A composite hydrogel and a preparation method and application thereof

Abstract

The present application relates to a kind of composite hydrogel and its preparation method and application, the composite hydrogel includes hydrogel framework and the nanoparticle loaded in the hydrogel framework;The hydrogel framework is formed by oxidized dextran and polylysine;Active ingredient is loaded in the nanoparticle, and the active ingredient is the substance with antibacterial, antioxidant and / or anti-inflammatory performance;The nanoparticle is aminozed nanoparticle;The composite hydrogel also includes rhodioside loaded in the hydrogel framework.The composite hydrogel of the present application has pH response, can control the release of drug according to the change of pH when wound infection, better promote wound healing, and, the composite hydrogel of the present application has mechanical strength, can play the role of protecting wound, also has certain flexibility, can adapt to physical activity and skin deformation.

Description

Technical Field

[0001] The present invention belongs to the technical field of biomedicine and medical equipment, and particularly relates to a composite hydrogel and a preparation method and application thereof. Background Art

[0002] This section is intended to provide a background or context to the embodiments of the invention that are recited in the claims. No statement herein is admitted to be prior art by virtue of its inclusion in this section.

[0003] Hydrogels are water-insoluble, colloid-like substances with a three-dimensional network structure, formed from water-soluble polymers or their monomers. This structure enables them to absorb large amounts of water or wound exudate while maintaining a certain shape and flexibility. Hydrogel dressings not only provide a moist environment for wounds, thereby maintaining cell activity at the wound site, promoting epithelial cell migration, and accelerating wound healing, but also possess excellent fluid absorption capacity, absorbing exuded tissue fluid and blood, keeping the wound surface clean and reducing secondary damage to the wound.

[0004] Diabetes mellitus is a common endocrine and metabolic disease characterized by chronic hyperglycemia caused by insufficient insulin secretion or insulin resistance. Chronic non-healing wounds are a common complication of diabetes, leading to prolonged hospitalization, economic burden, infection, gangrene, amputation, and death. It is estimated that 19-34% of diabetic patients will be affected by diabetic foot ulcers in their lifetime. Once a foot ulcer occurs, diabetic patients are more susceptible to invasive limb infections, which increases the risk of amputation. The treatment of chronic diabetic wounds is mainly symptomatic, including debridement and the use of appropriate antibiotics to promote healing. However, advanced glycation end products (AGEs) and a hyperglycemic environment can further hinder wound repair by altering the immune balance. Key pathways and mechanisms associated with diabetic wound healing include: ROS activation of downstream signaling pathways (NF-κB, ERK, c-Jun N-terminal kinase (JNK), and p38 mitogen-activated protein kinase (MAPK) pathways), inhibition of fibroblast proliferation and differentiation (Wnt / β-catenin, PI3K / Akt), and impacts on angiogenesis and epithelial cell migration (Notch signaling). The wound healing process in diabetic patients is often affected by multiple factors, leading to delayed or incomplete healing. This is also due to the disruption of multiple cellular and molecular mechanisms in the hyperglycemic environment. This leads to poor therapeutic efficacy and prognosis, which remains a significant clinical challenge. Therefore, the development of a hydrogel dressing for diabetic wound healing is urgently needed and holds great promise. Summary of the Invention

[0005] One object of the present invention is to provide a composite hydrogel that can sustainably release drugs, has pH responsiveness, and has antibacterial, anti-inflammatory and antioxidant properties.

[0006] The second object of the present invention is to provide a method for preparing the composite hydrogel.

[0007] The third object of the present invention is to provide the use of the above-mentioned composite hydrogel in wound healing dressings, which can promote fibroblast proliferation, inhibit the production of advanced glycation end products, inhibit the expression of advanced glycation end product receptors, and promote collagen production.

[0008] The fourth object of the present invention is to provide the use of the composite hydrogel in food preservation.

[0009] A fifth object of the present invention is to provide application of the composite hydrogel in the field of cosmetics.

[0010] In order to achieve the above object, the technical solution adopted by the present invention is:

[0011] The first aspect of the present invention provides a composite hydrogel comprising a hydrogel skeleton and nanoparticles loaded within the hydrogel skeleton; the hydrogel skeleton is formed by oxidizing dextran and polylysine; the nanoparticles are loaded with an active ingredient, wherein the active ingredient is a substance having antibacterial, antioxidant and / or anti-inflammatory properties; the nanoparticles are amino-modified nanoparticles; and the composite hydrogel further comprises salidroside loaded within the hydrogel skeleton.

[0012] According to some specific embodiments, the active ingredient is one or more of natural antimicrobial agents, antibiotics, silver ions, and antimicrobial peptides.

[0013] Furthermore, the active ingredients in the nanoparticles can be one or more water-soluble ingredients such as tannin, gentamicin, ciprofloxacin, vancomycin, lincomycin, minocycline, silver nitrate, nanosilver, CAP-18 antimicrobial peptide, cecropin, bacitracin, polymyxin B, etc., or can be one or more ingredients with poor water solubility such as resveratrol, terpenoids, alkaloids, flavonoids, polyphenols, imipenem, chloramphenicol, silver chloride, and gramicidin.

[0014] According to some embodiments, the nanoparticles have a mesoporous structure and / or a hollow structure.

[0015] According to some specific embodiments, the nanoparticles are one or more of silica nanoparticles, carbon nanotubes, Prussian blue nanoparticles, and perovskite nanoparticles.

[0016] According to some specific embodiments, the polylysine is ε-poly-L-lysine.

[0017] According to some specific embodiments, the mass ratio of the polylysine to the oxidized dextran is 0.4-1.2:1, for example, 0.4:1, 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1:1, 1.1:1 or 1.2:1.

[0018] According to some specific embodiments, the drug loading amount of the active ingredient in the nanoparticles is 40% to 50%.

[0019] According to some specific embodiments, the concentration of the nanoparticles loaded with active ingredients in the composite hydrogel is 0.25-4 mg / mL, for example, 0.25 mg / mL, 0.5 mg / mL, 1 mg / mL, 1.5 mg / mL, 2 mg / mL, 2.5 mg / mL, 3 mg / mL, 3.5 mg / mL or 4 mg / mL.

[0020] According to some specific embodiments, the concentration of salidroside in the composite hydrogel is 0.5-3 mg / mL, for example, 0.5 mg / mL, 1 mg / mL, 1.5 mg / mL, 2 mg / mL, 2.5 mg / mL or 3 mg / mL.

[0021] A second aspect of the present invention provides a method for preparing the composite hydrogel as described above, comprising the following steps:

[0022] (1) Prepare oxidized dextran solution;

[0023] (2) Preparation of amino-modified nanoparticles;

[0024] (3) loading the active ingredient into the pores of the amino-modified nanoparticles to obtain drug-loaded nanoparticles;

[0025] (4) The polylysine solution, the drug-loaded nanoparticles, salidroside and the oxidized dextran solution are uniformly mixed and reacted to obtain the composite hydrogel.

[0026] According to some specific embodiments, in step (1), the concentration of the oxidized dextran solution is 40-150 mg / mL, for example, 40 mg / mL, 50 mg / mL, 60 mg / mL, 70 mg / mL, 80 mg / mL, 90 mg / mL, 100 mg / mL, 110 mg / mL, 120 mg / mL, 130 mg / mL, 140 mg / mL or 150 mg / mL; further, the concentration of the oxidized dextran solution is 80-130 mg / mL.

[0027] According to some specific embodiments, in step (3), the mass ratio of the active ingredient to the amino-modified nanoparticles is 1:0.5-2, for example, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9 or 1:2; further, the active ingredient is added in excess relative to the amino-modified nanoparticles so that the active ingredient is adsorbed and saturated in the amino-modified nanoparticles as much as possible. In some embodiments, the drug loading of the active ingredient in the nanoparticles is 40% to 50%.

