Modified hydrogel for skin wound healing and preparation method thereof

Abstract

The application belongs to the technical field of medical gels, and particularly relates to a modified hydrogel for skin wound healing and a preparation method thereof, wherein the modified hydrogel comprises the following raw materials in parts by weight: drug-loaded GDVLNs 2-5 parts, chitosan 1-2 parts, an antioxidant 0.6-1.5 parts, LAP 0.2 part, MA 1.5 parts, a gel matrix 18 parts, and a buffer 100 parts. The drug-loaded GDVLNs prepared from traditional Chinese medicine active ingredients and ginseng vesicles have functions of resisting oxidative stress, promoting angiogenesis, and promoting cell proliferation. The MA-modified hydrogel system can realize slow release of the drug-loaded GDVLNs, and plays a long-acting role in promoting healing.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of medical gels, and particularly relates to a modified hydrogel for skin wound healing and a preparation method thereof. BACKGROUND

[0002] Under the background of the intelligent rapid development of regenerative medicine, skin wound healing materials have also shifted from traditional reliance on body self-repair to active control of intelligent dressings. In view of the development of new dressings, at present, mainly focuses on natural and synthetic polymer gels with good biocompatibility, electrospun nanofiber membranes, growth factor preparations, stem cell and derivative preparations, etc., which can accelerate healing by providing a humid environment, controlling wound exudation and promoting granulation tissue formation. With the development of intelligent responsive dressings, new materials such as pH response, enzyme response or light response can dynamically release drugs according to the wound state, showing great application research potential. However, due to the high complexity of the wound microenvironment, the richness of regulatory factors and pharmacological signaling pathways, and the high risk of inflammation and infection, the research of skin repair materials still faces great challenges.

[0003] As a traditional herbal medicine, ginseng has a wide range of pharmacological effects such as antioxidant, anticancer, immune enhancement and pro-angiogenic, and more and more research focuses on the active ingredients and medicinal pathways of ginseng. Among them, ginseng-based vesicle-like nanoparticles not only have good activity, but also are a natural nanocarrier, which can achieve the purpose of treatment and drug delivery simultaneously. Therefore, the development of an intelligent dressing based on ginseng-derived vesicles has important significance for promoting the proliferation and healing process of skin wound cells. SUMMARY

[0004] In view of the above situation, the present application provides a modified hydrogel for skin wound healing and a preparation method thereof. The active nanoparticles are prepared by loading traditional Chinese medicine active ingredients into ginseng vesicles for promoting skin healing, the three-dimensional cross-linked network structure formed by methacrylation modification of the gel disperses and maintains the activity of the nanoparticles, a drug-loaded hydrogel with temperature sensitivity and light curing characteristics is constructed, and the purposes of anti-infection, alleviating oxidative stress and promoting cell regeneration in the wound healing process are achieved.

[0005] To achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0006] The present application provides a modified hydrogel for skin wound healing, which comprises the following raw materials by weight: drug-loaded GDVLNs (ginseng-derived vesicle-like nanoparticles) 2-5 parts, chitosan 1-2 parts, antioxidant 0.6-1.5 parts, LAP (lithium phenyl-2, 4, 6-trimethylbenzoyl phosphinic acid) 0.2 parts, MA (methyl acrylate) 1.5 parts, gel matrix 18 parts and buffer 100 parts.

[0007] Further, the antioxidant is selected from any one of gallic acid, ferulic acid and tannic acid.

[0008] Further, the gel matrix is selected from any one of poloxamer, gelatin and sodium alginate.

[0009] Further, the buffer is 0.1 M PBS (phosphate) buffer with pH 7.4.

[0010] Further, the drug-loaded GDVLNs comprise the following raw materials: ginseng, resveratrol, baicalein, DSPE-PEG2000 (phospholipid polyethylene glycol copolymer) and sucrose, and the mass ratio of the ginseng, resveratrol, baicalein, DSPE-PEG2000 and sucrose is 1000:0.7:0.3:1:2.

