Chitin membrane dressing for promoting wound healing and method for preparing the same

Abstract

The application discloses a chitin membrane dressing for promoting wound healing and a preparation method thereof, and comprises the following components in parts by weight: a bacteriostatic slow-release gel carrier 36-40 parts, and a bacteriostatic repair and healing-promoting essential oil 6-8 parts; the bacteriostatic slow-release gel carrier is prepared by using modified chitin and modified dextran to prepare a gel and in-situ polymerization of an organic metal framework; and the bacteriostatic repair composition is obtained by extracting cortex phellodendri, wild chrysanthemum, portulaca oleracea, rhubarb, giant knotweed and aloe vera by using tea tree essential oil. The application proposes a method for preparing a gel dressing by using modified dextran and in-situ polymerization of a metal organic framework together with modified chitin, realizes multiple drug release, prolongs the effective time of drug action, replaces antibiotics by using plant extracts, and further realizes the technical effects of avoiding the use of antibiotics and bacteriostasis by multiple mechanisms.

Description

Technical Field

[0001] This invention belongs to the field of wound dressing technology, specifically referring to a chitin membrane dressing that promotes wound healing and its preparation method. Background Technology

[0002] Chitin, also known as chitosan, is widely found in the exoskeletons of insects and crustaceans, as well as in the cell walls of algae and fungi. Its abundance in nature is second only to cellulose, making it the world's most abundant animal-derived polysaccharide. Chitosan is the product obtained by deacetylation of chitin. Both chitin and chitosan exhibit good tissue compatibility, bioactivity, biodegradability, and non-immunogenicity, and promote wound healing. The organometallic framework structure composed of zinc ions and 2-methylimidazolium has a very large specific surface area and porous structure, exhibiting good adsorption properties and releasing zinc ions upon decomposition, thus possessing strong thermal stability. Dextran is a polysaccharide molecule composed of glucose molecules linked by β-1,4-glycosidic bonds. It is a natural polysaccharide widely found in the cell walls of plants and animals, serving as an important component of cell walls, and possesses good biocompatibility, biodegradability, and water absorption properties.

[0003] The existing technologies currently have the following main problems: 1. The use of antibiotics easily leads to bacterial resistance; 2. Plant extracts have a short duration of action and their effects are not ideal. Summary of the Invention

[0004] In response to the above situation and to overcome the shortcomings of the prior art, this invention provides a chitin membrane dressing that promotes wound healing and its preparation method. To address the problems of bacterial resistance caused by antibiotic use and the short duration of action of plant extracts, this invention proposes a method of preparing a gel dressing by modifying dextran and in-situ polymerizing a metal-organic framework with modified chitin. This achieves multiple sustained releases of the drug, prolongs the effective time of drug action, and replaces antibiotics with plant extracts, thereby achieving the technical effects of avoiding antibiotic use and inhibiting bacteria through multiple mechanisms.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The present invention proposes a chitin membrane dressing for promoting wound healing and its preparation method. The chitin membrane dressing for promoting wound healing comprises the following components in parts by weight: 36-40 parts of antibacterial sustained-release gel carrier and 6-8 parts of antibacterial repair and healing-promoting essential oil; the antibacterial sustained-release gel carrier is obtained by preparing a gel from modified chitin and modified dextran and then polymerizing an organometallic framework in situ; the antibacterial repair composition is obtained by extracting Phellodendron bark, wild chrysanthemum, purslane, rhubarb, Polygonum cuspidatum, and aloe vera from tea tree essential oil.

[0006] Preferably, the antibacterial sustained-release gel carrier comprises the following components in parts by weight: 25-30 parts chitin powder, 20-25 parts dextran powder, 13-17 parts chlorosulfonic acid-pyridine, 15-19 parts 2-methylimidazole, and 13-16 parts zinc nitrate.

[0007] Preferably, the antibacterial and repairing composition comprises the following components in parts by weight: 10-15 parts of Phellodendron bark, 3-4 parts of wild chrysanthemum, 5-9 parts of purslane, 10-13 parts of rhubarb, 2-5 parts of Polygonum cuspidatum, 13-15 parts of aloe vera, and 12-16 parts of tea tree oil.

[0008] Preferably, the preparation method of the antibacterial sustained-release gel carrier specifically includes the following steps:

[0009] S1. Add chitin powder to a 5-7% sodium hydroxide solution and stir in a 90°C water bath at 300 rpm for 2.5 h to obtain deacetylated chitin.

