Preparation method of sterile dressing
By combining modified menthyl citrate with bacterial cellulose, a sterile dressing with high antibacterial activity, active healing promotion, and long-lasting sustained release was prepared, which solved the problems of single function and poor biocompatibility of existing dressings and is suitable for the treatment of chronic wounds.
Patent Information
- Application Number
- CN202511787885.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-01
- Publication Date
- 2026-01-27
AI Technical Summary
Existing dressings are insufficient in terms of single-function antibacterial, anti-inflammatory, and analgesic properties, and have problems such as antibiotic abuse and resistance risks, drug burst release, and poor biocompatibility, making it difficult to meet the treatment needs of chronic wounds.
Modified menthyl citrate was combined with bacterial cellulose, and the bacterial cellulose was dissolved with DES solvent to form a three-dimensional network structure hydrogel. Nano-silver was synthesized in situ in the hydrogel, and dopamine was used as a reducing agent to achieve highly efficient antibacterial and long-lasting sustained release.
It achieves highly effective antibacterial properties, actively promotes healing, provides long-lasting sustained release, and has excellent biocompatibility. It is suitable for chronically infected wounds that are difficult to heal, and reduces the risk of antibiotic resistance and the possibility of drug burst release.
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Figure CN121401469A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of wound dressing technology, specifically relating to a method for preparing a sterile dressing. Background Technology
[0002] Wound care is one of the oldest medical practices in humankind. An ideal wound dressing should not only act as a physical barrier to prevent infection but also actively regulate the wound microenvironment to promote the healing process. From early natural materials to modern functional dressings, its development profoundly reflects the progress in materials science, medicine, and our understanding of wound healing mechanisms.
[0003] First-generation traditional dressings, such as gauze and cotton pads, primarily function to cover the wound, absorb exudate, and keep the wound dry. However, they have significant limitations: once saturated, they are prone to leakage; a dry environment can cause the dressing to adhere to newly formed granulation tissue, resulting in secondary damage during dressing changes; more importantly, the theory of keeping the wound dry has been proven to delay epithelial cell migration, thus slowing down the healing process.
[0004] The second generation of modern dressings emerged based on the theory of "moist wound healing." Their core principle is to create a moderately moist, sealed, and low-oxygen microenvironment for the wound, thereby significantly accelerating cell proliferation and migration. This category includes: Film dressings: breathable and water-resistant, suitable for superficial wounds with minimal exudation. Foam dressings: highly absorbent, suitable for moderate to severe exudative wounds. Hydrocolloid dressings: absorb exudate and form a gel, providing a moist environment, suitable for low to moderate exudative wounds. Alginate dressings: possessing extremely strong absorbency and hemostatic properties, suitable for cavitary wounds with significant exudation.
[0005] While second-generation dressings have achieved great success in moisturizing and exudate management, they often lack active biological functions. Faced with the increasingly severe global challenge of bacterial resistance and the complex treatment needs of chronic wounds (such as infection, pain, and inflammation), simple physical protection is far from sufficient. Therefore, the development of third-generation bioactive dressings—smart dressings that integrate antibacterial, anti-inflammatory, and analgesic therapeutic functions—has become a current focus of research and clinical translation.
[0006] However, even in the field of state-of-the-art antimicrobial dressings, several key issues remain to be addressed: Antibiotic abuse and resistance risks, biocompatibility issues of antimicrobial agents, application bottlenecks of natural active ingredients, insufficient functional singularity and synergy, drug delivery technology and release control, i.e., the release of large amounts of drugs in a short period of time, may not only lead to local toxicity, but also make it impossible to maintain long-term effective therapeutic concentrations. Summary of the Invention
[0007] In view of this, the purpose of this invention is to provide a method for preparing a sterile dressing, which has the advantages of high antibacterial efficiency, active healing promotion, long-lasting sustained release, excellent mechanical properties and outstanding biocompatibility.
[0008] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a method for preparing a sterile dressing, comprising the following preparation steps: S1. Dissolve menthyl citrate in acetone, add epichlorohydrin and triethylamine, and stir to react; after the reaction is complete, pour the mixture into ice water to precipitate, filter, wash the precipitate with cold water, and then vacuum dry to obtain modified menthyl citrate. S2. Mix choline chloride and citric acid, heat and stir until homogeneous to obtain DES solvent; S3. The bacterial cellulose membrane is treated with alkali, then washed with deionized water until neutral, freeze-dried and then pulverized to obtain bacterial cellulose powder; S4. Mix DES solvent and bacterial cellulose powder evenly, then add modified menthyl citrate and stir evenly, then add dopamine hydrochloride and stir evenly to obtain a mixture; S5. Pour the mixture into a mold, then slowly pour in AgNO3 solution and allow it to stand at low temperature for reaction. Then, heat it for cross-linking reaction, soak and wash it, and finally soak it in sterile PBS solution for low-temperature preservation to obtain sterile dressing.