[0011] Further, the preparation method of the drug-loaded GDVLNs is as follows:

[0012] S1: after the ginseng is cut into pieces, high-speed homogenization is carried out to obtain a homogenate, the homogenate is subjected to differential centrifugation to remove cell debris, large organelles and large vesicles, and the supernatant is collected, the supernatant mainly contains small-sized ginseng vesicles and soluble proteins, the supernatant is subjected to ultracentrifugation, and a milky white precipitate, i.e. GDVLNs, is collected;

[0013] S2: resveratrol, baicalein and DSPE-PEG2000 are dissolved in a mixed solvent prepared from anhydrous ethanol and chloroform in a volume ratio of 1:1 and transferred to a round-bottom flask, the mixed solvent is removed by rotary evaporation to obtain a composite film;

[0014] S3: after the GDVLNs are resuspended, they are added to the composite film, water bath heating is carried out for hydration and co-loading, the phospholipid film of the GDVLNs fuses with the composite film and material exchange occurs, the hydrophobic resveratrol and baicalein are loaded into the vesicles of the GDVLNs, at the same time, the DSPE-PEG2000 fuses with the phospholipid film of the GDVLNs, the DSPE hydrophobic end is embedded in the phospholipid film, and the PEG2000 hydrophilic end is exposed on the surface of the phospholipid film, to obtain a primary product;

[0015] S4: the primary product is subjected to ultrasonic homogenization to further promote drug loading of resveratrol and baicalein and particle size uniformity, after ultracentrifugation, an ultrafiltrate is obtained, sucrose is dissolved in the ultrafiltrate, and freeze-drying is carried out to obtain the drug-loaded GDVLNs.

[0016] The application further provides a preparation method of the modified hydrogel for skin wound healing, and the specific preparation method is as follows:

[0017] Step 1: dissolve chitosan and antioxidant together in 50 parts of buffer, stir in 60 DEG C water bath for 4 h, covalent crosslinking occurs between amino groups in chitosan and hydroxyl groups in antioxidant, forming a pre-polymer network, providing certain gel mechanical strength and long-lasting antioxidant capacity, obtaining crosslinked solution;

[0018] Step 2: dissolve the gel matrix to prepare a solution, add MA to modify the gel matrix, obtain a modified gel matrix, and then dissolve the modified gel matrix in 40 parts of buffer to obtain a modified solution;

[0019] Step 3: take the drug-loaded GDVLNs and dissolve them in 10 parts of buffer to obtain a nanoparticle solution, mix the nanoparticle solution with the crosslinked solution uniformly, add LAP to the mixture and stir to dissolve in the dark, obtain a precursor solution, mix the precursor solution with the modified solution to form a gel, adjust the mechanical strength of the gel by temperature or light, and obtain a modified hydrogel for skin wound healing.

[0020] The beneficial effects obtained by the present application are as follows:

[0021] The modified hydrogel for skin wound healing prepared by the present application contains ginsenosides, small RNA and proteins, etc. bioactive substances in naturally derived ginseng vesicles GDVLNs, and simultaneously loads resveratrol and baicalein, which are traditional Chinese medicine ingredients with antioxidant stress, pro-angiogenic, pro-cell proliferation and anti-infection properties, as a multifunctional carrier. The phospholipid bilayer with similar cell structure greatly improves the drug bioavailability and cell fusion regulation capacity, and more combines the inherent immune regulation function of the vesicle itself with the treatment function of the drug. The drug-loaded GDVLNs can be taken up by macrophages at the wound site, and through cell strong oxidation phosphorylation and glycolysis, drive the macrophages to polarize from the pro-inflammatory M1 phenotype to the anti-inflammatory and rough repair M2 phenotype, while releasing a large amount of cytokines to promote tissue regeneration, creating favorable conditions for skin repair. On this basis, the drug-loaded GDVLNs can also promote the proliferation and migration of fibroblasts, accelerate the synthesis of collagen and elastin, activate vascular endothelial cells, promote neovascularization, and solve the problem of insufficient blood supply to the wound. The phospholipid bilayer can also directly neutralize part of the active oxygen to protect the newly formed cells from oxidative damage.

[0022] In the construction of the gel system, the primary network with mechanical strength and long-lasting antioxidant capacity is constructed by in-situ crosslinking of chitosan and antioxidant such as gallic acid, providing stable microenvironment support for the wound. Further introduction of the temperature-sensitive gel matrix modified by methacrylation, through light curing technology, forms a mechanical strength adjustable intelligent hydrogel dressing. This multi-level gel system can well improve the dispersibility and activity retention of the drug-loaded GDVLNs, and the gel network which collapses over time also has the effect of slow release and controlled release, providing a long-acting active microenvironment for skin repair and healing. Attached Figure Description

[0023] Figure 1 The gel-forming properties of the modified hydrogel for skin wound healing prepared in Example 2 are characterized.

