lancet, and blood glucose concentration was measured with a commercial blood glucose meter (Contour Next EZ Blood Glucose Meter). Mice with non-fasting BG levels below 200 mg / dL were considered normoglycemic.

[0288] Example 12 - Intraperitoneal Glucose Tolerance Test (IPGTT) Analysis

[0289] IPGTT analysis was performed 2 or 3 months after transplantation. Mice with ZPU devices were fasted for approximately 16 hours prior to intraperitoneal injection of glucose solution (2 g / kg weight). BG levels were measured at desired time points.

[0290] Example 13 - In vitro and ex vivo glucose-stimulated insulin secretion

[0291] Krebs Ringer Bicarbonate (KRB) buffer (98.5 mM NaCl, 4.9 mM KCl, 2.6 mM CaCl2, 1.2 mM MgSO4.7H2O, 1.2 mM KH2PO4 and 25.9 mM NaHCO3, supplemented with 20 mM HEPES and 0.1% BSA (Serological)) was first prepared. For in vitro glucose-stimulated insulin secretion (GSIS) studies, the ZPU devices containing islets and the same number of naked islets were cultured in KRB buffer at 37°C, 5% CO2 for 1 hour, and then incubated with 2.8 mM or 16.7 mM D-glucose for 1 hour under the same conditions. The supernatant was collected and stored for future analysis. For in vitro GSIS research, the retrieved islet-containing ZPU device was placed in a KRB buffer supplemented with 2.8 mM D-glucose for 30 minutes and incubated for 1 hour in a KRB buffer solution supplemented with 2.8 mM or 16.7 mM D-glucose. The supernatant was collected and stored for future analysis. The manufacturer's instructions were followed to quantify the insulin content using a mouse / rat insulin ELISA kit (ALPCO). The absorbance of the reaction solution at 450 nm was measured in a Synergy microplate reader (Biotek). The stimulation index (SI) was obtained as the ratio of the insulin content after high glucose (16.7 mM) stimulation divided by the insulin content after low glucose (2.8 mM) solution.

[0292] Example 14 - Insulin content in the pancreas

[0293] To measure the total insulin content in the pancreas of diabetic mice, healthy mice and transplanted mice, homogenized pancreatic tissue was placed in acid-ethanol (1.5% HCl in 70% ethanol), cut into small pieces using scissors, digested overnight at -20°C, centrifuged and neutralized with pH 7.5 Tris buffer. The supernatant was collected and stored at -80°C for insulin content determination as described above.

[0294] Example 15 - Histological Analysis and Immunostaining

[0295] The retrieved devices were fixed in 4% paraformaldehyde, embedded in paraffin and then sliced ​​by the Cornell Histology Core Facility. The samples were sliced ​​on a microtome at a thickness of 5 μm. The paraffin sections were then stained with hematoxylin / eosin. For immunofluorescence staining, the histological slides were deparaffinized and then washed in xylene, ethanol and water in sequence. The slides were then boiled in EDTA solution for antigen exposure. Nonspecific binding was blocked with 10% goat serum for 45 minutes at room temperature. The slides were poured out and incubated overnight at 4°C with a primary rabbit anti-insulin antibody (1:200) and a primary mouse anti-glucagon antibody (1:200). The sections were washed and incubated with FITC-conjugated secondary antibodies Alexa Fluor 594 donkey anti-rabbit antibody (1:400 dilution) and Alexa Fluor 488 goat anti-mouse antibody (1:400 dilution) at room temperature for 30 minutes. Cell nuclei were labeled with DAPI, and fluorescent images were captured using the EVOSAMF4300 imaging system.

[0296] result

[0297] Synthesis, fabrication and characterization of nanofiber ZPU devices

[0298] ZPU polymer (exemplary structure shown in Figure 2A Scheme 1) was synthesized from sulfobetaine-diol (SB-diol), poly(tetramethylene ether) glycol (PTMG), hexamethylene diisocyanate (HDI) and 1,4-diaminobutane. SB-diol acts as a hard segment and is synthesized and introduced to improve the hydrophilicity, antifouling properties and biocompatibility of ZPU polymers. Non-biodegradable PTMG with a molecular weight of 2 KDa acts as a soft segment and is selected because the long soft segment can improve the mechanical strength of ZPU. HDI as a chemical building block is used to synthesize ZPU polymers. 1,4-diaminobutane as a chain extender is used to adjust the molecular weight of ZPU polymers. A series of ZPU polymers with various SB contents as part of the polymer backbone are synthesized by a convenient two-step polymerization as illustrated in Scheme 1. The synthesized zwitterionic polyurethane is called ZPU x , where x represents the molar ratio of SB-diol:PTMG. The synthetic polyurethane without SB content as a control is denoted as PU.