[0009] Preferably, the mass-to-volume ratio of menthyl citrate, acetone, epichlorohydrin, and triethylamine in S1 is 10g:50mL:(4-6)g:(5-8)g.
[0010] Preferably, the preparation method of the citrate menthyl ester in S1 is as follows: L-menthol, tert-butanol, and citric acid are heated to 60°C and stirred evenly in a mass-volume ratio of 15g:20g:100mL, and then 2g of immobilized lipase is added and the enzymatic reaction is carried out at 60°C for 48h. The solvent is then filtered and rotary evaporated to obtain citrate menthyl ester.
[0011] Further preferably, the lipase is Novozym 435.
[0012] Further preferably, the stirring reaction temperature in S1 is 50-55℃, and the time is 4-6h.
[0013] Further preferably, the vacuum drying temperature in S1 is 38-42℃, and the time is 18-24h.
[0014] L-Menthol has excellent antibacterial properties and good biocompatibility, but its water solubility is poor and its binding ability in gel materials is poor, making it easy to be lost. This application uses citric acid to modify menthol ester to improve its water solubility, and at the same time introduces active epoxy groups, which enable it to covalently crosslink with the hydroxyl groups of cellulose, so as to achieve stable anchoring and controlled release of the drug and solve the problems of hydrolysis and burst release.
[0015] Preferably, the molar ratio of choline chloride to citric acid in S2 is 1:2.
[0016] Preferably, the stirring temperature in step S2 is 80°C and the stirring time is 1-2 hours.
[0017] The DES solvent prepared by this invention is non-toxic, biodegradable, and inexpensive, and can efficiently dissolve cellulose and destroy its crystal structure.
[0018] Preferably, the bacterial cellulose membrane alkali treatment in S3 is performed by treating with 1% NaOH solution at 80°C for 1 hour.
[0019] Preferably, the mass ratio of DES solvent, bacterial cellulose powder, modified menthyl citrate, and dopamine hydrochloride in S4 is 100:(1-3):(0.1-1):(0.01-0.1).
[0020] DES efficiently dissolves bacterial cellulose and destroys its crystal structure. MC-EP is uniformly dispersed in the solution, preparing for subsequent covalent cross-linking. Dopamine is dispersed in the system, providing raw materials for subsequent in-situ polymerization.
[0021] Preferably, the volume ratio of the mixture to the AgNO3 solution in S5 is 10:(0.1-1).
[0022] Further preferably, the concentration of the AgNO3 solution is 0.01 M.
[0023] Preferably, the temperature for the low-temperature settling in S5 is 2-4°C, and the time is 12-24 hours.
[0024] Preferably, the temperature for the heating crosslinking reaction in S5 is 50°C and the time is 8-12 hours.
[0025] In this invention, AgNO3 solution is poured onto the top layer of the mixture as an antisolvent, dissolving bacterial cellulose in a green eutectic solvent to form a homogeneous solution. AgNO3 aqueous solution is a poor solvent; when the mixture comes into contact with a large amount of AgNO3 aqueous solution, solvent exchange occurs. Water molecules rapidly enter, while DES components (choline chloride and citric acid) diffuse out and enter the water. Bacterial cellulose has extremely low solubility in water, and its molecular chains rapidly precipitate, reassemble, and aggregate through intermolecular forces such as hydrogen bonds, forming a three-dimensional network hydrogel. The hydroxyl groups of cellulose itself have a certain reducing property; the added dopamine is a stronger reducing agent, and AgNO3 serves as a silver source, allowing for the in-situ synthesis of antibacterial nano-silver, which is distributed within the gel. Nano-silver possesses broad-spectrum and highly effective antibacterial capabilities, effective against Gram-positive bacteria, Gram-negative bacteria, and even fungi. Nano-silver and menthyl citrate can produce a synergistic antibacterial effect, thereby reducing the loading of MC and indirectly reducing the risk of hemolysis that may be caused by excessive MC.
