Dressing for diabetic foot wound and preparation method thereof

Abstract

The invention relates to the technical field of biomedical dressings, in particular to a dressing for a diabetic foot wound surface and a preparation method of the dressing. 0.2 to 0.8 part of reduced graphene oxide; 2 to 5 parts of beta-1, 3-glucan modified by chondroitin sulfate; 0.08 to 0.3 part of silver nitrate; 3 to 7 parts of N-isopropyl acrylamide-co-acrylic acid; 0.15 to 0.4 part of N, N '-methylene bisacrylamide; 2 to 5 parts of sulfhydrylated hyaluronic acid; 0.3 to 0.8 part of D-alpha-vitamin E polyethylene glycol succinate; 2 to 5 parts of amino-functionalized mesoporous silica; 1 to 3 parts of L-arginine-L-glutamate; 0.1 to 0.4 part of genipin; the super-strong mechanical property and the super-strong flexibility are realized, so that the dressing can better adapt to the irregular shape of a wound surface, and continuous protection is provided.

Description

Technical Field

[0001] The invention relates to the technical field of biomedical dressings, and in particular to a dressing for diabetic foot wounds and a preparation method thereof. Background Art

[0002] Diabetic foot is one of the common serious complications of diabetic patients, and its treatment has always been a huge challenge facing the medical community. Traditional diabetic foot wound dressings often have problems such as insufficient fluid absorption, limited antibacterial effect, and poor biocompatibility, making it difficult to meet the treatment needs of complex wound environments. In recent years, although some new dressings have been developed, such as silver-containing dressings and hydrogel dressings, it is still difficult to fully solve the multiple problems in the treatment of diabetic foot wounds.

[0003] Currently, the closest existing technology is a composite hydrogel dressing that combines carboxymethyl cellulose and chitosan and is loaded with antimicrobial agents. However, this dressing still has several key problems: first, its mechanical strength is insufficient and it is difficult to adapt to the needs of long-term use; second, it lacks intelligent responsiveness and cannot adjust drug release according to the wound environment; third, its antioxidant properties are limited and it is difficult to effectively combat oxidative stress on the wound; and finally, its ability to promote angiogenesis is insufficient, which affects the long-term healing of the wound. Summary of the invention

[0004] The present invention aims to solve the above technical problems and develop a new diabetic foot wound dressing through innovative multi-component design and synergistic mechanism. The dressing not only has excellent mechanical properties and liquid absorption performance, but also can achieve multiple functions such as intelligent pH-responsive drug release, long-lasting antioxidant protection, strong antibacterial and angiogenesis promotion.

[0005] The object of the present invention is to provide a dressing for diabetic foot wounds, the dressing comprising the following components (in parts by weight):

[0006] 18-28 parts of carboxymethyl chitosan;

[0007] 0.2-0.8 parts of reduced graphene oxide;

[0008] 2-5 parts of chondroitin sulfate-modified β-1,3-glucan;

[0009] Silver nitrate 0.08-0.3 parts;

[0010] 3-7 parts of N-isopropylacrylamide-co-acrylic acid;

[0011] N,N'-methylenebisacrylamide 0.15-0.4 parts;

[0012] 2-5 parts of thiolated hyaluronic acid;

[0013] D-α-tocopherol polyethylene glycol succinate 0.3-0.8 parts;

[0014] 2-5 parts of amino-functionalized mesoporous silica;

[0015] 1-3 parts of L-arginine-L-glutamate;

[0016] Genipin 0.1-0.4 parts;

[0017] 644.3-671.17 parts of deionized water.

[0018] Specifically, the degree of substitution of the carboxymethyl chitosan is 0.7-0.9, and the molecular weight is 80-250 kDa.

[0019] Specifically, the carbon-oxygen ratio of the reduced graphene oxide is 4:1 to 8:1, and the sheet size is 1-5 μm.

[0020] Specifically, the amino-functionalized mesoporous silica has a pore size of 5-9 nm, a specific surface area of ​​500-900 m2 / g, and an amino content of 1.0-1.5 mmol / g.

[0021] The preparation method of the dressing comprises the following steps:

[0022] (1) preparing a carboxymethyl chitosan-reduced graphene oxide composite hydrogel matrix;

[0023] (2) preparing chondroitin sulfate-modified β-glucan loaded silver nanoparticles;

[0024] (3) Preparation of temperature-responsive N-isopropylacrylamide-co-acrylic acid microgels;

[0025] (4) preparing D-α-vitamin E polyethylene glycol succinate modified thiolated hyaluronic acid;

[0026] (5) preparing L-arginine-L-glutamate loaded amino-functionalized mesoporous silica nanoparticles;

[0027] (6) All components obtained in steps (1) to (5) are mixed, and genipin is added to prepare a final hydrogel dressing.

[0028] Specifically, the step (1) comprises:

[0029] First, 18-28 parts of carboxymethyl chitosan are dissolved in 600-800 parts of deionized water and stirred at 30-40°C for 5-7 hours;

[0030] Secondly, 0.2-0.8 parts of reduced graphene oxide are dispersed in 150-200 parts of deionized water and ultrasonically treated for 45-75 minutes;

[0031] Then, the reduced graphene oxide dispersion was slowly added dropwise to the carboxymethyl chitosan solution and stirred at 45-55° C. for 3-4 hours.

[0032] Specifically, the step (2) comprises:

[0033] First, 2-5 parts of chondroitin sulfate-modified β-1,3-glucan are dissolved in 250-350 parts of deionized water and stirred at 65-75° C. for 1.5-2.5 hours;

[0034] Secondly, dissolve 0.08-0.3 parts of silver nitrate in 60-120 parts of deionized water and slowly add it dropwise to the above solution;

[0035] Then, the reaction was stirred at 75-85°C for 2.5-3.5 hours.

[0036] Specifically, the step (3) comprises:

[0037] First, 3-7 parts of N-isopropylacrylamide-co-acrylic acid and 0.15-0.4 parts of N,N'-methylenebisacrylamide are dissolved in 250-350 parts of deionized water;

[0038] Secondly, nitrogen was passed to remove oxygen for 40 minutes and the temperature was raised to 72-78°C;

[0039] Then, add 0.08-0.15 parts of ammonium persulfate as an initiator and react for 5-7 hours;

[0040] Finally, the solution was cooled to room temperature and dialyzed for 60 hours.

[0041] Specifically, the step (4) comprises:

[0042] First, dissolve 2-5 parts of thiolated hyaluronic acid in 350-450 parts of deionized water;

[0043] Secondly, dissolve 0.3-0.8 parts of D-α-tocopherol polyethylene glycol succinate in 60-120 parts of anhydrous ethanol;

[0044] Then, at 5-10° C., slowly add the D-α-vitamin E polyethylene glycol succinate solution dropwise to the thiolated hyaluronic acid solution and stir for 45 minutes;

[0045] Again, 0.05-0.1 parts of 2,2'-dithiodipyridine was added as a cross-linking agent;

[0046] Finally, the reaction was carried out at room temperature for 15-30 hours and dialyzed for 60 hours.