[0299] To fabricate the ZPU device, the ZPU polymer was electrospun onto a rotating aluminum rod to obtain nanofiber tubular tubes. The size of the nanofibers can be fine-tuned by adjusting the concentration of the ZPU polymer, while the wall thickness of the nanofiber tubes can be controlled by the deposition time. ZPU devices with different sizes (inner diameter: 1 to 5 mm; wall thickness: 100 to 200 μm) were fabricated and shown to be Figure 2B and 2C The ends of the ZPU device can be simply sealed by a heat sealer. SEM images show that the electrospun ZPU membrane has a nanoporous structure with randomly oriented nonwoven fibers ( Figure 2D ), the average fiber diameter is about 280nm.

[0300] To evaluate the bulk properties of the ZPU device, XPS analysis was used to determine the elemental composition and SB fraction. 2S ) and 168 eV (binding energy, S 2p ) centered, but not detected in PU, indicating sulfur atoms from SB groups ( Figure 2E ). In addition, PU and ZPU-2 polymers are based on their N 1S The spectrum clearly distinguishes Figure 2F ). ZPU-2 N 1s The spectrum consisted of two peaks, 402 eV from the quaternary ammonium of sulfobetaine and 399 eV from the carbamate nitrogen, while only one peak (399 eV) was detected for PU. This finding confirmed that the zwitterionic polyurethane containing SB groups was successfully synthesized. FT-IR results ( Figure 2G ) shows that for ZPU-2, at 1037cm -1 The peak at is attributed to SO3 - This characteristic peak is another convincing evidence for the presence of SB groups. The mechanical properties of the ZPU device were studied by tensile tests. It was found that the tensile strength and fracture strain ( Figure 2H ) decreases with increasing SB content. ZPU-1 devices with low SB content are elastic, while ZPU-3 devices with high SB content become brittle. ZPU-2 devices with medium SB content show mechanical robustness with fracture strain >1.5 and tensile stress >10 MPa.

[0301] Current encapsulation devices made of PTFE, PCL, and PU are hydrophobic. These devices tend to negatively affect mass transfer and induce severe biofouling and FBR. Surface modification can be applied to enhance surface wettability and biocompatibility, but there are still limitations. For example, the modification only occurs at a small depth from the surface, and the properties induced after modification can deteriorate over time (Liu et al., "Ultralow Fouling Polyacrylamide on Gold Surfaces ViaSurface-initiated Atom Transfer Radical Polymerization", Biomacromolecules 13(4): 1086-1092 (2012), which is incorporated herein by reference in its entirety). In this article, the hydrophilicity of the ZPU device is regulated by adjusting the SB content. The mass transfer of the device is evaluated using a water drop test. The surface of the PU device without any SB groups is shown to be hydrophobic. Even in the case of capillary-driven wicking, the entire water droplet remained on the nanoporous surface after 30 seconds ( Fig.2I ). In contrast, the water droplet immediately wets the ZPU-2 surface and is adsorbed by the device. The results indicate that the ZPU device has superior mass delivery relative to the PU device.

[0302] In order to apply ZPU nanoporous membranes as cell encapsulation devices, the membranes need to be stable (i.e., remain intact) in aqueous environments. Figure 2J ) showed that the nanofibers of ZPU-3 devices became fluffy one month after intraperitoneal implantation in C57BL / 6J mice, while ZPU-2 devices remained intact. If the SB content is too high, the fiber interaction of ZPU-3 polymers can be significantly weakened, especially in aqueous environments. A delicate balance is achieved between stability and hydrophilicity. Overall, ZPU-2 devices are selected as cell encapsulation devices due to their balanced hydrophilicity, mechanical robustness, and stability under in vivo conditions.

