An antibacterial hydrogel loaded with gold-iron phosphorus nanosheet and a preparation method and application thereof

Abstract

The application provides an antibacterial hydrogel loaded with gold-iron phosphorus trisulfide nanosheets and a preparation method and application thereof, and belongs to the technical field of hydrogel materials. Au-FePS3 nanosheets prepared in the application are loaded in quaternary ammonium salt chitosan (QC)-oxidized dextran (OD) hydrogel; the Au-FePS3 nanosheets have peroxidase (GOx) activity, peroxidase (POD) activity and photothermal properties, and there is cascade catalytic activity between GOx and POD, active oxygen mainly in the form of ·OH is generated, and the antibacterial and hypoglycemic effects can be simultaneously exerted on diabetic wounds; the QC-OD hydrogel has the effects of antibiosis, hemostasis, moisturizing and sustained release of the loaded substance, promotes wound healing, and is degradable and injectable; in addition, the Au-FePS3 nanosheets are loaded in the QC-OD hydrogel, so that the nanoscale enzyme can be prevented from agglomerating during use, and the enzyme activity is enhanced. The preparation process of the Au-FePS3 nanosheets and the QC-OD hydrogel in the application is simple, rapid and high in production efficiency, and the Au-FePS3 nanosheets and the QC-OD hydrogel are expected to be used for clinical treatment and improve the life quality of patients.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydrogel materials, and particularly relates to an antibacterial hydrogel loaded with gold-iron phosphorus nanosheet and a preparation method and application thereof. BACKGROUND

[0002] The treatment of diabetic wounds has long been a serious challenge in clinical practice. Current clinical methods for treating diabetic wounds include surgical debridement, use of dressings, antibiotics, negative pressure wound therapy, and hyperbaric oxygen therapy. However, the success rate of these traditional interventions is not ideal, and only less than 50% of wounds can completely heal, and the treatment time is often long and the economic cost is high.

[0003] Enzymes, as powerful biological catalysts, are mainly composed of proteins, and a few are catalytic RNA molecules. Typical chemical catalysts or industrial catalysts are usually used in harsh conditions such as high temperature, high pressure, organic solvents, and extreme pH environment. Enzymes are mainly used to catalyze the transformation of biological molecules, and these reactions are usually carried out under relatively mild conditions. Due to high catalytic activity and high substrate specificity, natural enzymes have been widely used in industry, medicine and biology. However, natural enzymes often have some inherent shortcomings, such as high cost of preparation and purification, low operational stability, sensitivity to reaction conditions, difficulty in recovery and reuse, etc. In order to overcome these shortcomings, researchers have long been committed to the exploration of artificial enzymes. Nanoenzymes are a kind of nanomaterials similar to the reaction mechanism of natural enzymes, with the advantages of low cost, high stability and good durability. Based on the above excellent performance, nanoenzymes have been widely used in the fields of biosensing, environmental therapy, disease diagnosis and treatment, antibacterial agents, cell protection of intracellular biological molecules, etc. For example, Chinese patent CN111939270A discloses a double-nanoenzyme antibacterial agent with sustained antibacterial effect and a preparation method thereof, the antibacterial agent has GOx-POD cascade activity and antibacterial ability; Chinese patent CN117772250A discloses a single-atom nanoenzyme based on a red blood cell template, a preparation method and application thereof, the single-atom nanoenzyme has significant antibacterial performance; Chinese patent CN117462604A discloses a nanometer enzyme of Chinese plum charcoal for promoting wound healing and its application. However, the nanoenzymes prepared by the above prior art all lack hypoglycemic effect, and their treatment ability for diabetic wounds is limited, and their preparation method is complex and difficult to mass-produce. Persistent bacterial infection and local high glucose level are problems that need to be solved in the treatment of diabetic wounds. At the same time, a treatment method with low cost and simple preparation and application is more likely to be applied. However, the current nanoenzyme materials cannot meet the above requirements at the same time. Therefore, it is a technical problem to be solved in the prior art to provide a nanoenzyme preparation method that can simultaneously exert antibacterial and hypoglycemic effects on diabetic wounds and has a simple preparation process. SUMMARY

[0004] The application aims to provide an antibacterial hydrogel loaded with gold-iron phosphorus trisulfide nanosheets and a preparation method and application thereof.

[0005] To achieve the above-mentioned application purposes, the application provides the following technical solutions.

[0006] The application provides a preparation method of an antibacterial hydrogel loaded with gold-iron phosphorus trisulfide nanosheets, comprising the following steps:

[0007] (1) dispersing FePS3 crystals in N-methylpyrrolidone, sequentially performing first ultrasonic treatment and first post-treatment to obtain FePS3 nanosheets;

[0008] The FePS3 nanosheets are prepared into a water dispersion of FePS3 nanosheets;

[0009] (2) mixing the water dispersion of FePS3 nanosheets obtained in the step (1) and polyvinylpyrrolidone, then adding HAuCl4·3H2O and NaBH4, sequentially performing second ultrasonic treatment and second post-treatment to obtain Au-FePS3 nanosheets;

[0010] (3) adding a sodium periodate solution into a dextran solution, performing a redox reaction under room temperature and light-shielding conditions, then sequentially performing dialysis, low-temperature standing and freeze-drying to obtain oxidized dextran;

[0011] (4) preparing the Au-FePS3 nanosheets obtained in the step (2) into an aqueous solution of Au-FePS3 nanosheets;

[0012] The oxidized dextran obtained in the step (3) is prepared into an aqueous solution of oxidized dextran;

[0013] The aqueous solution of Au-FePS3 nanosheets, the aqueous solution of oxidized dextran, an aqueous solution of quaternary ammonium salt chitosan and water are mixed, and stirring and standing are sequentially performed to obtain the antibacterial hydrogel loaded with gold-iron phosphorus trisulfide nanosheets.

[0014] Preferably, the concentration of the water dispersion of FePS3 nanosheets in the step (1) is 0.1-0.5 mg / mL.

[0015] Preferably, the ratio of the volume of the water dispersion of FePS3 nanosheets to the mass of polyvinylpyrrolidone in the step (2) is 10 mL:(0.3-1) g.

[0016] Preferably, the mass ratio of the FePS3 nanosheets in the aqueous dispersion of the FePS3 nanosheets to the molar amount of HAuCl4·3H2O and NaBH4 in the step (2) is 1 mg:(2×10 -3 ~8×10 -3 ) mmol:(2×10 -3 ~8×10 -3 ) mmol.

[0017] Preferably, the molar ratio of the dextran monomer in the dextran solution to the sodium periodate in the sodium periodate solution in the step (2) is 1:(1~2).

[0018] Preferably, the concentration of the Au-FePS3 nanosheets in the aqueous solution of the Au-FePS3 nanosheets in the step (4) is 0.5~2 mg / mL; and the concentration of the quaternary ammonium salt chitosan in the aqueous solution of the quaternary ammonium salt chitosan is 5~10 wt%.