[0024] Figure 2 The results of the cell compatibility study of the modified hydrogels for skin wound healing prepared in Examples 2, 4 and Comparative Examples 1-2 are as follows;

[0025] Figure 3 The results of the investigation on the effect of the modified hydrogel for skin wound healing prepared in Example 2 on macrophage polarization;

[0026] Figure 4 The results of the skin healing promotion ability of the modified hydrogels for skin wound healing prepared in Example 2 and Comparative Example 2 are presented. Detailed Implementation

[0027] 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.

[0028] 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.

[0029] Unless otherwise specified, all methods used in the following examples are conventional. Unless otherwise specified, all materials used in the following examples are new materials purchased from the market. All quantities are parts by weight. Specifically, the PBS buffer used is 0.1M pH 7.4 PBS buffer; the poloxamer used is PF-127; the gelatin used is medical-grade type A gelatin; the sodium alginate used is high-G type, with a molecular weight of 80-150 kDa; and the chitosan used is low molecular weight, 50-150 kDa, with a degree of deacetylation ≥90%.

[0030] In the following examples and comparative examples, the drug-loaded GDVLNs comprise the following raw materials in parts by weight: 2000 parts ginseng, 1.4 parts resveratrol, 0.6 parts baicalein, 2 parts DSPE-PEG2000, and 4 parts sucrose;

[0031] The preparation method of the drug-loaded GDVLNs is as follows:

[0032] S1: Take ginseng 2000 parts after cutting and mix with 2000 parts of PBS buffer containing protease inhibitors, 4°C pre-cooling, use tissue homogenizer 10000 rpm high speed homogenization 5 min at 4°C, get homogenate, centrifuge the homogenate at 4°C, 300xg for 10 min to remove cells, collect supernatant 1, centrifuge supernatant 1 at 4°C, 2000xg for 10 min to remove cell debris, collect supernatant 2, centrifuge supernatant 2 at 4°C, 10000xg for 10 min to remove apoptotic bodies, collect the supernatant, which mainly contains small-sized ginseng vesicles and soluble proteins, 4°C, 100000xg ultracentrifugation, collect the milky white precipitate, which is GDVLNs;

[0033] S2: Resveratrol 1.4 parts, baicalein 0.6 parts and DSPE-PEG2000 2 parts are dissolved in 20 parts of mixed solvent (volume ratio of anhydrous ethanol and chloroform 1:1) and transferred to a round-bottom flask, 40°C, 100 rpm rotary evaporation for 45 min to remove the mixed solvent, and a composite film is obtained;

[0034] S3: After resuspending GDVLNs with 100 parts of PBS buffer, add it to the composite film, and perform hydration at 50°C for 60 min with 200 rpm water bath heating and rotation. The phospholipid membrane of GDVLNs fuses with the composite film and material exchange occurs. The hydrophobic resveratrol and baicalein are loaded into the vesicles of GDVLNs, while DSPE-PEG2000 fuses with the phospholipid membrane of GDVLNs, with the DSPE hydrophobic end embedded in the phospholipid membrane and the PEG2000 hydrophilic end exposed on the surface of the phospholipid membrane, to obtain a primary product;

[0035] S4: Ultrasonic homogenization of the primary product for 3 min, using a probe sonicator, power 200 W, working 2 s, intermittent 5 s, to further promote drug loading of resveratrol and baicalein and uniform particle size. After centrifugation at 3500xg for 15 min using a 100 kDa ultrafiltration tube, an ultrafiltrate is obtained. Dissolve sucrose 4 parts in the ultrafiltrate and freeze-dry to obtain drug-loaded GDVLNs. Liquid chromatography detection shows that the drug loading of resveratrol in drug-loaded GDVLNs is 2.15% and the encapsulation efficiency is 87.3%, and the drug loading of baicalein is 0.76% and the encapsulation efficiency is 92.2%.

[0036] Example 1: The present embodiment provides a modified hydrogel for skin wound healing, which comprises the following raw materials by weight: drug-loaded GDVLNs 2 parts, chitosan 1 part, ferulic acid 1 part, LAP 0.2 part, MA 1.5 parts, poloxamer 18 parts and buffer 100 parts.