[0026] It contains at least the following beneficial technical effects: The sterile dressing provided by this invention has the advantages of high antibacterial efficiency, active healing promotion, long-lasting sustained release, excellent mechanical properties and outstanding biosafety. It solves the problems of antibiotic resistance risk, drug burst release, poor biocompatibility and single function in the prior art. It is especially suitable for the clinical treatment of chronic infected wounds that are difficult to heal, and has great scientific significance and broad prospects for industrial application. Attached Figure Description
[0027] Figure 1 This is a diagram showing the antibacterial effect. Detailed Implementation
[0028] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.
[0029] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.
[0030] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.
[0031] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be obvious to those skilled in the art. This application specification and embodiments are merely exemplary.
[0032] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.
[0033] Unless otherwise specified, "room temperature" and "normal temperature" in this invention refer to 25±2℃.
[0034] Unless otherwise specified, all raw materials or instruments used in the following embodiments of the present invention are commercially available.
[0035] Preparation of menthol citrate: L-menthol, tert-butanol, and citric acid were heated to 60°C and stirred until homogeneous at a mass-volume ratio of 15g:20g:100mL. Then, 2g of immobilized lipase Novozym 435 (enzyme activity 4762U / g) was added and the enzymatic reaction was carried out at 60°C for 48h. The solvent was then filtered and rotary evaporated to obtain menthol citrate.
[0036] Example 1: A method for preparing a sterile dressing, comprising the following preparation steps: S1. Dissolve menthyl citrate in acetone, add epichlorohydrin and triethylamine, and stir at 53°C for 5 hours. After the reaction is complete, pour the mixture into ice water to precipitate, filter, wash the precipitate with cold water, and then vacuum dry at 40°C for 20 hours to obtain modified menthyl citrate. The mass-volume ratio of menthyl citrate, acetone, epichlorohydrin, and triethylamine is 10g:50mL:5g:7g; S2. Choline chloride and citric acid were mixed at a molar ratio of 1:2 and heated and stirred at 80°C for 1.5 h to obtain DES solvent; S3. The bacterial cellulose membrane was treated with 1% NaOH solution at 80℃ for 1 h, then washed with deionized water until neutral, freeze-dried and pulverized to obtain bacterial cellulose powder; S4. Mix DES solvent and bacterial cellulose powder evenly, then add modified menthyl citrate and stir evenly, then add dopamine hydrochloride and stir evenly to obtain a mixture; wherein the mass ratio of DES solvent, bacterial cellulose powder, modified menthyl citrate and dopamine hydrochloride is 100:2:0.5:0.05; S5. Pour the mixture into a mold and then slowly pour in 0.01 M AgNO3 solution. Let it stand at 3°C for 18 hours. Then heat it to 50°C for a cross-linking reaction for 10 hours. After soaking in deionized water for 10 hours and washing it 3 times, finally soak it in sterile PBS solution and store it at low temperature to obtain a sterile dressing. The volume ratio of the mixture to the AgNO3 solution is 10:0.5.
[0037] Example 2, a method for preparing a sterile dressing, comprising the following preparation steps: S1. Dissolve menthyl citrate in acetone, add epichlorohydrin and triethylamine, and stir at 50°C for 4 hours. After the reaction is complete, pour the mixture into ice water to precipitate, filter, wash the precipitate with cold water, and then vacuum dry at 38°C for 18 hours to obtain modified menthyl citrate. The mass-to-volume ratio of menthyl citrate, acetone, epichlorohydrin, and triethylamine is 10g:50mL:4g:5g. S2. Choline chloride and citric acid are mixed at a molar ratio of 1:2 and heated and stirred at 80°C for 1 hour to obtain DES solvent; S3. The bacterial cellulose membrane was treated with 1% NaOH solution at 80℃ for 1 h, then washed with deionized water until neutral, freeze-dried and pulverized to obtain bacterial cellulose powder; S4. Mix DES solvent and bacterial cellulose powder evenly, then add modified menthyl citrate and stir evenly, then add dopamine hydrochloride and stir evenly to obtain a mixture; wherein the mass ratio of DES solvent, bacterial cellulose powder, modified menthyl citrate and dopamine hydrochloride is 100:1:0.1:0.01; S5. Pour the mixture into a mold and then slowly pour in 0.01 M AgNO3 solution. Let it stand at 2°C for 12 hours. Then heat it to 50°C for crosslinking reaction for 8 hours. After soaking in deionized water for 10 hours and washing 3 times, finally soak it in sterile PBS solution and store it at low temperature to obtain sterile dressing. The volume ratio of the mixture to AgNO3 solution is 10:0.1.