[0019] Preferably, the temperature for standing in the step (4) is 25~37℃, and the standing time is 2~10 min.

[0020] Preferably, the concentration of the quaternary ammonium salt chitosan-oxidized dextran hydrogel in the gold-iron phosphorus trisulfide nanosheet loaded antibacterial hydrogel in the step (4) is 3~7 wt%.

[0021] The application further provides the gold-iron phosphorus trisulfide nanosheet loaded antibacterial hydrogel prepared by the preparation method.

[0022] The application further provides the application of the gold-iron phosphorus trisulfide nanosheet loaded antibacterial hydrogel in the preparation of a drug for treating diabetic wounds.

[0023] This invention provides a method for preparing an antibacterial hydrogel loaded with gold-iron-phosphorus trisulfide nanosheets. First, Au-FePS3 nanosheets are prepared and loaded onto a quaternary ammonium chitosan (QC)-oxidized dextran (OD) hydrogel (referred to as QC-OD hydrogel). The Au-FePS3 nanosheets possess both the peroxidase (GOx) activity of Au nanoparticles and the peroxidase (POD) activity and photothermal properties of FePS3. Simultaneously, GOx and POD exhibit cascade catalytic activity, which can further generate reactive oxygen species, primarily ·OH, enabling simultaneous antibacterial and hypoglycemic effects on diabetic wounds. The QC-OD hydrogel exhibits antibacterial, hemostatic, moisturizing, and sustained-release effects, further promoting wound healing, and is biodegradable and injectable. Furthermore, loading Au-FePS3 nanosheets onto the QC-OD hydrogel prevents nanozyme aggregation during use and enhances enzyme activity. The novel nanosheet materials prepared by this invention provide a new direction for the treatment of diabetic wounds. The preparation process of Au-FePS3 nanosheets and QC-OD hydrogels is simple, rapid, and efficient, and is expected to be used in clinical treatment to improve patients' quality of life. Attached Figure Description

[0024] Figure 1 This is a TEM image of the FePS3 nanosheets prepared in Example 1 of the present invention;

[0025] Figure 2 The images shown are TEM images and lattice diagrams of the Au-FePS3 nanosheets prepared in Example 1 of this invention. From left to right, they are TEM images with a scale bar of 100 nm, 10 nm, and 5 nm, respectively, as well as the lattice diagram. In the lattice diagram, the upper image represents FePS3 and the lower image represents Au.

[0026] Figure 3 The image shows the elemental spectrum analysis of the Au-FePS3 nanosheets prepared in Example 1 of this invention. The first row, from left to right, shows the high-angle annular dark-field scanning transmission image, the Au elemental spectrum, and the Fe elemental spectrum. The second row, from left to right, shows the Merge (i.e., elemental combination) image, the P elemental spectrum, and the S elemental spectrum.

[0027] Figure 4 The image shows the XRD pattern of Au-FePS3 nanosheets prepared in Example 1 of this invention.

[0028] Figure 5 The pH changes over time for the Au-FePS3 nanosheet dispersion, glucose solution, and mixed solution containing Au-FePS3 nanosheets and glucose, as shown in the figure.

[0029] Figure 6The UV-visible absorption spectrum of the glucose solution and the mixed solution containing Au-FePS3 nanosheets and glucose of the present application;

[0030] Figure 7 The Michaelis-Menten kinetic equation graph of the glucose of different concentrations treated by Au-FePS3 nanosheets of the present application;

[0031] Figure 8 The absorbance statistics graph of PBS, H2O2 solution, Au-FePS3 nanosheet dispersion and mixed solution containing Au-FePS3 nanosheets and H2O2 at 650 nm of the present application;

[0032] Figure 9 The EPR spectrum of Au-FePS3 nanosheets and hydrogen peroxide in PBS solution of the present application;

[0033] Figure 10 The photothermal curve graph of the aqueous solution of Au-FePS3 nanosheets of different concentrations of the present application;

[0034] Figure 11 The TEM graphs of QC-OD hydrogel with concentrations of 3wt%, 5wt% and 7wt% and QC-OD@Au-FePS3 hydrogel prepared in Example 1 of the present application, wherein, from left to right, the first one is the TEM graph of QC-OD hydrogel with a concentration of 3wt%, the second one is the TEM graph of QC-OD hydrogel with a concentration of 5wt%, the third one is the TEM graph of QC-OD hydrogel with a concentration of 7wt%, and the fourth one is the TEM graph of QC-OD@Au-FePS3 hydrogel prepared in Example 1 (referred to as 5%+Au-FePS3);

[0035] Figure 12 The element mapping scanning result graph of QC-OD@Au-FePS3 hydrogel prepared in Example 1 of the present application, wherein, the first row, from left to right, is the Merge (i.e. the combination of various elements) graph, the C element graph, the O element graph and the N element graph; the second row, from left to right, is the Au element graph, the Fe element graph, the P element graph and the S element graph;

[0036] Figure 13 The rheological result graph of QC-OD hydrogel with concentrations of 3wt%, 5wt% and 7wt% (without loading Au-FePS3 nanosheets) of the present application, wherein, the left graph is the change with time, and the right graph is the change with frequency, the storage modulus is referred to as G', and the loss modulus is referred to as G";

[0037] Figure 14 The FTIR graph of QC-OD hydrogel with a concentration of 5wt% (without loading Au-FePS3 nanosheets) of the present application;

[0038] Figure 15 Fig. 11 is a graph showing the swelling rate and degradation rate of QC-OD hydrogel with concentrations of 3wt%, 5wt% and 7wt% respectively in the present application over time, wherein the left graph is the swelling rate and the right graph is the degradation rate;

[0039] Figure 16 Fig. 12 is a photograph showing the self-healing and adhesion of QC-OD hydrogel with a concentration of 5wt% in the present application, wherein the photographs from left to right are the photographs of being cut, adhering and healing within 5min respectively;

[0040] Figure 17 Fig. 13 is a photograph showing the injectability of QC-OD hydrogel with a concentration of 5wt% in the present application;

[0041] Figure 18 Fig. 14 is a photograph showing the liver of mice after treatment of blank control group, hemostatic sponge, QC-OD hydrogel with a concentration of 5wt% and QC-OD@Au-FePS3 hydrogel prepared in Example 1 in the present application, wherein the photographs from left to right are the photographs of blank control group, hemostatic sponge, QC-OD hydrogel with a concentration of 5wt% and QC-OD@Au-FePS3 hydrogel prepared in Example 1 respectively;

[0042] Figure 19 Fig. 15 is a photograph showing the wound of diabetic rats infected over time after different treatment in the present application;

[0043] Figure 20 Fig. 16 is a photograph showing the bacteriostatic effect in the wound of diabetic rats infected after different treatment in the present application, wherein the photographs from left to right are the photographs of PBS treatment, QC-OD hydrogel with a concentration of 5wt% treatment, QC-OD@Au-FePS3 hydrogel prepared in Example 1 treatment, and NIR and QC-OD@Au-FePS3 hydrogel prepared in Example 1 combined treatment respectively;