[0303] In vitro characterization of the ZPU device

[0304] Protein adsorption on the surface of medical devices is considered to be the initial and critical step of the foreign body response. Fibrinogen (Fg) was used as a model protein to evaluate the antifouling performance of ZPU devices, and PU devices as a control. Fg is a coagulation protein involved in platelet aggregation and blot clot formation (Jansen et al., "Zwitterionic PEG-PC Hydrogels Modulate the Foreign Body Response in a Modulus-dependent Manner", Biomacromolecules 19(7):2880-2888 (2018), which is incorporated herein by reference in its entirety). Relative to the PU device, the amount of Fg adsorbed on the ZPU device was 21.1% ( Figure 3A ). Apparently, the ZPU surface is highly resistant to nonspecific protein adsorption. Next, cell attachment on the ZPU device in vitro was investigated. After 3 days of incubation at 37°C, NIH / 3T3 cells rapidly attached, proliferated, and formed a confluent layer on the control PU device surface, whereas only scattered cells were observed on the ZPU device ( Figure 3B The cell densities on the PU and ZPU surfaces were 2.1×10 4 cells / mm 2 and 4.3×10 2 cells / cm 2 These results suggest that the ZPU device can reduce cell adhesion.

[0305] Macrophage activation on the ZPU device was studied by inoculating murine bone marrow-derived macrophages (BMDM) and examining the release of tumor necrosis factor-α (TNF-α), which is associated with pro-inflammatory macrophages (An et al., "Developing Robust, Hydrogel-based, Nanofiber-enabled Encapsulation Devices (NEEDs) for Cell Therapies," Biomaterials 37:40-48 (2015), which is incorporated herein by reference in its entirety). BMDM cultured on the ZPU device secreted low levels of TNF-α when compared to BMDM cultured on the PU device. Figure 3C ). This study demonstrates that incorporation of a zwitterionic moiety (SB) into polyurethane can attenuate inflammatory activation of macrophages in vitro.

[0306] To investigate the mass transfer in the ZPU device, static glucose-stimulated insulin secretion (GSIS) experiments were performed. Figure 3DThe ZPU device was shown to react to glucose changes and secrete insulin. In addition, the stimulation index (ratio of insulin value after high glucose stimulation divided by insulin value after low glucose stimulation) (3.21 ± 0.38) of the islets encapsulated in the ZPU device was not statistically different from the stimulation index of the free islets (3.17 ± 0.25). Although the ZPU film is relatively thick (about 200 μm), mass diffusion is not impaired. This is in good agreement with the previous hydrophilicity test. The results further confirm that the hydrophilic ZPU device can provide excellent mass transfer.

[0307] Evaluation of the safety of ZPU devices

[0308] The safety of encapsulation devices is critical for clinical applications, especially when using human embryonic stem cell (hESC)-derived insulin-producing cells. The device needs to create a durable physical barrier to exclude immune cells and mediators that are harmful to the encapsulated cells, and also prevent the encapsulated cells from escaping the device. Therefore, encapsulation devices that can prevent cell penetration and escape will be crucial for long-term applications in clinical settings. Fine tuning the fiber size in relation to the pore size to prevent cell penetration or escape. Figure 4A As shown in , the size of ZPU fibers can be easily adjusted by the concentration of the polymer solution. The size of ZPU fibers increases with the increase of polymer concentration.

[0309] To verify whether the ZPU device can provide a physical immune protection barrier, three ZPU devices with different fiber sizes ( Figure 4A ) were implanted into the intraperitoneal space of C57BL / 6J mice for 1 month. The ZPU device with an average fiber diameter of 280 nm completely excluded cell penetration ( Figure 4B and 4C ). Almost all cells are blocked by the outermost layer. For the other two devices with average fiber diameters of 417 and 649 nm, different numbers of cells ( Figure 4D ) penetrated into the device, and for the device with the largest fiber size, some cells even migrated inside. The above results indicate that ZPU devices can be engineered to prevent cell entry and escape.