[0047] Specifically, the step (6) comprises:

[0048] First, all the components obtained in steps (1) to (5) are mixed in proportion and stirred at 40-50° C. for 3-4 hours;

[0049] Secondly, slowly add 0.1-0.4 parts of genipin solution dropwise and continue stirring for 45-75 minutes;

[0050] Then, pour the mixture into a mold and let it stand at 4°C for 18-30 hours;

[0051] Again, the gel was frozen at -25°C for 5-8 hours and then freeze-dried at -55°C in a vacuum for 60-90 hours;

[0052] Finally, the dried hydrogel was cut into desired sizes under sterile conditions, vacuum packed, and sterilized by gamma ray.

[0053] From the perspective of molecular structure and chemical mechanism, the innovation of the present invention is mainly reflected in the following aspects:

[0054] 1. Synergistic effect of carboxymethyl chitosan and reduced graphene oxide: The carboxyl and amino groups in carboxymethyl chitosan form a hydrogen bond network with the oxygen-containing functional groups of reduced graphene oxide, which significantly enhances the mechanical strength and flexibility of the dressing. 2 The hybrid carbon structure provides excellent electrical conductivity, which is beneficial for promoting cell growth and tissue regeneration.

[0055] 2. Chondroitin sulfate modified β-glucan loaded with silver nanoparticles: The sulfate group of chondroitin sulfate forms a coordination bond with silver ions, which not only improves the stability of silver nanoparticles, but also enhances their interaction with bacterial cell walls. β-glucan, through its special helical structure, provides an ideal loading platform for silver nanoparticles, achieving a sustained antibacterial effect.

[0056] 3. Smart responsiveness of N-isopropylacrylamide-co-acrylic acid copolymer: The copolymer achieves dual responsiveness through temperature-sensitive N-isopropylacrylamide units and pH-sensitive acrylic acid units. In the acidic environment of the wound surface, the protonation of the acrylic acid unit causes the conformational change of the polymer chain, thereby triggering drug release.

[0057] 4. D-α-Tocopherol polyethylene glycol succinate modified hyaluronic acid: This modification connects the antioxidant α-tocopherol to hyaluronic acid through an ester bond, which not only provides long-lasting antioxidant protection, but also enhances the water retention and viscoelasticity of the hydrogel through the polyethylene glycol chain segment.

[0058] 5. Synergy of L-arginine-L-glutamate and amino-functionalized mesoporous silica: L-arginine, as a NO precursor, generates NO through nitric oxide synthase (NOS) catalysis, promoting vasodilation. L-glutamate regulates the local pH value and optimizes NOS activity. Amino-functionalized mesoporous silica effectively loads and slowly releases L-arginine-L-glutamate through electrostatic interaction and hydrogen bonding, while its porous structure is conducive to the adsorption and release of oxygen.

[0059] 6. Genipin as a multifunctional cross-linking agent: Genipin reacts with the amino groups in the dressing ingredients through its aldehyde group to form a cross-linking network. At the same time, its unique molecular structure also has antibacterial and anti-inflammatory effects, further enhancing the comprehensive performance of the dressing.

[0060] Through these innovative designs and synergistic mechanisms, the present invention achieves the following beneficial effects:

[0061] 1. Super strong mechanical properties and flexibility enable the dressing to better adapt to the irregular shape of the wound and provide continuous protection.

[0062] 2. Intelligent pH-responsive drug release can accurately regulate drug release according to the wound microenvironment and improve the treatment effect.

[0063] 3. Long-lasting antioxidant protection, effectively combating oxidative stress on the wound surface and promoting tissue repair.

[0064] 4.Strong and sustained antibacterial properties, effectively preventing and controlling wound infection.

[0065] 5. Significantly promote the ability of angiogenesis, improve wound microcirculation, and accelerate the healing process.

[0066] 6. Excellent biocompatibility and versatility, providing a comprehensive treatment plan for diabetic foot wounds.

[0067] In summary, the present invention successfully developed a new type of diabetic foot wound dressing with multiple functions through the ingenious design and synergistic effect of multiple components, which provides a new and efficient solution for the treatment of this field, has important clinical application value and broad market prospects. DETAILED DESCRIPTION

[0068] The novel hydrogel dressing for diabetic foot wound of the present invention comprises the following components: 18-28 parts of carboxymethyl chitosan; trade name: CM-Chitosan, manufacturer: Sigma-Aldrich; degree of substitution: 0.7-0.9, molecular weight: 80-250 kDa; 0.2-0.8 parts of reduced graphene oxide; RGO, manufacturer: ACS Material, LLC, carbon-oxygen ratio: 4:1 to 8:1, sheet size: 1-5 μm; chondroitin sulfate-modified β-1,3-glucan: 2-5 parts; silver nitrate 0.08-0.3 parts; purity: ≥99.8%; N-isopropylacrylamide-co-acrylic acid: 3-7 parts; N,N'-methylenebisacrylamide: 0.15-0.4 parts; trade name: MBA, manufacturer: Sigma-Aldrich; purity: ≥99.5%; thiolated hyaluronic acid: 2-5 parts; D-α-vitamin E polyethylene glycol succinate: 0.3-0.8 parts; trade name: Vitamin E TPGS, manufacturer: BASF SE; PEG molecular weight: 1000 Da; amino-functionalized mesoporous silica: 2-5 parts; trade name: SBA-15-NH2, manufacturer: ACS Material, LLC; pore size: 5-9nm, specific surface area: 500-900m 2 / g, amino content: 1.0-1.5mmol / g; L-arginine-L-glutamate: 1-3 parts; trade name: Arginine glutamate, manufacturer: Ajinomoto Co., Inc.; purity: ≥98.5%; genipin: 0.1-0.4 parts; trade name: Genipin, manufacturer: Wako Pure Chemical Industries, Ltd. purity: ≥98%; deionized water: appropriate amount, adjust the solid content to 10-15wt.%.

[0069] Preparation of β-1,3-glucan modified with acid chondroitin: a) Dissolve 5-10 parts of β-1,3-glucan in 200-300 parts of deionized water and stir at 50-60°C for 1-2 hours. b) Dissolve 2-4 parts of sodium chondroitin sulfate in 100-150 parts of deionized water. c) Add 1-2 parts of N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDC·HCl,) and 0.5-1 parts of N-hydroxysuccinimide (NHS) to the chondroitin sulfate solution at 0-5°C and stir for 30 minutes. d) Slowly add the activated chondroitin sulfate solution dropwise to the β-glucan solution and react at room temperature for 12-24 hours. e) Dialyze for 72 hours and freeze-dry to obtain the product.

[0070] Preparation of N-isopropylacrylamide-co-acrylic acid: a) Add 8-12 parts of N-isopropylacrylamide and 1-3 parts of acrylic acid into a three-necked flask and dissolve them with 200-300 parts of deionized water. b) Deoxygenate with nitrogen for 45 minutes and heat to 65-70°C. c) Add 0.1-0.2 parts of ammonium persulfate as an initiator and react for 5-7 hours. d) Cool to room temperature, dialyze for 72 hours to remove unreacted monomers, and freeze-dry to obtain the product.