[0028] According to some specific embodiments, in step (4), the pH of the polylysine solution is 7-9, for example, 7, 7.2, 7.4, 7.6, 7.8, 8, 8.2, 8.4, 8.6, 8.8 or 9.

[0029] According to some specific embodiments, in step (4), the concentration of the polylysine solution is 30-150 mg / mL, for example, 30 mg / mL, 40 mg / mL, 50 mg / mL, 60 mg / mL, 7w0 mg / mL, 80 mg / mL, 90 mg / mL, 100 mg / mL, 110 mg / mL, 120 mg / mL, 130 mg / mL, 14w0 mg / mL or 150 mg / mL; further, the concentration of the polylysine solution is 70-120 mg / mL.

[0030] According to some specific embodiments, in step (4), the mass ratio of the polylysine to the oxidized dextran is 0.4-1.2:1, for example, 0.4:1, 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1:1, 1.1:1 or 1.2:1. Furthermore, the mass ratio of the polylysine to the oxidized dextran is 0.7-1.2:1.

[0031] According to some specific embodiments, in step (4), the concentration of the drug-loaded nanoparticles in the composite hydrogel is 0.25-4 mg / mL, for example, 0.25 mg / mL, 0.5 mg / mL, 1 mg / mL, 1.5 mg / mL, 2 mg / mL, 2.5 mg / mL, 3 mg / mL, 3.5 mg / mL, or 4 mg / mL. Furthermore, the concentration of the drug-loaded nanoparticles in the composite hydrogel is 0.5-1.5 mg / mL.

[0032] According to some specific embodiments, in step (4), the concentration of salidroside in the composite hydrogel is 0.5-3 mg / mL, for example, 0.5 mg / mL, 1 mg / mL, 1.5 mg / mL, 2 mg / mL, 2.5 mg / mL, or 3 mg / mL. Furthermore, the concentration of salidroside in the composite hydrogel is 0.5-3 mg / mL.

[0033] According to some specific embodiments, the specific method of step (1) is: mixing a sodium periodate solution with a dextran suspension, reacting for 3 to 8 hours, then adding ethylene glycol to quench the reaction, dialyzing the reaction solution, and then preparing the oxidized dextran solution.

[0034] Furthermore, in step (1), the mass ratio of the dextran to the sodium periodate is 1:0.4-1.5, for example, 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4 or 1:1.5.

[0035] Furthermore, in step (1), the mass ratio of glucan to distilled water in the glucan suspension is 1-5:100, for example, 1:100, 2:100, 3:100, 4:100 or 5:100.

[0036] Furthermore, in step (1), the reaction temperature is 25-40°C, for example, 25°C, 26°C, 27°C, 28°C, 29°C, 30°C, 31°C, 32°C, 33°C, 34°C, 35°C, 36°C, 37°C, 38°C, 39 or 40°C.

[0037] Furthermore, in step (1), the quenching reaction time is 1-2 hours.

[0038] According to some specific embodiments, the specific method of step (2) is: dissolving the template in a mixed solvent of deionized water and anhydrous ethanol, adjusting the pH value of the solution to 8-14, adding a silicon source and reacting for 14-18 hours; after the reaction, centrifuging, washing and drying to obtain silica nanoparticles with the template; resuspending the nanoparticles with isopropanol, and then adding 3-aminopropyltriethoxysilane and reacting at room temperature for 2-6 hours; after the reaction, centrifuging and drying to obtain amino-containing silica nanoparticles with the template; and finally removing the template with an extractant to obtain amino-containing nanoparticles.

[0039] Furthermore, in step (2), the template is cetyltrimethylammonium bromide (CTAB).

[0040] Furthermore, in step (2), the volume ratio of the deionized water to the anhydrous ethanol in the mixed solvent is 3-5:1, for example, 3:1, 3.5:1, 4:1, 4.5:1 or 5:1.

[0041] Furthermore, in step (2), the feed ratio of the template agent to the mixed solvent is 120-160 mL (e.g., 120 mL, 125 mL, 130 mL, 135 mL, 140 mL, 150 mL or 160 mL) of the mixed solvent per 1 g of the template agent.

[0042] Furthermore, in step (2), ammonia water is used to adjust the pH.

[0043] Furthermore, in step (2), the silicon source is tetraethyl orthosilicate (TEOS).

[0044] Furthermore, in step (2), the extractant is a mixed solvent of anhydrous ethanol and concentrated hydrochloric acid in a volume ratio of 35-80:1. For example, the volume ratio of anhydrous ethanol to concentrated hydrochloric acid is 35:1, 40:1, 45:1, 50:1, 55:1, 60:1, 65:1, 70:1, 75:1 or 80:1.

[0045] Furthermore, in step (2), when the template is removed by the extractant, the feeding ratio of the amino-silica nanoparticles with the template to the extractant is 200-520 mL (for example, 200 mL, 220 mL, 240 mL, 260 mL, 280 mL, 300 mL, 320 mL, 340 mL, 360 mL, 380 mL, 400 mL, 420 mL, 440 mL, 460 mL, 480 mL, 500 mL, 520 mL) of the extractant per 1 g of the amino-silica nanoparticles with the template.

[0046] Furthermore, in step (2), the specific method for removing the template agent with the extractant is as follows: mixing the amino-containing silica nanoparticles with the template agent with the extractant, refluxing for 6-24 hours, refluxing 1-3 times, centrifuging at 8000-10000 rpm for 3-5 minutes, washing the precipitate with anhydrous ethanol 2-4 times, and drying in an oven at 60-80°C to obtain amino-containing nanoparticles.

[0047] According to some specific embodiments, the specific method of step (3) is: dissolving the active ingredient in a solvent, then adding the amino-modified nanoparticles prepared in step (2), stirring in the dark at room temperature for 12-24 hours, centrifuging, washing and drying after the reaction is completed to obtain drug-loaded nanoparticles.

[0048] Furthermore, in step (3), the active ingredient is resveratrol, and the solvent is anhydrous ethanol.

[0049] Furthermore, in step (3), the concentration of the active ingredient dissolved in the solvent is 1-10 mg / mL, for example, 1 mg / mL, 2 mg / mL, 3 mg / mL, 4 mg / mL, 5 mg / mL, 6 mg / mL, 7 mg / mL, 8 mg / mL, 9 mg / mL or 10 mg / mL.

[0050] According to some specific embodiments, the specific method of step (4) is: dissolving polylysine in water and adjusting the pH to obtain a polylysine solution; then uniformly mixing the polylysine solution, the drug-loaded nanoparticles and the salidroside, adding the oxidized dextran solution, stirring and dissolving to form a uniform solution, and reacting to obtain the composite hydrogel.

[0051] Furthermore, in step (4), 1-3 mol / L NaOH is used to adjust the pH.

[0052] A third aspect of the present invention provides a use of the composite hydrogel as described above or the composite hydrogel prepared by the preparation method as described above in the preparation of a hydrogel dressing for promoting wound healing.

[0053] Furthermore, the wound is a diabetic wound. Furthermore, the wound is an ulcer wound in a diabetic patient. The composite hydrogel can promote fibroblast proliferation, inhibit the production of advanced glycation end products, inhibit the expression of advanced glycation end product receptors, and promote collagen production, thereby facilitating the healing of diabetic wounds.

[0054] A fourth aspect of the present invention provides use of the composite hydrogel as described above or the composite hydrogel prepared by the preparation method as described above in food preservation.