[0010] S2. Add the deacetylated chitin obtained in S1 to an isopropanol aqueous solution with a volume concentration of 75% to obtain a mixed solution. Add sodium hydroxide to the mixed solution at a rate of 0.12-0.18 g / mL. Stir in a water bath at 50°C for 30 min. Then add chloroacetic acid solution dropwise at a rate of 0.07-0.09 g / mL. React for 4 h to obtain the reaction solution.

[0011] S3. Add a 70% ethanol solution at a volume ratio of 2:1 to the reaction solution obtained in S1. Desalt and dehydrate with 90% ethanol solution, and dry to obtain modified chitin.

[0012] S4. Add dextran powder to N,N-dimethylformamide solution, add chlorosulfonic acid-pyridine, react in a water bath at 45-55℃ for 100-120 min, and adjust the pH to 9-10 to obtain sulfonated dextran.

[0013] S5. Add the sulfonated dextran powder obtained in S4 to water to obtain a sulfonated glucose solution. Add sodium periodate to the sulfonated glucose solution, add zinc nitrate powder, adjust the pH to 2-3, and react in a water bath in the dark for 3-5 hours to obtain a mixed solution. Add ethylene glycol at a concentration of 66-78 mg / mL to the mixed solution to remove sodium periodate. Filter, wash, and dry to obtain modified dextran.

[0014] S6. Dissolve zinc nitrate powder in water, add the modified dextran obtained in S5, stir evenly, add 2-methylimidazole, stir in a 30-40℃ water bath at 100-140 rpm for 8-10 min, then add the modified chitin obtained in S3 and continue stirring for 15-20 min to obtain the antibacterial sustained-release gel carrier.

[0015] Preferably, in S1, the amount of chitin powder added to the sodium hydroxide solution is 0.08-0.09 g / mL;

[0016] Preferably, in S2, the amount of deacetylated chitin added to the isopropanol aqueous solution is 0.1-0.12 g / mL;

[0017] Preferably, in step S4, the amount of dextran powder added to the N,N-dimethylformamide solution is 0.13-0.18 mol / L;

[0018] Preferably, in step S5, the amount of sulfonated dextran added to water is 18-22 mg / mL;

[0019] Preferably, in step S5, the amount of sodium periodate added to the sulfonated glucose solution is 23-25 ​​mg / mL.

[0020] Preferably, the preparation method of the antibacterial repair composition specifically includes the following steps:

[0021] (1) Take Phellodendron bark, wild chrysanthemum, purslane, rhubarb, Japanese knotweed and aloe vera, wash them, screen out pests and diseased plants, freeze dry, pulverize and mix them, and pass them through a 60-mesh sieve to obtain mixed powder;

[0022] (2) Add the mixed powder to water at an addition rate of 0.1-0.2 g / mL, add cellulase and pectinase, sonicate at 60-80 W for 20-30 min at 40-45℃, add tea tree oil, stir in a water bath at 40℃ for 3-5 h, and filter to obtain the antibacterial repair composition.

[0023] The present invention also provides a method for preparing a chitinous membrane dressing that promotes wound healing, specifically including the following steps: adding an antibacterial repair composition to an antibacterial sustained-release gel carrier, stirring at 60 rpm for 7 min to obtain a chitinous membrane dressing that promotes wound healing.

[0024] The beneficial effects achieved by this invention are as follows: This invention enhances the antibacterial ability of chitin through deacetylation modification, improves its water solubility by O-carboxymethyl modification while retaining amino groups, and enhances the antioxidant activity and affinity for Zn through sulfonation modification of dextran. 2+ The binding ability of 2-methylimidazolium enables in-situ polymerization of Zn... 2+ An organic framework was synthesized on the dextran molecular chain as the core, and sulfonated dextran was oxidized to obtain a modified dextran with an aldehyde structure. This modified dextran, combined with chitin modified with a primary amine structure, was used to prepare an antibacterial gel carrier with dual sustained-release effects. This carrier was then loaded with an antibacterial and repairing composition prepared from extracts of Phellodendron bark, wild chrysanthemum, purslane, rhubarb, Polygonum cuspidatum, and aloe vera to obtain a chitinous membrane dressing that promotes wound healing. When applied to the wound, it forms an antibacterial and repairing film. The antibacterial and repairing composition and Zn...2+ The addition of [a specific ingredient] enhances the antibacterial ability of the gel carrier; the organometallic framework can load antibacterial and repairing substances, and upon decomposition, releases Zn with antibacterial properties. 2+ Antibacterial and repairing substances are incorporated into the hydrogel network structure and then released onto the wound surface through the hydrogel for continuous drug delivery, greatly extending the effective time of drug action and reducing the damage to cells and tissues caused by high concentrations of drugs. Phellodendron bark, rhubarb, Polygonum cuspidatum, and aloe vera are rich in antibacterial substances and polysaccharides, such as flavonoids and terpenoids, which can fight bacteria in multiple ways, avoiding the use of antibiotics and infection of wounds by drug-resistant strains. Polysaccharides can promote wound healing, and the antibacterial gel carrier extends the effective period of antibacterial and repairing substances and maintains their structural stability. Attached Figure Description