[0038] Example 3, a method for preparing a sterile dressing, comprising the following preparation steps: S1. Dissolve menthyl citrate in acetone, add epichlorohydrin and triethylamine, and stir at 55°C for 6 hours. After the reaction is complete, pour the mixture into ice water to precipitate, filter, wash the precipitate with cold water, and then vacuum dry at 42°C for 24 hours to obtain modified menthyl citrate. The mass-to-volume ratio of menthyl citrate, acetone, epichlorohydrin, and triethylamine is 10g:50mL:6g:8g; S2. Choline chloride and citric acid were mixed at a molar ratio of 1:2 and heated and stirred at 80°C for 2 hours to obtain DES solvent; S3. The bacterial cellulose membrane was treated with 1% NaOH solution at 80℃ for 1 h, then washed with deionized water until neutral, freeze-dried and pulverized to obtain bacterial cellulose powder; S4. Mix DES solvent and bacterial cellulose powder evenly, then add modified menthyl citrate and stir evenly, then add dopamine hydrochloride and stir evenly to obtain a mixture; wherein the mass ratio of DES solvent, bacterial cellulose powder, modified menthyl citrate and dopamine hydrochloride is 100:3:1:0.1; S5. Pour the mixture into a mold and then slowly pour in 0.01 M AgNO3 solution. Let it stand at 4°C for 24 hours. Then heat it to 50°C for cross-linking reaction for 12 hours. After soaking in deionized water for 10 hours and washing 3 times, finally soak it in sterile PBS solution and store it at low temperature to obtain sterile dressing. The volume ratio of the mixture to AgNO3 solution is 10:1.
[0039] Comparative Example 1 A method for preparing a sterile dressing includes the following preparation steps: S1. Choline chloride and citric acid were mixed at a molar ratio of 1:2 and heated and stirred at 80°C for 1.5 h to obtain DES solvent; S2. The bacterial cellulose membrane was treated with 1% NaOH solution at 80℃ for 1 h, then washed with deionized water until neutral, freeze-dried and pulverized to obtain bacterial cellulose powder; S3. Mix DES solvent and bacterial cellulose powder evenly, then add L-menthol and stir evenly, then add dopamine hydrochloride and stir evenly to obtain a mixture; wherein the mass ratio of DES solvent, bacterial cellulose powder, L-menthol and dopamine hydrochloride is 100:2:0.5:0.05; S5. Pour the mixture into a mold and then slowly pour in 0.01 M AgNO3 solution. Let it stand at 3°C for 18 hours. Then heat it to 50°C for a cross-linking reaction for 10 hours. After soaking in deionized water for 10 hours and washing it 3 times, finally soak it in sterile PBS solution and store it at low temperature to obtain a sterile dressing. The volume ratio of the mixture to the AgNO3 solution is 10:0.5.
[0040] Comparative Example 2 A method for preparing a sterile dressing includes the following preparation steps: S1. Choline chloride and citric acid were mixed at a molar ratio of 1:2 and heated and stirred at 80°C for 1.5 h to obtain DES solvent; S2. The bacterial cellulose membrane was treated with 1% NaOH solution at 80℃ for 1 h, then washed with deionized water until neutral, freeze-dried and pulverized to obtain bacterial cellulose powder; S3. Mix DES solvent and bacterial cellulose powder evenly, then add menthyl citrate and stir evenly, then add dopamine hydrochloride and stir evenly to obtain a mixture; wherein the mass ratio of DES solvent, bacterial cellulose powder, menthyl citrate and dopamine hydrochloride is 100:2:0.5:0.05; S5. Pour the mixture into a mold and then slowly pour in 0.01 M AgNO3 solution. Let it stand at 3°C for 18 hours. Then heat it to 50°C for a cross-linking reaction for 10 hours. After soaking in deionized water for 10 hours and washing it 3 times, finally soak it in sterile PBS solution and store it at low temperature to obtain a sterile dressing. The volume ratio of the mixture to the AgNO3 solution is 10:0.5.