[0310] In vivo biocompatibility of the ZPU device

[0311] The performance of implanted devices is often hampered by foreign body reactions (FBRs). Therefore, there is an urgent need to develop novel medical devices with low FBRs. Immunocompetent C57BL / 6J mice were selected because this strain has been shown to induce strong FBRs against foreign implants (Veiseh et al., "Size-and Shape-dependent Foreign Body Immune Response to Materials Implanted In Rodents and Non-human Primates", Nature Materials 14(6):643-651 (2015), which is incorporated herein by reference in its entirety). The FBR of blank ZPU devices was evaluated at selected time points after implantation (2 weeks, 1 month, 3 months, and 6 months). PU devices were selected as positive controls for comparison. At 14 days, it was observed that the ZPU devices had extremely thin cell overgrowth (7.2±1.6 μm) around them, while the PU devices induced much thicker cell overgrowth (24.2±2.7 μm) ( Figure 5A ). The results showed that the ZPU device with SB portion can effectively reduce cell growth. It is generally believed that thicker cell overgrowth around the device has a negative impact on mass transfer. Encouraged by the short-term results, further longer-term studies (i.e., 1, 3, and 6 months) were performed. Similar and consistent results were obtained: the cell overgrowth on the ZPU device was significantly thinner ( Figure 5A The thickness of cell overgrowth on the ZPU device at 1, 3, and 6 months was 4.9±0.4, 7.7±1.8, and 9.8±4.0 μm, respectively, which was approximately 28.9, 16.3, 29.6, and 26.7% of the thickness deposited on the PU surface, respectively ( Figure 5B ). These quantifications showed that ZPU devices significantly reduced cellular overgrowth in the intraperitoneal space of C57BL / 6J mice in both the short-term (14 days) and long-term (180 days). In addition, all implanted ZPU devices (n=15) were easily retrieved without tissue adhesion, while 4 of the 15 PU devices had tissue adhesion, making retrieval difficult.

[0312] Correction of diabetes in mice

[0313] After confirming the mechanical, mass transfer and antifouling properties of the ZPU device as well as its safety and biocompatibility, its therapeutic potential as a cell encapsulation platform for the treatment of T1D was explored. Rat islets were first mixed into an alginate solution. The alginate solution loaded with islets was then injected into the device, and then cross-linked using a mixture of calcium and barium ions. After sealing the open end, the ZPU device encapsulating rat islets (500-600 islet equivalents per mouse) was transplanted into the peritoneal cavity of diabetic C57BL / 6J mice induced by streptozotocin (STZ), and its ability to restore normal blood sugar was evaluated. Fig. 6A Blood glucose concentration (BG) over time after transplantation is shown. Within one week after transplantation, BG levels of all transplanted mice dropped to the normoglycemic range (BG < 200 mg / dL). Eight of the 13 mice remained normoglycemic for 2 months until the device was retrieved. After retrieval, BG levels in the cured mice increased, confirming device function. In addition, the device was easily retrieved and there was no tissue adhesion. An intraperitoneal glucose tolerance test (IPGTT) was performed 2 months after transplantation ( Figure 6B ). Transplanted mice gradually achieved normoglycemia within 90 minutes, further confirming the functionality of the transplanted islets. However, even after 120 minutes, the BG of diabetic mice failed to drop to the normal range. Glucose stimulated insulin secretion (GSIS) test of the retrieved ZPU device ( Figure 6C ) showed that the islets responded to glucose changes and secreted insulin, which is further evidence of normal islet function. In another set of 3-month transplant experiments, 3 of 4 mice were cured until retrieval. IPGTT and GSIS ( Fig.6D and 6E ) analysis to verify the vitality and normal function of the transplanted islets. The pancreatic insulin content of transplanted mice, diabetic mice and healthy mice was also measured. The pancreatic insulin content of transplanted mice and diabetic mice was only 1% of that of healthy mice. This result shows that the ZPU device containing pancreatic islets delivers most of the insulin to control blood sugar levels.

[0314] Post-retrieval characterization also showed that a large number of healthy rat islets were present in the islet-loaded alginate hydrogel after careful peeling of the nanofiber membrane of the retrieved device ( Fig. 6F Many of the retrieved islets showed healthy morphology as intact islets before transplantation, as shown by H&E staining of cross sections ( Figure 6G Although encapsulated cells or xenogeneic donor tissue slightly increased FBR, histological analysis ( Figure 6H ) confirmed the presence of thin cell deposits as small as approximately 8.9 ± 1.3 μm around the ZPU device. The viability and normal function of the transplanted islets were further verified by positive insulin staining ( Fig.6I). In addition, the device was easily retrieved and there was no tissue adhesion. Finally, there was no cell entry and escape from the device as verified by histological analysis ( Figure 6J For the 3-month transplantation experiment, histological analysis and positive insulin staining ( Figure 6K and 6L ) confirmed the long-term function of the device. Some mice with early failure to correct hyperglycemia could be attributed to unintentional variables such as disintegration of the cell-laden alginate, device defects and islet number or intrinsic biological changes. Taken together, the data described above provide proof of concept for the use of the ZPU device for T1D treatment.