[0025] Figure 1 These are the results of the antibacterial tests of the drug solutions described in Examples 1-3 and Comparative Examples 1-3 of the present invention;

[0026] Figure 2 The graphs show the results of the oxidation stability of Examples 1-3 and Comparative Examples 1-3 of the present invention;

[0027] Figure 3 The graph shows the results of the hydrogel toxicity test obtained in Examples 1-3 of this invention;

[0028] Figure 4 The results of the trauma test in mice of the blank group, Examples 1-3, and the control group of this invention are shown in the figure.

[0029] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof. Detailed Implementation

[0030] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those familiar to those skilled in the art. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to this invention. The preferred embodiments and materials described herein are for illustrative purposes only and do not limit the scope of this application.

[0032] Unless otherwise specified, the experimental methods used in the following examples are conventional methods; unless otherwise specified, the experimental materials and test strains used in the following examples were purchased from commercial channels.

[0033] Example 1

[0034] A chitin membrane dressing that promotes wound healing comprises the following components in parts by weight: 40 parts of antibacterial sustained-release gel carrier and 8 parts of antibacterial repair and healing-promoting essential oil.

[0035] The antibacterial sustained-release gel carrier comprises the following components in parts by weight: 30 parts chitin powder, 25 parts dextran powder, 17 parts chlorosulfonic acid-pyridine, 19 parts 2-methylimidazole, and 16 parts zinc nitrate.

[0036] The antibacterial and repairing composition comprises the following components in parts by weight: 15 parts of Phellodendron bark, 4 parts of wild chrysanthemum, 9 parts of purslane, 13 parts of rhubarb, 5 parts of Polygonum cuspidatum, 15 parts of aloe vera, and 16 parts of tea tree essential oil.

[0037] The preparation method of the antibacterial sustained-release gel carrier specifically includes the following steps:

[0038] S1. Chitin powder was added to a 5% sodium hydroxide solution at a dosage of 0.09 g / mL and stirred in a 90°C water bath at 300 rpm for 2.5 h to obtain deacetylated chitin.

[0039] S2. The deacetylated chitin obtained in S1 was added to a 75% isopropanol aqueous solution at a dosage of 0.12 g / mL to obtain a mixed solution. Sodium hydroxide was added to the mixed solution at a dosage of 0.18 g / mL. The mixture was stirred in a water bath at 50°C for 30 min. Then, chloroacetic acid solution was added dropwise at a dosage of 0.09 g / mL. The reaction was allowed to proceed for 4 h to obtain the reaction solution.

[0040] S3. Add a 70% ethanol solution at a volume ratio of 2:1 to the reaction solution obtained in S1. Desalt and dehydrate with 90% ethanol solution, and dry to obtain modified chitin.

[0041] S4. Add dextran powder at a concentration of 0.18 mol / L to N,N-dimethylformamide solution, add chlorosulfonic acid-pyridine, react in a water bath at 55°C for 120 min, and adjust the pH to 10 to obtain sulfonated dextran.

[0042] S5. Add the sulfonated dextran powder obtained in S4 to water at a dosage of 22 mg / mL to obtain a sulfonated glucose solution. Add sodium periodate at a dosage of 25 mg / mL to the sulfonated glucose solution. Add zinc nitrate powder to adjust the pH to 3. Heat in a water bath and react in the dark for 5 hours to obtain a mixed solution. Add ethylene glycol at a dosage of 78 mg / mL to the mixed solution to remove sodium periodate. Filter, wash and dry to obtain modified dextran.

