Smart Aerogel Wound Dressing That Can Be Cleaned

Abstract

An aerogel wound dressing comprising one or more aerogel layers comprising a sensing component for monitoring a wound environment, and a method of treating a wound using the aerogel wound dressing. The wound dressing includes a base layer that may include a sensing component and an optional removable layer that can be removed upon saturation with wound exudate when used to treat a wound. The method of treating a wound includes applying the aerogel wound dressing to the wound, monitoring for infection, replacing the wound dressing upon infection, and replacing the removable layer upon saturation with wound exudate.

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims the benefit of U.S. Provisional Patent Application No. 63 / 350,963, filed on June 10, 2022, which is hereby incorporated by reference in its entirety.

[0002] Statement Regarding Federally Sponsored Research and Development This invention was made with government support under Grant No. CMMI - 1826030 awarded by the National Science Foundation. The United States government has certain rights in this invention.

[0003] The present invention relates to the field of medical devices, and more particularly to wound dressings for the treatment of wounds, including chronic wounds. In certain embodiments, the present invention relates to an aerogel - based wound dressing that promotes the healing process of wounds, including chronic wounds. In further embodiments, the present invention relates to a method of treating a wound using an aerogel - based wound dressing.

Background Art

[0004] Wound healing is a complex process. Certain wounds, such as chronic wounds, do not heal for weeks to years, introducing further complexity to the healing process. The goal of wound care is to accelerate healing and prevent wounds from becoming chronic. The four stages of wound healing include hemostasis, inflammation, proliferation, and remodeling. In chronic wounds, the healing process remains in the inflammatory phase where localized swelling, redness, heat, and pain are experienced by the patient. At this stage, generally, a fluid consisting of water, salts, proteins, fluid from damaged blood vessels, debris from damaged tissue, growth factors, etc. exudes from the wound. This fluid is known as wound exudate. Appropriate exudate management and removal are extremely important for such wounds to heal and progress to the later stages of wound healing. Furthermore, it is important to prevent the wound from being infected by pathogens in the surrounding environment. Any such infection can delay healing or cause further damage to the wound. When a wound is infected by a pathogen, a "biofilm", which is a membranous tissue formed by microorganisms, is formed, which adheres to the wound surface and produces destructive enzymes and toxins that promote the inflammatory phase in the wound.

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the current situation, the need to monitor insufficient exudate absorption by dressings and wound infections is one of several reasons why wound dressings often need to be changed constantly. When the dressing is changed, the wound bed is disrupted and the wound is exposed to the surrounding environment, increasing the risk of biofilm formation and delayed healing. For this reason, a new type of wound dressing that can absorb a large amount of exudate and can remain on the wound for a longer period is advantageous. High absorption of exudate from the wound and restriction of bacteria / viruses from the environment are two very important properties that wound dressings, especially those for chronic wounds, should possess. Therefore, there is a need for a cleanable and smart dressing that has all of the above-mentioned properties.

Means for Solving the Problems

[0006] One embodiment of the present invention provides an aerogel wound dressing including an aerogel layer, wherein the aerogel layer contains a sensing component.

[0007] Another embodiment of the present invention provides the aerogel wound dressing according to any of the above embodiments, wherein the sensing component indicates a change in the pH of the wound exudate absorbed by the aerogel layer.

[0008] Another embodiment of the present invention provides the aerogel wound dressing according to any of the above embodiments, wherein the sensing component changes color due to a change in the pH of the wound exudate absorbed by the aerogel layer.

[0009] Another embodiment of the present invention provides the aerogel wound dressing according to any of the above embodiments, wherein the sensing component contains curcumin.

[0010] Another embodiment of the present invention provides the aerogel wound dressing according to any of the above embodiments, wherein the sensing component is added to the first aerogel layer during the formation of the first aerogel layer.

[0011] Another embodiment of the present invention provides the aerogel wound dressing according to any of the above embodiments, wherein the sensing component includes a probe connected to an external sensing device.

[0012] Another embodiment of the present invention provides the aerogel wound dressing according to any of the above embodiments, wherein the first aerogel layer absorbs exudate that is 10 times or more by weight relative to the weight of the first aerogel layer.

[0013] Another embodiment of the present invention provides the aerogel wound dressing according to any of the above embodiments, further including a second aerogel layer in contact with the first aerogel layer, wherein the second aerogel layer is removable from the aerogel wound dressing.

[0014] Another embodiment of the present invention provides the aerogel wound dressing according to any of the above embodiments, wherein the second aerogel layer absorbs the fluid absorbed by the first aerogel layer.

[0015] Another embodiment of the present invention provides an aerogel wound dressing according to any of the above embodiments, wherein the first aerogel layer includes a first plurality of interconnected pores and the second aerogel layer includes a second plurality of interconnected pores.

[0016] Another embodiment of the present invention provides an aerogel wound dressing according to any of the above embodiments, wherein the average pore diameter of the first plurality of interconnected pores is larger than the average pore diameter of the second plurality of interconnected pores.