[0315] discuss

[0316] Although cell encapsulation represents one of the promising approaches for T1D treatment, clinical use remains challenging, in part because of the lack of appropriate devices that simultaneously meet several requirements for islet encapsulation. For example, hydrogel-based devices often have poor mechanical properties. Some porous membranes, such as PTFE or polyurethane, easily induce severe FBR and have mass diffusion constraints. Zwitterionic polyurethane polymers with adjustable hydrophilicity were synthesized, and ZPU-2 was identified as a polymer with the desired characteristics. A nanofiber encapsulation device made of ZPU-2 polymer was designed and fabricated. This is the first time that zwitterionic polyurethane has been applied as a cell encapsulation device. The optimized ZPU device has a combination of hydrophilicity and mechanical robustness. In addition, the ZPU device exhibits excellent mass transfer, as demonstrated in rapid water droplet absorption and in vitro GSIS tests. The mechanical robustness and excellent mass transfer properties of the ZPU device meet two criteria for islet encapsulation.

[0317] In addition, medical devices need to have antifouling properties in the case of complex biological media (such as body fluids, blood and cell lysates). Especially for nanoporous devices, a serious problem is the contamination of attached proteins and cells, which can cause pore blockage and negative effects on mass transfer. Nanofiber ZPU devices show high resistance to protein adsorption and cell attachment. Appropriate packaging devices are needed to solve not only immune rejection but also long-term safety issues, especially when using human embryonic stem cell (hESC) derived cells. ZPU devices with appropriate nanofiber size (<281nm) are mechanically durable and completely exclude cell penetration into the device, while allowing sufficient mass transfer required for transplanted cells. At the same time, all encapsulated cells are accommodated by the device and will not escape therefrom. The safety of the ZPU device is another important advantage for islet encapsulation.

[0318] Another key criterion for encapsulation devices is the ability to mitigate fibrotic reactions. The biocompatibility of current devices is still unsatisfactory for islet encapsulation. Hydrogel coatings are commonly used to improve the biocompatibility of medical devices. However, hydrogel coatings are prone to swelling and even rupture under in vivo conditions, thereby compromising device function (An et al., "Development of a robust, hydrogel-based, nanofiber-enabled encapsulation device (NEED) for cell therapy", Biomaterials 37: 40-48 (2015), which is incorporated herein by reference in its entirety). It was unexpectedly found that ZPU devices without any hydrogel coatings can mitigate cell overgrowth, making it as low as 10 μm for up to 6 months, while conventional PU devices induce much thicker cell overgrowth. The data are consistent with previous work (Liu et al., "Zwitterionically Modified Alginates Mitigate Cellular Overgrowth for Cell Encapsulation," Nature Communications, 10(1): 1-14 (2019), which is incorporated herein by reference in its entirety), supporting that the zwitterionic group plays an important role in the biocompatibility of the material due to its strong hydration. This zwitterionic modification that mitigates cell deposition can be applied to completely different materials. The excellent biocompatibility and ease of manufacturing make the ZPU device desirable for islet encapsulation. To demonstrate the potential application of this ZPU device, rat islets were encapsulated to restore normal blood sugar in diabetic mice for up to about 3 months.

[0319] The encapsulation and transplantation of insulin-producing cells represent a promising therapy for type 1 diabetes (T1D). However, it remains a challenge to encapsulate devices that are both safe (i.e., no cell escape / penetration and no rupture) and functional (i.e., low foreign body reaction and high-quality diffusion). In order to address this challenge, a series of zwitterionic polyurethanes (ZPUs) with sulfobetaine (SB) in the PU backbone were synthesized and used to manufacture encapsulated devices with adjustable nanoporous structures by electrospinning. Compared with conventional polyurethanes (PUs), ZPU devices exhibit similar and stable mechanical properties, but are much more hydrophilic and antifouling, and induce lower foreign body reactions (FBR) or cell overgrowth for up to 6 months after intraperitoneal implantation in C57BL / 6 mice. ZPU devices with a nanofiber size of about 280 nm prevent cell penetration in mice and achieve diabetes correction for up to about 3 months. The ZPU device, with its low FBR zwitterionic chemistry and highly porous yet durable nanofiber structure, provides a promising candidate for the development of safe and functional cell encapsulation devices for type 1 diabetes and other diseases.