[0037] The present embodiment also provides a preparation method of a modified hydrogel for skin wound healing, and the specific preparation method is as follows:

[0038] Step 1: Take ferulic acid 1 part to dissolve in 5 parts of anhydrous ethanol to obtain a ferulic acid solution, take chitosan 1 part to dissolve in 50 parts of buffer to obtain a chitosan solution, slowly add the ferulic acid solution to the chitosan solution at 4℃ and 800 rpm, after the dropwise addition is completed, stir in a 60℃ water bath for 4 h, volatilize the anhydrous ethanol, and at the same time promote the covalent crosslinking between the amino groups in the chitosan and the hydroxyl groups in the ferulic acid to form a prepolymer network, providing certain gel mechanical strength and persistent and stable antioxidant capacity, to obtain a crosslinked solution;

[0039] Step 2: Dissolve poloxamer 18 parts in 100 parts of dichloromethane to prepare a poloxamer solution, add 0.5 parts of DMAP (4-dimethylaminopyridine) and 1 part of TEA (triethylamine) and stir uniformly, then add MA 1.5 parts dropwise under ice bath, nitrogen protection and light protection, after the dropwise addition is completed, stir at room temperature and 500 rpm for 24 h to obtain a reaction liquid, slowly pour the reaction liquid into 10 times the volume of ice-cold anhydrous ether to precipitate a white precipitate, centrifuge, wash with ice-ethanol and dry to obtain a modified gel matrix, redissolve the modified gel matrix in 40 parts of buffer to obtain a modified solution;

[0040] Step 3: Dissolve the drug-loaded GDVLNs 2 parts in 10 parts of buffer to obtain a nanoparticle solution, mix the nanoparticle solution and the crosslinked solution uniformly, add LAP 0.2 parts to the mixture and stir to dissolve in the dark to obtain a precursor solution, mix the precursor solution and the modified solution under ice bath conditions, inject into a mold, incubate at 37℃ to trigger gel formation, and then irradiate with 405 nm light to solidify, to obtain a modified hydrogel for skin wound healing.

[0041] Example 2: The present example provides a modified hydrogel for skin wound healing, which comprises the following raw materials by weight: drug-loaded GDVLNs 4 parts, chitosan 2 parts, gallic acid 0.6 parts, LAP 0.2 parts, MA 1.5 parts, poloxamer 18 parts and buffer 100 parts.

[0042] The present example also provides a preparation method of a modified hydrogel for skin wound healing, and the specific preparation method is as follows:

[0043] Step 1: Dissolve gallic acid 0.6 parts in 5 parts of anhydrous ethanol to obtain a gallic acid solution, dissolve chitosan 2 parts in 50 parts of buffer to obtain a chitosan solution, slowly add the gallic acid solution to the chitosan solution at 4℃ and 800 rpm, after the dropwise addition is completed, stir in a 60℃ water bath for 4 h, the amino groups in the chitosan and the hydroxyl groups in the gallic acid covalently crosslink to form a prepolymer network, providing certain gel mechanical strength and persistent and stable antioxidant capacity, to obtain a crosslinked solution;

[0044] Step 2: Poloxamer 18 parts were dissolved in 100 parts of dichloromethane to prepare a poloxamer solution, 0.5 parts of DMAP and 1 part of TEA were added and stirred uniformly, then MA 1.5 parts were added dropwise in an ice bath under nitrogen protection and light protection, after the dropwise addition was completed, the reaction was stirred at room temperature at 500 rpm for 24 h to obtain a reaction liquid, the reaction liquid was slowly poured into 10 times the volume of ice-cold anhydrous ether, and white precipitate was precipitated, which was centrifuged, washed with ice-ethanol and dried to obtain a modified gel matrix, which was redissolved in 40 parts of buffer to obtain a modified solution;

[0045] Step 3: 4 parts of drug-loaded GDVLNs were dissolved in 10 parts of buffer to obtain a nanoparticle solution, the nanoparticle solution was mixed uniformly with the crosslinking solution, 0.2 parts of LAP was added and dissolved under light protection to obtain a precursor solution, the precursor solution was mixed with the modified solution under ice bath conditions, injected into a mold, incubated at 37°C to trigger gel formation, and then irradiated with 405 nm light to solidify, to obtain a modified hydrogel for skin wound healing.