[0044] Figure 21 Fig. 17 is a flow chart of the antibacterial hydrogel loaded with gold-iron phosphorus trisulfide nanosheets prepared in Example 1 of the present application. DETAILED DESCRIPTION

[0045] The present application provides a preparation method of antibacterial hydrogel loaded with gold-iron phosphorus trisulfide nanosheets, comprising the following steps:

[0046] (1) dispersing FePS3 crystals in N-methylpyrrolidone, sequentially performing first ultrasonic treatment and first post-treatment to obtain FePS3 nanosheets;

[0047] The FePS3 nanosheets are prepared into a water dispersion of FePS3 nanosheets;

[0048] (2) mixing the water dispersion of the FePS3 nanosheets obtained in step (1) and polyvinylpyrrolidone, then adding HAuCl4.3H2O and NaBH4, and sequentially performing second ultrasonic treatment and second post-treatment to obtain Au-FePS3 nanosheets;

[0049] (3) adding a sodium periodate solution into a dextran solution to perform a gelation reaction under room temperature and light shielding conditions, then sequentially performing dialysis, low-temperature standing and freeze-drying to obtain oxidized dextran;

[0050] (4) preparing the Au-FePS3 nanosheets obtained in step (2) into an aqueous solution of Au-FePS3 nanosheets;

[0051] preparing the oxidized dextran obtained in step (3) into an aqueous solution of oxidized dextran;

[0052] mixing the aqueous solution of Au-FePS3 nanosheets, the aqueous solution of oxidized dextran, an aqueous solution of quaternary ammonium salt chitosan and water, and sequentially performing stirring and standing to obtain an antibacterial hydrogel loaded with gold-iron phosphorus trisulfide nanosheets.

[0053] In the present application, the raw materials used are all commercially available products in the art, unless otherwise specified.

[0054] In the present application, the FePS3 crystal is dispersed in N-methylpyrrolidone, and sequentially subjected to first ultrasonic treatment and first post-treatment to obtain FePS3 nanosheets.

[0055] In the present application, the particle size of the FePS3 crystal is preferably 50-200 nm.

[0056] In the present application, the concentration of the FePS3 crystal dispersion obtained by dispersing FePS3 crystal in N-methylpyrrolidone is preferably 1-7 mg / mL, and more preferably 1.5-4 mg / mL.

[0057] In the present application, the power of the first ultrasonic treatment is 500-800 W, and more preferably 600 W; the time of the first ultrasonic treatment is 12-18 h, and more preferably 13-17 h, and further preferably 15 h. The power and time of the first ultrasonic treatment are controlled in the above ranges to promote the exfoliation of FePS3 crystal.

[0058] obtaining high-quality FePS3 crystal

[0059] In the present application, the first post-treatment includes sequentially performing centrifugation, washing and drying.

[0060] In the present application, the centrifugation and washing are preferably centrifugation of the solution obtained by the first ultrasonic treatment at 4000 rpm for 10 min to remove large pieces, centrifugation of the supernatant at 14000 rpm for 30 min, centrifugation of the obtained precipitate at 14000 rpm for 30 min after washing with ethanol, collection of the precipitate, washing with water, and centrifugation of the precipitate at 14000 rpm for 30 min after washing with water. In the present application, the drying is preferably freeze-drying or drying in an oven, and more preferably freeze-drying. In the present application, the freeze-drying is preferably drying in a freeze dryer at a temperature of less than -80℃ and an air pressure of less than 3.0 pa for 72 h after freezing the precipitate obtained by centrifugation at -20℃ for 12 h.

[0061] In the present application, the lateral diameter of the FePS3 nanosheet is preferably 50-200 nm, and more preferably 100 nm. The present application controls the lateral diameter of the FePS3 nanosheet in the above range to improve the enzyme activity and photothermal properties of the Au-FePS3 nanosheet prepared subsequently per unit mass, thereby improving the therapeutic effect of the antibacterial hydrogel prepared finally on a diabetic wound surface.

[0062] After obtaining the FePS3 nanosheet, the present application prepares a water dispersion of the FePS3 nanosheet.

[0063] In the present application, the concentration of the water dispersion of the FePS3 nanosheet is preferably 0.1-0.5 mg / mL. The present application controls the concentration of the water dispersion of the FePS3 nanosheet in the above range to regulate the size uniformity of the Au-FePS3 nanosheet prepared subsequently, improve the enzyme activity and photothermal properties of the Au-FePS3 nanosheet, and thereby improve the therapeutic effect of the antibacterial hydrogel prepared finally on a diabetic wound surface.

[0064] After obtaining the water dispersion of the FePS3 nanosheet, the present application mixes the water dispersion of the FePS3 nanosheet and polyvinylpyrrolidone, and then adds HAuCl4·3H2O and NaBH4 to obtain Au-FePS3 nanosheets by sequentially performing second ultrasonic treatment and second post-treatment.

[0065] In the present application, the ratio of the volume of the water dispersion of the FePS3 nanosheet to the mass of polyvinylpyrrolidone is preferably 10 mL:(0.3-1) g, more preferably 10 mL:(0.4-0.7) g, and further preferably 10 mL:0.6 g. In the present application, the mixing method of the water dispersion of the FePS3 nanosheet and polyvinylpyrrolidone is preferably ultrasonic dispersion at a power of 400 W for 20-50 min.

[0066] In the present application, the mass ratio of FePS3 nanosheets in the aqueous dispersion of the FePS3 nanosheets to the molar amount of HAuCl4·3H2O and NaBH4 is preferably 1 mg:(2×10 -3 ~ 8×10 -3 ) mmol:(2×10 -3 ~ 8×10 -3 ) mmol, more preferably 1 mg:(4×10 -3 ~ 7×10 -3 ) mmol:(4×10 -3 ~ 7×10 -3 ) mmol. In the present application, the molar ratio of HAuCl4·3H2O to NaBH4 is preferably 1:1.

[0067] In the present application, the time of the second ultrasonic treatment is preferably 20-50 min; the power of the second ultrasonic treatment is preferably 400 W. In the present application, the second post-treatment preferably comprises centrifugation, water washing and drying. In the present application, the centrifugation and washing are preferably centrifugation at 14000 rpm for 30 min, and then the obtained precipitate is washed with water and centrifuged at 14000 rpm for 30 min, and the precipitate is collected. In the present application, the drying is preferably freeze-drying or oven drying, more preferably freeze-drying. In the present application, the freeze-drying is preferably freeze-drying of the precipitate obtained by centrifugation at -20℃ for 24 h, and then drying in a freeze dryer at a gas pressure < 3.0 pa and a temperature < -80℃ for 72 h.

[0068] In the present application, the lateral diameter of the Au-FePS3 nanosheets is preferably 150-300 nm, more preferably 200 nm. In the present application, the diameter of the Au nanoparticles on the Au-FePS3 nanosheets is preferably 1-10 nm, more preferably 2-5 nm.