[0017] Another embodiment of the present invention provides an aerogel wound dressing according to any of the above embodiments, wherein the first aerogel layer includes a sensing component.

[0018] Another embodiment of the present invention provides an aerogel wound dressing according to any of the above embodiments, wherein the second aerogel layer is arranged to be replaceable by a user during saturation and removal of the second aerogel layer.

[0019] Another embodiment of the present invention provides an aerogel wound dressing according to any of the above embodiments, wherein the first aerogel layer is arranged to remain in a predetermined position during removal of the second aerogel layer.

[0020] Another embodiment of the present invention provides an aerogel wound dressing according to any of the above embodiments, wherein the first aerogel layer includes a sensing component.

[0021] Another embodiment of the present invention provides an aerogel wound dressing according to any of the above embodiments, wherein a pathogenic agent cannot pass through the first aerogel layer.

[0022] Another embodiment of the present invention provides an aerogel wound dressing according to any of the above embodiments, wherein the first aerogel layer is formed from at least one of cellulose, cellulose nanocrystals, chitosan, Kevlar® (registered trademark), lignin, or any combination thereof, and the second aerogel layer is formed from at least one of cellulose, cellulose nanocrystals, chitosan, Kevlar® (registered trademark), lignin, or any combination thereof.

[0023] Another embodiment of the present invention provides an aerogel wound dressing according to any of the above embodiments, wherein the sensing component is sensitive to the pH of the wound exudate absorbed by the aerogel wound dressing.

[0024] Another embodiment of the present invention provides an aerogel wound dressing according to any of the above embodiments, wherein the sensing component exhibits a change in the pH of the wound exudate in response to the presence of pathogens or pathogenic by-products in the wound exudate.

[0025] Another embodiment of the present invention provides an aerogel wound dressing according to any of the above embodiments, wherein the sensing component changes color due to a change in the pH of the wound exudate.

[0026] Another embodiment of the present invention provides an aerogel wound dressing according to any of the above embodiments, wherein the sensing component exhibits keto-enol tautomerism.

[0027] Another embodiment of the present invention provides an aerogel wound dressing according to any of the above embodiments, wherein the sensing component contains curcumin.

[0028] Another embodiment of the present invention provides an aerogel wound dressing according to any of the above embodiments, wherein the sensing component is added to the aerogel layer during the formation of the aerogel layer.

[0029] Another embodiment of the present invention provides an aerogel wound dressing according to any of the above embodiments, wherein the sensing component includes a probe connected to an external sensing device.

[0030] Another embodiment of the present invention provides an aerogel wound dressing according to any of the above embodiments, wherein the aerogel layer contains a biopolymer.

[0031] Another embodiment of the present invention provides an aerogel wound dressing according to any of the above embodiments, wherein the biopolymer contains at least one of cellulose, cellulose nanocrystals, chitosan, Kevlar®, lignin, or any combination thereof.

[0032] Another embodiment of the present invention provides an aerogel wound dressing according to any of the above embodiments, wherein the aerogel layer contains two or more biopolymers.

[0033] Another embodiment of the present invention provides an aerogel wound dressing according to any of the above embodiments, wherein the aerogel layer contains a biopolymer gel grown inside another biopolymer gel.

[0034] Another embodiment of the present invention provides an aerogel wound dressing according to any of the above embodiments, wherein the aerogel layer contains a biopolymer.

[0035] Another embodiment of the present invention provides an aerogel wound dressing according to any of the above embodiments, wherein the aerogel layer has a filtration efficiency of 98.9% or more.

[0036] Another embodiment of the present invention provides an aerogel wound dressing according to any of the above embodiments, wherein pathogenic agents cannot pass through the aerogel layer.

[0037] Another embodiment of the present invention provides an aerogel wound dressing according to any of the above embodiments, wherein the aerogel layer absorbs exudate at a weight of 10 times or more the weight of the aerogel layer.

[0038] Another embodiment of the present invention provides an aerogel wound dressing according to any of the above embodiments, wherein the aerogel layer is characterized by a microstructure.

[0039] Another embodiment of the present invention provides an aerogel wound dressing of any of the above embodiments, wherein the microstructure comprises a plurality of interconnected pores.

[0040] Another embodiment of the present invention provides an aerogel wound dressing of any of the above embodiments, wherein the pores of the plurality of interconnected pores have a pore size of about 2 nm to about 50 nm.

[0041] Another embodiment of the present invention provides an aerogel wound dressing of any of the above embodiments, wherein the microstructure has a polymer domain thickness of about 10 nm to about 50 nm.

[0042] One embodiment of the present invention provides an aerogel wound dressing comprising a first aerogel layer and a second aerogel layer in contact with the first aerogel layer, wherein the second aerogel layer is removable from the aerogel wound dressing.