[0043] S6. Dissolve zinc nitrate powder in water, add the modified dextran obtained in S5, stir evenly, add 2-methylimidazole, stir at 140 rpm in a 40°C water bath for 10 min, then add the modified chitin obtained in S3 and continue stirring for 20 min to obtain the antibacterial sustained-release gel carrier.

[0044] The preparation method of the antibacterial and repairing composition specifically includes the following steps:

[0045] (1) Take Phellodendron bark, wild chrysanthemum, purslane, rhubarb, Japanese knotweed and aloe vera, wash them, screen out pests and diseased plants, freeze dry, pulverize and mix them, and pass them through a 60-mesh sieve to obtain mixed powder;

[0046] (2) Add the mixed powder to water at an addition rate of 0.2 g / mL, add cellulase and pectinase, sonicate at 80 W for 30 min at 45℃, add tea tree oil, stir in a water bath at 40℃ for 5 h, and filter to obtain the antibacterial repair composition.

[0047] The present invention also provides a method for preparing a chitinous membrane dressing that promotes wound healing, specifically including the following steps: adding an antibacterial repair composition to an antibacterial sustained-release gel carrier, stirring at 60 rpm for 7 min to obtain a chitinous membrane dressing that promotes wound healing.

[0048] Example 2

[0049] A chitin membrane dressing that promotes wound healing comprises the following components in parts by weight: 36 parts of antibacterial sustained-release gel carrier and 6 parts of antibacterial repair and healing-promoting essential oil.

[0050] The antibacterial sustained-release gel carrier comprises the following components in parts by weight: 25 parts chitin powder, 20 parts dextran powder, 13 parts chlorosulfonic acid-pyridine, 15 parts 2-methylimidazole, and 13 parts zinc nitrate.

[0051] The antibacterial and repairing composition comprises the following components in parts by weight: 10 parts of Phellodendron bark, 3 parts of wild chrysanthemum, 5 parts of purslane, 10 parts of rhubarb, 2 parts of Polygonum cuspidatum, 13 parts of aloe vera, and 12 parts of tea tree essential oil.

[0052] The preparation method of the antibacterial sustained-release gel carrier specifically includes the following steps:

[0053] S1. Chitin powder was added to a 5% sodium hydroxide solution at a dosage of 0.08 g / mL and stirred in a 90°C water bath at 300 rpm for 2.5 h to obtain deacetylated chitin.

[0054] S2. The deacetylated chitin obtained in S1 was added to a 75% isopropanol aqueous solution at a dosage of 0.1 g / mL to obtain a mixed solution. Sodium hydroxide was added to the mixed solution at a dosage of 0.12 g / mL. The mixture was stirred in a water bath at 50°C for 30 min. Then, chloroacetic acid solution was added dropwise at a dosage of 0.07 g / mL. The reaction was allowed to proceed for 4 h to obtain the reaction solution.

[0055] S3. Add a 70% ethanol solution at a volume ratio of 2:1 to the reaction solution obtained in S1. Desalt and dehydrate with 90% ethanol solution, and dry to obtain modified chitin.

[0056] S4. Add dextran powder at a concentration of 0.13 mol / L to N,N-dimethylformamide solution, add chlorosulfonic acid-pyridine, react in a water bath at 45°C for 100 min, and adjust the pH to 9 to obtain sulfonated dextran.

[0057] S5. Add the sulfonated dextran powder obtained in S4 to water at a dosage of 18 mg / mL to obtain a sulfonated glucose solution. Add sodium periodate to the sulfonated glucose solution at a dosage of 23 mg / mL. Add zinc nitrate powder to adjust the pH to 2. Heat in a water bath and react in the dark for 3 hours to obtain a mixed solution. Add ethylene glycol to the mixed solution at a dosage of 66 mg / mL to remove sodium periodate. Filter, wash and dry to obtain modified dextran.

[0058] S6. Dissolve zinc nitrate powder in water, add the modified dextran obtained in S5, stir evenly, add 2-methylimidazole, stir at 100 rpm in a 30°C water bath for 8 min, then add the modified chitin obtained in S3 and continue stirring for 15 min to obtain the antibacterial sustained-release gel carrier.