[0069] In the present application, the sodium periodate aqueous solution is added to the dextran solution, and a gelation reaction is carried out at room temperature in the dark, and then dialysis, low-temperature standing and freeze-drying are sequentially carried out to obtain oxidized dextran.

[0070] In the present application, the concentration of sodium periodate in the sodium periodate aqueous solution is preferably 80-120 g / L, more preferably 100 g / L. In the present application, the molar ratio of dextran monomers in the dextran solution to sodium periodate in the sodium periodate solution is preferably 1:(1-2), more preferably 1:1.5. The present application controls the molar ratio of dextran monomers in the dextran solution to sodium periodate in the sodium periodate solution in the above range to improve the toughness of the hydrogel prepared subsequently.

[0071] In the present application, the time of the gelation reaction is preferably 4-8 h, more preferably 6 h. In the present application, the dialysis is preferably dialysis for 2-4 days using a dialysis bag with a molecular weight cut-off (MwCO) of 3500, and the dialysis solution is replaced every day until the dialysis solution remains clear and colorless after dialysis for 1 day. In the present application, the low-temperature standing is preferably standing at -80℃ for 1 day, and in the present application, the freeze-drying is preferably drying in a freeze dryer at a pressure of ≤3.0 pa and a temperature of ≤-80℃ for 72 h.

[0072] After obtaining the Au-FePS3 nanosheets, the present application prepares an aqueous solution of Au-FePS3 nanosheets from the Au-FePS3 nanosheets.

[0073] In the present application, the concentration of Au-FePS3 nanosheets in the aqueous solution of Au-FePS3 nanosheets is preferably 0.5-2 mg / mL, more preferably 0.8-1.5 mg / mL.

[0074] After obtaining the oxidized dextran, the present application prepares an aqueous solution of oxidized dextran from the oxidized dextran.

[0075] In the present application, the concentration of oxidized dextran in the aqueous solution of oxidized dextran is preferably 5-10 wt%, more preferably 7 wt%.

[0076] After obtaining the aqueous solution of Au-FePS3 nanosheets and the aqueous solution of oxidized dextran, the present application mixes the aqueous solution of Au-FePS3 nanosheets, the aqueous solution of oxidized dextran, the aqueous solution of quaternary ammonium salt chitosan, and water, and sequentially stirs and stands to obtain an antibacterial hydrogel loaded with gold-iron phosphorus trisulfide nanosheets.

[0077] In the present application, the concentration of quaternary ammonium salt chitosan in the aqueous solution of quaternary ammonium salt chitosan is preferably 5-10 wt%, more preferably 7 wt%.

[0078] In the present application, the stirring speed is preferably 100-150 rpm, more preferably 120 rpm; the stirring time is preferably 10 s-1 min, more preferably 0.5 min. In the present application, the standing temperature is preferably 25-37℃; the standing time is preferably 2-10 min. The present application controls the conditions of stirring and standing in the above ranges, which is conducive to gelation and obtaining an antibacterial hydrogel loaded with gold-iron phosphorus trisulfide nanosheets with good comprehensive performance.

[0079] In the present application, the concentration of quaternary ammonium salt chitosan-oxidized dextran hydrogel in the antibacterial hydrogel loaded with gold-iron phosphorus trisulfide nanosheets is preferably 3-7 wt%, more preferably 5 wt%.

[0080] The Au-FePS3 nanosheet provided by the application has the advantages of simple preparation method, low cost, and the like, and is expected to be used for industrial production; the QC-OD hydrogel has the advantages of easy availability of raw materials, simple preparation method, and the like, and can be prepared in a large amount at a time; the ultra-high specific surface area of the FePS3 nanosheet prepared by the application is beneficial to loading of Au nanoparticles, and can promote a surface / interface-mediated POD catalytic reaction process, and meanwhile, the use of the QC-OD hydrogel for loading avoids agglomeration of the nanoscale enzyme, and further ensures enzymatic reaction activity; the Au-FePS3 nanosheet prepared by the application can consume local glucose, and relieve oxidative stress, blood vessel and nerve lesions caused by a high-sugar environment.

[0081] The application further provides an antibacterial hydrogel loaded with gold-iron phosphorus trisulfide nanosheets and prepared by the preparation method in the above technical solution.

[0082] The antibacterial hydrogel loaded with gold-iron phosphorus trisulfide nanosheets in the application can generate ROS through GOx-POD cascade activity of the Au-FePS3 nanosheet, and cooperatively resist bacteria in combination with photothermal therapy and a quaternary ammonium salt group in the QC-OD hydrogel, so as to solve the problem of infection, wherein the quaternary ammonium salt group endows chitosan with solubility, and the negatively charged characteristic can adsorb bacteria and increase permeability of a bacterial membrane, on this basis, ROS generated by the activity of the POD can more easily enter the bacteria and play an antibacterial performance, and further generate a synergistic antibacterial effect; the local thermotherapy mediated by the Au-FePS3 nanosheet can promote local blood circulation of a wound, and further increase oxygen supply, improve a hypoxic microenvironment, and promote proliferation and migration of fibroblasts and vascular endothelial cells, and promote wound healing; and the QC-OD hydrogel has the functions of antibacterial, hemostatic, moisturizing, and sustained release of a load, and degradability and injectability.

[0083] The application further provides application of the antibacterial hydrogel loaded with gold-iron phosphorus trisulfide nanosheets in the above technical solution in preparation of a drug for treating a diabetic wound.

[0084] The technical solutions in the application will be clearly and completely described below by combining with the embodiments in the application. Obviously, the described embodiments are only some of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by a person of ordinary skill in the art without creative labor fall within the protection scope of the application.

[0085] Embodiment 1

[0086] A preparation method of an antibacterial hydrogel loaded with gold-iron phosphorus trisulfide nanosheets, comprising the following steps:

[0087] (1) 100 mg of FePS3 crystals were dispersed in 50 mL of N-methylpyrrolidone (NMP, AR, >99.0%) and then subjected to first ultrasonic treatment in an ice bath at a power of 600 W for 15 h, with an ultrasonic working time of 5 s and an interval of 3 s. The solution obtained by the first ultrasonic treatment was centrifuged at 4000 rpm for 10 min to remove large pieces, and then the supernatant was centrifuged at 14000 rpm for 30 min. The obtained precipitate was washed with ethanol and then centrifuged at 14000 rpm for 30 min. The precipitate was collected and washed with water and then centrifuged at 14000 rpm for 30 min. The precipitate was collected. The precipitate was frozen at -20 °C for 12 h and then dried in a freeze dryer at a pressure of <3.0 pa and a temperature of <-80 °C for 72 h to obtain 35 mg of FePS3 nanosheets;

[0088] 4 mg of FePS3 nanosheets were dispersed in 40 mL of water to obtain a water dispersion of FePS3 nanosheets;