[0041] Comparative Example 3 A method for preparing a sterile dressing includes the following preparation steps: S1. Dissolve menthyl citrate in acetone, add epichlorohydrin and triethylamine, and stir at 53°C for 5 hours. After the reaction is complete, pour the mixture into ice water to precipitate, filter, wash the precipitate with cold water, and then vacuum dry at 40°C for 20 hours to obtain modified menthyl citrate. The mass-volume ratio of menthyl citrate, acetone, epichlorohydrin, and triethylamine is 10g:50mL:5g:7g; S2. The bacterial cellulose membrane was treated with 1% NaOH solution at 80℃ for 1 h, then washed with deionized water until neutral, freeze-dried and pulverized to obtain bacterial cellulose powder; S3. Mix 0.1M 1-ethyl-3-methylimidazolium acetate solution and bacterial cellulose powder evenly, then add modified menthyl citrate and stir evenly, then add dopamine hydrochloride and stir evenly to obtain a mixture; wherein the mass ratio of 1-ethyl-3-methylimidazolium acetate solution, bacterial cellulose powder, modified menthyl citrate, and dopamine hydrochloride is 100:2:0.5:0.05; S4. Pour the mixture into a mold and then slowly pour in 0.01 M AgNO3 solution. Let it stand at 3°C for 18 hours. Then heat it to 50°C for a cross-linking reaction for 10 hours. After soaking in deionized water for 10 hours and washing it 3 times, finally soak it in sterile PBS solution and store it at low temperature to obtain a sterile dressing. The volume ratio of the mixture to the AgNO3 solution is 10:0.5.
[0042] Comparative Example 4 A method for preparing a sterile dressing includes the following preparation steps: S1. Dissolve menthyl citrate in acetone, add epichlorohydrin and triethylamine, and stir at 53°C for 5 hours. After the reaction is complete, pour the mixture into ice water to precipitate, filter, wash the precipitate with cold water, and then vacuum dry at 40°C for 20 hours to obtain modified menthyl citrate. The mass-volume ratio of menthyl citrate, acetone, epichlorohydrin, and triethylamine is 10g:50mL:5g:7g; S2. Choline chloride and citric acid were mixed at a molar ratio of 1:2 and heated and stirred at 80°C for 1.5 h to obtain DES solvent; S3. The bacterial cellulose membrane was treated with 1% NaOH solution at 80℃ for 1 h, then washed with deionized water until neutral, freeze-dried and pulverized to obtain bacterial cellulose powder; S4. Mix DES solvent and bacterial cellulose powder evenly, then add modified menthyl citrate and stir evenly, then add dopamine hydrochloride and stir evenly to obtain a mixture; wherein the mass ratio of DES solvent, bacterial cellulose powder, modified menthyl citrate and dopamine hydrochloride is 100:2:0.5:0.05; S5. Pour the mixture into a mold and then slowly pour in 2% w / v glutaraldehyde solution. Let it stand at 37°C for 18 hours. Then heat it to 50°C for a crosslinking reaction for 10 hours. After soaking in deionized water for 10 hours and washing it 3 times, finally soak it in sterile PBS solution and store it at low temperature to obtain a sterile dressing. The volume ratio of the mixture to AgNO3 solution is 10:0.5.
[0043] Experimental Example 1 Antibacterial test Experimental materials: dressings prepared in Examples 1-3 and Comparative Examples 1-4, commercially available silver dressing as a positive control, and PBS gauze as a negative control.
[0044] Strains: Staphylococcus aureus, Escherichia coli.
[0045] Experimental methods: Each group of dressings was prepared into circular pieces of the same diameter and placed on agar plates inoculated with bacterial solution. After incubation at 37°C for 24 hours, the diameter of the inhibition zone was measured. Figure 1 .
[0046] The antibacterial zone of the dressing material prepared in Examples 1-3 of this invention is significantly larger than that of the comparative example and the negative control, and slightly higher than that of commercial silver dressing, and is effective against both bacteria; moreover, according to Comparative Examples 1-2, the modification of L-menthol can improve the antibacterial ability, the use of traditional solvents in Comparative Example 3 leads to a decrease in antibacterial effect, and the use of traditional crosslinking agents in Comparative Example 4 significantly reduces the antibacterial ability.
[0047] Experimental Example 2 Mechanical property testing Determining the mechanical strength, flexibility, and swelling properties of the dressing. Experimental methods: Tensile strength and elongation at break: tested using a universal testing machine.
[0048] Swelling rate: Weigh the dry dressing (Wd), immerse it in PBS until equilibration, remove it, blot off the surface moisture, and weigh it (Ws). Swelling rate (%) = [(Ws-Wd) / Wd] × 100%.
