Composite dressing for repairing burns and scalds and preparation method thereof

Abstract

The invention belongs to the technical field of wound dressings, and particularly relates to a burn and scald repair composite dressing and a preparation method thereof. Wherein the burn and scald repair composite dressing is composed of a composite sponge and a nanofiber membrane adhered to the composite sponge, and the nanofiber membrane is prepared from the following raw materials in parts by weight: 10-20 parts of chitosan, 20-30 parts of a silk fibroin solution and 5-10 parts of calcium peroxide; cMC and CS in the composite sponge form an amido bond three-dimensional network through a cross-linking agent, and TA is stacked and embedded into the network through chemical bonds, so that the tensile strength is improved, and the deformation resistance is enhanced; the composite sponge improves the water retention capacity through hydrogen bonds, and after absorbing exudate, the composite sponge is in a gel state to keep the wound moist; a TA phenolic hydroxyl group in the composite sponge and an inner layer silk fibroin amido group form a hydrogen bond, so that the overall mechanical stability of the dressing is improved; and the added calcium peroxide reacts with the percolate to release oxygen and calcium ions, so that the anoxic environment of the wound surface is improved, and cell metabolism is promoted.

Description

Technical Field

[0001] The invention belongs to the technical field of wound dressings, and particularly relates to a burn and scald repair composite dressing and a preparation method thereof. Background Art

[0002] Currently, a wide variety of burn and scald dressings are available on the market, but all have limitations. Traditional natural materials, such as gauze, while biocompatible, suffer from poor mechanical strength, easily adhere to the wound surface, and can easily cause secondary damage when replaced. Synthetic dressings, such as polyurethane film, while offering excellent physical properties, lack biocompatibility, are inadequate for promoting wound healing, and lack antimicrobial and bioactive properties. Furthermore, most dressings have a single design, failing to simultaneously meet the multiple requirements of shielding against external contaminants, effectively absorbing exudate, and promoting tissue regeneration. For example, conventional single-layer dressings struggle to balance breathability and moisture retention within the wound, hindering the maintenance of a healing environment. Functionally, existing dressings often rely on a single antimicrobial component for their antimicrobial properties, which can easily lead to drug resistance and lack the ability to dynamically regulate the wound healing process. Furthermore, most dressings lack temperature sensitivity, making application difficult and dressing changes painful when applied to large wounds.

[0003] In terms of preparation methods, traditional processes have many shortcomings. For example, when materials are gelled and modified, process defects often lead to structural damage and reduced porosity, affecting the performance of the dressing. Conventional methods such as emulsion polymerization make it difficult to accurately control the microstructure of the dressing, and the prepared dressings have limited effects in exudate management and bioactive substance loading. With the development of medical technology and the increasing requirements of patients for treatment effects, there is an urgent need to develop a burn and scald repair composite dressing with better performance and its preparation method to solve the problems existing in the existing technology. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the present invention provides a burn and scald repair composite dressing and a preparation method thereof; in the preparation process of the composite sponge of the present invention, CMC and CS form amide bonds to cross-link to form a three-dimensional network, and TA is embedded in the network, so that the tensile strength is improved and the structure is stable and not easy to be damaged and deformed; after the composite cross-linking of MC and CS, the water absorption space is increased, and TA forms hydrogen bonds with water molecules to improve the water absorption and water retention capacity, and after absorbing exudate, it remains in a gel state and keeps the wound surface moist; when the composite sponge is compounded with the nanofiber membrane, the calcium ions in the composite sponge undergo ion exchange with the amino groups of chitosan, and at the same time, the phenolic hydroxyl groups of TA in the composite sponge react with the nanofiber membrane. The amide groups of silk fibroin in the rice fiber membrane form hydrogen bonds. The two forces work together to tightly combine the two layers of materials, forming a stable interpenetrating network structure, thereby improving the overall mechanical properties and structural stability of the dressing. After calcium peroxide comes into contact with wound exudate, it slowly decomposes to produce oxygen and calcium ions. The released oxygen improves the hypoxic environment of the wound and promotes cellular aerobic respiration and metabolism. On the one hand, calcium ions participate in the complexation of chitosan and growth factors in the inner nanofiber membrane, prolonging the release cycle of growth factors. On the other hand, they interact with CS and TA in the composite sponge to regulate the degradation rate of the material to match the wound healing process.