[0089] (2) 2.4 g of polyvinylpyrrolidone was added to the water dispersion of FePS3 nanosheets obtained in step (1) and ultrasonically dispersed for 30 min. Then, 2 mL of HAuCl4·3H2O (10 mM) and 2 mL of NaBH4 (10 mM) were added, and second ultrasonic treatment was performed at 400 W for 30 min. The solution obtained by the second ultrasonic treatment was centrifuged at 14000 rpm for 30 min. The obtained precipitate was washed with water and then centrifuged at 14000 rpm for 30 min. The precipitate was collected. The precipitate was frozen at -20 °C for 24 h and then dried in a freeze dryer at a pressure of 2.0 pa and a temperature of -80 °C for 72 h to obtain 5 mg of Au-FePS3 nanosheets;

[0090] (3) 10 g of dextran was dissolved in 100 mL of deionized water to obtain a dextran solution. A sodium periodate solution with a concentration of 100 g / L was prepared by mixing sodium periodate with a molar ratio of 1:1.5. The above sodium periodate solution was added to the dextran solution, and a gelation reaction was carried out at room temperature in the dark for 6 h. Then, 2 mL of ethylene glycol was added to terminate the reaction. The dialysis bag with a molecular weight cut-off (MwCO) of 3500 was used for dialysis, and the dialysis liquid was changed every day. On the third day, the dialysis liquid was clear and colorless. The dialysis solution was placed in a refrigerator at -80 °C for 1 day and then freeze-dried to obtain white oxidized dextran;

[0091] (4) The Au-FePS3 nanosheets obtained in step (2) were prepared into an aqueous solution of Au-FePS3 nanosheets with a concentration of 1 mg / mL;

[0092] The oxidized dextran obtained in step (3) was prepared into an aqueous solution of oxidized dextran with a concentration of 7 wt% of oxidized dextran;

[0093] 200 μL of the aqueous solution of Au-FePS3 nanosheets, 357 μL of the aqueous solution of oxidized dextran, 357 μL of the aqueous solution of quaternary ammonium chitosan with a concentration of 7 wt%, and 86 μL of deionized water were mixed and stirred at 120 rpm for 0.5 min, and then allowed to stand at 37 °C for 5 min to obtain 1 mL of antibacterial hydrogel loaded with gold-iron-phosphorus trisulfide nanosheets (abbreviated as QC-OD@Au-FePS3 hydrogel);

[0094] The concentration of QC-OD hydrogel in the antibacterial hydrogel loaded with gold-iron-phosphorus trisulfide nanosheets is 5 wt%.

[0095] Figure 21 This is a flowchart illustrating the preparation of an antibacterial hydrogel loaded with gold-iron-phosphorus trisulfide nanosheets in Example 1 of the present invention.

[0096] The TEM images of the FePS3 nanosheets prepared in Example 1 were obtained using a Talos F200S TEM scanner and a Thermo Fisher Scientific (USA) as shown below. Figure 1 As shown. By Figure 1 It can be seen that the FePS3 nanosheets prepared in Example 1 have a lateral diameter of 100 nm.

[0097] TEM images and lattice diagrams of the Au-FePS3 nanosheets prepared in Example 1 were obtained using a Talos F200S TEM scanner and Thermo Fisher Scientific (USA). Figure 2 As shown. By Figure 2 It can be seen that the Au-FePS3 nanosheets prepared in Example 1 have a lateral diameter of 200 nm, wherein Au nanoparticles are uniformly dispersed on the nanosheets with a diameter of 2-5 nm. The formation of Au and FePS3 lattice is visible, indicating that its microscopic physical structure is well preserved.

[0098] The elemental spectrum analysis of the Au-FePS3 nanosheets prepared in Example 1, obtained using a Talos F200S and Thermo Fisher Scientific (USA), is shown below. Figure 3 As shown. By Figure 3 Strong signals of Au, Fe, P, and S elements were observed, demonstrating the good elemental distribution of the Au-FePS3 nanosheets prepared in Example 1, and their affinity for... Figure 2 The observations were consistent.

[0099] The XRD pattern of the Au-FePS3 nanosheets prepared in Example 1 was obtained using SmartLab, Rigaku (Japan), as shown below. Figure 4 As shown, by Figure 4It can be seen that by comparison with the pure phase XRD pattern, the phase of the sample is preliminarily confirmed (PDF #02-1095, PDF #33-0672), indicating that the Au-FePS3 nanosheets prepared in Example 1 are composed of Au and Fe2P2S6.

[0100] Activity identification of Au-FePS3 nanosheets prepared in Example 1 (i.e. GOx / POD enzyme)

[0101] The detection method is: respectively prepare Au-FePS3 nanosheet (prepared in Example 1) dispersion solution with a concentration of 0.20 mg / mL, 40 mM glucose solution, and mixed solution of Au-FePS3 nanosheet (prepared in Example 1) with a concentration of 0.20 mg / mL and glucose with a concentration of 40 mM. The pH value of the above different solutions is detected over time, and the pH value is used to indicate the formation of gluconic acid. The pH change over time of Au-FePS3 nanosheet dispersion solution, glucose solution and mixed solution containing Au-FePS3 nanosheet and glucose is shown in Figure 5 Figure 5 It can be seen that the significant decrease of the pH of the mixed solution indicates the formation of gluconic acid, indicating that the Au-FePS3 nanosheet can decompose glucose and generate gluconic acid.

[0102] UV-visible absorption spectrum of different reaction solutions

[0103] Detection method two: using glucose detection kit, respectively detecting the glucose concentration in 40 mM glucose solution and mixed solution of Au-FePS3 nanosheet (prepared in Example 1) with a concentration of 0.20 mg / mL and glucose with a concentration of 40 mM. The UV-visible absorption spectrum of glucose solution and mixed solution containing Au-FePS3 nanosheet and glucose is shown in Figure 6 Figure 6 It can be seen that the significant decrease of the absorbance of the mixed solution indicates the decrease of the glucose concentration, indicating that the Au-FePS3 nanosheet prepared in Example 1 can decompose glucose.

[0104] And the prior art Chinese patent CN118477099A discloses an AuNPs@MOF nanoenzyme, which lacks antibacterial effect and cannot solve the problem of infection in diabetic wound, and the technical scheme does not quantify the GOx enzyme activity. In the present application, the GOx enzyme activity is quantified.

[0105] Michaelis-Menten kinetic analysis of Au-FePS3 nanosheet prepared in Example 1 with glucose as substrate

[0106] ​​Detection method: in the presence of 0.20 mg / mL Au-FePS3 nanosheets (prepared in Example 1) in glucose concentration of 2.5, 5, 10, 20, 50 and 100 mM solution, the glucose concentration after 1 min was measured, and the corresponding Michaelis-Menten kinetic equation was calculated with glucose as substrate. The Michaelis-Menten kinetic equation graph of different concentrations of glucose after Au-FePS3 nanosheets treatment is shown in Figure 7 As shown in Figure 7 The Au-FePS3 nanosheets prepared in Example 1 have good GOx catalytic activity.