[0043] Another embodiment of the present invention provides an aerogel wound dressing of any of the above embodiments, wherein the first aerogel layer is characterized by a first microstructure.

[0044] Another embodiment of the present invention provides an aerogel wound dressing of any of the above embodiments, wherein the first microstructure comprises a plurality of interconnected macropores.

[0045] Another embodiment of the present invention provides an aerogel wound dressing of any of the above embodiments, wherein the macropores of the plurality of interconnected macropores have a pore size of about 50 nm to about 200 nm.

[0046] Another embodiment of the present invention provides an aerogel wound dressing of any of the above embodiments, wherein the second aerogel layer is characterized by a second microstructure.

[0047] Another embodiment of the present invention provides an aerogel wound dressing of any of the above embodiments, wherein the second microstructure comprises a plurality of interconnected micropores.

[0048] Another embodiment of the present invention provides an aerogel wound dressing of any of the above embodiments, wherein the micropores of the plurality of interconnected micropores have a pore size of about 2 nm to about 50 nm.

[0049] Another embodiment of the present invention provides an aerogel wound dressing of any of the above embodiments, wherein the first aerogel layer contains a first biopolymer.

[0050] Another embodiment of the present invention provides an aerogel wound dressing of any of the above embodiments, wherein the second aerogel layer contains a second biopolymer.

[0051] Another embodiment of the present invention provides an aerogel wound dressing of any of the above embodiments, wherein the first aerogel layer and the second aerogel layer contain a biopolymer.

[0052] Another alternative embodiment of the present invention provides an aerogel wound dressing of any of the above embodiments, wherein the first aerogel layer contains a first plurality of pores, the second aerogel layer contains a second plurality of pores, and the average size of the first plurality of pores is the same as the average size of the second plurality of pores.

[0053] Another embodiment of the present invention provides an aerogel wound dressing of any of the above embodiments, wherein the first aerogel layer contains a first plurality of pores, the second aerogel layer contains a second plurality of pores, and the average size of the first plurality of pores is larger than the average size of the second plurality of pores.

[0054] Another embodiment of the present invention provides an aerogel wound dressing of any of the above embodiments, wherein the first aerogel layer contains a sensing component.

[0055] Another embodiment of the present invention provides an aerogel wound dressing of any of the above embodiments, wherein the first aerogel layer has a filtration efficiency of 98.9% or more.

[0056] Another embodiment of the present invention provides an aerogel wound dressing of any of the above embodiments, in which a pathogenic agent cannot pass through the first aerogel layer.

[0057] One embodiment of the present invention provides a method for treating a wound, the method including applying an aerogel wound dressing to the wound.

[0058] Another embodiment of the present invention provides a method for treating a wound of any of the above embodiments, further including a step of monitoring, by a sensing component, for the presence of a pathogen, removing the aerogel wound dressing from the wound when the sensing component indicates the presence of the pathogen, and applying a treatment to the aerogel wound dressing when the sensing component indicates the presence of the pathogen.

[0059] Another embodiment of the present invention provides a method for treating a wound of any of the above embodiments, the multi-layer aerogel wound dressing including a first aerogel layer containing a sensing component and a second aerogel layer in contact with the first aerogel layer, the second aerogel layer being removable from the aerogel wound dressing, further including a step of removing the second aerogel layer from the wound upon saturation with exudate, and a step of attaching a replacement second aerogel layer to the first aerogel layer such that the replacement second aerogel layer removes exudate from the first aerogel layer.

[0060] Another embodiment of the present invention provides a method for treating a wound of any of the above embodiments, the aerogel wound dressing including a sensing component.

[0061] Another embodiment of the present invention further provides a method for treating a wound of any of the above embodiments, the aerogel wound dressing including a sensing component.

[0062] Another embodiment of the present invention further provides a method for treating a wound of any of the above embodiments, including removing the aerogel wound dressing from the wound when the sensing component indicates the presence of a pathogen.

[0063] Another embodiment of the present invention further provides a method of treating a wound according to any of the above embodiments, including treating the aerogel wound dressing when the sensing component indicates the presence of a pathogen.

[0064] Another embodiment of the present invention provides a method of treating a wound according to any of the above embodiments, wherein the aerogel wound dressing comprises a first aerogel layer and a second aerogel layer in contact with the first aerogel layer, and the second aerogel layer is removable from the aerogel wound dressing, the method being a multi-layer wound dressing.

[0065] Another embodiment of the present invention further provides a method of treating a wound according to any of the above embodiments, including removing the second aerogel layer when the wound exudate is saturated.

[0066] Another embodiment of the present invention further includes attaching a replacement second aerogel layer to the first aerogel layer, the replacement second aerogel layer being in contact with the first aerogel layer and being adapted to remove exudate from the first aerogel layer, and provides a method of treating a wound according to any of the above embodiments.