[0055] The hydrogel can exert its antibacterial effect by interfering with bacterial cell wall synthesis, inhibiting bacterial biofilm formation, causing DNA damage, inducing the death of spoilage microorganisms, and inhibiting bacterial quorum sensing. Salidroside has good antioxidant and free radical scavenging capabilities, thereby effectively inhibiting food spoilage and extending shelf life. Moreover, the hydrogel has the effect of delaying the release of active ingredients, which can prolong the antibacterial and antioxidant capabilities; it can also lock in moisture, so the above composite hydrogel can be used for food preservation.

[0056] A fifth aspect of the present invention provides a use of the composite hydrogel as described above or the composite hydrogel prepared by the preparation method as described above in the field of cosmetics.

[0057] This hydrogel can be used to prepare a gel mask, which can promote fibroblast proliferation and collagen production, help rebuild the skin epidermis, and repair the skin barrier. It is especially suitable for repairing damaged sensitive skin. Salidroside has antioxidant, anti-aging, and anti-inflammatory effects, and can play a role in treating dermatitis.

[0058] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0059] The composite hydrogel of the present invention is loaded with substances having antibacterial, antioxidant and / or anti-inflammatory properties, as well as salidroside. Oxidized dextran and polylysine serve as the hydrogel skeleton, and the aldehyde groups in the oxidized dextran react with the polylysine and amino groups on the nanoparticles to form a Schiff base reaction. Therefore, the composite hydrogel of the present invention is pH responsive and can control the release of drugs according to changes in pH during wound infection, thereby better promoting wound healing. Furthermore, the composite hydrogel of the present invention has both mechanical strength to protect wounds and a certain degree of flexibility to adapt to physical activity and skin deformation. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0061] Figure 1 is the potential distribution diagram of mesoporous silica drug-loaded particles;

[0062] Figure 2 This is a scanning electron micrograph of mesoporous silica drug-loaded particles;

[0063] Figure 3 is the FTIR image of the hydrogel;

[0064] Figure 4 The rheological test results of hydrogel;

[0065] Figure 5 is the scanning electron microscopy image of the hydrogel;

[0066] Figure 6 This is the cumulative release result of salidroside from OES@P hydrogel at different pH;

[0067] Figure 7 This is the cumulative release result of resveratrol from OES@P hydrogel at different pH;

[0068] Figure 8 Figure 2 shows the antibacterial test results of OES@P hydrogel against different bacteria.

[0069] Figure 9 Figure 2 is the cell viability test results of OES@P hydrogel extracts with different concentrations;

[0070] Figure 10 Figure 2 is the result of cell migration experiment on OES@P hydrogel;

[0071] Figure 11 Figure 2 is the CML inhibition experimental results of OES@P hydrogel;

[0072] Figure 12 This is the docking result diagram of resveratrol, salidroside and advanced glycation end products receptor;

[0073] Figure 13 Macroscopic images of mouse wound changes;

[0074] Figure 14 Figure 2 shows the wound healing experimental results of OES@P hydrogel. DETAILED DESCRIPTION

[0075] The present invention is based on amino-modified mesoporous silica nanoparticles loaded with resveratrol, uses oxidized dextran and polylysine to form a hydrogel skeleton, and cross-links the molecular drug salidroside to construct a dual-drug-loaded composite hydrogel. The composite hydrogel has pH responsiveness and can control the release of drugs according to changes in pH during wound infection, thereby better promoting wound healing. In addition, the composite hydrogel of the present invention has both mechanical strength to protect wounds and a certain degree of flexibility to adapt to physical activities and skin deformation.

[0076] Resveratrol is a non-flavonoid polyphenol organic compound. It is an antitoxin produced by many plants when stimulated. Its chemical formula is C 14 H 12 O3, molecular weight 228.243, is a white or light yellow powder. It can be synthesized in grape leaves and grape skins, and is a biologically active ingredient in wine and grape juice. It has multiple biological activities such as antioxidant, anti-inflammatory, anti-cancer, anti-fibrosis, and cardiovascular and cerebrovascular protection. It is poorly soluble in water and easily soluble in organic solvents such as ether, methanol, acetone, and ethyl acetate. Resveratrol is a typical representative of poorly soluble drugs. The low drug loading capacity of existing drug carriers is the main challenge hindering the practical application of poorly soluble drugs such as resveratrol. The present application can greatly improve the drug loading capacity of resveratrol by dissolving resveratrol in anhydrous ethanol and then loading it into the pores of mesoporous silica nanoparticles.

[0077] Salidroside (2-[4-hydroxyphenyl]ethyl β-d-glucopyranoside) is an active glycoside small molecule extracted from the traditional Chinese medicine Rhodiola rosea. With a molecular weight of 300 kDa, it exhibits antioxidant, anti-inflammatory, anti-tumor, and anti-radioactive properties. It is widely used in the treatment of coronary heart disease and myocardial ischemia. It also possesses antioxidant and anti-apoptotic properties and has the potential to promote high-altitude acclimatization. Salidroside exerts cytoprotective activity by regulating oxidative stress-induced apoptosis.

[0078] This application selects resveratrol and salidroside as therapeutic drugs, and resveratrol is loaded in mesoporous silica, and salidroside is cross-linked in the hydrogel skeleton. When the composite hydrogel is used for diabetic wounds, SAL is rapidly released in the early stage of wound healing, which has antioxidant and anti-inflammatory effects, protects cell activity, reduces inflammation and oxidative stress, and inhibits cell apoptosis. Subsequently, in the continuous acidic environment of the chronic wound site, the Schiff base bonds that fix the mesoporous silica in the hydrogel are easily broken, and at the same time, the hydrogel skeleton formed by cross-linking ε-poly-L-lysine and oxidized dextran partially collapses, and the RES of the nanoparticles is slowly and continuously released, sequentially promoting the migration of fibroblasts, promoting fibroblasts to produce collagen, and promoting angiogenesis, ultimately achieving rapid healing of chronic diabetic wounds.

[0079] Dextran has excellent biological activities, such as enhancing angiogenesis and promoting tissue regeneration during wound healing. ε-poly-L-lysine (EPL), a natural antimicrobial peptide secreted by Streptomyces, has a broad antimicrobial spectrum against both Gram-positive and Gram-negative bacteria. Therefore, dextran and poly-lysine were chosen as the hydrogel backbone to enhance antimicrobial activity and promote angiogenesis and collagen deposition.

[0080] The hydrogel of the present application is prepared by a Schiff base reaction between the aldehyde group (-CHO) on oxidized dextran and ε-poly-L-lysine (EPL) and (-NH2) on amino-modified mesoporous silica. The Schiff bond is pH-responsive and can control the release of drugs according to the changes in pH during wound infection, thereby promoting wound healing.

[0081] Mesoporous silica nanoparticles (MSNs) in this application's hydrogel exhibit numerous advantages, including inherent anti-inflammatory activity, high surface area, high pore volume, macropores, adaptability to surface modification, high loading capacity, and a controllable mesoporous structure, making them highly suitable as drug delivery vehicles. They offer broad application prospects and excellent biocompatibility. Amino-functionalized MSNs (MSNs-NH2) exhibit high drug loading and biocompatibility.

[0082] Hereinafter, only certain exemplary embodiments are briefly described. As will be appreciated by those skilled in the art, the described embodiments may be modified in various ways without departing from the spirit or scope of the embodiments of the present invention. Therefore, the drawings and description are to be regarded as illustrative in nature and not restrictive.

[0083] All features disclosed in the present invention, or all steps in the methods or processes disclosed, except for mutually exclusive features or steps, may be combined in any manner.

[0084] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with specific examples. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments, and unless otherwise stated, they can be replaced by other equivalent or alternative features with similar purposes. Unless otherwise stated, each feature is just an example of a series of equivalent or similar features. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Therefore, the detailed description of the embodiments of the present invention provided below is not intended to limit the scope of the invention for which protection is claimed, but merely represents selected embodiments of the present invention.