[0005] The present invention provides a burn and scald repair composite dressing, which is composed of a composite sponge and a nanofiber membrane adhered to the composite sponge, wherein the nanofiber membrane comprises the following raw materials in parts by weight: 10-20 parts of chitosan, 20-30 parts of silk fibroin solution, 5-10 parts of calcium peroxide, and 1-3 parts of growth factor solution; The composite sponge comprises the following raw materials in a mass ratio: CMC (hydroxymethyl cellulose): CS (chitosan): TA (tannic acid): cross-linking agent = 1:1-2:0.2-0.5:0.1; The preparation of the composite sponge comprises the following steps: A1: CMC was dissolved in deionized water to form a CMC solution with a mass concentration of 2%. The CMC solution was ultrasonically treated for 20 min. CS was dissolved in a 1% acetic acid solution to form a CS solution. The CS solution was then added to the CMC solution to form a mixed solution. A2, adding the crosslinking agent to the mixture, stirring for 4 h, adjusting the pH to 3.5, continuing to add TA, stirring to form a sponge precursor crosslinking solution, injecting the sponge precursor crosslinking solution into a mold and freeze-drying to form a sponge precursor; A3, the sponge precursor was placed in a closed dry ammonia environment provided by (NH4)2CO3 for 12 h for chemical cross-linking, and then placed in a 45 °C oven and heated for 4 h to obtain a composite sponge.

[0006] Furthermore, the growth factor solution is: recombinant human epidermal growth factor dissolved in phosphate buffer to prepare a growth factor solution with a concentration of 10-50 μg / mL.

[0007] Furthermore, the cross-linking agent is a mixture of EDC (1-ethyl-3-dimethylaminopropyl) carbodiimide) and NHS (N-hydroxysuccinimide), and the mass ratio of the two is 2:1.

[0008] Furthermore, the method for preparing the nanofiber membrane comprises the following steps: S1, weighing chitosan, adding acetic acid solution with a volume concentration of 2% to form a chitosan solution with a mass volume concentration of 1-3%, adding silk fibroin solution with a mass volume concentration of 8-12%, calcium peroxide and growth factor solution to the chitosan solution, and adding polyethylene glycol at the same time, stirring evenly to form a blend; S2, the blended liquid is loaded into a syringe and electrospun to form silk fibroin-chitosan fibers. The spinning voltage is set to 15-20 kV, the distance between the nozzle and the receiving plate is 15-20 cm, the propulsion speed is 0.5-1 mL / h, and the spinning time is 2-3 h. The silk fibroin-chitosan fibers are deposited on the receiving plate to form a nanofiber membrane.

[0009] Furthermore, the dosage ratio of the polyethylene glycol to the chitosan solution is 0.2 g:1 mL.

[0010] The present invention also provides a method for preparing a burn and scald repair composite dressing, which specifically comprises the following steps: Step 1: Lay the composite sponge flat on a flat substrate, cut the nanofiber membrane into sheets of the same size as the composite sponge, and cover and stick them on the composite sponge to form a composite dressing precursor; Step 2: Place the composite dressing precursor into a sealed container containing saturated calcium chloride vapor and treat for 1-2 hours to form a composite dressing precursor. Then take out the composite dressing precursor and dry it at room temperature for 24 hours to obtain a burn and scald repair composite dressing.