[0049] Table 1
[0050] As shown in Table 1, the dressing prepared in the embodiments of the present invention has good mechanical properties and can effectively absorb wound exudate, providing a moist environment for the wound. The dispersibility and binding force of L-menthol affect the overall strength of the dressing; at the same time, the present invention uses silver ion solution as a multifunctional crosslinking agent, which has good mechanical properties and high bactericidal rate.
[0051] Experimental Example 3 In vitro cytotoxicity test Experimental cells: Human skin fibroblasts (HSFs) Experimental methods: Each group of dressings was immersed in cell culture medium to prepare an extract. After co-culturing with cells for 24 hours, the cell viability was detected, as shown in Table 2.
[0052] Table 2
[0053] As shown in Table 2, Comparative Examples 1 and 2 contain high concentrations of free L-menthol, which exhibits certain toxicity. Compared with Comparative Example 4, Example 1 does not contain silver ions, and its cytotoxicity is slightly lower than that of Example 1, indicating that the addition of silver ions in this invention does not significantly increase toxicity.
[0054] Experiment Example 4 In vitro wound healing experiment Experimental materials: dressings prepared in Examples 1-3 and Comparative Examples 1-4, commercially available silver dressing as a positive control, and PBS gauze as a negative control.
[0055] Experimental cells: Human skin fibroblasts Experimental methods: Scratch Assay: A "scratch" simulating a wound was created on a cell monolayer and covered with a dressing. The closure rate of the scratch area was observed and measured at 3, 7, and 14, as shown in Table 3.
[0056] Table 3
[0057] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A method for preparing a sterile dressing, characterized in that, The preparation steps include the following: S1. Dissolve menthyl citrate in acetone, add epichlorohydrin and triethylamine, and stir to react; after the reaction is complete, pour the mixture into ice water to precipitate, filter, wash the precipitate with cold water, and then vacuum dry to obtain modified menthyl citrate. S2. Mix choline chloride and citric acid, heat and stir until homogeneous to obtain DES solvent; S3. The bacterial cellulose membrane is treated with alkali, then washed with deionized water until neutral, freeze-dried and then pulverized to obtain bacterial cellulose powder; S4. Mix DES solvent and bacterial cellulose powder evenly, then add modified menthyl citrate and stir evenly, then add dopamine hydrochloride and stir evenly to obtain a mixture; S5. Pour the mixture into a mold, then slowly pour in AgNO3 solution and allow it to stand at low temperature for reaction. Then, heat it for cross-linking reaction, soak and wash it, and finally soak it in sterile PBS solution for low-temperature preservation to obtain sterile dressing.
2. The preparation method according to claim 1, characterized in that, The mass-to-volume ratio of menthyl citrate, acetone, epichlorohydrin, and triethylamine in S1 is 10g:50mL:(4-6)g:(5-8)g.
3. The preparation method according to claim 1, characterized in that, The preparation method of the menthol citrate in S1 is as follows: L-menthol, tert-butanol, and citric acid are heated to 60°C and stirred evenly in a mass-volume ratio of 15g:20g:100mL. Then, 2g of immobilized lipase is added and the enzymatic reaction is carried out at 60°C for 48h. The solvent is then filtered and rotary evaporated to obtain menthol citrate.
4. The preparation method according to claim 1, characterized in that, The molar ratio of choline chloride to citric acid in S2 is 1:
2.
5. The preparation method according to claim 1, characterized in that, The stirring temperature in S2 is 80℃, and the stirring time is 1-2 hours.
6. The preparation method according to claim 1, characterized in that, In S3, the bacterial cellulose membrane is treated with 1% NaOH solution at 80°C for 1 hour.
7. The preparation method according to claim 1, characterized in that, The mass ratio of DES solvent, bacterial cellulose powder, modified menthyl citrate, and dopamine hydrochloride in S4 is 100:(1-3):(0.1-1):(0.01-0.1).
8. The preparation method according to claim 1, characterized in that, The volume ratio of the mixed solution and AgNO3 solution in S5 is 10:(0.1-1).
9. The preparation method according to claim 1, characterized in that, The temperature for the low-temperature settling in S5 is 2-4℃, and the time is 12-24h.
10. The preparation method according to claim 1, characterized in that, The temperature for the heating crosslinking reaction in S5 is 50°C, and the time is 8-12 hours.