[0067] Another embodiment of the present invention provides a method of treating a wound according to any of the above embodiments, wherein the aerogel wound dressing is applied to the wound for 20 days or more. BRIEF DESCRIPTION OF THE DRAWINGS

[0068]

Figure 1

[0069]

Figure 2A

[0070]

Figure 2B

[0071]

Figure 2C

[0072] The present invention relates to the use of an aerogel in a wound dressing as a means for improving the function of the wound dressing to promote wound healing and improve wound care. The aerogel wound dressing provides a highly absorbent dressing that requires less frequent changing and eliminates the need for cumbersome negative pressure wound therapy (NPWT) devices to enhance the wound healing environment. In some embodiments, the present invention relates to a method of treating a wound using a wound dressing comprising an aerogel and an aerogel composite.

[0073] An aerogel is a substance having a low density and high porosity and typically consisting of 90 - 99% air by volume. Aerogels are known for their unique physical properties such as low thermal conductivity, high surface area, and high specific surface area. The cause of these properties is the porous microstructure created during the formation of the aerogel. The porous microstructure of the aerogel is a decisive property. The pore structure of the aerogel can be controlled by adjusting synthesis parameters such as precursor concentration, solvent selection, and drying conditions. This enables the production of aerogels with a wide range of pore diameters from microporous to mesoporous to macroporous.

[0074] As used herein, pore diameter may mean average pore diameter. As will be understood by those skilled in the art, the porous structure of an aerogel has a distribution of pore diameters. As used herein, pore diameter may mean when most of the pores of a particular aerogel composition fall within a defined range.

[0075] Microporous aerogels have pore diameters of less than 2 nm and are often used in applications such as gas separation and catalysis. Mesoporous aerogels have pore diameters of 2 - 50 nm and are generally used in applications such as energy storage and drug delivery. Macroporous aerogels have pore diameters greater than 50 nm and are often used in applications such as thermal insulation and sound absorption.

[0076] In one or more embodiments, an aerogel suitable for use in a wound dressing according to the present invention includes mesopores. In one or more embodiments, the mesopores have pore sizes of from about 2 nm to about 50 nm.

[0077] In one or more embodiments, an aerogel suitable for use in a wound dressing according to the present invention includes macropores. In one or more embodiments, the macropores have pore sizes of from about 50 nm to about 500 nm, in other embodiments from about 50 nm to about 450 nm, in other embodiments from about 50 nm to about 400 nm, in other embodiments from about 50 nm to about 350 nm, in other embodiments from about 50 nm to about 300 nm, in other embodiments from about 50 nm to about 250 nm, in other embodiments from about 50 nm to about 200 nm.

[0078] Pore diameter is a very important parameter in determining the capillary action of an aerogel. Capillary action is the ability of a liquid to flow through narrow spaces such as the interconnected pores of an aerogel. The driving force for capillary action is the surface tension of the liquid that draws the liquid into the narrow space. Generally, smaller pores cause greater capillary action. This is because smaller pores have a higher surface area - volume ratio, which increases the surface tension at the liquid - gel interface. As a result, the liquid can flow easily through the smaller pores even against gravity.

[0079] Regarding wound healing, the capillary action of the aerogel is important for promoting a moist wound healing environment while removing wound exudate from the wound surface. The interconnected pores of the aerogel can absorb wound exudate and retain it within the aerogel. The capillary action of the aerogel can keep the wound in a moist state, which is beneficial for wound healing.

[0080] Also, it is important to control the pore size to prevent excessive fluid retention, which can cause maceration of the surrounding healthy tissue. Therefore, the pore size of the aerogel used in wound dressings should be optimized to achieve the desired level of capillary action while also preventing fluid overload.

[0081] Advantageously, the aerogel suitable for use in embodiments of the present invention serves as an air-permeable barrier against bacteria and viruses. The interconnected pores of the aerogel used according to some embodiments of the present invention allow oxygen to diffuse through the aerogel and reach the wound. The same interconnected pores filter or reject the entry of bacteria or viruses into the aerogel. This filtration protects the wound from infection by bacteria or viruses by preventing the wound from coming into contact with bacteria or viruses present in the environment.

[0082] In one or more embodiments, the aerogel has a filtration efficiency for nanoparticles sized 25 nm to 250 nm of about 98.9% or more, in other embodiments about 99.0% or more, in other embodiments about 99.1% or more, in other embodiments about 99.2% or more, in other embodiments about 99.3% or more, in other embodiments about 99.4% or more, in other embodiments about 99.5% or more, in other embodiments about 99.6% or more, in other embodiments about 99.7% or more, in other embodiments about 99.8% or more, in other embodiments about 99.9% or more.

[0083] In one or more embodiments, the aerogel has a filtration efficiency of about 95% or more, in other embodiments about 96% or more, in other embodiments about 97% or more, in other embodiments about 98% or more, and in other embodiments about 99% or more of E. Coli bacteria.