[0085] Unless otherwise specified, the terms used in this invention generally have the meanings commonly understood by those skilled in the art. The implementation conditions used in the examples may be further adjusted according to the specific requirements of the application. Unspecified implementation conditions are conventional conditions in the industry. The technical features involved in the various embodiments of the present invention may be combined with each other as long as they do not conflict with each other.

[0086] In the present invention, all operations unless otherwise specified were performed at room temperature. The raw materials used in this application can be purchased commercially or prepared by conventional methods in the prior art. In the present invention, unless otherwise specified, "%" refers to mass percentage. The mass fraction of concentrated hydrochloric acid is 36% to 37%. The solvent in both the polylysine solution and the oxidized dextran solution is deionized water. Example 1

[0087] The composite hydrogel of this embodiment is prepared by the following steps:

[0088] (1) 1 g of sodium periodate was added to 50 mL of 2% dextran suspension and reacted at room temperature for 6 h. Then, 2 mL of ethylene glycol was added and reacted for 1.5 h. The reaction solution was dialyzed for 72 h to obtain oxidized dextran. The oxidized dextran was then prepared into an oxidized dextran solution with a concentration of 100 mg / mL.

[0089] (2) Preparation of amino-modified mesoporous silica: 0.9 g of hexadecyltrimethylammonium bromide (CTAB) was dissolved in a mixed solvent of 90 mL of deionized water and 30 mL of anhydrous ethanol, and ammonia water was added to adjust the pH value of the solution to 9-11. 0.8 mL of tetraethyl orthosilicate was added and reacted for 16 h. After the reaction, the mixture was centrifuged, washed and dried to obtain silica nanoparticles with a template. The nanoparticles were resuspended in isopropanol, and then 0.8 mL of 3-aminopropyltriethoxysilane was added and reacted at room temperature for 4 h. After the reaction, the mixture was centrifuged at 8000 rpm for 3 min, washed three times with distilled water and anhydrous ethanol, and then dried. 0.30 g of the dried product was placed in a mixed solvent of 2 mL of concentrated hydrochloric acid and 120 mL of anhydrous ethanol and refluxed for 24 h. The reflux operation was repeated three times to ensure that the template CTAB was completely removed. The refluxed product was centrifuged at 8000 rpm for 3 min, the precipitate was repeatedly washed with anhydrous ethanol, dried at 60 ° C, and then ground to obtain amino-modified mesoporous silica MSN-NH2.

[0090] (3) Preparation of drug-loaded amino-modified mesoporous silica: Resveratrol (RES) was dissolved in anhydrous ethanol to obtain a RES concentration of 5 mg / mL. Then, the amino-modified mesoporous silica MSN-NH2 prepared in step (2) was added at a mass ratio of MSN-NH2 to RES of 1:1. The mixture was stirred in the dark at room temperature for 24 h. After the reaction, the mixture was centrifuged, washed, and dried to obtain RES-loaded nanoparticles MSN-NH2. 2@ RES; wherein, the centrifugation process is 8000rpm, 3min; after testing, the nanoparticles MSN-NH loaded with RES 2@ The drug loading of RES in RES is approximately 45%;

[0091] (4) Preparation of oxidized dextran / ε-poly-L-lysine / mesoporous silica dual-drug loaded composite hydrogel: ε-poly-L-lysine was dissolved in water and the pH was adjusted to 8 with 2 mol / L NaOH to obtain a 70 mg / mL ε-poly-L-lysine solution; 0.5 mL of the 70 mg / mL ε-poly-L-lysine solution and 1 mg of RES-loaded nanoparticles MSN-NH 2@ RES and 2.5 mg of salidroside SAL were mixed evenly and added into 0.5 mL of 100 mg / mL oxidized dextran solution. The mixture was stirred and dissolved to form a uniform solution. The reaction was continued for about 1 min to obtain oxidized dextran / ε-poly-L-lysine / mesoporous silica dual-drug loaded composite hydrogel (OES@P). Example 2

[0092] The composite hydrogel of this embodiment is prepared by the following steps:

[0093] (1) 1 g of sodium periodate was added to 50 mL of 2% dextran suspension and reacted at room temperature for 6 h. Then 2 mL of ethylene glycol was added and reacted for 1.5 h. The reaction solution was dialyzed for 72 h to obtain oxidized dextran. The oxidized dextran was then prepared into an oxidized dextran solution with a concentration of 120 mg / mL.

[0094] (2) Preparation of amino-modified mesoporous silica: 0.9 g of hexadecyltrimethylammonium bromide (CTAB) was dissolved in a mixed solvent of 90 mL of deionized water and 30 mL of anhydrous ethanol, and ammonia water was added to adjust the pH value of the solution to 9-11. 0.8 mL of tetraethyl orthosilicate (TEOS) was added and reacted for 16 h. After the reaction, the mixture was centrifuged, washed, and dried to obtain silica nanoparticles with a template. The nanoparticles were resuspended in isopropanol, and then 0.8 mL of 3-aminopropyltriethoxysilane was added and reacted at room temperature for 4 h. After the reaction, the mixture was centrifuged at 8000 rpm for 3 min, washed three times with distilled water and anhydrous ethanol, and dried. 0.30 g of the dried product was placed in a mixed solvent of 2 mL of concentrated hydrochloric acid and 120 mL of anhydrous ethanol and refluxed for 24 h. The reflux operation was repeated 3 times. The reflux product was centrifuged at 8000 rpm for 3 min to ensure that the template agent CTAB was completely removed. The precipitate was repeatedly washed with anhydrous ethanol, dried at 60 ° C, and then ground to obtain amino-modified mesoporous silica MSN-NH2.

[0095] (3) Preparation of drug-loaded amino-modified mesoporous silica: Resveratrol (RES) was dissolved in anhydrous ethanol to obtain a RES concentration of 5 mg / mL. Then, the amino-modified mesoporous silica MSN-NH2 prepared in step (2) was added at a mass ratio of MSN-NH2 to RES of 1:1. The mixture was stirred in the dark at room temperature for 24 h. After the reaction, the mixture was centrifuged, washed, and dried to obtain RES-loaded nanoparticles MSN-NH2. 2@ RES; wherein, the centrifugation process is 8000rpm, 3min; after testing, the nanoparticles MSN-NH loaded with RES 2@ The drug loading of RES in RES is approximately 45%;

[0096] (4) Preparation of oxidized dextran / ε-poly-L-lysine / mesoporous silica dual-drug loaded composite hydrogel: ε-poly-L-lysine was dissolved in water and the pH was adjusted to 8 with 2 mol / L NaOH to obtain a 100 mg / mL ε-poly-L-lysine solution; 0.5 mL of 100 mg / mL ε-poly-L-lysine solution and 1 mg of RES-loaded nanoparticles MSN-NH 2@RES and 1.5 mg of salidroside SAL were mixed evenly and added into 0.5 mL of 120 mg / mL oxidized dextran solution. The mixture was stirred and dissolved to form a uniform solution. The reaction was carried out for about 1-5 min to obtain oxidized dextran / ε-poly-L-lysine / mesoporous silica dual-drug loaded composite hydrogel (OES@P-2). Example 3

[0097] The composite hydrogel of this embodiment is prepared by the following steps:

[0098] (1) 0.6 g of sodium periodate was added to 50 mL of 2% dextran suspension and reacted at room temperature for 3 h. Then 2 mL of ethylene glycol was added and reacted for 1.5 h. The reaction solution was dialyzed for 72 h to obtain oxidized dextran, which was then prepared into an oxidized dextran solution with a concentration of 60 mg / mL.