[0059] The preparation method of the antibacterial and repairing composition specifically includes the following steps:

[0060] (1) Take Phellodendron bark, wild chrysanthemum, purslane, rhubarb, Japanese knotweed and aloe vera, wash them, screen out pests and diseased plants, freeze dry, pulverize and mix them, and pass them through a 60-mesh sieve to obtain mixed powder;

[0061] (2) Add the mixed powder to water at a dosage of 0.1 g / mL, add cellulase and pectinase, sonicate at 60 W for 20 min at 40℃, add tea tree oil, stir in a water bath at 40℃ for 3 h, and filter to obtain the antibacterial repair composition.

[0062] The present invention also provides a method for preparing a chitinous membrane dressing that promotes wound healing, the specific preparation steps of which are the same as those in Example 1.

[0063] Example 3

[0064] A chitin membrane dressing that promotes wound healing comprises the following components in parts by weight: 38 parts of antibacterial sustained-release gel carrier and 7 parts of antibacterial repair and healing-promoting essential oil.

[0065] The antibacterial sustained-release gel carrier comprises the following components in parts by weight: 28 parts chitin powder, 23 parts dextran powder, 15 parts chlorosulfonic acid-pyridine, 17 parts 2-methylimidazole, and 15 parts zinc nitrate.

[0066] The antibacterial and repairing composition comprises the following components in parts by weight: 12 parts of Phellodendron bark, 3.5 parts of wild chrysanthemum, 7 parts of purslane, 12 parts of rhubarb, 4 parts of Polygonum cuspidatum, 12 parts of aloe vera, and 14 parts of tea tree essential oil.

[0067] The preparation method of the antibacterial sustained-release gel carrier specifically includes the following steps:

[0068] S1. Chitin powder was added to a 5% sodium hydroxide solution at a dosage of 0.085 g / mL and stirred in a 90°C water bath at 300 rpm for 2.5 h to obtain deacetylated chitin.

[0069] S2. The deacetylated chitin obtained in S1 was added to a 75% isopropanol aqueous solution at a dosage of 0.115 g / mL to obtain a mixed solution. Sodium hydroxide was added to the mixed solution at a dosage of 0.16 g / mL. The mixture was stirred in a water bath at 50°C for 30 min. Then, chloroacetic acid solution was added dropwise at a dosage of 0.08 g / mL. The reaction was allowed to proceed for 4 h to obtain the reaction solution.

[0070] S3. Add a 70% ethanol solution at a volume ratio of 2:1 to the reaction solution obtained in S1. Desalt and dehydrate with 90% ethanol solution, and dry to obtain modified chitin.

[0071] S4. Add dextran powder at a concentration of 0.15 mol / L to N,N-dimethylformamide solution, add chlorosulfonic acid-pyridine, react in a water bath at 50°C for 110 min, and adjust the pH to 9.5 to obtain sulfonated dextran.

[0072] S5. Add the sulfonated dextran powder obtained in S4 to water at a dosage of 20 mg / mL to obtain a sulfonated glucose solution. Add sodium periodate to the sulfonated glucose solution at a dosage of 24 mg / mL. Add zinc nitrate powder to adjust the pH to 2.5. Heat in a water bath and react in the dark for 4 hours to obtain a mixed solution. Add ethylene glycol to the mixed solution at a dosage of 70 mg / mL to remove sodium periodate. Filter, wash and dry to obtain modified dextran.

[0073] S6. Dissolve zinc nitrate powder in water, add the modified dextran obtained in S5, stir evenly, add 2-methylimidazole, stir at 120 rpm in a 35°C water bath for 9 min, then add the modified chitin obtained in S3 and continue stirring for 16 min to obtain the antibacterial sustained-release gel carrier.

[0074] The preparation method of the antibacterial and repairing composition specifically includes the following steps:

[0075] (1) Take Phellodendron bark, wild chrysanthemum, purslane, rhubarb, Japanese knotweed and aloe vera, wash them, screen out pests and diseased plants, freeze dry, pulverize and mix them, and pass them through a 60-mesh sieve to obtain mixed powder;

[0076] (2) Add the mixed powder to water at an addition rate of 0.115 g / mL, add cellulase and pectinase, sonicate at 70 W for 25 min at 42 °C, add tea tree oil, stir in a water bath at 40 °C for 4 h, and filter to obtain the antibacterial repair composition.

[0077] The present invention also provides a method for preparing a chitinous membrane dressing that promotes wound healing, the specific preparation steps of which are the same as those in Example 1.