[0011] Compared with the prior art, the present invention has the following beneficial effects: The burn and scald repair composite dressing prepared by the present invention has good antibacterial properties and efficient wound repair ability, can quickly repair the wound, and ensures that the dressing plays a role in the entire wound repair process. CMC and CS in the composite sponge form a three-dimensional network of amide bonds through EDC / NHS cross-linking, and TA is embedded in the network through hydrogen bonds and π-π stacking, which improves tensile strength, stabilizes the structure and enhances deformation resistance; the composite sponge improves water retention through hydrogen bonds with water molecules, and after absorbing exudate, it becomes a gel state to maintain the moisture of the wound; after CMC, CS and TA form a composite sponge, on the one hand, it forms a dual antibacterial defense line; on the other hand, it removes ROS from the wound to reduce oxidative stress, promotes fibroblast adhesion and collagen synthesis, and accelerates tissue repair; by regulating the raw material ratio and the degree of cross-linking, the sponge degradation rate matches the wound healing process, and no secondary removal is required. Polyethylene glycol acts as a porogen with silk fibroin and chitosan through van der Waals forces, and precipitates to form nanoscale pores during the spinning process, which is beneficial to the sustained release of growth factors and provides multiple contact sites for the combination of the two layers of materials. When the composite sponge is compounded with the nanofiber membrane, the calcium ions in the composite sponge undergo ion exchange with the amino groups of the inner layer of chitosan. At the same time, the phenolic hydroxyl groups of the sponge TA form hydrogen bonds with the amide groups of the inner layer of silk fibroin. The dual effects make the two layers tightly combined, construct an interpenetrating network structure, and improve the overall mechanical stability of the dressing; the added calcium peroxide reacts with the exudate to release oxygen and calcium ions. Oxygen improves the hypoxic environment of the wound and promotes cell metabolism. On the one hand, calcium ions complex the inner layer of chitosan-growth factor to extend the release cycle, and on the other hand, regulate the degradation rate of the sponge; the chitosan of the inner nanofiber membrane forms a triple antibacterial barrier with the sponge CS and TA, and the amino acid residues of silk fibroin synergistically clear ROS with TA, enhancing the anti-inflammatory and antioxidant effects; the silk fibroin-chitosan nanofibers protect the growth factor from rapid degradation, and the TA in the composite sponge regulates its release rhythm through hydrogen bonds and hydrophobic effects, exerting its effects in the inflammatory phase, proliferation phase, and remodeling phase in sequence, achieving precise regulation of the entire wound repair cycle. Through the interaction between materials, the degradation rate of the dressing and the release rate of growth factors are coordinated and regulated. As the wound heals, the dressing gradually degrades, avoiding the need for secondary surgery to remove it. The growth factors are continuously released until the wound is completely repaired, ensuring that the dressing plays a role in the entire process of wound repair, while reducing residual risks and improving the safety and effectiveness of treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a schematic diagram of the structure of the burn and scald repair composite dressing of the present invention; Figure 2 The cell proliferation rate after 48 hours of treatment with the burn and scald repair composite dressing of the present invention; Figure 3 The wound closure rate at different healing times using the burn and scald repair composite dressing of the present invention. DETAILED DESCRIPTION

[0013] In order to enable those skilled in the art to better understand the technical solution of the present invention and to make the above-mentioned features, purposes and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with examples. The examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

[0014] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as those familiar to those skilled in the art. Furthermore, any methods and materials similar or equivalent to those described herein can be applied to the present invention. The preferred embodiments and materials described herein are for illustrative purposes only and are not intended to limit the scope of this application.

[0015] In the following examples, unless otherwise specified, conventional methods are used; the materials used in the following examples, unless otherwise specified, are all new materials purchased from the market.

[0016] Example 1: This example provides a burn and scald repair composite dressing, which is composed of a composite sponge and a nanofiber membrane attached to the composite sponge, wherein the nanofiber membrane comprises the following raw materials in parts by weight: 10 parts chitosan, 20 parts silk fibroin solution, 5 parts calcium peroxide, and 1 part growth factor solution; The composite sponge comprises the following raw materials in a mass ratio: CMC:CS:TA:crosslinking agent=1:1:0.2:0.1; The preparation method of the composite sponge comprises the following steps: A1: CMC was dissolved in deionized water to form a 2% CMC solution. The CMC solution was ultrasonically treated for 20 min. CS was dissolved in a 1% acetic acid solution to form a CS solution. The CS solution was then added to the CMC solution and stirred at 300 rpm for 45 min to form a mixed solution. A2, a mixture of EDC and NHS in a mass ratio of 2:1 was added to the mixed solution, stirred at 200 rpm for 4 h, the pH was adjusted to 3.5 with 1 mol / L hydrochloric acid solution, TA was added, and stirred at 200 rpm for 30 min to form a sponge precursor cross-linked solution, which was then injected into a mold and freeze-dried at -60 °C for 8 h to form a sponge precursor; A3, the sponge precursor was placed in a closed dry ammonia environment provided by (NH4)2CO3 for 12 h for chemical cross-linking, and then placed in a 45 °C oven and heated for 4 h to obtain a composite sponge.