[0046] Example 3: The present example provides a modified hydrogel for skin wound healing, which comprises the following raw materials by weight: drug-loaded GDVLNs 5 parts, chitosan 1.5 parts, tannic acid 1.5 parts, LAP 0.2 parts, MA 1.5 parts, gelatin 18 parts and buffer 100 parts.

[0047] The present example also provides a preparation method of a modified hydrogel for skin wound healing, and the specific preparation method is as follows:

[0048] Step 1: 1.5 parts of tannic acid were dissolved in 5 parts of deionized water to obtain a tannic acid solution, and 1.5 parts of chitosan were dissolved in 50 parts of buffer to obtain a chitosan solution, then the tannic acid solution was slowly added to the chitosan solution under 4°C and 800 rpm, after the dropwise addition was completed, the mixture was stirred in a 60°C water bath for 4 h to obtain a crosslinking solution;

[0049] Step 2: 18 parts of gelatin were dissolved in 162 parts of 50°C preheated deionized water to obtain a gelatin solution, and 1.5 parts of MA were slowly added to the gelatin solution under 50°C and 100 rpm, after the dropwise addition was completed, the reaction was continued at 300 rpm for 3 h to obtain a modified liquid, the modified liquid was dialyzed in a 12 kDa dialysis bag for 2 days, and the water was changed every 12 h, to obtain a modified gel matrix, which was lyophilized and redissolved in 40 parts of buffer to obtain a modified solution;

[0050] Step 3: Take the drug-loaded GDVLNs 4 parts and dissolve them in 10 parts of buffer solution to obtain a nanoparticle solution. Mix the nanoparticle solution with the crosslinking solution uniformly, add LAP 0.2 parts to it, stir to dissolve in the dark, obtain a precursor solution, mix the precursor solution with the modified solution under ice bath conditions, inject into the mold, incubate at 37°C to trigger gel formation, then irradiate with 405 nm light to solidify, and obtain a modified hydrogel for skin wound healing.

[0051] Example 4: The present example provides a modified hydrogel for skin wound healing, which comprises the following raw materials by weight: drug-loaded GDVLNs 4 parts, chitosan 2 parts, gallic acid 0.6 parts, LAP 0.2 parts, MA 1.5 parts, gelatin 18 parts and buffer solution 100 parts.

[0052] The present example also provides a preparation method of a modified hydrogel for skin wound healing, and the specific preparation method is as follows:

[0053] Step 1: Take gallic acid 0.6 parts and dissolve it in 5 parts of anhydrous ethanol to obtain a gallic acid solution. Take chitosan 2 parts and dissolve it in 50 parts of buffer solution to obtain a chitosan solution. Slowly add the gallic acid solution to the chitosan solution at 4°C and 800 rpm. After the addition is completed, stir in a water bath at 60°C for 4 h to obtain a crosslinking solution.

[0054] Step 2: Dissolve gelatin 18 parts in 162 parts of deionized water preheated to 50°C to obtain a gelatin solution. Slowly add MA 1.5 parts to the gelatin solution at 50°C and 100 rpm. After the addition is completed, continue to react at 300 rpm for 3 h to obtain a modified solution. The modified solution is dialyzed in a 12 kDa dialysis bag for 2 days, with water changed every 12 h. After lyophilization, the modified gel matrix is reconstituted in 40 parts of buffer solution to obtain a modified solution.

[0055] Step 3: Take the drug-loaded GDVLNs 4 parts and dissolve them in 10 parts of buffer solution to obtain a nanoparticle solution. Mix the nanoparticle solution with the crosslinking solution uniformly, add LAP 0.2 parts to it, stir to dissolve in the dark, obtain a precursor solution, mix the precursor solution with the modified solution under ice bath conditions, inject into the mold, incubate at 37°C to trigger gel formation, then irradiate with 405 nm light to solidify, and obtain a modified hydrogel for skin wound healing.

[0056] Example 5: The present example provides a modified hydrogel for skin wound healing, which comprises the following raw materials by weight: drug-loaded GDVLNs 4 parts, chitosan 2 parts, gallic acid 0.6 parts, LAP 0.2 parts, MA 1.5 parts, sodium alginate 18 parts and buffer solution 100 parts.