[0084] The aerogel is formed by changing a gel into an aerogel. The material composition of the aerogel suitable for use in the present invention is determined by the gel and the process used to change the gel into an aerogel. As discussed above, the gel and process used also affect the resulting porous microstructure of the aerogel.

[0085] The selection of materials also depends on the use of the aerogel in wound dressings for biomedical applications. In accordance with the objectives of the present invention, suitable aerogel compositions are safe for use on wounds including chronic wounds. Further, the selection of materials for aerogel formation depends on the mechanical properties required for use in wound dressings. In some embodiments, the aerogel composition may include a biopolymer. In other embodiments, the aerogel composition may include a mixture of biopolymers. In other embodiments, the aerogel composition may include a biopolymer gel grown inside another.

[0086] As used herein, biopolymer may mean a polymer that is compatible for use in animals. Biopolymer may also mean a polymer derived from biomass or other natural sources including natural polymers produced by the cells of living organisms. The biocompatibility of the aerogel material allows for the use of dressings on a wide range of wounds including chronic wounds that require long-term treatment. The aerogel layer provides a highly absorbent and breathable layer that conforms to the contour of the wound surface and promotes a moist wound healing environment conducive to tissue regeneration. The use of a biocompatible aerogel material further enhances the effectiveness of the dressing by minimizing the risk of infection or other complications that may arise from the use of biocompatible materials.

[0087] In some embodiments, materials suitable for the aerogel composition include biopolymers. In some embodiments, biopolymers include polynucleotides, polypeptides, and polysaccharides. In some embodiments, polypeptides include proteins and amino acids, such as collagen, actin, and fibrin. In some embodiments, polysaccharides include starch, cellulose, and alginates. Other biopolymers include natural rubber, chitin, lignin, cutin, suberin, and melanin. In some embodiments, materials suitable for the aerogel composition include chitosan, cellulose, cellulose nanocrystals, lignin, and combinations of two or more.

[0088] In some embodiments, materials suitable for the aerogel composition include biocompatible polymers, including those that are synthetically produced.

[0089] In some embodiments, the mechanical properties of the aerogel can be improved by forming a composite aerogel. In these and other embodiments, a sol network, or framework, can be formed first. Then the sol of a second gel can diffuse into the framework and then gelate. Advantageously, this composite structure reduces the shrinkage of the aerogel during solvent exchange and leads to improved nucleation and growth. In such embodiments, the framework can include synthetic fibers. Synthetic fibers suitable for use in the present invention include, without limitation, Kevlar®.

[0090] According to some embodiments, the present invention is an aerogel comprising a layer of an aerogel material comprising a sensing component. The sensing component is designed to provide real-time feedback regarding the wound environment, enabling decisions based on sufficient information regarding the monitoring and treatment of the healing process.

[0091] In one embodiment, the sensing component can be a pH sensor that detects changes in the acidity or alkalinity of the wound environment. In another embodiment, the sensing component can be a temperature sensor that measures the temperature of the wound surface. Other possible sensing components can include pressure sensors, oxygen sensors, or sensors that detect the presence of specific bacteria, viruses, or other pathogens.

[0092] In some embodiments, the sensing component in these embodiments can be an additive that changes color in response to a pH change. In accordance with the objectives of the present invention, the additive to the aerogel composition should be biocompatible. This type of additive is generally known as a pH indicator. The pH indicator can be incorporated into the aerogel either during the aerogel synthesis process or as a post-treatment step. The sensing additive can be included during gel formation or during solvent exchange and drying of the gel. The sensing additive can also be included in the aerogel by emulsion templating, precipitation, or precipitation with a non-solvent during the solvent exchange step. The pH indicator can be selected based on its sensitivity to a specific pH range that can be tailored to the needs of wound healing applications.

[0093] When the aerogel wound dressing comes into contact with the wound bed, the pH indicator can detect changes in the pH level of the wound exudate. The pH indicator changes color in response to the pH change, which can be visually detected. This can provide a simple and non-invasive means of monitoring the pH level of the wound over time.

[0094] In some embodiments, the color change of the pH indicator can be correlated with specific pH values that can be determined through calibration experiments. This can provide a quantitative measurement of the pH level, which can be recorded and tracked over time to monitor the progress of wound healing.

[0095] In summary, in some embodiments of the aerogel wound dressing of claim 1, the sensing component is designed to measure the pH level of the wound bed using a pH indicator additive. The pH indicator provides a simple and non-invasive means of monitoring the pH level of the wound over time by changing color in response to a change in pH.

[0096] In some embodiments, the sensing agent is a compound that exhibits keto-enol tautomerism. Tautomers are isomers in which the arrangement of protons and double bonds in a molecule is different. Keto-enol tautomerism is a type of tautomerism that involves the transfer of a proton between the carbonyl group (keto) and the hydroxyl group (enol) of an organic molecule.