[0017] The growth factor solution is prepared by dissolving recombinant human epidermal growth factor in phosphate buffer to prepare a growth factor solution with a concentration of 10 μg / mL.

[0018] The method for preparing the nanofiber membrane comprises the following steps: S1. Weigh chitosan and add 2% acetic acid solution to form a chitosan solution with a mass volume concentration of 1-3%. Add 8% silk fibroin solution, calcium peroxide, and growth factor solution to the chitosan solution. Simultaneously, add polyethylene glycol at a ratio of 0.2 g:1 mL of polyethylene glycol to chitosan solution. Stir at 300 rpm to form a blend. S2, the blended liquid is loaded into a syringe and electrospun to form silk fibroin-chitosan fibers. The electrospinning voltage is set to 15 kV, the distance between the nozzle and the receiving plate is 15 cm, the propulsion speed is 0.5 mL / h, and the spinning time is 2 h. The silk fibroin-chitosan fibers are deposited on the receiving plate to obtain a nanofiber membrane.

[0019] This embodiment also provides a method for preparing a burn and scald repair composite dressing, which specifically includes the following steps: Step 1: Spread 50 composite sponges on a flat substrate, cut the nanofiber membrane into sheets of the same size as the composite sponge, and cover and stick them on the composite sponge to form a composite dressing precursor: Step 2: Place the composite dressing precursor into a sealed container containing saturated calcium chloride vapor and treat it for 1 hour to form a composite dressing precursor. Then take out the composite dressing precursor and dry it at room temperature for 24 hours to obtain a burn repair composite dressing.

[0020] Example 2: This example provides a burn and scald repair composite dressing, which is composed of a composite sponge and a nanofiber membrane adhered to the composite sponge, wherein the nanofiber membrane comprises the following raw materials in parts by weight: 15 parts chitosan, 25 parts silk fibroin solution, 8 parts calcium peroxide, and 2 parts growth factor solution; The composite sponge comprises the following raw materials in a mass ratio: CMC:CS:TA:crosslinking agent=1:1.5:0.3:0.1; The preparation method of the composite sponge comprises the following steps: A1: CMC was dissolved in deionized water to form a 2% CMC solution. The CMC solution was ultrasonically treated for 20 min. CS was dissolved in a 1% acetic acid solution to form a CS solution. The CS solution was then added to the CMC solution and stirred at 300 rpm for 45 min to form a mixed solution. A2, a mixture of EDC and NHS in a mass ratio of 2:1 was added to the mixed solution, stirred at 200 rpm for 4 h, the pH was adjusted to 3.5 with 1 mol / L hydrochloric acid solution, TA was added, and stirred at 200 rpm for 30 min to form a sponge precursor cross-linked solution, which was then injected into a mold and freeze-dried at -60 °C for 8 h to form a sponge precursor; A3, the sponge precursor was placed in a closed dry ammonia environment provided by (NH4)2CO3 for 12 h, and then placed in a 45°C oven and heated for 4 h to obtain a composite sponge.

[0021] The growth factor solution is prepared by dissolving recombinant human epidermal growth factor in phosphate buffer to prepare a growth factor solution with a concentration of 10-50 μg / mL.