[0057] The present example also provides a preparation method of a modified hydrogel for skin wound healing, and the specific preparation method is as follows:

[0058] Step 1: Gallic acid 0.6 parts was dissolved in 5 parts of anhydrous ethanol to obtain a gallic acid solution, and chitosan 2 parts was dissolved in 50 parts of a buffer solution to obtain a chitosan solution. The gallic acid solution was slowly added to the chitosan solution at 4°C and 800 rpm, and after the dropwise addition was completed, the mixture was stirred in a 60°C water bath for 4 h to obtain a crosslinking solution;

[0059] Step 2: Sodium alginate 18 parts was slowly added to 162 parts of deionized water, and after stirring at room temperature and 500 rpm for 2 h, 2 parts of DMAP was added to continue stirring until the lipid was completely dissolved. The pH was adjusted to 8.0 with 1 M NaOH solution to obtain a sodium alginate solution. MA 1.5 parts was added dropwise to the sodium alginate solution, and after completion, the mixture was reacted at room temperature, in the dark, and at 500 rpm for 24 h to obtain a reaction solution. Ten times the volume of anhydrous ethanol was added to the reaction solution, and the mixture was suction-filtered to obtain a precipitate, which was dried and then re-dissolved in 40 parts of a buffer solution to obtain a modified solution;

[0060] Step 3: Drug-loaded GDVLNs 4 parts were dissolved in 10 parts of a buffer solution to obtain a nanoparticle solution. The nanoparticle solution was mixed uniformly with the crosslinking solution, and LAP 0.2 parts was added to the mixture under light protection to dissolve. The precursor solution was mixed with the modified solution under ice bath conditions, and then injected into a mold. The mixture was incubated at 37°C to trigger gel formation, and then irradiated with 405 nm light to solidify, thereby obtaining a modified hydrogel for skin wound healing.

[0061] Comparative Example 1 differs from Example 2 in that an equal weight of GDVLNs is used instead of drug-loaded GDVLNs, and the remaining raw material composition and preparation steps are the same as those of Example 2.

[0062] Comparative Example 2 differs from Example 2 in that drug-loaded GDVLNs are replaced by an intermediate amount of resveratrol and baicalein in the drug-loaded GDVLNs to prepare a modified hydrogel. The addition amount of resveratrol and baicalein is calculated as 2.15% and 0.76% of the drug loading amount, respectively, which is 0.09 parts and 0.03 parts, respectively. The composition of the raw materials is as follows: resveratrol 0.09 parts, baicalein 0.03 parts, chitosan 2 parts, gallic acid 0.6 parts, LAP 0.2 parts, MA 1.5 parts, poloxamer 18 parts, and buffer solution 100 parts. The preparation method is the same as that of Example 2.

[0063] Gelation performance investigation: The modified hydrogel for skin wound healing prepared in Example 2 was taken, and the fluid states before and after molding were recorded, respectively. The results are shown in Figure 1 .

[0064] Cell compatibility investigation: 0.2 mL of the modified hydrogel prepared in Example 2, Example 4 and Comparative Example 1-2 was respectively taken to the bottom of a 96-well plate for solidification, and co-cultured with L929 (mouse fibroblast cells) and C166 (mouse vascular endothelial cells) for 12 and 24 h to investigate the cell compatibility of the hydrogel, with normally cultured cells as the control group, and wells without added cells as the blank group, and the cell survival rate was detected by CCK-8 method, cell survival rate (%) = (experimental group absorbance - control group absorbance) / (control group absorbance - blank group absorbance) x 100%, and the results are shown in Figure 2 .

[0065] Macrophage polarization investigation: the modified hydrogel prepared in Example 2 was co-cultured with RAW264.7 cells for 24 h, and the cell phenotype was detected by flow cytometry, with normally cultured cells as the blank group, and LPS (lipopolysaccharide) was used to stimulate cells to construct an inflammation model as the LPS group, and the flow cytometry investigation results and the ratio of macrophage phenotypes M2:M1 are shown in Figure 3 .

[0066] Skin wound healing investigation: 18 six-week-old rats were randomly divided into three groups, which were blank group, Comparative Example 2 group and Example 2 group, and a skin wound model was established, and a 2 cm diameter skin gap was cut on the back of each rat, and the wound was photographed and recorded at 0 d and 7 d after administration, and the results are shown in Figure 4 .