[0078] Comparative Example 1

[0079] This comparative example provides a dressing that differs from Example 3 only in that it does not contain an organometallic framework; the other components and their contents are the same as in Example 3.

[0080] Comparative Example 2

[0081] This comparative example provides a dressing that differs from Example 3 only in that the chitin is not modified in the composition, while the other components and their contents are the same as in Example 3.

[0082] Comparative Example 3

[0083] This comparative example provides a dressing that differs from Example 3 only in that the dextran is not modified in the components, while the other components and their contents are the same as in Example 3.

[0084] Experimental Example

[0085] 1. Antibacterial test

[0086] The concentration was 1.2 × 10⁻⁶. 85 mL of cfu / mL E. coli were used as experimental groups. 1 mL of the dressings obtained in Examples 1-3 and Comparative Examples 1-3 were taken and placed in test tubes. The mixtures were centrifuged at 120 rpm for 2 min, then added to the suspension. 1 mL of physiological saline was added to the control group. All mixtures were thoroughly mixed and stored at 37°C for 10 min. 1 mL of each mixture was then added to a test tube containing 5 mL of PBS buffer, diluted three times, and 1 mL was placed in a sterile dish. Agar medium was added, and the mixtures were incubated at 37°C for 24 h. Plate counts were performed, and the inhibition rate was calculated using the following formula:

[0087] Antibacterial rate = (number of colonies in control group - number of colonies in experimental group) / number of colonies in control group × 100%.

[0088] Figure 1 The figures show the results of antibacterial tests of the solutions described in Examples 1-3 and Comparative Examples 1-3 of this invention. As shown, the inhibition rates against *Escherichia coli* in Examples 1-3 were 100%, 100%, and 100%, respectively. The inhibition rates against *Staphylococcus aureus* in Comparative Examples 1-3 were 62.3%, 53.5%, and 66.2%, respectively. The inhibition rates against *E. coli* in Examples 1-3 were significantly higher than those in Comparative Example 1. The use of an organometallic framework effectively improves the antibacterial effect of the dressing. The inhibition rates against *E. coli* in Examples 1-3 were significantly higher than those in Comparative Example 2. [The text abruptly ends here, likely due to an incomplete sentence or missing information.] Modification effectively improves the antibacterial effect of dressings. The inhibition rate of Escherichia coli in Examples 1-3 is significantly higher than that in Comparative Example 2. Modification of dextran effectively improves the antibacterial effect of dressings. The organometallic framework can further adsorb antibacterial substances and reduce the impact of light and high temperature on its structural stability. The zinc ions carried are released along with the antibacterial substances during decomposition, playing a good synergistic role in antibacterial effect. After deacetylation modification of chitin, the amino cations it carries have a good antibacterial effect. After modification of dextran, it can enhance the binding ability with zinc ions, enabling the metal-organic framework to undergo original polymerization.

[0089] 2. Oxidation test

[0090] The dressings obtained in Examples 1-3 and Comparative Examples 1-3 were subjected to accelerated oxidation tests under constant temperature of 60°C and irradiation with a 50W incandescent lamp. Samples were taken at 0h and 24h, and the POV (peroxide value) of the antibacterial repair composition contained therein was determined by sodium thiosulfate titration (GB / T5009). The POV value measured at 0d was used as the baseline value, and the ΔPOV value was calculated using the following formula:

[0091] Δpov value = measured pov value - baseline value.

[0092] Figure 2The figures show the results of the oxidation stability of Examples 1-3 and Comparative Examples 1-3 of the present invention. As shown in the figure, at 5 days, the Δpov values ​​of Examples 1-3 were 8.6 meq / kg, 8.3 meq / kg, and 8.9 meq / kg, respectively, while the Δpov values ​​of Comparative Examples 1-3 were 12.2 meq / kg, 10.5 meq / kg, and 13.3 meq / kg, respectively. The Δpov values ​​of Examples 1-3 were significantly lower than those of Comparative Example 1, indicating that the organometallic framework can reduce the oxidation rate of the oil phase components and protect the stability of substances such as flavonoids and terpenes in tea tree oil extract. The Δpov values ​​of Examples 1-3 were significantly higher than those of Comparative Example 2, indicating that the modified chitin can reduce the oxidation rate of the oil phase components and protect the active ingredients. The Δpov values ​​of Examples 1-3 were significantly higher than those of Comparative Example 3, indicating that the modified dextran can reduce the oxidation rate of the oil phase components and protect the active ingredients.