[0107] Absorbance detection method of different reaction solutions at 650 nm: four groups of different reaction solutions were prepared and added into four 1.5 mL centrifuge tubes, respectively. In the PBS group, 490 uL of PBS (pH = 7.4) and 10 uL of TMB (10 mg / mL) were added; in the H2O2 group, 440 uL of PBS (pH = 7.4), 10 uL of TMB (10 mg / mL) and 50 uL of H2O2 solution (0.1 M) were added; in the Au-FePS3 group, 480 uL of PBS (pH = 7.4), 10 uL of TMB (10 mg / mL) and 10 uL of Au-FePS3 nanosheet (prepared in Example 1) dispersion solution (10 mg / mL) were added; in the Au-FePS3+H2O2 group, 430 uL of PBS (pH = 7.4), 10 uL of TMB (10 mg / mL), 50 uL of H2O2 solution (0.1 M) and 10 uL of Au-FePS3 nanosheet (prepared in Example 1) dispersion solution (10 mg / mL) were added. After 10 s of reaction of different reaction solutions in the centrifuge tubes, they were centrifuged at 12000 rpm for 5 min, and the supernatant was added into a 96-well plate to detect the absorbance at 650 nm. The absorbance statistical graph of PBS, H2O2 solution, Au-FePS3 nanosheet dispersion solution (i.e. Au-FePS3 group) and mixed solution containing Au-FePS3 nanosheet and H2O2 (i.e. Au-FePS3+H2O2 group) at 650 nm is shown in Figure 8 As shown in Figure 8 It can be seen that the Au-FePS3 nanosheets prepared in Example 1 can mediate the color development reaction of TMB, proving that they have POD catalytic activity.

[0108] EPR spectrum of Au-FePS3 nanosheets prepared in Example 1 and hydrogen peroxide in PBS solution

[0109] Detection method: DMPO was used as the capture agent, and the detection was performed in the dark environment for 1 min. The equipment used was a German Bruker EMXplus-6 / 1, and the EPR spectrum of Au-FePS3 nanosheets and hydrogen peroxide in PBS solution was obtained as shown in Figure 9 . As can be seen from Figure 9 , the EPR spectrum proves that the Au-FePS3 nanosheets prepared in Example 1 mainly produce ROS in the form of ·OH in the catalysis of H2O2.

[0110] Photothermal ability identification of Au-FePS3 nanosheets prepared in Example 1

[0111] Detection method: Different concentrations of Au-FePS3 nanosheet (0, 0.05, 0.10, 0.20 mg / mL) solution was irradiated under laser with a wavelength of 808 nm and a power of 0.8 W / cm 2 for 5 minutes, and the real-time temperature was recorded. The photothermal curve of the aqueous solution of Au-FePS3 nanosheets with different concentrations is shown in Figure 10 . As can be seen from Figure 10 , the Au-FePS3 nanosheets prepared in Example 1 have excellent photothermal ability, and the photothermal temperature can be adjusted by the concentration of the material.

[0112] And the prior art Chinese patent CN117772250A discloses a single-atom nano-enzyme based on a red blood cell template, a preparation method and application thereof, but the photothermal temperature of the single-atom nano-enzyme based on the red blood cell template can reach 70℃, which can cause damage to human tissues. The prior art CN117772250A does not explore the adjustability of the photothermal ability of the nano-enzyme. The photothermal temperature of the Au-FePS3 nanosheets prepared in the present application is suitable and will not cause damage to the human body. At the same time, the present application explores the photothermal characteristics under different concentrations of Au-FePS3 nanosheet solution and different NIR power.

[0113] Characterization of QC-OD@Au-FePS3 hydrogel prepared in Example 1

[0114] Detection method: QC-OD hydrogels with concentrations of 3wt%, 5wt%, and 7wt% (without loading Au-FePS3 nanosheets) were prepared according to the method of Example 1. Sigma 300 (Carl Zeiss AG, Germany) was used to detect the TEM images of QC-OD hydrogels with concentrations of 3wt%, 5wt%, and 7wt% and QC-OD@Au-FePS3 hydrogel prepared in Example 1, as shown in Figure 11 . As can be seen from Figure 11It can be seen that QC-OD hydrogels of different concentrations all have a loose and porous structure and the ability to load nanozymes Au-FePS3. In the QC-OD@Au-FePS3 hydrogel prepared in Example 1, Au-FePS3 is uniformly distributed in the pores of the QC-OD hydrogel.

[0115] The elemental spectrum of the QC-OD@Au-FePS3 hydrogel prepared in Example 1, obtained by using a Sigma 300 (Carl Zeiss AG, Germany), is shown in Figure 12. Figure 12 It can be seen that the Au-FePS3 nanosheets are uniformly distributed in the hydrogel network in the QC-OD@Au-FePS3 hydrogel prepared in Example 1.

[0116] Rheological results of QC-OD hydrogels at different concentrations

[0117] Testing Methods: QC-OD hydrogels (without Au-FePS3 nanosheets) prepared by the above method at concentrations of 3 wt%, 5 wt%, and 7 wt% were tested using a Mars40 rheometer (Haake Technik GmbH, Germany) in parallel plate mode. During the time-scan, strain and frequency were fixed at 1% and 1 Hz, respectively. During the frequency-scan, strain was fixed at 1%. The rheological results of QC-OD hydrogels (without Au-FePS3 nanosheets) at concentrations of 3 wt%, 5 wt%, and 7 wt% are shown in the figure below. Figure 13 As shown, where Figure 13 The right-middle figure shows a rheological frequency scan. Figure 13 The left-middle image shows the rheological time scan. (From...) Figure 13 It can be seen that the QC-OD hydrogel exhibits suitable storage modulus (G') and loss modulus (G”), which is consistent with the characteristics of hydrogels.

[0118] FTIR results of QC-OD hydrogel

[0119] Detection method: The FTIR spectrum of 5 wt% QC-OD hydrogel (without Au-FePS3 nanosheets) was obtained using a Nicolet iS20 (Thermo Fisher Scientific, USA). Figure 14 As shown, by Figure 14 As can be seen, FTIR further confirms the formation of QC-OD hydrogel. The QC-OD hydrogel forms at 1652 cm⁻¹. -1 The peak at 3430 cm⁻¹ indicates a carbon-nitrogen double bond, confirming the formation of a Schiff bond. The remaining peaks correspond to the individual monomers. -1 The peak at 2921 cm⁻¹ corresponds to the stretching vibration of OH. -1 and 1480cm -1The peaks correspond to the asymmetric stretching and bending vibrations of -CH2 in quaternary ammonium chitosan, respectively, at 1379 cm⁻¹. -1 The peak corresponds to the bending vibration of -CHO in oxidized dextran, 1069 cm⁻¹ -1 The peak corresponds to the stretching vibration of CO.