[0099] (2) Preparation of amino-modified mesoporous silica: 0.9 g of CTAB was dissolved in a mixed solvent of 90 mL of deionized water and 30 mL of anhydrous ethanol, and ammonia was added to adjust the pH value of the solution to 9-11. 0.8 mL of tetraethyl orthosilicate was added and reacted for 16 h. After the reaction, the silica nanoparticles with template were centrifuged, washed and dried to obtain silica nanoparticles. The nanoparticles were resuspended with isopropanol, and then 0.8 mL of 3-aminopropyltriethoxysilane was added and reacted at room temperature for 4 h. After the reaction, the silica nanoparticles were centrifuged at 8000 rpm for 3 min, washed three times with distilled water and anhydrous ethanol, and then dried. 0.30 g of the dried product was placed in a mixed solvent of 2 mL of concentrated hydrochloric acid and 120 mL of anhydrous ethanol and refluxed for 24 h. The reflux operation was repeated three times to ensure that the template CTAB was completely removed. The refluxed product was centrifuged at 8000 rpm for 3 min, the precipitate was repeatedly washed with anhydrous ethanol, dried at 60 ° C, and then ground to obtain amino-modified mesoporous silica MSN-NH2.

[0100] (3) Preparation of drug-loaded amino-modified mesoporous silica: Resveratrol (RES) was dissolved in anhydrous ethanol to obtain a RES concentration of 5 mg / mL. Then, the amino-modified mesoporous silica MSN-NH2 prepared in step (2) was added at a mass ratio of MSN-NH2 to RES of 1:1. The mixture was stirred in the dark at room temperature for 24 h. After the reaction, the mixture was centrifuged, washed, and dried to obtain RES-loaded nanoparticles MSN-NH2. 2@ RES; wherein, the centrifugation process is 8000rpm, 3min; after testing, the nanoparticles MSN-NH loaded with RES 2@ The drug loading of RES in RES is approximately 45%;

[0101] (4) Preparation of oxidized dextran / ε-poly-L-lysine / mesoporous silica dual-drug loaded composite hydrogel: ε-poly-L-lysine was dissolved in water and the pH was adjusted to 8 with 2 mol / L NaOH to obtain a 40 mg / mL ε-poly-L-lysine solution; 0.5 mL of the 40 mg / mL ε-poly-L-lysine solution and 1 mg of RES-loaded nanoparticles MSN-NH 2@ RES and 2 mg of salidroside SAL were mixed evenly and added into 0.5 mL of 60 mg / mL oxidized dextran solution. The mixture was stirred and dissolved to form a uniform solution. The reaction was carried out for about 10 min to obtain oxidized dextran / ε-poly-L-lysine / mesoporous silica dual-drug loaded composite hydrogel (OES@P-3). Example 4

[0102] The composite hydrogel of this embodiment is prepared by the following steps:

[0103] (1) 1.5 g of sodium periodate was added to 50 mL of 2% dextran suspension and reacted at room temperature for 6 h. Then 2 mL of ethylene glycol was added and reacted for 1.5 h. The reaction solution was dialyzed for 72 h to obtain oxidized dextran, which was then prepared into an oxidized dextran solution with a concentration of 150 mg / mL.

[0104] (2) Preparation of amino-modified mesoporous silica: 0.9 g of CTAB was dissolved in a mixed solvent of 90 mL of deionized water and 30 mL of anhydrous ethanol, and ammonia was added to adjust the pH value of the solution to 9-11. 0.8 mL of tetraethyl orthosilicate was added and reacted for 16 h. After the reaction, the silica nanoparticles with template were centrifuged, washed and dried to obtain silica nanoparticles. The nanoparticles were resuspended with isopropanol, and then 0.8 mL of 3-aminopropyltriethoxysilane was added and reacted at room temperature for 4 h. After the reaction, the silica nanoparticles were centrifuged at 8000 rpm for 3 min, washed three times with distilled water and anhydrous ethanol, and then dried. 0.30 g of the dried product was placed in a mixed solvent of 2 mL of concentrated hydrochloric acid and 120 mL of anhydrous ethanol and refluxed for 24 h. The reflux operation was repeated three times to ensure that the template CTAB was completely removed. The refluxed product was centrifuged at 8000 rpm for 3 min, the precipitate was repeatedly washed with anhydrous ethanol, dried at 60 ° C, and then ground to obtain amino-modified mesoporous silica MSN-NH2.

[0105] (3) Preparation of drug-loaded amino-modified mesoporous silica: Resveratrol (RES) was dissolved in anhydrous ethanol to obtain a RES concentration of 5 mg / mL. Then, the amino-modified mesoporous silica MSN-NH2 prepared in step (2) was added at a mass ratio of MSN-NH2 to RES of 1:1. The mixture was stirred in the dark at room temperature for 24 h. After the reaction, the mixture was centrifuged, washed, and dried to obtain RES-loaded nanoparticles MSN-NH2. 2@RES; wherein, the centrifugation process is 8000rpm, 3min; after testing, the nanoparticles MSN-NH loaded with RES 2@ The drug loading of RES in RES is approximately 45%;

[0106] (4) Preparation of oxidized dextran / ε-poly-L-lysine / mesoporous silica dual-drug loaded composite hydrogel: ε-poly-L-lysine was dissolved in water and the pH was adjusted to 8 with 2 mol / L NaOH to obtain a 60 mg / mL ε-poly-L-lysine solution; 0.5 mL of the 60 mg / mL ε-poly-L-lysine solution and 1 mg of RES-loaded nanoparticles MSN-NH 2@ RES and 2 mg of salidroside SAL were mixed evenly and added into 0.5 mL of 150 mg / mL oxidized dextran solution. The mixture was stirred and dissolved to form a uniform solution. The reaction was continued for about 0.5 min to obtain oxidized dextran / ε-poly-L-lysine / mesoporous silica dual-drug-loaded composite hydrogel (OES@P-4). Comparative Example 1

[0107] The hydrogel of this comparative example was prepared by the following steps:

[0108] (1) 1 g of sodium periodate was added to 50 mL of 2% dextran suspension and reacted at room temperature for 6 h. Then 2 mL of ethylene glycol was added and reacted for 1.5 h. The reaction solution was dialyzed for 72 h to obtain oxidized dextran, which was then prepared into an oxidized dextran solution with a concentration of 100 mg / mL.

[0109] (2) Dissolve ε-poly-L-lysine in water and adjust the pH to 8 with 2 mol / L NaOH to obtain a 70 mg / mL ε-poly-L-lysine solution. Then, add 0.5 mL of the 70 mg / mL ε-poly-L-lysine solution to 0.5 mL of the 100 mg / mL oxidized dextran solution, stir and dissolve to form a uniform solution, and react for about 1 min to obtain the oxidized dextran / ε-poly-L-lysine skeleton hydrogel (OE). Comparative Example 2

[0110] The preparation method of the hydrogel in this comparative example is basically the same as that in Example 1, except that salidroside SAL is not added in step (4).

[0111] That is, step (4) of this comparative example is:

[0112] ε-poly-L-lysine was dissolved in water and the pH was adjusted to 8 with 2 mol / L NaOH to obtain a 70 mg / mL ε-poly-L-lysine solution. 0.5 mL of the 70 mg / mL ε-poly-L-lysine solution and 1 mg of RES-loaded nanoparticles MSN-NH 2@ RES was added to 0.5 mL of 100 mg / mL oxidized dextran solution, stirred and dissolved to form a uniform solution, and reacted for about 1 min to obtain oxidized dextran / ε-poly-L-lysine skeleton hydrogel (OE@P). Comparative Example 3

[0113] The preparation method of the hydrogel in this comparative example is basically the same as that in Example 1, except that steps (2) and (3) are omitted, and the RES-loaded nanoparticles MSN-NH2@RES are not added in the last step.