[0022] The method for preparing the nanofiber membrane comprises the following steps: S1. Weigh chitosan and add 2% acetic acid solution to form a 2% chitosan solution. Add 10% silk fibroin solution, calcium peroxide, and growth factor solution to the chitosan solution. Simultaneously, add polyethylene glycol at a ratio of 0.2 g:1 mL of polyethylene glycol to chitosan solution. Stir at 300 rpm to form a blend. S2, the blended liquid is loaded into a syringe for electrospinning. The electrospinning voltage is set to 20 kV, the distance between the nozzle and the receiving plate is 20 cm, the propulsion speed is 1 mL / h, and the spinning time is 3 h to form silk fibroin-chitosan fibers. The silk fibroin-chitosan fibers are deposited on the receiving plate to obtain a nanofiber membrane.

[0023] This embodiment also provides a method for preparing a burn and scald repair composite dressing, which specifically includes the following steps: Step 1: Spread 60 composite sponges on a flat substrate, cut the nanofiber membrane into sheets of the same size as the composite sponge, and cover the composite sponge to form a composite dressing precursor; Step 2: Place the composite dressing precursor into a sealed container containing saturated calcium chloride vapor and treat it for 2 hours to form a composite dressing precursor. Then take out the composite dressing precursor and dry it at room temperature for 24 hours to obtain a burn repair composite dressing.

[0024] Example 3: This example provides a burn and scald repair composite dressing, which is composed of a composite sponge and a nanofiber membrane adhered to the composite sponge, wherein the nanofiber membrane comprises the following raw materials in parts by weight: 20 parts chitosan, 30 parts silk fibroin solution, 10 parts calcium peroxide, and 3 parts growth factor solution; The composite sponge comprises the following raw materials in a mass ratio: CMC:CS:TA:crosslinking agent=1:2:0.5:0.1; The preparation method of the composite sponge comprises the following steps: A1: CMC was dissolved in deionized water to form a 2% CMC solution. The CMC solution was ultrasonically treated for 20 min. CS was dissolved in a 1% acetic acid solution to form a CS solution. The CS solution was then added to the CMC solution and stirred at 300 rpm for 45 min to form a mixed solution. A2, a mixture of EDC and NHS in a mass ratio of 2:1 was added to the mixed solution, stirred at 200 rpm for 4 h, the pH was adjusted to 3.5 with 1 mol / L hydrochloric acid solution, TA was added, and stirred at 200 rpm for 30 min to form a sponge precursor cross-linked solution, which was then injected into a mold and freeze-dried at -60 °C for 8 h to form a sponge precursor; A3, the sponge precursor was placed in a closed dry ammonia environment provided by (NH4)2CO3 for 12 h for chemical cross-linking, and then placed in a 45 °C oven and heated for 4 h to obtain a composite sponge.

[0025] The growth factor solution is prepared by dissolving recombinant human epidermal growth factor in phosphate buffer to prepare a growth factor solution with a concentration of 50 μg / mL.

[0026] The method for preparing the nanofiber membrane comprises the following steps: S1. Weigh chitosan and add 2% acetic acid solution to form a 3% chitosan solution. Add 12% silk fibroin solution, calcium peroxide, and growth factor solution to the chitosan solution. Simultaneously, add polyethylene glycol at a ratio of 0.2 g:1 mL of polyethylene glycol to chitosan solution. Stir at 300 rpm to form a blend. S2, the blended liquid was loaded into a syringe for electrospinning. The electrospinning voltage was set to 20 kV, the distance between the nozzle and the receiving plate was 20 cm, the propulsion speed was 1 mL / h, and the spinning time was 3 h to form silk fibroin-chitosan fibers. The silk fibroin-chitosan fibers were deposited on the receiving plate to form a nanofiber membrane.

[0027] This embodiment also provides a method for preparing a burn and scald repair composite dressing, which specifically includes the following steps: Step 1: Lay 70 composite sponges flat on a flat substrate, cut the nanofiber membrane into sheets of the same size as the composite sponge, and cover and stick them on the composite sponge to form a composite dressing precursor; Step 2: Place the composite dressing precursor into a sealed container containing saturated calcium chloride vapor and treat it for 2 hours to form a composite dressing precursor. Then take out the composite dressing precursor and dry it at room temperature for 24 hours to obtain a burn repair composite dressing.

[0028] The difference between Comparative Example 1 and Example 1 is that the addition of the composite sponge is omitted, and the rest is exactly the same as Example 1.