[0093] 3. Cytotoxicity test

[0094] Take 200 mg of each of the dressings obtained in Examples 1-3, soak them in 10 mL of basic culture medium for 10 h, filter the extracts, and then dilute them 30 and 50 times respectively to obtain diluted solutions; adjust the concentration of fibroblasts cultured to the 3rd generation to 1×10 5 / mL, suspended in basal medium, and seeded into 96-well plates. 100uL of medium was added to each well and cultured until cells adhered. After washing twice with PBS, 100uL of diluent was added to each well. 100uL of basal medium was added as a control. After 24h of culture, 10uL of CCK-8 was added to each well. After incubation for 48h, the absorbance at 450nm was measured, and the viability was calculated using the following formula:

[0095] Survival rate = (Experimental group absorbance value / Control group absorbance value) × 100%.

[0096] Figure 3 The results of the toxicity test of the hydrogels obtained in Examples 1-3 of this invention are shown in the figure. As shown, the survival rates after culturing with the hydrogels obtained in Examples 1-3 diluted 30 times were 110%, 109%, and 112%, respectively. After culturing with the hydrogels obtained in Examples 1-3 diluted 50 times, the survival rates were 103%, 106%, and 104%, respectively. The fact that the cell survival rate exceeded 100% in the experiment indicates that the dressing is non-cytotoxic, the cells can proliferate and develop normally, and will not have an adverse effect on the wound. Moreover, as the concentration of the extract increases, the cell survival rate can be improved, cell proliferation can be promoted, and the wound healing speed can be increased.

[0097] 4. Mouse trauma test

[0098] Six-week-old mice were fasted overnight and injected intraperitoneally with streptozotocin (STZ) at a dose of 50 mg / kg (body weight) for five consecutive days. Two weeks later, blood glucose was measured using a glucose meter. When the non-fasting blood glucose level consistently exceeded 16.7 mmol, diabetic mice were obtained. Ten normal mice were used as the control group, and forty diabetic mice were randomly divided into four groups. The mice were anesthetized, their back hair was shaved, and a full-thickness skin wound with a diameter of 8 mm was created on the back of each mouse using a piercing device. The experimental groups were treated with the application methods described in Examples 1-3, while the control and control groups received no treatment. Serum tumor necrosis factor-α (TNF-α) levels were measured using chemiluminescence immunoassay at 1 day and 7 days.

[0099] Figure 4 The figures show the results of the wound test in mice of the blank group, Examples 1-3, and the control group of this invention. As shown in the figure, the serum tumor necrosis factor-α (TNF-α) levels on day 1 in the blank group, Examples 1-3, and the control group were 3.12 ng / mL, 4.86 ng / mL, 4.83 ng / mL, 4.85 ng / mL, and 4.86 ng / mL, respectively. The serum tumor necrosis factor-α (TNF-α) levels on day 7 were 3.36 ng / mL, 2.39 ng / mL, 2.31 ng / mL, 2.36 ng / mL, and 4.97 ng / mL, respectively. As shown in the figure, the serum tumor necrosis factor-α concentration in Examples 1-3 was significantly lower on day 7 compared to day 1, while it was slightly higher in the blank group and the control group. This indicates that Examples 1-3 have the effect of reducing the stimulation of inflammatory cytokines, which can improve the wound healing speed and prevent wound infection.

[0100] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

[0101] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention. The actual application is not limited to this. In conclusion, if those skilled in the art are inspired by this description and design similar methods and embodiments without departing from the spirit of the present invention, they should all fall within the protection scope of the present invention.