[0097] As discussed above, the sensing agent can be incorporated as an additive into the aerogel layer of the wound dressing. When the wound dressing is in contact with wound exudate, the pH indicator undergoes proton transfer between the keto and enol forms in response to a change in pH level. This proton transfer causes a change in the absorption spectrum of the pH indicator, resulting in a color change that can be visually detected.

[0098] The pH indicator is not particularly limited, and one of ordinary skill in the art could select a suitable pH indicator without undue experimentation. In various embodiments, suitable pH indicators can include, without limitation, curcumin. Advantageously, curcumin is known to have beneficial effects on oxidative and inflammatory conditions.

[0099] As shown in FIGS. 2A-2C, an aerogel wound dressing according to an embodiment of the present invention exhibits a color change of the wound dressing when exposed to an artificial wound fluid that increases the pH of the wound dressing. In FIG. 2A, it is shown that the unused aerogel wound dressing has a yellow color. In FIG. 2B, the aerogel wound dressing is exposed to an artificial infected wound fluid that increases the pH of the aerogel wound dressing, and the color is beginning to change from yellow to red. In FIG. 2C, the entire aerogel wound dressing is a reddish-brown color indicating the change caused by the absorption of the artificial wound exudate.

[0100] Other additives may be included in the aerogel composition suitable for use in the present invention. For example, the aerogel composition can be used as a means for delivering drug therapy to a wound. The drug therapy is not particularly limited, and those skilled in the art will be able to select an appropriate drug therapy without undue experimentation. In various embodiments, suitable drug therapies can include, without limitation, biocides and antibiotics.

[0101] In some embodiments, two aerogels can be used in the wound dressing according to the present invention. In these and other embodiments, the two aerogels can be arranged as a base layer and an upper layer, also referred to as a first layer and a second layer, respectively. In these and other embodiments, the base layer functions to remove exudate from the wound surface, while the upper layer removes exudate from the base layer. Without wishing to be bound by theory, it is believed that the capillary action resulting from the pore size of the aerogel provides the driving force necessary to remove exudate from the base layer through the interface between the base layer and the upper layer to the upper layer. In these and other embodiments, the capillary action can be provided by a base layer having a porous structure with a pore size larger than the pore size of the porous structure of the upper layer.

[0102] Referring now to FIG. 1, a multi-layer aerogel wound dressing is generally indicated by the numeral 100. The multi-layer aerogel wound dressing 100 includes a first layer 101, also referred to as a base layer, and a second layer 102, also referred to as an upper layer. The multi-layer aerogel wound dressing 100 is applied to the wound surface 11 of the subject 10 such that the first layer 102 contacts the wound surface 11. The first layer 101 includes a macroporous structure. The second layer 102 exhibits a mesoporous structure. Arrow 121 is a typical flow of exudate flowing from the wound surface 11 through the first layer 101 to the second layer 102. Arrow 122 is typical of air passing through the multi-layer aerogel wound dressing 100, and oxygen can penetrate through the first layer 101 and the second layer 102 to reach the wound surface 11. Arrow 123 is typical of the rejection of pathogens, including bacteria and viruses, by the multi-layer aerogel wound dressing 100 as a result of the mesoporous structure of the second layer 102.

[0103] In an embodiment according to the present invention, the base layer comprises an aerogel having macropores. In these and other embodiments, the upper layer comprises an aerogel having mesopores. In such embodiments, due to the difference in pore size between the two layers, exudate can collect in the upper layer while the bottom layer can be kept moist. Advantageously, removal of the exudate prevents the formation of biofilms while the two layers of aerogel protect the wound from bacteria, viruses, and other pathogens. Further, the bilayer structure provides for removal and replacement of the upper layer upon saturation of the upper layer by exudate. In these and other embodiments, the base layer can remain in contact with the wound while removing and replacing the upper layer with a clean upper layer, providing continuous removal of exudate without the trauma associated with wound dressing replacement.

[0104] In an embodiment according to the present invention, one or more of the base layer and the upper layer may comprise a sensing agent according to the above description.

[0105] The role of a wound dressing is to provide optimal conditions for wound healing while protecting the wound from further trauma and invasion by pathogenic microorganisms. It is also important that the dressing can be removed without damaging the wound surface to prevent further damage during dressing replacement. In an embodiment according to the present invention, an aerogel wound dressing comprising at least an aerogel layer is provided. In some embodiments, the aerogel layer comprises an aerogel composition according to any of the descriptions included above.

[0106] In some embodiments, the aerogel layer of the aerogel wound dressing is the bottom layer in contact with the wound.

[0107] In some embodiments, the aerogel wound dressing may further comprise a fiber dressing as the bottom layer in contact with the wound. In other embodiments, the aerogel wound dressing may comprise a foam dressing as the bottom layer in contact with the wound.