[0029] The difference between Comparative Example 2 and Example 1 is that the addition of calcium peroxide is omitted, and the rest is exactly the same as Example 1.

[0030] Experimental example: Mechanical Properties: The burn and scald repair composite dressings prepared in Examples 1-3 and Comparative Examples 1-2 were used as samples. The compressive properties of the samples were tested using a texture analyzer (TPA, FTC, American). The compression rate was set to 1 mm / s. Samples with a diameter of 12 mm were immersed in PBS and subjected to a compression set of 50%. The test results are reported in Table 1.

[0031] Water / Blood Absorption Rate: The burn and scald repair composite dressings prepared in Examples 1-3 and Comparative Examples 1-2 of the present invention were used as samples to test their water and blood absorption rates. The weighed sample (W1) was soaked in water / blood for 5 minutes. Excess water on the surface of the sponge was removed and the weight (W2) was weighed. The water / blood absorption rate was calculated as follows: Water / Blood Absorption Rate = (W2 - W1) / W1 × 100%, where W2 and W1 are the weights of the dry sponge completely saturated with water / blood. The results are recorded in Table 1.

[0032] Antibacterial performance: The burn and scald repair composite dressings prepared in Examples 1-3 and Comparative Examples 1-2 of the present invention were used as samples. The samples were cut into a disc with a height of 2 mm and a diameter of 1 mm and sterilized under ultraviolet light for 30 minutes. 400 μL of PBS solution was added to the sterilized sponge for full soaking, and then 10 μL of bacterial solution (10 6 CFU / mL) and incubate at 37 ℃ for 4 h. After incubation, dilute the bacterial solution and take 10 μL of bacterial solution to spread on the agar plate. After incubation at 37 ℃ for 24 h, observe the colonies on the agar plate and take pictures. Cut the sample into a disc with a height of 2 mm and a diameter of 12 mm. After sterilization under ultraviolet light for 30 min, place the sponge on the agar plate coated with the bacterial solution and incubate in a 37 ℃ incubator for 24 h. Observe the inhibition zone and take pictures. Take 50 μL of bacterial solution (10 6CFU / mL) was dropped onto the sponge and incubated at 37°C for 4 hours. Then, 950 µL of LB liquid medium was added. 200 µL of this bacterial solution was transferred to a 96-well plate and the OD value was measured at a wavelength of 600 nm using a microplate reader. The group containing only the bacterial solution and medium was set as the control group. The inhibition rate was calculated as follows: Inhibition rate (%) = (Od control -Od sponge ) / OD control × 100%, where OD control is the absorbance of the bacterial solution in the control group, DD sponge is the absorbance of the bacterial solution in the sponge group, and the results are recorded in Table 1.

[0033] Table 1

[0034] The results in Table 1 show that the burn and scald repair composite dressing prepared by the present invention has good mechanical strength and can quickly recover deformation after compression deformation, indicating that it has excellent elastic recovery performance. It can maintain structural stability when fitting to the uneven burn and scald wound surface, and continue to play a protective and repair role; the water absorption rate can reach more than 2200% of its own weight, thanks to the porous network structure and hydrophilic groups of the Fu'ehao sponge, thus showing ultra-high water absorption; due to the viscosity of blood and the coagulation effect of the burn and scald repair dressing, the blood absorption amount is less than the absorption amount, but can still reach more than 1200% of its own weight, indicating that the burn and scald repair composite dressing prepared by the present invention has excellent water / blood absorption capacity, can effectively deal with the situation of large amounts of bleeding and exudation on the burn and scald wound surface, and create a moist repair environment for the wound surface; the antibacterial property reaches 99%, indicating that the burn and scald composite dressing prepared by the present invention has good antibacterial performance, so as to protect the wound from external bacterial infection, reduce adverse effects such as inflammation caused by infection, and promote recovery.