[0120] Swelling and degradation rates of QC-OD hydrogels at different concentrations

[0121] Detection method: Swelling: QC-OD hydrogels (without Au-FePS3 nanosheets) with concentrations of 3wt%, 5wt%, and 7wt% prepared above were immersed in 1mL of PBS. They were weighed at specific time points (0, 1, 2, 4, 6, 8, 10, 12, 16, and 24h). Before measuring the weight of the hydrogel samples, surface moisture was removed. The swelling rate was calculated using the following formula:

[0122]

[0123] Where W0 is the initial weight of the hydrogel sample, and Wn is the weight of the hydrogel sample after n hours.

[0124] Degradation: The QC-OD hydrogels (without Au-FePS3 nanosheets) prepared above at concentrations of 3wt%, 5wt%, and 7wt% were immersed in 1mL of PBS, respectively. They were removed at specific time points (0, 4, 8, 12, 16, 24, 48, and 72h), lyophilized, and weighed. The degradation rate was calculated using the following formula:

[0125]

[0126] Where Wd0 is the initial dry weight of the hydrogel sample, and Wdn is the dry weight of the hydrogel sample after n hours.

[0127] The swelling rate and degradation rate of QC-OD hydrogels with concentrations of 3wt%, 5wt%, and 7wt% obtained above are shown in the figure below. Figure 15 As shown, by Figure 15 It can be seen that the QC-OD hydrogel swells rapidly on the first day and reaches an equilibrium state in 4–6 days. By day 9, the 3 wt% QC-OD hydrogel is almost completely degraded, while the 5 wt% and 7 wt% hydrogels are mostly degraded.

[0128] Self-healing and adhesion of QC-OD hydrogel

[0129] Test method: A piece of 5wt% QC-OD hydrogel was cut open and then adhered together. After 5 minutes, it was lifted and the healing process was observed. The self-healing and adhesion properties of the 5wt% QC-OD hydrogel were obtained as shown in the following image.Figure 16 As shown in Figure 16 It can be seen that the QC-OD hydrogel has self-healing and adhesion.

[0130] Injectability of QC-OD hydrogel

[0131] Detection method: QC-OD hydrogel with a concentration of 5wt% was loaded into a 1mL syringe and pushed out, and the injectability of QC-OD hydrogel with a concentration of 5wt% was obtained. The actual picture is as shown in Figure 17 As shown in Figure 17 It can be seen that the QC-OD hydrogel has injectability.

[0132] Hemostatic ability of QC-OD@Au-FePS3 hydrogel prepared in Example 1

[0133] Detection method: SD rats were anesthetized with 10mL / kg 4wt% chloral hydrate and fixed on the surgical pad, and the mouse liver was exposed through the abdominal incision, and the pre-weighed filter paper was placed on the paraffin film and placed under the liver; a needle of a 1mL syringe was used to form a bleeding point on the liver, and then QC-OD hydrogel with a concentration of 5wt%, or QC-OD@Au-FePS3 hydrogel prepared in Example 1 was immediately placed on the bleeding point, and a blank control group without any treatment was set, and the weight of the filter paper after absorbing blood was measured after 3min. The actual picture of the mouse liver after treatment of the blank control group, hemostatic sponge, QC-OD hydrogel with a concentration of 5wt%, and QC-OD@Au-FePS3 hydrogel prepared in Example 1 is as shown in Figure 18 As shown in Figure 18 It can be seen that the QC-OD@Au-FePS3 hydrogel prepared in Example 1 has good hemostatic ability.

[0134] Animal experiment: healing of infected wounds of diabetic rats under different treatments.

[0135] Detection method: Sprague-Dawley rats (6 weeks) were from Wuhan Mabell Biosciences Co., Ltd., China, and were approved for use by the Animal Research Ethics Committee of Tongji Medical College, Huazhong University of Science and Technology. Induction of diabetes: the rats were first fed with high-fat food for four weeks, and then intraperitoneally injected with streptozotocin (50mg / kg, Sigma, USA) every day for three days. The fasting blood glucose level was continuously detected for three times, and it was confirmed to be diabetic when it was higher than 11.1mmol / L. Skin wound modeling and healing: under sodium pentobarbital anesthesia (50mg / kg), a full-thickness wound (diameter 15mm) was made on the back of the rat with a sharp circular punch. The wound was treated with 100μL of Staphylococcus aureus suspension (3×10 8The above diabetic rats infected wounds were treated with PBS, QC-OD hydrogel with a concentration of 5wt%, QC-OD@Au-FePS3 hydrogel prepared in Example 1, and NIR and QC-OD@Au-FePS3 hydrogel prepared in Example 1, respectively, for 10 minutes. The real-time images of the diabetic rats infected wounds after different treatment over time are shown in Figure 19 As can be seen from the above, Figure 19 The QC-OD@Au-FePS3 hydrogel prepared in Example 1 can promote the healing of the infected wounds of diabetic rats, and the treatment of QC-OD hydrogel, Au-FePS3 nanosheet and NIR has a synergistic effect.

[0136] In addition, the treatment of the single-atom nanoscale enzyme based on the red blood cell template disclosed in the prior art Chinese patent CN117772250A requires additional provision of hydrogen peroxide to generate ROS to exert antibacterial and therapeutic effects. The Au-FePS3 nanosheet prepared in the present application has GOx-POD cascade catalytic activity, which can directly decompose glucose in the local diabetic wound to produce hydrogen peroxide and further produce ROS to exert antibacterial ability.

[0137] Detection of antibacterial effect of different treatments in diabetic rat infected wounds

[0138] Detection method: On the 3rd day of the above animal experiment, the wound tissue was collected and soaked in 1ml of PBS, and then 100ul of suspension was smeared on the agar plate and cultured at 37℃ for 24h. The antibacterial effect of diabetic rat infected wounds after different treatment is shown in Figure 20 As can be seen from the above, Figure 20 The QC-OD@Au-FePS3 hydrogel prepared in Example 1 has excellent antibacterial ability, and the antibacterial ability of quaternary ammonium salt group (QC-OD hydrogel), ROS (GOx-POD cascade activity) and photothermal effect (NIR treatment) has a synergistic effect.