[0071] Preparation of thiolated hyaluronic acid: a) Dissolve 5-8 parts of sodium hyaluronate in 300-400 parts of deionized water. b) Slowly add 2-4 parts of thiolethylamine hydrochloride and 1-2 parts of EDC·HCl at 0-5°C. c) Adjust the pH to 4.5-5.5 and react at room temperature for 8-12 hours. d) Dialyze for 48 hours and freeze-dry to obtain the product.

[0072] The diabetic foot wound dressing of the present invention realizes a series of unique functions and remarkable beneficial effects through a carefully designed multi-component combination and a synergistic mechanism.

[0073] 1. Structural enhancement and conductivity mechanism: A complex interaction network is formed between carboxymethyl chitosan and reduced graphene oxide (rGO). The carboxyl (-COOH) and amino (-NH2) groups on carboxymethyl chitosan and the oxygen-containing functional groups (such as -OH, -COOH) on the surface of rGO form a stable three-dimensional network structure through hydrogen bonding. This network not only enhances the mechanical strength of the dressing, but also improves its flexibility. At the same time, the sp 2 The hybrid carbon structure gives the dressing good conductivity, which is beneficial to promote the conduction of electrical signals between cells and accelerate tissue regeneration.

[0074] 2. Smart drug release mechanism: N-isopropylacrylamide-co-acrylic acid (NIPAM-co-AA) copolymer plays a dual role of temperature and pH response in the dressing. At normal body temperature (about 37°C), the NIPAM segment undergoes a phase change, causing the polymer chain to shrink and form a dense structure. When the pH of the wound surface decreases (such as in an infected state), the carboxyl group of the AA segment will be protonated, causing the polymer chain to stretch, thereby releasing the loaded drug. This smart response mechanism ensures that the drug is released precisely when needed (such as when an infection occurs).

[0075] 3. Sustained antibacterial mechanism: Chondroitin sulfate-modified β-1,3-glucan loaded with silver nanoparticles forms a unique antibacterial system. The sulfate group of chondroitin sulfate forms a coordination bond with silver ions, which not only stabilizes the silver nanoparticles but also enhances their interaction with the bacterial cell wall. The helical structure of β-glucan provides an ideal loading platform for silver nanoparticles, achieving a slow and sustained release of silver ions. This design not only enhances the antibacterial effect, but also reduces the toxicity to normal cells.

[0076] 4. Antioxidant protection mechanism: (±)-α-tocopherol polyethylene glycol succinate modified hyaluronic acid constitutes a powerful antioxidant system. As a fat-soluble antioxidant, α-tocopherol can effectively remove lipid peroxides and free radicals. The polyethylene glycol segment increases the water solubility and biocompatibility of α-tocopherol, while hyaluronic acid provides an ideal carrier to ensure the sustained release of antioxidants. This design not only provides long-lasting antioxidant protection, but also maintains the appropriate moisture of the wound surface through the moisturizing effect of hyaluronic acid.

[0077] 5. Mechanism of promoting angiogenesis: The combination of L-arginine-L-glutamate and amino-functionalized mesoporous silica forms an efficient angiogenesis-promoting system. L-arginine, as a precursor of nitric oxide (NO), generates NO under the action of nitric oxide synthase (NOS), promoting vasodilation and neovascularization. L-glutamate optimizes the activity of NOS by regulating the local pH value. Amino-functionalized mesoporous silica effectively loads and slowly releases L-arginine-L-glutamate through electrostatic interactions and hydrogen bonds. At the same time, its porous structure is conducive to the adsorption and release of oxygen, further improving the microenvironment of the wound surface.

[0078] 6. Multifunctional cross-linking network mechanism: Genipin, as a cross-linking agent, undergoes Schiff base reaction with amino groups in dressing ingredients (such as amino groups in chitosan) through its aldehyde group to form a stable cross-linking network. This not only enhances the structural stability of the dressing, but also gives the dressing additional antibacterial and anti-inflammatory functions. The antibacterial mechanism of genipin is through inhibiting bacterial protein synthesis, while its anti-inflammatory effect may be related to inhibiting the production of inflammatory factors.

[0079] These carefully designed compatibility mechanisms work synergistically to produce the following significant beneficial effects:

[0080] 1. Excellent mechanical properties: The dressing has high strength and good flexibility, can adapt to irregular wound surfaces and provide lasting protection.

[0081] 2. Intelligent drug release: Precisely control drug release according to pH changes on the wound surface, improve treatment efficacy, and reduce drug waste and potential side effects.

[0082] 3. Continuous and effective antibacterial effect: long-term inhibition of bacterial growth, effective prevention and control of wound infection, and accelerated healing process.

[0083] 4. Comprehensive antioxidant protection: Reduces damage to tissues caused by oxidative stress, promotes cell growth and tissue repair.

[0084] 5. Promote angiogenesis: improve wound microcirculation, accelerate the delivery of oxygen and nutrients, and significantly speed up healing.

[0085] 6. Maintain a suitable wound environment: Create ideal conditions for wound healing through fluid absorption, moisturizing and oxygen supply.

[0086] 7. Good biocompatibility: Use natural and biocompatible materials to minimize adverse reactions and is suitable for long-term use.

[0087] 8. Multifunctional synergy: Through multiple mechanisms of action, it comprehensively improves the healing process of diabetic foot wounds and enhances the treatment effect.

[0088] In summary, the present invention has developed a diabetic foot wound dressing with multiple functions and significant advantages through innovative compatibility design and in-depth mechanism research. This dressing not only solves the limitations of traditional dressings, but also comprehensively improves the treatment effect through multiple mechanisms of action, providing an innovative solution for the clinical treatment of diabetic foot wounds.

[0089] Example 1

[0090] The present embodiment provides a dressing for diabetic foot wound and a preparation method thereof. The dressing comprises the following components (by weight): 18 parts of carboxymethyl chitosan, 0.2 parts of reduced graphene oxide, 2 parts of chondroitin sulfate-modified β-1,3-glucan, 0.08 parts of silver nitrate, 3 parts of N-isopropylacrylamide-co-acrylic acid, 0.15 parts of N,N'-methylenebisacrylamide, 2 parts of thiolated hyaluronic acid, 0.3 parts of D-α-vitamin E polyethylene glycol succinate, 2 parts of amino-functionalized mesoporous silica, 1 part of L-arginine-L-glutamate, 0.1 parts of genipin, and 671.17 parts of deionized water.

[0091] In this embodiment, the degree of substitution of carboxymethyl chitosan is 0.7 and the molecular weight is 80 kDa. The carbon-oxygen ratio of reduced graphene oxide is 4:1, and the sheet size is 1 μm. The pore size of amino-functionalized mesoporous silica is 5 nm, the specific surface area is 500 m2 / g, and the amino content is 1.0 mmol / g.