[0114] That is, the last step of this comparative example is:

[0115] ε-poly-L-lysine was dissolved in water and the pH was adjusted to 8 with 2 mol / L NaOH to obtain a 70 mg / mL ε-poly-L-lysine solution. Then, 0.5 mL of the 70 mg / mL ε-poly-L-lysine solution and 2.5 mg of salidroside SAL were added to 0.5 mL of the 100 mg / mL oxidized dextran solution, stirred and dissolved to form a uniform solution, and reacted for about 1 minute to obtain the oxidized dextran / ε-poly-L-lysine skeleton hydrogel (OES).

[0116] Characterization of mesoporous silica drug-loaded particles

[0117] The powdered sample of amino-modified mesoporous silica MSN-NH2 and the nanoparticles loaded with RES in Example 2 were used respectively. 2@ The freeze-dried powdered sample of RES and resveratrol RES were redissolved in distilled water to prepare a 1 mg / mL solution. The potential distribution was measured using a Zeta potential analyzer. The results are as follows: Figure 1 As shown in the results, it can be seen that at pH = 7.4, the Zeta potential decreased significantly (-14mV to -24.8mV), indicating that the drug loading was successful.

[0118] Malvern nanoparticle size and scanning electron microscopy were used to determine the size of RES-loaded nanoparticles MSN-NH 2@ Average particle size of RES. Figure 2 MSN-NH 2@ The scanning electron microscopy results of RES, from Figure 2 It can be seen that the RES-loaded nanoparticles have uniform and spherical particle sizes, with a particle size of about 250-270 nm.

[0119] Structural characterization of dual-drug loaded composite hydrogel

[0120] For the freeze-dried powdered sample of the hydrogel OES@P in Example 1, 1.0 mg of the sample was mixed with potassium bromide (KBr) powder at a mass ratio of 1:150, ground evenly, and pressed into a transparent sheet. The sample was scanned at a wavelength of 4000-400 cm -1 Fourier infrared spectroscopy was performed under the same conditions as OES@P. ε-poly-L-lysine (EPL), dextran (DEX), oxidized dextran (ODEX), the hydrogel in Comparative Example 1 (OE), salidroside (SAL), the hydrogel in Comparative Example 3 (OES), resveratrol (RES), and RES-loaded nanoparticles (MSN-NH2@RES) were tested by Fourier infrared spectroscopy in the same manner as OES@P. The test results are shown in Figure 2. Figure 3 shown.

[0121] From the infrared structure analysis results, it can be seen that 1636cm -1 The stretching vibration of C=O in the sugar chain structure is 1015 -1 and 1155 -1 , 1384cm -1 The COC stretching and COH bending vibrations indicate that the structure is polysaccharide; while the 1720 cm -1 The C=O stretching vibration in the open chain structure of sugar and 2920cm -1 and 2890cm -1 The stretching vibration of the aldehyde proton at 1720 cm-1 proved that the aldehyde group was generated, and the oxidation of dextran was successful; -1 disappeared, and 1650 -1 and 1540cm -1 The formation of imine bonds indicates that the hydrogel is successfully cross-linked. -1 3500cm -1 The physical adsorption and hydrogen bonding of resveratrol RES can also be seen, proving that the drug loading is successful. SAL is mainly bound to the hydrogel through hydrogen bonding and hydrophobic interaction.

[0122] Optimize the hydrogel formula based on the rheological properties of the hydrogel

[0123] The hydrogel frequency of all examples was scanned and the rheological test results were shown in Figure 4 ,from Figure 4As can be seen, the hydrogels of all examples meet the G' > G", with the storage modulus (G') being higher than the loss modulus (G"), indicating that the hydrogels maintain their original hydrogel network structure in the low- to medium-frequency range, thus possessing considerable three-dimensional network stability. Furthermore, the EPL and ODEX content in the hydrogel matrix affects the rheological and mechanical properties of the hydrogels, while the addition of RES-loaded nanoparticles has little effect on the mechanical properties. With increasing imine bond content, the hydrogels exhibit improved mechanical properties, which can be attributed to a higher crosslink density. The hydrogel of Example 3 is relatively soft and lacks mechanical strength, but diabetic wound dressings still require a certain level of strength and stability to protect wounds and prevent external abrasions. The hydrogel of Example 4 has an excessively high crosslink density, resulting in small pores in the hydrogel, making it unable to absorb sufficient exudate. The hydrogel loses elasticity and becomes brittle, affecting the flexibility and comfort of the hydrogel dressing. Therefore, the hydrogel dressings of Examples 1 and 2 offer both mechanical strength, ensuring wound protection, and flexibility, allowing them to adapt to physical activity and skin deformation.

[0124] The cross-section of the freeze-dried hydrogel sample was fixed on a conductive double-sided tape and then placed in an ion sputtering coating instrument. The surface of the sample was sprayed with gold in a vacuum environment. The gold plating conditions were an operating voltage of 15keV and an operating current of 15mA. The sample morphology was then observed. Figure 5 The three-dimensional porous structure of the hydrogel can be observed, which is consistent with the rheological results. The porous structure of Example 1 is more uniform and has good mechanical strength, making it more suitable for hydrogel dressings.

[0125] Analysis of drug release results from dual-drug loaded composite hydrogel

[0126] Typically, wound healing is a dynamic and orderly physiological process consisting of three consecutive and overlapping phases: hemostasis and inflammation, proliferation, and tissue remodeling. Impairment in any of these phases can lead to chronic wounds. However, persistent high blood sugar levels in diabetic wounds induce the production of advanced glycation end products (AGEs), which directly release a large number of reactive oxygen species (ROS), severely disrupting the wound's redox microenvironment. Drug release experiments were conducted on the hydrogel from Example 1 at two pH values: 7.4 and 5.0, corresponding to the healthy in vivo environment and the wound environment, respectively. At pH 7.4, due to the relatively stable Schiff base bonds of the fixed mesoporous silica, only part of the salidroside SAL can diffuse and release outside the hydrogel. SAL inhibits oxidative stress damage and relieves neuropathic pain. During the hemostatic and inflammatory stages, the pH at the wound site will drop slightly, and the Schiff base bonds of the fixed mesoporous silica in the hydrogel are easily broken. At the same time, the hydrogel skeleton formed by cross-linking ε-poly-L-lysine and oxidized dextran partially collapses, so that the originally cross-linked resveratrol and the salidroside in the skeleton can be released in large quantities. In the early stage of wound healing, SAL is rapidly released, which has antioxidant and anti-inflammatory effects, protects cell activity, reduces inflammation and oxidative stress, and inhibits cell apoptosis. Subsequently, in the sustained acidic environment of the chronic wound site, the resveratrol in the nanoparticles is slowly and continuously released, sequentially promoting the migration of fibroblasts, promoting the production of collagen by fibroblasts, and promoting angiogenesis, ultimately achieving rapid healing of chronic diabetic wounds (among which, Figure 6 is the cumulative release result of salidroside from OES@P hydrogel at different pH, Figure 7 (Figure 5) is the cumulative release results of resveratrol from OES@P hydrogel at different pH values.

[0127] OES@P hydrogel has a good ability to inhibit the growth of Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. The results of the co-incubation experiment of hydrogel and bacterial solution showed that the amount of bacteria decreased significantly after 24 hours of incubation, indicating that OES@P hydrogel has a good antibacterial effect. The test results are as follows Figure 8 As shown in the figure, M represents the result after 24 h of incubation with bacterial solution, and OES@P represents the experimental result of co-incubation of hydrogel and bacterial solution.