[0035] Figure 1 This is a schematic diagram of the structure of the burn and scald repair composite dressing prepared by the present invention. The inner fiber membrane and the composite sponge are tightly combined. During use, they can fully absorb the permeate and promote wound repair. Figure 2 It can be seen that the cell proliferation rate was still greater than 90% after 48 h of treatment, indicating that the burn and scald repair composite dressing prepared by the present invention has good cell compatibility and has no obvious effect on cell proliferation; Figure 3 The results showed that the burn and scald repair composite dressing prepared by the present invention has a good effect in promoting the healing of skin burn and scald wounds, with a wound healing rate of over 90%, which is almost complete healing. This shows that the burn and scald repair composite dressing prepared by the present invention has an excellent repair effect on burns and scalds.

[0036] In summary, the burn and scald repair composite dressing prepared by the present invention, thanks to the three-dimensional network constructed by the composite sponge, possesses excellent mechanical strength and elastic recovery, adapting to the needs of wound surface fitting. Relying on the synergistic effects of multiple hydrophilic components, it achieves a water / blood absorption efficiency exceeding 1200% of its own weight, effectively dealing with exudate and bleeding. Chitosan, calcium peroxide, and other ingredients work together to achieve an antibacterial rate of nearly 99%, building a solid line of defense against infection. These various properties complement each other synergistically, providing a favorable repair environment for burn and scald wounds. The dressing demonstrates significant application value and potential in the field of burn and scald wound care and repair, and is expected to provide a better solution for clinical and daily burn and scald care.

[0037] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A burn and scald repair composite dressing, characterized in that: The nanofiber membrane is composed of a composite sponge and a nanofiber membrane attached to the composite sponge. The nanofiber membrane comprises the following raw materials in parts by weight: 10-20 parts of chitosan, 20-30 parts of silk fibroin solution, 5-10 parts of calcium peroxide, and 1-3 parts of growth factor solution. The composite sponge comprises the following raw materials in a mass ratio: CMC:CS:TA:crosslinking agent=1:1-2:0.2-0.5:0.1; The preparation method of the composite sponge comprises the following steps: A1, CMC was dissolved in deionized water to form a CMC solution, the CMC solution was ultrasonically treated, CS was dissolved in acetic acid solution to form a CS solution, and then the CS solution was added to the CMC solution to form a mixed solution; A2, adding a cross-linking agent to the mixture, stirring, adjusting the pH, continuing to add TA, stirring to form a sponge precursor cross-linking solution, and freeze-drying to form a sponge precursor; A3, chemically cross-linking the sponge precursor and then heating it to obtain a composite sponge.

2. The burn and scald repair composite dressing according to claim 1, characterized in that: In step A3, the chemical crosslinking is performed by placing the sponge precursor in a closed dry ammonia environment provided by (NH4)2CO3 for 12 hours.

3. The burn and scald repair composite dressing according to claim 1, characterized in that: The cross-linking agent is a mixture of EDC and NHS, and the mass ratio of the two is 2:

1.

4. The burn and scald repair composite dressing according to claim 1, characterized in that: The method for preparing the nanofiber membrane comprises the following steps: S1, weigh chitosan, add acetic acid solution to form a chitosan solution, add silk fibroin solution, calcium peroxide and growth factor solution to the chitosan solution, and add polyethylene glycol at the same time, stir well to form a blend solution; S2, electrospinning the blended liquid to form silk fibroin-chitosan fibers, and depositing the silk fibroin-chitosan fibers to obtain a nanofiber membrane.

5. The burn and scald repair composite dressing according to claim 4, characterized in that: In step S1, the dosage ratio of the polyethylene glycol to the chitosan solution is 0.2 g:1 mL.

6. The burn and scald repair composite dressing according to claim 4, characterized in that: In step S2, the spinning parameters are set as follows: spinning voltage is 15-20 kV, the distance between the nozzle and the receiving plate is 15-20 cm, the propulsion speed is 0.5-1 mL / h, and the spinning time is 2-3 h.

7. A method for preparing the burn and scald repair composite dressing according to any one of claims 1 to 6, characterized in that: The specific steps include: Step 1: Lay the composite sponge flat and cover the nanofiber membrane on the composite sponge to form a composite dressing precursor; Step 2: placing the composite dressing precursor in saturated calcium chloride vapor for treatment and drying to obtain a burn and scald repair composite dressing.

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