[0108] In some embodiments, the aerogel wound dressing comprises two layers formed from an aerogel composition according to any of the descriptions included above. In these and other embodiments, the aerogel wound dressing may include a first aerogel layer as a base layer and a second aerogel layer as a top layer. In these and other embodiments, the top layer may be removable from the base layer. In these and other embodiments, the top layer may have a pore size smaller than the pore size of the base layer. In these and other embodiments, the base layer may include a sensing component that provides insight into the wound environment. In these and other embodiments, the sensing component may include a sensing component as described above.

[0109] In some embodiments, the aerogel wound dressing may be held in place on the wound using a medical adhesive.

[0110] In some embodiments, the aerogel wound dressing according to the present invention can be considered a primary wound dressing. In these and other embodiments, a secondary wound dressing known in the art can be used to secure the aerogel wound dressing in place. In these and other embodiments, the secondary dressing can be removed to access the primary wound dressing, either to monitor the sensing component or to remove and replace the second layer of a multi-layer aerogel wound dressing.

[0111] In some embodiments, the aerogel wound dressing according to the present invention is sized according to the type of wound to be treated. In some embodiments, the aerogel wound dressing according to the present invention is sized according to standards known in the art of wound dressings. A wound dressing of appropriate size reliably covers the entire surface area of the wound being treated by the wound dressing.

[0112] In some embodiments, the aerogel wound dressing according to the present invention absorbs a fluid having a weight that is 10 times or more the weight per unit weight of the aerogel wound dressing, in other embodiments a fluid having a weight that is 15 times or more the weight per unit weight of the aerogel wound dressing, in other embodiments a fluid having a weight that is 20 times or more the weight per unit weight of the aerogel wound dressing, in other embodiments a fluid having a weight that is 25 times or more the weight per unit weight of the aerogel wound dressing, in other embodiments a fluid having a weight that is 30 times or more the weight per unit weight of the aerogel wound dressing, in other embodiments a fluid having a weight that is 35 times or more the weight per unit weight of the aerogel wound dressing, in other embodiments a fluid having a weight that is 40 times or more the weight per unit weight of the aerogel wound dressing, in other embodiments a fluid having a weight that is 45 times or more the weight per unit weight of the aerogel wound dressing, in other embodiments a fluid having a weight that is 50 times or more the weight per unit weight of the aerogel wound dressing, in other embodiments a fluid having a weight that is 55 times or more the weight per unit weight of the aerogel wound dressing, in other embodiments a fluid having a weight that is 60 times or more the weight per unit weight of the aerogel wound dressing.

[0113] In some embodiments that include a removable second layer that contacts the first layer, the removable second layer can be the same thickness as the first layer. In other embodiments, the removable second layer can be a greater thickness than the first layer. As will be readily understood by those skilled in the art, the thickness of the layer directly affects the amount of wound exudate absorbed by that layer.

[0114] In use, the aerogel wound dressing according to the present invention provides a highly absorbent and breathable dressing that conforms to the contour of the wound surface. The sensing component, when present, provides real-time feedback regarding the wound environment and enables monitoring of the healing process. The unique combination of the aerogel material and the sensing component provides a versatile and effective wound dressing that can be used to treat a wide range of wounds, including chronic wounds that are difficult to heal using traditional treatments.

[0115] Embodiments of the present invention provide a method of treating a wound using an aerogel wound dressing. In some embodiments, the method of treating a wound may include applying an aerogel wound dressing to the wound. In these and other embodiments, the application may include applying an optional secondary wound dressing to secure the aerogel wound dressing in place. In these and other embodiments, the aerogel wound dressing may remove exudate from the wound as described above. In some embodiments, the aerogel wound dressing may include a sensing component. In these and other embodiments, the method may include monitoring the sensing component for the presence of a pathogen. As discussed above, the presence of determining whether a pathogen is present in the wound environment may be indicated by the sensing component. In these and other embodiments, the method may further include removing the aerogel wound dressing from the wound when the sensing component indicates the presence of a pathogen. Removal enables the wound to be treated as necessary.

[0116] In embodiments where the method includes applying an aerogel wound dressing that includes at least an aerogel base layer and an aerogel upper layer, the method may further include removing the aerogel upper layer upon saturation of the aerogel upper layer by exudate from the wound. In these and other embodiments, the method may further include replacing the aerogel upper layer with a replacement aerogel upper layer such that exudate continues to be removed from the wound. In these and other embodiments, the method may include leaving the base layer of the aerogel wound dressing in contact with the wound for 7 or more days, in other embodiments 14 or more days, in other embodiments 15 or more days, in other embodiments 16 or more days, in other embodiments 17 or more days, in other embodiments 18 or more days, in other embodiments 19 or more days, in other embodiments 20 or more days, in other embodiments 21 or more days.