[0092] The preparation method of the dressing comprises the following steps:

[0093] (1) Preparation of carboxymethyl chitosan-reduced graphene oxide composite hydrogel matrix:

[0094] First, 18 parts of carboxymethyl chitosan were dissolved in 600 parts of deionized water and stirred at 30°C for 5 hours. Second, 0.2 parts of reduced graphene oxide were dispersed in 150 parts of deionized water and ultrasonically treated for 45 minutes. Then, the reduced graphene oxide dispersion was slowly added dropwise to the carboxymethyl chitosan solution and stirred at 45°C for 3 hours.

[0095] (2) Preparation of chondroitin sulfate modified β-glucan loaded silver nanoparticles:

[0096] First, 2 parts of chondroitin sulfate-modified β-1,3-glucan were dissolved in 250 parts of deionized water and stirred at 65°C for 1.5 hours. Next, 0.08 parts of silver nitrate were dissolved in 60 parts of deionized water and slowly added dropwise to the above solution. Then, the mixture was stirred and reacted at 75°C for 2.5 hours.

[0097] (3) Preparation of temperature-responsive N-isopropylacrylamide-co-acrylic acid microgel:

[0098] First, 3 parts of N-isopropylacrylamide-co-acrylic acid and 0.15 parts of N,N'-methylenebisacrylamide were dissolved in 250 parts of deionized water. Next, nitrogen was passed through to deoxygenate for 40 minutes and the temperature was raised to 72°C. Then, 0.08 parts of ammonium persulfate was added as an initiator and the reaction was allowed to proceed for 5 hours. Finally, the mixture was cooled to room temperature and dialyzed for 60 hours.

[0099] (4) Preparation of D-α-vitamin E polyethylene glycol succinate modified thiolated hyaluronic acid:

[0100] First, 2 parts of thiolated hyaluronic acid were dissolved in 350 parts of deionized water. Second, 0.3 parts of D-α-vitamin E polyethylene glycol succinate were dissolved in 60 parts of anhydrous ethanol. Then, the D-α-vitamin E polyethylene glycol succinate solution was slowly added dropwise to the thiolated hyaluronic acid solution at 5°C and stirred for 45 minutes. Again, 0.05 parts of 2,2'-dithiodipyridine was added as a cross-linking agent. Finally, the reaction was carried out at room temperature for 15 hours and dialyzed for 60 hours.

[0101] (5) Preparation of L-arginine-L-glutamate loaded amino functionalized mesoporous silica nanoparticles:

[0102] First, 2 parts of amino-functionalized mesoporous silica were dispersed in 250 parts of deionized water and ultrasonicated for 40 minutes. Secondly, 1 part of L-arginine-L-glutamate was dissolved in 120 parts of deionized water. Then, the L-arginine-L-glutamate solution was slowly added dropwise to the mesoporous silica dispersion and stirred at 30°C for 5 hours. Finally, centrifugation was performed, washed with deionized water 4 times, and freeze-dried to obtain the loaded product.

[0103] (6) Preparation of final hydrogel dressing:

[0104] First, all the components obtained in steps (1)-(5) are mixed in proportion and stirred at 40°C for 3 hours. Secondly, 0.1 parts of genipin solution (dissolved in a small amount of anhydrous ethanol) are slowly added dropwise and stirring is continued for 45 minutes. Then, the mixture is poured into a mold and allowed to stand at 4°C for 18 hours. Again, the gel is frozen at -25°C for 5 hours and then vacuum freeze-dried at -55°C for 60 hours. Finally, the dried hydrogel is cut into the desired size under sterile conditions, vacuum packed, and sterilized with gamma rays (25kGy).

[0105] Example 2

[0106] The present embodiment provides a dressing for diabetic foot wound and a preparation method thereof. The dressing comprises the following components (by weight): 23 parts of carboxymethyl chitosan, 0.5 parts of reduced graphene oxide, 3.5 parts of chondroitin sulfate-modified β-1,3-glucan, 0.19 parts of silver nitrate, 5 parts of N-isopropylacrylamide-co-acrylic acid, 0.275 parts of N,N'-methylenebisacrylamide, 3.5 parts of thiolated hyaluronic acid, 0.55 parts of D-α-vitamin E polyethylene glycol succinate, 3.5 parts of amino-functionalized mesoporous silica, 2 parts of L-arginine-L-glutamate, 0.25 parts of genipin, and 657.685 parts of deionized water.

[0107] In this embodiment, the degree of substitution of carboxymethyl chitosan is 0.8 and the molecular weight is 165 kDa. The carbon-oxygen ratio of reduced graphene oxide is 6:1, and the sheet size is 3 μm. The pore size of amino-functionalized mesoporous silica is 7 nm, the specific surface area is 700 m2 / g, and the amino content is 1.25 mmol / g.

[0108] The preparation method of the dressing comprises the following steps:

[0109] (1) Preparation of carboxymethyl chitosan-reduced graphene oxide composite hydrogel matrix:

[0110] First, 23 parts of carboxymethyl chitosan were dissolved in 700 parts of deionized water and stirred at 35°C for 6 hours. Secondly, 0.5 parts of reduced graphene oxide were dispersed in 175 parts of deionized water and ultrasonically treated for 60 minutes. Then, the reduced graphene oxide dispersion was slowly added dropwise to the carboxymethyl chitosan solution and stirred at 50°C for 3.5 hours.

[0111] (2) Preparation of chondroitin sulfate modified β-glucan loaded silver nanoparticles:

[0112] First, 3.5 parts of chondroitin sulfate-modified β-1,3-glucan were dissolved in 300 parts of deionized water and stirred at 70°C for 2 hours. Next, 0.19 parts of silver nitrate were dissolved in 90 parts of deionized water and slowly added dropwise to the above solution. Then, the mixture was stirred and reacted at 80°C for 3 hours.

[0113] (3) Preparation of temperature-responsive N-isopropylacrylamide-co-acrylic acid microgel:

[0114] First, 5 parts of N-isopropylacrylamide-co-acrylic acid and 0.275 parts of N,N'-methylenebisacrylamide were dissolved in 300 parts of deionized water. Next, nitrogen was passed through to deoxygenate for 40 minutes and the temperature was raised to 75°C. Then, 0.115 parts of ammonium persulfate was added as an initiator and the reaction was carried out for 6 hours. Finally, the mixture was cooled to room temperature and dialyzed for 60 hours.

[0115] (4) Preparation of D-α-vitamin E polyethylene glycol succinate modified thiolated hyaluronic acid:

[0116] First, 3.5 parts of thiolated hyaluronic acid were dissolved in 400 parts of deionized water. Second, 0.55 parts of D-α-vitamin E polyethylene glycol succinate were dissolved in 90 parts of anhydrous ethanol. Then, at 7.5°C, the D-α-vitamin E polyethylene glycol succinate solution was slowly added dropwise to the thiolated hyaluronic acid solution and stirred for 45 minutes. Again, 0.075 parts of 2,2'-dithiodipyridine was added as a cross-linking agent. Finally, the reaction was carried out at room temperature for 22.5 hours and dialyzed for 60 hours.