[0128] Advanced glycation end products (AGEs) are aging-associated molecules that are a major factor in human aging and a key contributor to organ dysfunction in diabetic patients. AGEs accumulate in diabetic wounds. Therefore, a diabetic wound model was simulated by treating cells with high-glucose medium supplemented with 100 μg / mL AGEs. Fibroblasts (HSF) and epidermal cells (Hacat) were prepared as suspensions in serum-containing cell culture medium and seeded into 96-well plates at a volume of 150 μL, with 5,000 cells per well. The plates were cultured in a 5% CO2 incubator. After the cells adhered, the medium was aspirated from the plates. The model and experimental groups were treated with high-glucose medium supplemented with 100 μg / mL AGEs for 24 hours. The OES@P hydrogel extract was then diluted with fresh cell culture medium to prepare solutions of varying concentrations. These solutions were then added to the 96-well plates and incubated for 48 hours. The culture supernatant was aspirated, and 100 μL of 0.5% MTT solution was added to each well. After incubation for 3 hours, the supernatant was discarded. 100 μL of DMSO was then added to each well. The absorbance was measured at 570 nm. The effect of the hydrogel on the growth of fibroblasts and epidermal cells treated with high glucose and AGEs was calculated based on the absorbance.

[0129] Figure 9 Figure 5 is the result of the cell viability experiment, where C represents the control group, i.e., no high-glucose medium + AGEs treatment was used, and M represents the model group, i.e., after treatment with high-glucose medium + AGEs for 24 h, no OES@P hydrogel extract was added. Figure 9 The results showed that a high-sugar and AGE-rich environment significantly affected the survival rates of fibroblasts and epidermal cells. Treatment with high-sugar AGEs significantly decreased the survival rates of these cells, reaching approximately 58%. This suggests that this could affect the fibroblasts' ability to produce collagen. Hydrogel extracts of varying concentrations were non-toxic to both fibroblasts and epidermal cells, promoting their proliferation in a dose-dependent manner. The 50mg / mL OES@P hydrogel extract-treated group showed a 34% increase in cell survival compared to the model group. These results further demonstrate the successful preparation of the hydrogel wound dressing.

[0130] The scratch test, also known as the wound healing test, is a method for measuring cell migration and repair ability, similar to the in vitro wound healing model. On a monolayer of adherent cells cultured in vitro, a line is drawn in the central area of ​​cell growth with a micropipette tip, the cells in the central part are removed, and then the cells are cultured for 24h and 48h of the experiment to observe the growth and migration ability of the surrounding cells. Fibroblasts are the main constituent cells of the dermis, and the migration of fibroblasts plays a key role in wound healing. The diabetic wound healing effect of the hydrogel was studied in vitro under high sugar and AGEs conditions. The experimental results are as follows. Figure 10As shown, the scratch test showed that compared with the control group (C), the migration of cells in the model group (M) slowed down. After drug treatment, the wound area of ​​the hydrogel extract-treated group decreased. Compared with OE, OES, and OE@P, the OES@P group had a better therapeutic effect, with a 48h migration rate greater than 76%, which was 2.79 times, 1.46 times, and 1.38 times that of the OE, OES, and OE@P groups.

[0131] Long-term hyperglycemia in diabetes can cause an increase in non-enzymatic glycation reactions in the body, forming a series of stable covalent compounds AGEs. Carboxymethyl lysine (CML) is one of the most common structural forms of AGEs and is considered to be an important indicator component of AGEs. At the cellular level, the wound healing mechanism is studied by detecting changes in CML content. Methyglyoxal (MGO) is an active dicarbonyl compound and an important intermediate in the production of AGEs. AGEs can be generated in the pathological process of diabetes. A HSF cell model with glycation damage induced by 400 μM methylglyoxal MGO was used to simulate diabetic wounds. The extracts of 50 mg / mL, 100 mg / mL, and 200 mg / mL OES@P hydrogels were added and treated for 48 hours. The CML content in the supernatant was detected. The test results are as follows: Figure 11 As shown. Figure 11 As can be seen, the composite hydrogel significantly reduced the level of CML in glycated cells in a concentration-dependent manner. An extract containing 200 mg / mL of the composite hydrogel exhibited a 34.9% inhibition rate on intracellular CML, demonstrating a strong ability to inhibit glycation reactions. Cell-based experiments demonstrate that the composite hydrogel exhibits excellent glycation-reducing effects in diabetic wounds, inhibiting the accumulation of AGEs in wounds.

[0132] The receptor for advanced glycation end products (RAGE) can recognize and bind to advanced glycation end products (AGEs), and plays a key role in various physiological and pathological processes such as inflammatory response, immune regulation, cell proliferation and apoptosis. Inhibition of the receptor for advanced glycation end products (RAGE) has been shown to reduce diabetic complications. RAGE is expressed at low levels under normal physiological conditions, but is highly upregulated under chronic inflammation due to the accumulation of various RAGE ligands. In molecular docking, binding energy is an important indicator, and generally speaking, the lower the binding energy, the better. It is generally believed that when the binding energy is lower than -5kcal / mol, the docking results are relatively stable. For example Figure 12As shown, resveratrol has a binding energy of -6.5 kcal / mol with RAGE, primarily through hydrogen bonding and hydrophobic interactions. It forms hydrogen bonds with ARG-179 and exhibits hydrophobic interactions with ARG-178, THR-177, and ARG-179. The binding energy of salidroside with RAGE is -5.7 kcal / mol. The amino acid residues involved in the interaction between salidroside and the protein pocket, including SER-65, GLY-69, VAL-63, and TRP-61, demonstrate a strong binding relationship. AGEs bind to RAGE, inhibiting the proliferation of human dermal fibroblasts and promoting apoptosis. Furthermore, AGEs are known to increase the production of reactive oxygen species (ROS), leading to cell membrane and endoplasmic reticulum damage and perpetuating chronic inflammation. Resveratrol and salidroside can inhibit the expression of the receptor for advanced glycation end products and promote diabetic wound healing.

[0133] Six-week-old male Balb / c mice (3 ± 19 g) were used to establish a type 2 diabetes model. To establish the diabetic mouse model, the mice were fed a high-sugar, high-fat diet for four weeks. Subsequently, they were intraperitoneally injected with 50 mg / kg of streptozotocin (STZ) for five consecutive days. Full-thickness wounds were created on the backs of the mice to confirm the effect of OES@P hydrogel on wound healing in diabetic mice. All mice were divided into four groups, each consisting of six mice. The control group (C) received no treatment, the model group (M), and the experimental groups received wound treatment with OE hydrogel, OES hydrogel, OE@P hydrogel, or OES@P hydrogel, respectively. All experiments were performed under isoflurane gas anesthesia. Optical images of the wounds were recorded on days 0, 4, 9, and 12 after surgery. Histological sections of the diabetic mouse wounds were stained. On the final day of the experiment, the mice were sacrificed, and the wound tissue was removed, fixed in 4% neutral formalin solution, and embedded in paraffin. The tissues were cut into 5 μm thick sections and stained with hematoxylin and eosin (H&E) and Masson's stain.