[0067] Figure 1 The results show that the gel has good fluidity before solidification, which is suitable for injection or application on the wound site, and solidifies after temperature and light, with good formability.

[0068] Figure 2 The results show that the modified hydrogels prepared in Example 2, Example 4 and Comparative Example 1-2 have good cell compatibility, and will not produce toxicity to normal physiological cells when used for skin wound repair.

[0069] Figure 3 The results show that compared with the LPS group, the phenotype of RAW264.7 cells treated with the modified hydrogel prepared in Example 2 changes, the number of Q2 zone cells increases, and the number of Q1 zone cells decreases, that is, the macrophages are polarized from M1 phenotype to M2 phenotype, and the M2 phenotype can inhibit the release of inflammatory factors, thereby promoting the transition from the inflammation stage to the healing stage at the skin wound site and improving the repair efficiency.

[0070] Figure 4 The results show that compared with the skin healing of rats in the blank group and Comparative Example 2 group, the rats in Example 2 group have good healing after 7 d of administration, indicating that GDVLNs have a positive effect on skin repair in promoting macrophage polarization.

[0071] While embodiments of the application have been shown and described, it is to be understood that the embodiments described are merely exemplary and that changes in form and detail can be made without departing from the spirit and scope of the application, which is defined by the appended claims and their equivalents.

[0072] The above description of the application and its embodiments is not restrictive, and the embodiments shown in the drawings are only one of the embodiments of the application, and the actual application is not limited thereto. In general, if a person skilled in the art is inspired by it, without departing from the purpose of the invention, without creative design, similar ways and embodiments of the technical solution should belong to the protection scope of the application.

Claims

1. A modified hydrogel for skin wound healing, characterized by, The modified hydrogel comprises the following raw materials by weight: drug-loaded GDVLNs 2-5 parts, chitosan 1-2 parts, antioxidant 0.6-1.5 parts, LAP 0.2 parts, methacrylic anhydride 1.5 parts, gel matrix 18 parts and buffer 100 parts; The drug-loaded GDVLNs comprise the following raw materials: ginseng, resveratrol, baicalein, DSPE-PEG2000 and sucrose, and the preparation method of the drug-loaded GDVLNs is as follows: S1: After the ginseng is cut into pieces, it is mixed with PBS buffer containing protease inhibitors and pre-cooled at 4°C to prepare a homogenate, and differential and ultracentrifugation are performed to collect the precipitate to obtain GDVLNs; S2: Resveratrol, baicalein and DSPE-PEG2000 are dissolved and rotary evaporated to obtain a composite film; S3: The GDVLNs are hydrated with the composite film to obtain a primary product; S4: The primary product is homogenized and ultrafiltrated to obtain an ultrafiltrate, and sucrose is added to the ultrafiltrate and freeze-dried to obtain the drug-loaded GDVLNs.

2. The modified hydrogel according to claim 1, wherein the modified hydrogel is a hydrogel having a water content of 70% or more. The mass ratio of the ginseng, resveratrol, baicalein, DSPE-PEG2000 and sucrose is 1000:0.7:0.3:1:2; In step S2, the dissolving process uses a mixed solvent prepared from anhydrous ethanol and chloroform in a volume ratio of 1:

1.

3. The modified hydrogel according to claim 1, wherein the modified hydrogel is a hydrogel having a water content of 70% or more. The antioxidant is selected from any one of gallic acid, ferulic acid and tannic acid; The gel matrix is selected from any one of poloxamer, gelatin and sodium alginate.

4. A method for preparing the modified hydrogel for skin wound healing according to any one of claims 1 to 3, characterized by, The specific preparation method is as follows: Step 1: Dissolve chitosan and antioxidant in 50 parts of buffer to obtain a crosslinking solution; Step 2: After the gel matrix is modified by methacrylic anhydride, it is dissolved in 40 parts of buffer to obtain a modified solution; Step 3: Dissolve the drug-loaded GDVLNs in 10 parts of buffer, mix with the crosslinking solution, add LAP, and obtain a precursor solution. Mix the precursor solution with the modified solution to perform gelation molding to obtain the modified hydrogel for skin wound healing.

5. The method for preparing a modified hydrogel for skin wound healing according to claim 4, characterized in that, In step 3, the process of adding LAP is carried out in the dark; The gelation molding process is adjusted by temperature or light.

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