[0117] (5) Preparation of L-arginine-L-glutamate loaded amino functionalized mesoporous silica nanoparticles:

[0118] First, 3.5 parts of amino-functionalized mesoporous silica were dispersed in 300 parts of deionized water and ultrasonicated for 40 minutes. Secondly, 2 parts of L-arginine-L-glutamate were dissolved in 150 parts of deionized water. Then, the L-arginine-L-glutamate solution was slowly added dropwise to the mesoporous silica dispersion and stirred at 35°C for 6 hours. Finally, centrifugation was performed, washed with deionized water 4 times, and freeze-dried to obtain the loaded product.

[0119] (6) Preparation of final hydrogel dressing:

[0120] First, all the components obtained in steps (1)-(5) are mixed in proportion and stirred at 45°C for 3.5 hours. Secondly, 0.25 parts of genipin solution (dissolved in a small amount of anhydrous ethanol) are slowly added dropwise and stirring is continued for 60 minutes. Then, the mixture is poured into a mold and allowed to stand at 4°C for 24 hours. Again, the gel is frozen at -25°C for 6.5 hours and then vacuum freeze-dried at -55°C for 75 hours. Finally, the dried hydrogel is cut into the desired size under sterile conditions, vacuum packed, and sterilized with gamma rays (25kGy).

[0121] Example 3

[0122] The present embodiment provides a dressing for diabetic foot wound and a preparation method thereof. The dressing comprises the following components (by weight): 28 parts of carboxymethyl chitosan, 0.8 parts of reduced graphene oxide, 5 parts of chondroitin sulfate-modified β-1,3-glucan, 0.3 parts of silver nitrate, 7 parts of N-isopropylacrylamide-co-acrylic acid, 0.4 parts of N,N'-methylenebisacrylamide, 5 parts of thiolated hyaluronic acid, 0.8 parts of D-α-vitamin E polyethylene glycol succinate, 5 parts of amino-functionalized mesoporous silica, 3 parts of L-arginine-L-glutamate, 0.4 parts of genipin, and 644.3 parts of deionized water.

[0123] In this embodiment, the degree of substitution of carboxymethyl chitosan is 0.9 and the molecular weight is 250 kDa. The carbon-oxygen ratio of reduced graphene oxide is 8:1, and the sheet size is 5 μm. The pore size of amino-functionalized mesoporous silica is 9 nm, the specific surface area is 900 m2 / g, and the amino content is 1.5 mmol / g.

[0124] The preparation method of the dressing comprises the following steps:

[0125] (1) Preparation of carboxymethyl chitosan-reduced graphene oxide composite hydrogel matrix:

[0126] First, 28 parts of carboxymethyl chitosan were dissolved in 800 parts of deionized water and stirred at 40°C for 7 hours. Second, 0.8 parts of reduced graphene oxide were dispersed in 200 parts of deionized water and ultrasonically treated for 75 minutes. Then, the reduced graphene oxide dispersion was slowly added dropwise to the carboxymethyl chitosan solution and stirred at 55°C for 4 hours.

[0127] (2) Preparation of chondroitin sulfate modified β-glucan loaded silver nanoparticles:

[0128] First, 5 parts of chondroitin sulfate-modified β-1,3-glucan were dissolved in 350 parts of deionized water and stirred at 75°C for 2.5 hours. Next, 0.3 parts of silver nitrate were dissolved in 120 parts of deionized water and slowly added dropwise to the above solution. Then, the reaction was stirred at 85°C for 3.5 hours.

[0129] (3) Preparation of temperature-responsive N-isopropylacrylamide-co-acrylic acid microgel:

[0130] First, 7 parts of N-isopropylacrylamide-co-acrylic acid and 0.4 parts of N,N'-methylenebisacrylamide were dissolved in 350 parts of deionized water. Next, nitrogen was passed through to deoxygenate for 40 minutes and the temperature was raised to 78°C. Then, 0.15 parts of ammonium persulfate was added as an initiator and the reaction was allowed to proceed for 7 hours. Finally, the mixture was cooled to room temperature and dialyzed for 60 hours.

[0131] (4) Preparation of D-α-vitamin E polyethylene glycol succinate modified thiolated hyaluronic acid:

[0132] First, 5 parts of thiolated hyaluronic acid were dissolved in 450 parts of deionized water. Second, 0.8 parts of D-α-vitamin E polyethylene glycol succinate were dissolved in 120 parts of anhydrous ethanol. Then, at 10°C, the D-α-vitamin E polyethylene glycol succinate solution was slowly added dropwise to the thiolated hyaluronic acid solution and stirred for 45 minutes. Again, 0.1 parts of 2,2'-dithiodipyridine was added as a cross-linking agent. Finally, the reaction was carried out at room temperature for 30 hours and dialyzed for 60 hours.

[0133] (5) Preparation of L-arginine-L-glutamate loaded amino functionalized mesoporous silica nanoparticles:

[0134] First, 5 parts of amino-functionalized mesoporous silica were dispersed in 350 parts of deionized water and ultrasonicated for 40 minutes. Secondly, 3 parts of L-arginine-L-glutamate were dissolved in 180 parts of deionized water. Then, the L-arginine-L-glutamate solution was slowly added dropwise to the mesoporous silica dispersion and stirred at 40°C for 7 hours. Finally, centrifugation was performed, washed with deionized water 4 times, and freeze-dried to obtain the loaded product.

[0135] (6) Preparation of final hydrogel dressing:

[0136] First, all the components obtained in steps (1)-(5) are mixed in proportion and stirred at 50°C for 4 hours. Secondly, 0.4 parts of genipin solution (dissolved in a small amount of anhydrous ethanol) are slowly added dropwise and stirring is continued for 75 minutes. Then, the mixture is poured into a mold and allowed to stand at 4°C for 30 hours. Again, the gel is frozen at -25°C for 8 hours and then vacuum freeze-dried at -55°C for 90 hours. Finally, the dried hydrogel is cut into the desired size under sterile conditions, vacuum packed, and sterilized with gamma rays (25kGy).

[0137] Example 4

[0138] The present embodiment provides a dressing for diabetic foot wound and a preparation method thereof. The dressing comprises the following components (by weight): 25 parts of carboxymethyl chitosan, 0.6 parts of reduced graphene oxide, 4 parts of chondroitin sulfate-modified β-1,3-glucan, 0.22 parts of silver nitrate, 6 parts of N-isopropylacrylamide-co-acrylic acid, 0.32 parts of N,N'-methylenebisacrylamide, 4 parts of thiolated hyaluronic acid, 0.65 parts of D-α-vitamin E polyethylene glycol succinate, 4 parts of amino-functionalized mesoporous silica, 2.5 parts of L-arginine-L-glutamate, 0.3 parts of genipin, and 652.41 parts of deionized water.

[0139] In this embodiment, the degree of substitution of carboxymethyl chitosan is 0.85 and the molecular weight is 200 kDa. The carbon-oxygen ratio of reduced graphene oxide is 7:1, and the sheet size is 4 μm. The pore size of amino-functionalized mesoporous silica is 8 nm, the specific surface area is 800 m2 / g, and the amino content is 1.4 mmol / g.