[0134] The results showed that after 4 weeks of high-sugar and high-fat diet, the fasting blood glucose of mice after STZ injection was greater than 11.1mmol / L compared with the control group, indicating that the type 2 diabetes model was successfully established. By recording the macroscopic images of the mouse wounds, calculating the wound area, measuring the wound healing rate of the mice, and performing histological analysis on the healed wounds, the effect of the hydrogel wound dressing on promoting diabetic wound healing was comprehensively evaluated. The macroscopic images of the mouse wound changes were as follows: Figure 13 As shown in Figure 2, the time-varying diabetic wound healing rate was obtained by analyzing the changes in wound area ( Figure 14(M vs. C, OE, OES, OE@P, OES@P: *; OES@P vs. OE, OES, OE@P: #). Results showed that wound healing in the model group was significantly delayed compared to the control group. This may be due to the high-glucose microenvironment of diabetic wounds, which leads to metabolic system disturbances, prolonged wound inflammation, and slow wound recovery. The wound healing rate in the OES@P group was significantly faster than that in the hydrogel OE, OES, OE@P, and control groups. On day 4, compared to the model group, the wound healing rates in the OES and OE@P treatment groups increased by 4.6-fold and 4.65-fold, respectively, while the OES@P treatment group increased by 6.04-fold. The healing rates in the OES@P group were 1.3-fold and 1.28-fold higher than those in the OES and OE@P groups, respectively. On day 9, compared with the model group, the wound healing rates in the OES and OE@P treatment groups increased by 1.16-fold and 1.15-fold, respectively, and in the OES@P treatment group by 1.43-fold. The OES@P healing rate was 1.2 times that of the OES and OE@P groups. On day 12, the OES@P healing rate was 1.19-fold and 1.18-fold higher than that of the OES and OE@P groups. Compared with the control group and the hydrogel scaffold group, the OES@P hydrogel treatment group had the highest wound healing rates at 75.4% and 96.1% on days 9 and 12 after treatment, respectively. This is attributed to the OES@P hydrogel's ability to maintain a moist wound environment and promote fibroblast migration. Furthermore, the OES@P hydrogel exhibits excellent antibacterial properties, scavenging reactive oxygen species accumulated in diabetic wound tissue and reducing wound infection, achieving a preventive effect. It also inhibits the accumulation of AGEs, promotes fibroblast proliferation, and stimulates collagen synthesis, thereby promoting wound healing.

[0135] In summary, the prepared OES@P hydrogel has good antibacterial properties and can promote diabetic wound healing by inhibiting the production of CML in glycosylated cells, inhibiting the expression of advanced glycation end product receptors, inhibiting bacterial growth and reproduction, promoting fibroblast proliferation and promoting collagen deposition. It has the potential to be used as a diabetic wound dressing.

[0136] The above embodiments are intended only to illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made in accordance with the spirit of the present invention are intended to be covered by the scope of protection of the present invention.

Claims

1. Use of a composite hydrogel in the preparation of a hydrogel dressing for promoting wound healing, the composite hydrogel comprising a hydrogel skeleton and nanoparticles loaded within the hydrogel skeleton; characterized in that: The hydrogel skeleton is formed by oxidized dextran and polylysine; the nanoparticles are loaded with an active ingredient, which is resveratrol; the nanoparticles are amino-modified mesoporous silica nanoparticles; the composite hydrogel further comprises salidroside loaded in the hydrogel skeleton; the wound is a wound of a diabetic patient; the polylysine is ε-poly-L-lysine; the mass ratio of the polylysine to the oxidized dextran is 0.4-1.2:1, the drug loading of the active ingredient in the nanoparticles is 40%-50%, the concentration of the nanoparticles loaded with the active ingredient in the composite hydrogel is 0.25-4 mg / mL, and the concentration of salidroside in the composite hydrogel is 0.5-3 mg / mL; The preparation method of the composite hydrogel comprises the following steps: (1) Prepare oxidized dextran solution; (2) Preparation of amino-modified nanoparticles; (3) loading the active ingredient into the pores of the amino-modified nanoparticles to obtain drug-loaded nanoparticles; (4) The polylysine solution, the drug-loaded nanoparticles, salidroside and the oxidized dextran solution are uniformly mixed and reacted to obtain the composite hydrogel.

2. The use according to claim 1, characterized in that: The mass ratio of the polylysine to the oxidized dextran is 0.7-0.9:1; and / or, The concentration of the nanoparticles loaded with active ingredients in the composite hydrogel is 0.5-3 mg / mL; and / or, The concentration of salidroside in the composite hydrogel is 1-3 mg / mL.

3. The use according to claim 1, characterized in that: In step (1), the concentration of the oxidized dextran solution is 40-150 mg / mL; and / or, In step (3), the mass ratio of the active ingredient to the amino-modified nanoparticles is 1:0.5-2; and / or, In step (4), the pH of the polylysine solution is 7-9; and / or, In step (4), the concentration of the polylysine solution is 30-150 mg / mL; and / or, In step (4), the concentration of the drug-loaded nanoparticles in the composite hydrogel is 0.5-1.5 mg / mL; and / or, In step (4), the concentration of salidroside in the composite hydrogel is 1.5-2.5 mg / mL.

4. The use according to claim 3, characterized in that: In step (1), the concentration of the oxidized dextran solution is 100-120 mg / mL, and in step (4), the concentration of the polylysine solution is 70-100 mg / mL.

5. The use according to claim 1, characterized in that: The specific method of step (1) is: mixing sodium periodate solution with dextran suspension, reacting for 3 to 8 hours, then adding ethylene glycol to quench the reaction, dialyzing the reaction solution, and then preparing the oxidized dextran solution; The specific method of step (2) is as follows: dissolving the template in a mixed solvent of deionized water and anhydrous ethanol, adjusting the pH value of the solution to 8-14, adding a silicon source and reacting for 14-18 hours; after the reaction, centrifuging, washing and drying to obtain silica nanoparticles with the template; resuspending the nanoparticles with isopropanol, and then adding 3-aminopropyltriethoxysilane and reacting at room temperature for 2-6 hours; after the reaction, centrifuging and drying to obtain amino-containing silica nanoparticles with the template; finally, removing the template with an extractant to obtain amino-containing nanoparticles; The specific method of step (3) is as follows: dissolving the active ingredient in a solvent, then adding the amino-modified nanoparticles prepared in step (2), stirring at room temperature in the dark for 12-24 hours, centrifuging, washing and drying after the reaction to obtain drug-loaded nanoparticles; The specific method of step (4) is: dissolving polylysine in water and adjusting the pH to obtain a polylysine solution; then uniformly mixing the polylysine solution, the drug-loaded nanoparticles and the salidroside, adding the oxidized dextran solution, stirring and dissolving to form a uniform solution, and reacting to obtain the composite hydrogel.

6. The use according to claim 5, characterized in that: In step (1), the mass ratio of the glucan to the sodium periodate is 1:0.4-1.5, and / or the mass ratio of the glucan to distilled water in the glucan suspension is 1-5:100, and / or the reaction temperature is 25-40° C., and / or the quenching reaction time is 1-2 h; In step (2), the template is hexadecyltrimethylammonium bromide, and / or the volume ratio of the deionized water to the anhydrous ethanol in the mixed solvent is 3-5:1, and / or the feed ratio of the template to the mixed solvent is 120-160 mL of the mixed solvent per 1 g of the template, and / or ammonia water is used to adjust the pH, and / or the silicon source is tetraethyl orthosilicate, and / or the extractant is a mixed solvent of anhydrous ethanol and concentrated hydrochloric acid in a volume ratio of 35-80:1, and / or the When the template agent is removed by the extractant, the feed ratio of the amino-silica nanoparticles with the template agent to the extractant is 200-520 mL of the extractant per 1 g of the amino-silica nanoparticles with the template agent, and / or the specific method of removing the template agent with the extractant is: mixing the amino-silica nanoparticles with the template agent and the extractant, refluxing for 6-24 hours, refluxing 1-3 times, centrifuging at 8000-10000 rpm for 3-5 minutes, washing the precipitate with anhydrous ethanol 2-4 times, and drying in an oven at 60-80°C to obtain amino-silica nanoparticles; In step (3), the active ingredient is resveratrol, the solvent is anhydrous ethanol, and / or the concentration of the active ingredient dissolved in the solvent is 1-10 mg / mL; In step (4), 1-3 mol / L NaOH is used to adjust the pH.

7. The use according to claim 1, characterized in that: The wound is an ulcer wound of a diabetic patient.

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