[0117] Embodiments of the present invention as described above can be created according to the following method. In some embodiments, it is formed according to the desired final properties of the aerogel from which the gel composition is obtained. In these and other embodiments, this may include providing the desired additives during gel formation. In these and other embodiments, gel formation includes providing a sol that undergoes a sol-gel transition. In some embodiments, a second sol of a second gel can diffuse into the sol network or framework generated from the first gel. In such embodiments, the second sol is gelled after diffusion. The shape of the resulting aerogel can be determined by the mold in which the gel composition solidifies. Using various molds, different aerogels can be produced depending on the type of wound to be treated by the resulting aerogel wound dressing.

[0118] After the gel has solidified in the mold, the gel can be subjected to solvent exchange. In some embodiments, additives can be included in the gel during the solvent exchange step. In some embodiments, after the solvent exchange step, the gel can undergo a supercritical drying step.

[0119] Other techniques known in the art may be suitable for creating the aerogel composition according to the above embodiments.

[0120] In light of the above, it will be understood that the present invention significantly advances the art by providing a wound dressing and a method of treating wounds that are structurally and functionally improved in various ways. Although specific embodiments of the present invention have been disclosed in detail above, it will be understood that the present invention is not limited by the above disclosure as modifications of the present invention will be readily apparent to those skilled in the art. The scope of the present invention must be recognized from the claims set forth below.

Examples

[0121] To illustrate and embody the present invention, the aerogel wound dressing of the present invention was synthesized and evaluated as described above to more fully determine the following properties.

[0122] Test specimens of various wound dressings were tested to determine their absorption capacity. The wound dressings include Duoderm, Algisite, Drawtex, Aquacel, and the aerogel wound dressing according to certain embodiments of the present invention. Each test specimen was immersed in 100 ml of water, and the mass increase was recorded over time. The results are shown in Table I. [Table 1]

[0123] The aerogel wound dressing according to the present invention exhibits excellent absorption per unit weight compared to other types of wound dressings.

[0124] Test specimens of wound dressings were tested to determine the filtration efficiency of nanometer-sized impurities. This test simulates the performance of the dressing in the presence of microorganisms. Test specimens of Algisite, Drawtex, Aquacel, and the aerogel wound dressing according to certain embodiments of the present invention were exposed to a solution containing NaCl nanoparticles having a size of 25 nm to 250 nm at a flow rate of 20 liters / min. The results of this test are shown in Table II. [Table 2]

[0125] Using the above experimental parameters and settings, the data and information provided herein support the invention recited in the claims. Although the present invention has been described in detail with specific reference to several embodiments detailed herein, other embodiments can achieve the same results. Changes and modifications of the present invention will be apparent to those skilled in the art, and the present invention encompasses all such modifications and equivalents within the scope of the appended claims.

Claims

1. an aerogel wound dressing comprising a first aerogel layer, wherein the first aerogel layer comprises a sensing component.

2. The aerogel wound bandage according to claim 1, wherein the sensing component indicates a change in the pH of the wound exudate absorbed by the first aerogel layer.

3. The aerogel wound bandage according to claim 2, wherein the sensing component changes color in response to a change in the pH of the wound exudate absorbed by the first aerogel layer.

4. The aerogel wound dressing according to claim 1, wherein the sensing component contains curcumin.

5. The aerogel further comprises a second aerogel layer in contact with the first aerogel layer, wherein the second aerogel layer is removable from the aerogel wound dressing. The first aerogel layer is formed from at least one of cellulose, cellulose nanocrystals, chitosan, Kevlar®, lignin, or any combination thereof, and the second aerogel layer is formed from at least one of cellulose, cellulose nanocrystals, chitosan, Kevlar®, lignin, or any combination thereof. The aerogel wound dressing according to claim 1.

6. The first aerogel layer includes a first plurality of interconnected pores, the second aerogel layer includes a second plurality of interconnected pores, and the average pore diameter of the first plurality of interconnected pores is greater than the average pore diameter of the second plurality of interconnected pores. The aerogel wound dressing according to claim 5.

7. The aerogel wound bandage is arranged such that the second aerogel layer can be replaced by the user upon saturation and removal, and the aerogel wound bandage is arranged such that the first aerogel layer remains in place when the second aerogel layer is removed. The aerogel wound dressing according to claim 5.

8. A method for treating a wound, comprising applying an aerogel wound dressing to the wound.

9. The aerogel wound dressing contains a sensing component, The above method further, The sensing component is monitored for the presence of pathogens; When the sensing component indicates the presence of a pathogen, remove the aerogel wound dressing from the wound; When the sensing component indicates the presence of a pathogen, the aerogel wound dressing is treated. The method according to claim 8, further comprising the following:

10. The aerogel wound dressing mentioned above: A first aerogel layer containing the aforementioned sensing component; and A second aerogel layer in contact with the first aerogel layer. A multilayer aerogel wound dressing comprising the second aerogel layer being removable from the aerogel wound dressing: The above method further, A step of removing the second aerogel layer from the wound when the exudate is saturated; The method according to claim 9, further comprising the step of attaching a substitute second aerogel layer to the first aerogel layer so that the substitute second aerogel layer removes exudate from the first aerogel layer.

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