[0320] A series of non-biodegradable and mechanically stable zwitterionic polyurethanes with various SB contents as part of the PU backbone were designed and synthesized. ZPU polymers were processed by electrospinning to obtain nanofiber devices for islet encapsulation. Its hydrophilicity, mechanical stability, excellent mass transfer and excellent antifouling properties have been demonstrated. The fiber size of the ZPU device can be easily adjusted to prevent cell entry and escape. More importantly, compared with conventional PU devices, the ZPU device was shown to effectively reduce cell overgrowth after implantation. The use of ZPU devices for cell encapsulation in T1D treatment has been demonstrated. ZPU devices can facilitate cell replacement therapy for T1D and other hormone deficiency diseases.

[0321] Although preferred embodiments have been depicted and described in detail herein, it will be apparent to those skilled in the relevant art that various modifications, additions, substitutions, etc. may be made without departing from the spirit of the present application, and such modifications, additions, substitutions, etc. are therefore deemed to be within the scope of the present application as defined in the appended claims.

Claims

1. A fiber of one or more biocompatible polymers having a diameter of 1 nm to 10,000 nm, wherein the polymer has a backbone with a positively charged component comprising a zwitterionic moiety, and wherein the polymer is a zwitterionic sulfobetaine-based polyurethane polymer of formula (I): in X is substituted or unsubstituted C 1-20 Alkylene, or Y is C 1-20 Alkylene, Z is independently selected at each occurrence from C 1-6 Alkylene and dimethylsilyl; Q is R 1 C 1-10 alkyl; R 2 SO3 - 、CO2 - , phosphate or a, b, c, d and n are independently selected from integers from 1 to 20; e and f are independently integers selected from 1 to 10,000,000; g is an integer selected from 0 to 10,000,000; and Represents a connection point.

2. A fiber of one or more biocompatible polymers having a diameter of 1 nm to 10,000 nm, wherein the polymer has a backbone with a positively charged component comprising a zwitterionic moiety, and wherein the polymer is a zwitterionic sulfobetaine-based nylon polymer of formula (II) in R 1 C 1-10 alkyl; R 2 SO3 - 、CO2 - , phosphate or a, b, c, d, e and f are independently selected from integers from 1 to 20; g and h are integers selected from 1 to 10,000,000; and Represents a connection point.

3. A fiber of one or more biocompatible polymers having a diameter of 1 nm to 10,000 nm, wherein the polymer has a backbone with a positively charged component comprising a zwitterionic moiety, and wherein the polymer is a zwitterionic sulfobetaine-based polydimethylsiloxane polymer of formula (III) in X and Y are independently selected from substituted or unsubstituted C 1-20 Alkylene; Q is O or NH; Z is polydimethylsiloxane; R 1 H or C 1-10 alkyl; R 2 SO3 - 、CO2 - or phosphate; a, b and c are integers independently selected from 1 to 20; and d and e are independently integers selected from 1 to 10,000,000.

4. An implantable therapeutic delivery system comprising: A housing defining a chamber, wherein the housing is porous and formed from a fiber according to any one of claims 1-3.

5. The implantable therapeutic delivery system of claim 4, wherein the polymer is a zwitterionic sulfobetaine-based polyurethane polymer of formula (I).

6. The implantable therapeutic delivery system of claim 4, wherein the polymer is a zwitterionic sulfobetaine-based nylon polymer of formula (II).

7. The implantable therapeutic delivery system of claim 4, wherein the polymer is a zwitterionic sulfobetaine-based polydimethylsiloxane polymer of formula (III).

8. The implantable therapeutic delivery system of claim 4, wherein the housing is an elongated hollow porous tube extending between a first end and a second end, wherein the fibers are wrapped around the chamber.

9. The implantable therapeutic delivery system of claim 8, wherein the porous tube has a sealed first end.

10. The implantable therapeutic delivery system of claim 8, wherein the chamber of the hollow porous tube contains a hydrogel.

11. The implantable therapeutic delivery system of claim 10, wherein the hydrogel comprises alginate.

12. The implantable therapeutic delivery system of claim 10, wherein the hydrogel and porous fiber tube are cross-linked.

13. The implantable therapeutic delivery system of claim 10, wherein the elongated hollow porous tube is sealed at the first end and the second end such that the chamber is closed.