[0140] The preparation method of the dressing comprises the following steps:

[0141] (1) Preparation of carboxymethyl chitosan-reduced graphene oxide composite hydrogel matrix:

[0142] First, 25 parts of carboxymethyl chitosan were dissolved in 750 parts of deionized water and stirred at 37°C for 6.5 hours. Second, 0.6 parts of reduced graphene oxide were dispersed in 180 parts of deionized water and ultrasonically treated for 65 minutes. Then, the reduced graphene oxide dispersion was slowly added dropwise to the carboxymethyl chitosan solution and stirred at 52°C for 3.7 hours.

[0143] (2) Preparation of chondroitin sulfate modified β-glucan loaded silver nanoparticles:

[0144] First, 4 parts of chondroitin sulfate-modified β-1,3-glucan were dissolved in 320 parts of deionized water and stirred at 72°C for 2.2 hours. Next, 0.22 parts of silver nitrate were dissolved in 100 parts of deionized water and slowly added dropwise to the above solution. Then, the reaction was stirred at 82°C for 3.2 hours.

[0145] (3) Preparation of temperature-responsive N-isopropylacrylamide-co-acrylic acid microgel:

[0146] First, 6 parts of N-isopropylacrylamide-co-acrylic acid and 0.32 parts of N,N'-methylenebisacrylamide were dissolved in 320 parts of deionized water. Next, nitrogen was passed through to deoxygenate for 40 minutes and the temperature was raised to 76°C. Then, 0.13 parts of ammonium persulfate was added as an initiator and the reaction was allowed to proceed for 6.5 hours. Finally, the mixture was cooled to room temperature and dialyzed for 60 hours.

[0147] (4) Preparation of D-α-vitamin E polyethylene glycol succinate modified thiolated hyaluronic acid:

[0148] First, 4 parts of thiolated hyaluronic acid were dissolved in 420 parts of deionized water. Second, 0.65 parts of D-α-vitamin E polyethylene glycol succinate were dissolved in 100 parts of anhydrous ethanol. Then, at 8°C, the D-α-vitamin E polyethylene glycol succinate solution was slowly added dropwise to the thiolated hyaluronic acid solution and stirred for 45 minutes. Again, 0.085 parts of 2,2'-dithiodipyridine was added as a crosslinking agent. Finally, the reaction was carried out at room temperature for 25 hours and dialyzed for 60 hours.

[0149] (5) Preparation of L-arginine-L-glutamate loaded amino functionalized mesoporous silica nanoparticles:

[0150] First, 4 parts of amino-functionalized mesoporous silica were dispersed in 320 parts of deionized water and ultrasonicated for 40 minutes. Secondly, 2.5 parts of L-arginine-L-glutamate were dissolved in 160 parts of deionized water. Then, the L-arginine-L-glutamate solution was slowly added dropwise to the mesoporous silica dispersion and stirred at 37°C for 6.5 hours. Finally, centrifugation was performed, washed with deionized water 4 times, and freeze-dried to obtain the loaded product.

[0151] (6) Preparation of final hydrogel dressing:

[0152] First, all the components obtained in steps (1)-(5) are mixed in proportion and stirred at 47°C for 3.7 hours. Secondly, 0.3 parts of genipin solution (dissolved in a small amount of anhydrous ethanol) are slowly added dropwise and stirring is continued for 65 minutes. Then, the mixture is poured into a mold and allowed to stand at 4°C for 26 hours. Again, the gel is frozen at -25°C for 7 hours and then vacuum freeze-dried at -55°C for 80 hours. Finally, the dried hydrogel is cut into the desired size under sterile conditions, vacuum packed, and sterilized with gamma rays (25kGy).

[0153] Comparative Example 1

[0154] This comparative example provides a dressing for diabetic foot wounds and a preparation method thereof, aiming to verify the synergistic effect of carboxymethyl chitosan and reduced graphene oxide. The composition of the dressing is the same as that of Example 1, but does not contain reduced graphene oxide.

[0155] The preparation method is substantially the same as that of Example 1, except that the addition of reduced graphene oxide is omitted in step (1). The other steps remain unchanged.

[0156] By comparison with Example 1, it can be found that the mechanical strength and conductivity of the dressing are significantly reduced in the absence of reduced graphene oxide. This proves that the synergistic effect between carboxymethyl chitosan and reduced graphene oxide is essential for improving the overall performance of the dressing. Reduced graphene oxide not only enhances the mechanical properties of the dressing, but also provides a certain conductivity, which is conducive to promoting cell growth and tissue regeneration.

[0157] Comparative Example 2

[0158] This comparative example is intended to verify the role of chondroitin sulfate-modified β-glucan in the preparation of silver nanoparticles. The composition of the dressing is the same as that of Example 2, but unmodified β-1,3-glucan is used instead of chondroitin sulfate-modified β-1,3-glucan.

[0159] The preparation method is basically the same as that of Example 2, except that unmodified β-1,3-glucan is used in step (2). The other steps remain unchanged.

[0160] By comparison with Example 2, it can be observed that the silver nanoparticles prepared using unmodified β-glucan have poor stability and a wider particle size distribution. This indicates that the modification of chondroitin sulfate significantly improves the stability and uniformity of silver nanoparticles. Chondroitin sulfate not only enhances the antibacterial effect of silver nanoparticles, but also simulates the extracellular matrix, providing better biocompatibility, thereby promoting the wound healing process.

[0161] Comparative Example 3

[0162] This comparative example is intended to verify the effect of temperature and pH responsiveness of N-isopropylacrylamide-co-acrylic acid copolymer on the performance of the dressing. The composition of the dressing is the same as that of Example 3, but pure N-isopropylacrylamide is used to replace N-isopropylacrylamide-co-acrylic acid copolymer.

[0163] The preparation method is basically the same as that of Example 3, except that pure N-isopropylacrylamide is used in step (3). The other steps remain unchanged.

[0164] Compared with Example 3, the dressing prepared in this comparative example only has temperature responsiveness and lacks pH responsiveness. The results show that the drug release and water absorption properties of the dressing under different pH environments do not change significantly. This proves the importance of N-isopropylacrylamide-co-acrylic acid copolymer in the dressing, which not only gives the dressing temperature responsiveness, but also provides pH responsiveness, enabling the dressing to more accurately regulate drug release and water absorption properties, thereby better adapting to the complex environment of diabetic foot wounds.

[0165] Comparative Example 4

[0166] This comparative example is intended to verify the effect of D-α-vitamin E polyethylene glycol succinate modification on the antioxidant properties of hyaluronic acid. The composition of the dressing is the same as that of Example 4, but unmodified hyaluronic acid is used instead of hyaluronic acid modified with D-α-vitamin E polyethylene glycol succinate.

[0167] The preparation method is basically the same as that of Example 4, except that the modification process of D-α-tocopherol polyethylene glycol succinate is omitted in step (4). The other steps remain unchanged.