Claims

1. A chitinous membrane dressing that promotes wound healing, characterized in that: The product is made from the following components in parts by weight: 36-40 parts of antibacterial sustained-release gel carrier and 6-8 parts of antibacterial repair composition; the antibacterial sustained-release gel carrier is obtained by preparing a gel from modified chitin and modified dextran and then polymerizing an organometallic framework in situ; the antibacterial repair composition is obtained by extracting Phellodendron bark, wild chrysanthemum, purslane, rhubarb, Polygonum cuspidatum, and aloe vera from tea tree essential oil; the raw materials for preparing the antibacterial sustained-release gel carrier include the following components in parts by weight: 25-30 parts of chitin powder, 20-25 parts of dextran powder, 13-17 parts of chlorosulfonic acid-pyridine, 15-19 parts of 2-methylimidazole, and 13-16 parts of zinc nitrate; the antibacterial repair composition is made from the following components in parts by weight: 10-15 parts of Phellodendron bark, 3-4 parts of wild chrysanthemum, 5-9 parts of purslane, 10-13 parts of rhubarb, 2-5 parts of Polygonum cuspidatum, 13-15 parts of aloe vera, and 12-16 parts of tea tree essential oil. The preparation method of the antibacterial sustained-release gel carrier specifically includes the following steps: S1. Add chitin powder to a 5-7% sodium hydroxide solution and stir in a 90°C water bath at 300 rpm for 2.5 h to obtain deacetylated chitin. S2. Add the deacetylated chitin obtained in S1 to an isopropanol aqueous solution with a volume concentration of 75% to obtain a mixed solution. Add sodium hydroxide to the mixed solution at a rate of 0.12-0.18 g / mL. Stir in a water bath at 50°C for 30 min. Then add chloroacetic acid solution dropwise at a rate of 0.07-0.09 g / mL. React for 4 h to obtain the reaction solution. S3. Add a 70% ethanol solution at a volume ratio of 2:1 to the reaction solution obtained in S1. Desalt and dehydrate with 90% ethanol solution, and dry to obtain modified chitin. S4. Add dextran powder to N,N-dimethylformamide solution, add chlorosulfonic acid-pyridine, react in a water bath at 45-55℃ for 100-120 min, and adjust the pH to 9-10 to obtain sulfonated dextran. S5. Add the sulfonated dextran powder obtained in S4 to water to obtain a sulfonated glucose solution. Add sodium periodate to the sulfonated glucose solution, add zinc nitrate powder, adjust the pH to 2-3, heat in a water bath and react in the dark for 3-5 hours to obtain a mixed solution. Add ethylene glycol to the mixed solution at a dosage of 66-78 mg / mL to remove sodium periodate. Filter, wash and dry to obtain modified dextran. S6. Dissolve zinc nitrate powder in water, add the modified dextran obtained in S5, stir evenly, add 2-methylimidazole, stir in a 30-40℃ water bath at 100-140 rpm for 8-10 min, then add the modified chitin obtained in S3 and continue stirring for 15-20 min to obtain the antibacterial sustained-release gel carrier.

2. A method for preparing a chitinous membrane dressing for promoting wound healing according to claim 1, characterized in that: Specifically, the steps include: adding the antibacterial repair composition to the antibacterial sustained-release gel carrier, stirring at 60 rpm for 7 minutes to obtain a chitinous membrane dressing that promotes wound healing.

3. The method for preparing the chitinous membrane dressing for promoting wound healing according to claim 2, characterized in that: The preparation method of the antibacterial repair composition specifically includes the following steps: (1) Take Phellodendron bark, wild chrysanthemum, purslane, rhubarb, Japanese knotweed and aloe vera, wash them, screen out pests and diseased plants, freeze dry, pulverize and mix them, and pass them through a 60-mesh sieve to obtain mixed powder; (2) Add the mixed powder to water at an addition rate of 0.1-0.2 g / mL, add cellulase and pectinase, sonicate at 60-80 W for 20-30 min at 40-45℃, add tea tree oil, stir in a water bath at 40℃ for 3-5 h, and filter to obtain the antibacterial repair composition.

4. The method for preparing the chitinous membrane dressing for promoting wound healing according to claim 3, characterized in that: In S1, the amount of chitin powder added to the sodium hydroxide solution is 0.08-0.09 g / mL.

5. The method for preparing the chitinous membrane dressing for promoting wound healing according to claim 4, characterized in that: In S2, the amount of deacetylated chitin added to the isopropanol aqueous solution is 0.1-0.12 g / mL.

6. The method for preparing the chitinous membrane dressing for promoting wound healing according to claim 5, characterized in that: In S4, the amount of dextran powder added to the N,N-dimethylformamide solution is 0.13-0.18 mol / L.

7. The method for preparing the chitinous membrane dressing for promoting wound healing according to claim 6, characterized in that: In S5, the amount of sulfonated dextran added to water is 18-22 mg / mL; the amount of sodium periodate added to the sulfonated glucose solution is 23-25 ​​mg / mL.

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