14. The implantable therapeutic delivery system of claim 13, further comprising: A cell preparation is enclosed within a chamber, which releases a therapeutic agent from the chamber through the elongated hollow porous tube.

15. The implantable therapeutic delivery system of claim 14, wherein the cells are pancreatic islet cells.

16. The implantable therapeutic delivery system of claim 14, wherein the cells are stem cells.

17. The implantable therapeutic delivery system of claim 8, wherein the elongated hollow porous tube has pores with a diameter of 10 nm to 1 mm.

18. The implantable therapeutic delivery system of claim 8, wherein the elongated hollow porous tube has a tensile strength of 0.01 MPa to 100 MPa.

19. The implantable therapeutic delivery system of claim 8, wherein the lumen of the elongated hollow porous tube has a diameter of 0.1 mm to 10 cm.

20. The implantable therapeutic delivery system of claim 8, wherein the elongated hollow porous tube has a wall thickness of 10 μm to 1 cm.

21. The implantable therapeutic delivery system of claim 8, wherein the elongated hollow porous tube has a length of 1 cm to 10 m.

22. A method for preparing an implantable therapeutic delivery system comprising: Providing a fiber according to any one of claims 1 to 3; applying the fibers around a former to produce an elongated porous tube; removing the elongated porous tube from the mold to produce an elongated hollow porous tube defining a chamber therein and extending between a first open end and a second open end; sealing the first open end of the elongated hollow porous tube so that the first open end is closed and the second open end is open; inserting a hydrogel into the chamber through the second open end; cross-linking the hydrogel to the fibers of the elongated hollow porous tube; as well as The second open end of the elongated hollow porous tube is sealed.

23. The method of claim 22, wherein the hydrogel comprises a cell preparation.

24. The method of claim 23, wherein the cells are pancreatic islet cells.

25. The method of claim 22, wherein the cross-linking comprises: The implantable therapeutic delivery system is exposed to a cross-linking agent.

26. The method of claim 22, wherein the polymer is a zwitterionic sulfobetaine-based polyurethane polymer of formula (I).

27. The method of claim 22, wherein the polymer is a zwitterionic sulfobetaine-based nylon polymer of formula (II).

28. The method of claim 22, wherein the polymer is a zwitterionic sulfobetaine-based polydimethylsiloxane polymer of formula (III).

29. The method of claim 22, wherein the applying comprises electrospinning.

30. Use of the implantable therapeutic delivery system according to claim 15 in the preparation of a medicament for treating diabetes.

31. Use of the implantable therapeutic delivery system of claim 14 in the preparation of a medicament for delivering a therapeutic agent to a subject.

32. A surgical suture comprising the fiber of any one of claims 1-3.

33. A vascular stent comprising the fiber according to any one of claims 1 to 3.

34. A zwitterionic sulfobetaine-based nylon polymer of formula (II) in R 1 C 1-10 alkyl; R 2 SO3 - 、CO2 - , phosphate or a, b, c, d, e and f are independently selected from integers from 1 to 20; g and h are integers selected from 1 to 10,000,000; and Represents a connection point.

35. The nylon polymer of claim 34, wherein the polymer comprises a molar ratio of g:h in the range of 0.01:0.99 to 0.99:0.

01.

36. The nylon polymer of claim 34, wherein the polymer has a number average molecular weight of 1,000 to 1,000,000 grams per mole of polymer.

37. The nylon polymer of claim 34, wherein the polymer has a glass transition point of -60°C to 300°C.

38. The nylon polymer of claim 34, wherein R 1 C 1-6 alkyl.

39. A polydimethylsiloxane polymer based on zwitterionic sulfobetaine of formula (III) in X and Y are independently selected from substituted or unsubstituted C 1-20 Alkylene; Q is O or NH; Z is polydimethylsiloxane; R 1 H or C 1-10 alkyl; R 2 SO3 - 、CO2 - or phosphate; a, b and c are integers independently selected from 1 to 20; and d and e are independently integers selected from 1 to 10,000,000.

40. The polydimethylsiloxane polymer of claim 39, wherein the polymer comprises a molar ratio of d:e in the range of 0.01:0.99 to 0.99:0.

01.

41. The polydimethylsiloxane polymer of claim 39, wherein the polymer has a number average molecular weight of 1,000 to 1,000,000 grams per mole of polymer.

42. The polydimethylsiloxane polymer of claim 39, wherein the polymer has a glass transition point of -60°C to 300°C.

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