[0168] By comparison with Example 4, it can be found that although the unmodified hyaluronic acid still has good moisturizing properties, the antioxidant capacity of the dressing is significantly reduced. This shows that the modification of D-α-tocopherol polyethylene glycol succinate not only provides long-lasting antioxidant protection, but also enhances the viscoelasticity of the hydrogel. This modification helps to reduce oxidative stress on the wound surface and improves the mechanical properties of the dressing, thereby promoting wound healing more effectively.

[0169] Comparative Example 5

[0170] This comparative example is intended to verify the synergistic effect of L-arginine-L-glutamate and amino-functionalized mesoporous silica. The composition of the dressing is the same as that of Example 1, but L-arginine is used to replace L-arginine-L-glutamate, and unfunctionalized mesoporous silica is used.

[0171] The preparation method is basically the same as that of Example 1, except that L-arginine and unfunctionalized mesoporous silica are used in step (5). The other steps remain unchanged.

[0172] Compared with Example 1, the dressing prepared in this comparative example performed poorly in terms of NO generation and oxygen supply. The results showed that L-arginine-L-glutamate not only provided NO precursors but also adjusted the local pH value, while amino-functionalized mesoporous silica improved the loading efficiency and release control of L-arginine-L-glutamate. This synergistic effect significantly improved the angiogenesis and oxygen supply capabilities of the dressing, thereby accelerating the wound healing process.

[0173] Comparative Example 6

[0174] This comparative example is intended to verify the multiple effects of genipin as a cross-linking agent. The composition of the dressing is the same as that of Example 2, but glutaraldehyde is used instead of genipin as the cross-linking agent.

[0175] The preparation method is basically the same as that of Example 2, except that an equal amount of glutaraldehyde is used in place of genipin in step (6). The other steps remain unchanged.

[0176] By comparison with Example 2, it can be observed that although glutaraldehyde can also achieve effective cross-linking, the antibacterial and anti-inflammatory properties of the dressing are significantly reduced. This demonstrates the unique advantage of genipin as a cross-linking agent: it not only avoids the potential toxicity of traditional cross-linking agents, but also gives the dressing additional antibacterial and anti-inflammatory functions. The use of this multifunctional cross-linking agent significantly improves the comprehensive performance of the dressing and provides a safer and more effective solution for the treatment of diabetic foot wounds.

[0177] Through these six comparative examples, the synergistic effects and unique functions of the key components of the present invention are fully verified. The results clearly show that the dressing formula proposed by the present invention has significant advantages in mechanical properties, antibacterial properties, drug release control, antioxidant capacity, angiogenesis and biocompatibility, which fully proves its innovativeness and practical value in the field of diabetic foot wound treatment.

[0178] In order to comprehensively evaluate the effectiveness and superiority of the present invention, a series of test experiments were designed, covering the key performance indicators of the dressing. These tests not only reflect the core innovation of the present invention, but also reflect the synergistic mechanism between the components.

[0179] 1. Mechanical properties test

[0180] Experimental method: The tensile strength and elongation at break of the dressing were measured using a universal material testing machine (Instron 5967). The sample was cut into a dumbbell shape (100 mm long, 10 mm wide), the test speed was set to 10 mm / min, the ambient temperature was 25°C, and the relative humidity was 50%.

[0181] 2. Antibacterial performance test

[0182] Experimental method: The inhibition zone method was used, with Staphylococcus aureus (ATCC 25923) and Escherichia coli (ATCC25922) as indicator bacteria. A dressing sample with a diameter of 10 mm was placed on an agar plate inoculated with bacteria, and the diameter of the inhibition zone was measured after incubation at 37°C for 24 hours.

[0183] 3. Liquid absorption performance and water vapor transmission rate test

[0184] Experimental methods:

[0185] a) Liquid absorption performance: The dressing sample (50 mm×50 mm) was immersed in simulated wound exudate (PBS solution, pH 7.4), and was weighed every 1 hour until 8 hours, and the liquid absorption rate was calculated.

[0186] b) Water Vapor Transmission Rate (WVTR): Using the wet cup method, the dressing sample was fixed on a cup filled with distilled water and the weight loss was measured within 24 hours at 32°C and 50% relative humidity.

[0187] 4. pH-responsive drug release test

[0188] Experimental method: Tetracycline hydrochloride was selected as a model drug and loaded into the dressing. The drug-loaded dressing samples (100 mg) were placed in PBS buffers at pH 5.5, 7.4, and 8.5, respectively, and released at 37°C. Samples were taken at predetermined time points, and the drug concentration was determined using a UV-Vis spectrophotometer to plot the cumulative release curve.

[0189] 5. Antioxidant performance test

[0190] Experimental method: DPPH free radical scavenging ability test was used. The dressing sample (50 mg) was soaked in 2 mL of 0.1 mM DPPH ethanol solution and reacted at room temperature in the dark for 30 minutes. The absorbance was measured at a wavelength of 517 nm using a UV-Vis spectrophotometer to calculate the free radical scavenging rate.

[0191] 6. In vitro cell compatibility and angiogenesis-promoting ability test

[0192] Experimental methods:

[0193] a) Cytocompatibility: The MTT assay was used to evaluate the effects of the dressing extract on human dermal fibroblasts (HFF-1). After culturing the cells for 24, 48, and 72 hours, the cell viability was determined.

[0194] b) Promoting angiogenesis: Human umbilical vein endothelial cell (HUVEC) tube formation experiment was performed. HUVEC cells were seeded on Matrigel, and the dressing extract was added and cultured for 8 hours, and the tube formation was observed and quantified.

[0195] Test results:

[0196] Table 1. Mechanical properties and antibacterial properties test results

[0197]

[0198] Table 2. Test results of liquid absorption performance, water vapor transmission rate and antioxidant performance

[0199]

[0200] According to the test results, Example 3 performs best and can be regarded as the best embodiment of the present invention. Combining the test data with the chemical mechanism of the present invention, the following unexpected technical effects are found:

[0201] 1. Super strong mechanical properties and flexibility: The tensile strength of Example 3 reaches 3.5MPa, and the elongation at break is as high as 225%. This excellent mechanical property is derived from the synergistic effect of carboxymethyl chitosan and reduced graphene oxide. Reduced graphene oxide not only enhances the strength of the dressing, but also significantly improves the flexibility of the dressing by forming a hydrogen bond network with carboxymethyl chitosan. This unique structure enables the dressing to better adapt to the irregular shape of the wound surface and provide continuous protection.

[0202] 2. Excellent antibacterial performance: The diameters of the inhibition zones of Example 3 against Staphylococcus aureus and Escherichia coli reached 21.3 mm and 19.0 mm, respectively, far exceeding those of other samples. This powerful antibacterial effect is attributed to the synergistic effect of chondroitin sulfate-modified β-glucan loaded silver nanoparticles. Chondroitin sulfate not only improves the stability of silver nanoparticles, but also enhances their interaction with bacterial cell walls, thereby significantly improving the antibacterial effect.

[0203] 3. Intelligent pH-responsive drug release: In the pH-responsive drug release test (data not shown), Example 3 exhibited significant pH-dependent release behavior. In an acidic environment (pH 5.5), the drug release rate was significantly accelerated, which matches the acidic environment of diabetic foot wounds. This intelligent release property originates from the design of N-isopropylacrylamide-co-acrylic acid copolymer, which not only achieves temperature response, but also introduces pH responsiveness, enabling the dressing to accurately regulate drug release according to the wound microenvironment.

[0204] 4. Long-lasting antioxidant protection: The DPPH free radical scavenging rate of Example 3 is as high as 79.8%, which is much higher than that of other samples, especially Comparative Example 4 (58.7%). This excellent antioxidant performance is attributed to the modification of hyaluronic acid with D-α-tocopherol polyethylene glycol succinate. This modification not only provides long-lasting antioxidant protection, but also improves the overall performance of the dressing by enhancing the viscoelasticity of the hydrogel.

[0205] 5. Synergistic promotion of angiogenesis: In an in vitro cell experiment (data not shown), Example 3 significantly promoted the lumen formation of HUVEC cells. This ability to promote angiogenesis stems from the synergistic effect of L-arginine-L-glutamate and amino-functionalized mesoporous silica. L-arginine-L-glutamate not only promotes vasodilation as a NO precursor, but also regulates local pH. Amino-functionalized mesoporous silica provides controllable oxygen release, and the synergistic effect of the two significantly enhances the ability of the dressing to promote angiogenesis.

[0206] 6. Multifunctional cross-linked network: Using genipin as a cross-linking agent not only avoids the potential toxicity of traditional cross-linking agents, but also gives the dressing additional antibacterial and anti-inflammatory functions. The formation of this multifunctional cross-linked network is a highlight of the present invention, which not only ensures the structural stability of the dressing, but also further enhances the comprehensive therapeutic effect of the dressing.

[0207] In summary, the present invention realizes a diabetic foot wound dressing with multiple functions such as super mechanical properties, intelligent response drug release, long-lasting antioxidant protection, strong antibacterial and angiogenesis promotion through the ingenious design and synergistic effect of multiple components. These unexpected technical effects not only reflect the innovation of the present invention, but also provide a new and efficient solution for the treatment of diabetic foot wounds.

Claims

1. A dressing for diabetic foot wounds, characterized in that: The dressing comprises the following components (by weight): 18-28 parts of carboxymethyl chitosan; 0.2-0.8 parts of reduced graphene oxide; 2-5 parts of chondroitin sulfate-modified β-1,3-glucan; Silver nitrate 0.08-0.3 parts; 3-7 parts of N-isopropylacrylamide-co-acrylic acid; N,N'-methylenebisacrylamide 0.15-0.4 parts; 2-5 parts of thiolated hyaluronic acid; D-α-tocopherol polyethylene glycol succinate 0.3-0.8 parts; 2-5 parts of amino-functionalized mesoporous silica; 1-3 parts of L-arginine-L-glutamate; Genipin 0.1-0.4 parts; 644.3-671.17 parts of deionized water.

2. The dressing according to claim 1, characterized in that The degree of substitution of the carboxymethyl chitosan is 0.7-0.9, and the molecular weight is 80-250 kDa.

3. The dressing according to claim 1, characterized in that The carbon-oxygen ratio of the reduced graphene oxide is 4:1 to 8:1, and the sheet size is 1-5 μm.

4. The dressing according to claim 1, characterized in that The amino-functionalized mesoporous silica has a pore size of 5-9 nm and a specific surface area of ​​500-900 m 2 / g, and the amino content is 1.0-1.5mmol / g.

5. The method for preparing a dressing according to any one of claims 1 to 4, characterized in that: The following steps are involved: (1) preparing a carboxymethyl chitosan-reduced graphene oxide composite hydrogel matrix; (2) preparing chondroitin sulfate-modified β-glucan loaded silver nanoparticles; (3) Preparation of temperature-responsive N-isopropylacrylamide-co-acrylic acid microgels; (4) preparing D-α-vitamin E polyethylene glycol succinate modified thiolated hyaluronic acid; (5) preparing L-arginine-L-glutamate loaded amino-functionalized mesoporous silica nanoparticles; (6) All components obtained in steps (1) to (5) are mixed, and genipin is added to prepare a final hydrogel dressing.

6. The preparation method according to claim 5, characterized in that: The step (1) comprises: First, 18-28 parts of carboxymethyl chitosan are dissolved in 600-800 parts of deionized water and stirred at 30-40°C for 5-7 hours; Secondly, 0.2-0.8 parts of reduced graphene oxide are dispersed in 150-200 parts of deionized water and ultrasonically treated for 45-75 minutes; Then, the reduced graphene oxide dispersion was slowly added dropwise to the carboxymethyl chitosan solution and stirred at 45-55° C. for 3-4 hours.

7. The preparation method according to claim 5, characterized in that: The step (2) comprises: First, 2-5 parts of chondroitin sulfate-modified β-1,3-glucan are dissolved in 250-350 parts of deionized water and stirred at 65-75° C. for 1.5-2.5 hours; Secondly, dissolve 0.08-0.3 parts of silver nitrate in 60-120 parts of deionized water and slowly add it dropwise to the above solution; Then, the reaction was stirred at 75-85°C for 2.5-3.5 hours.

8. The preparation method according to claim 5, characterized in that: The step (3) comprises: First, 3-7 parts of N-isopropylacrylamide-co-acrylic acid and 0.15-0.4 parts of N,N'-methylenebisacrylamide are dissolved in 250-350 parts of deionized water; Secondly, nitrogen was passed to remove oxygen for 40 minutes and the temperature was raised to 72-78°C; Then, add 0.08-0.15 parts of ammonium persulfate as an initiator and react for 5-7 hours; Finally, the solution was cooled to room temperature and dialyzed for 60 hours.

9. The preparation method according to claim 5, characterized in that: The step (4) comprises: First, dissolve 2-5 parts of thiolated hyaluronic acid in 350-450 parts of deionized water; Secondly, dissolve 0.3-0.8 parts of D-α-tocopherol polyethylene glycol succinate in 60-120 parts of anhydrous ethanol; Then, at 5-10° C., slowly add the D-α-vitamin E polyethylene glycol succinate solution dropwise to the thiolated hyaluronic acid solution and stir for 45 minutes; Again, 0.05-0.1 parts of 2,2'-dithiodipyridine was added as a cross-linking agent; Finally, the reaction was carried out at room temperature for 15-30 hours and dialyzed for 60 hours.

10. The preparation method according to claim 5, characterized in that: The step (6) comprises: First, all the components obtained in steps (1) to (5) are mixed in proportion and stirred at 40-50° C. for 3-4 hours; Secondly, slowly add 0.1-0.4 parts of genipin solution dropwise and continue stirring for 45-75 minutes; Then, pour the mixture into a mold and let it stand at 4°C for 18-30 hours; Again, the gel was frozen at -25°C for 5-8 hours and then freeze-dried at -55°C in a vacuum for 60-90 hours; Finally, the dried hydrogel was cut into desired sizes under sterile conditions, vacuum packed, and sterilized by gamma ray.

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