[0139] Example 2

[0140] A preparation method of an antibacterial hydrogel loaded with gold-iron phosphorus trisulfide nanosheet, comprising the following steps:

[0141] (1) 100 mg of FePS3 crystals were dispersed in 25 mL of N-methylpyrrolidone (NMP, AR, >99.0%) and then subjected to first ultrasonic treatment in an ice bath at a power of 800 W for 12 h, with an ultrasonic working time of 5 s and an interval of 3 s. The solution obtained by the first ultrasonic treatment was centrifuged at 4000 rpm for 10 min to remove large pieces, and then the supernatant was centrifuged at 14000 rpm for 30 min. The obtained precipitate was washed with ethanol and then centrifuged at 14000 rpm for 30 min, and the precipitate was collected. The precipitate was washed with water and then centrifuged at 14000 rpm for 30 min, and the precipitate was collected. The precipitate was frozen at -20 °C for 24 h, and then dried in a freeze dryer at a pressure of 2.0 pa and a temperature of -80 °C for 72 h, to obtain 30 mg of FePS3 nanosheets;

[0142] 10 mg of FePS3 nanosheets were dispersed in 40 mL of water to obtain a water dispersion of FePS3 nanosheets;

[0143] (2) 2.4 g of polyvinylpyrrolidone was added to the water dispersion of FePS3 nanosheets obtained in step (1), and ultrasonic dispersion was performed for 30 min. Then, 2.5 mL of HAuCl4·3H2O (20 mM) and 2.5 mL of NaBH4 (20 mM) were added, and second ultrasonic treatment was performed at 300 W for 30 min. The solution obtained by the second ultrasonic treatment was centrifuged at 14000 rpm for 30 min, and the obtained precipitate was washed with water and then centrifuged at 14000 rpm for 30 min. The precipitate was collected and dried in an oven at 37 °C to obtain 13 mg of Au-FePS3 nanosheets;

[0144] (3) 5 g of dextran was dissolved in 50 mL of deionized water to obtain a dextran solution. A 100 g / L aqueous solution of sodium periodate was prepared according to a molar ratio of dextran monomer to sodium periodate of 1:1.5. The above-mentioned sodium periodate solution was added to the dextran solution, and a gelation reaction was carried out at room temperature in the dark for 8 h. Then, 2 mL of ethylene glycol was added dropwise to terminate the reaction. Dialysis was performed using a dialysis bag with a molecular weight cut-off (MwCO) of 3500, and the dialysis solution was changed every day. On the third day, the dialysis solution was clear and colorless. The dialysis solution was placed in a refrigerator at -80 °C for 1 day, and then freeze-dried to obtain a white product, oxidized dextran;

[0145] (4) The Au-FePS3 nanosheets obtained in step (2) were prepared into an aqueous solution of Au-FePS3 nanosheets with a concentration of 1 mg / mL;

[0146] The oxidized dextran obtained in step (3) was prepared into an aqueous solution of oxidized dextran with a concentration of 7 wt% of oxidized dextran;

[0147] Mix 200 uL of the Au-FePS3 nanosheet aqueous solution, 357 uL of the oxidized dextran aqueous solution, 357 uL of the quaternary ammonium salt chitosan aqueous solution with a concentration of 7 wt% of quaternary ammonium salt chitosan, and 86 uL of deionized water, stir at 120 rpm for 1 min, and then stand at 25℃ for 5 min to obtain 1 mL of the gold-iron phosphorus trisulfide nanosheet-loaded antibacterial hydrogel (referred to as QC-OD@Au-FePS3 hydrogel);

[0148] The concentration of the QC-OD hydrogel in the gold-iron phosphorus trisulfide nanosheet-loaded antibacterial hydrogel is 5 wt%.

[0149] Example 3

[0150] A preparation method of a gold-iron phosphorus trisulfide nanosheet-loaded antibacterial hydrogel, comprising the following steps:

[0151] (1) Disperse 50 mg of FePS3 crystals in 20 mL of N-methylpyrrolidone (NMP, AR, >99.0%) and then perform first ultrasonic treatment in an ice bath with a power of 600 W for 15 h, with an ultrasonic working time of 5 seconds and an interval of 3 seconds. Centrifuge the solution obtained by the first ultrasonic treatment at 4000 rpm for 10 min to remove large pieces, then centrifuge the supernatant at 14000 rpm for 30 min, wash the obtained precipitate with ethanol and then centrifuge at 14000 rpm for 30 min, collect the precipitate, wash it with water and then centrifuge at 14000 rpm for 30 min, collect the precipitate, and dry the precipitate in a 37℃ oven to obtain 14 mg of FePS3 nanosheets;

[0152] Disperse 14 mg of FePS3 nanosheets in 40 mL of water to obtain a water dispersion of FePS3 nanosheets;

[0153] (2) Add 2.4 g of polyvinylpyrrolidone to the water dispersion of FePS3 nanosheets obtained in step (1) and ultrasonically disperse for 30 min, then add 3 mL of HAuCl4·3H2O (20 mM) and 3 mL of NaBH4 (20 mM), and perform second ultrasonic treatment at 400 W for 30 min. Centrifuge the solution obtained by the second ultrasonic treatment at 14000 rpm for 30 min, wash the obtained precipitate with water and then centrifuge at 14000 rpm for 30 min, collect the precipitate, and dry the precipitate in a 37℃ oven to obtain 15 mg of Au-FePS3 nanosheets;

[0154] (3) take 5 g of dextran, dissolve in 50 mL of deionized water to obtain a dextran solution; prepare 100 g / L sodium periodate aqueous solution according to the molar ratio of dextran monomer: sodium periodate of 1:1.2; add the above sodium periodate solution to the dextran solution, and carry out gelation reaction at room temperature in the dark for 6 h, then add 2 mL of ethylene glycol to terminate the reaction; dialysis is carried out by using a dialysis bag with a molecular weight cut-off (MwCO) of 3500, and the dialysis liquid is replaced every day; on the third day, the dialysis liquid is clear and colorless; the dialysis solution is placed in a refrigerator at-80℃ for 1 day, and then placed in a freeze dryer to obtain a white product, oxidized dextran;

[0155] (4) the Au-FePS3 nanosheet solution obtained in the step (2) is prepared into an Au-FePS3 nanosheet aqueous solution with a concentration of 1 mg / mL;

[0156] The oxidized dextran obtained in the step (3) is prepared into an oxidized dextran aqueous solution with an oxidized dextran concentration of 7 wt%;

[0157] 200 uL of the Au-FePS3 nanosheet aqueous solution, 357 uL of the oxidized dextran aqueous solution, 357 uL of a quaternary ammonium salt chitosan aqueous solution with a quaternary ammonium salt chitosan concentration of 7 wt%, and 86 uL of deionized water are mixed, stirred at 60 rpm for 0.5 min, and then placed at 37℃ for 5 min to obtain 1 mL of a gold-iron phosphorus trisulfide nanosheet loaded antibacterial hydrogel (referred to as QC-OD@Au-FePS3 hydrogel);

[0158] The concentration of the QC-OD hydrogel in the gold-iron phosphorus trisulfide nanosheet loaded antibacterial hydrogel is 5 wt%.

[0159] As can be seen from the above, the gold-iron phosphorus trisulfide nanosheet loaded antibacterial hydrogel prepared by the present application has important significance for improving the high-sugar, continuous infection and hypoxic microenvironment of diabetic wounds, promoting wound healing, and provides an effective strategy for diabetic wound treatment.

[0160] The above only describes the preferred embodiments of the present application, and it should be pointed out that those skilled in the art can make several improvements and refinements without departing from the principles of the present application, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A method for preparing an antibacterial hydrogel loaded with gold-iron-phosphorus trisulfide nanosheets, characterized in that, Includes the following steps: (1) FePS3 crystals were dispersed in N-methylpyrrolidone and subjected to first ultrasonic treatment and first post-treatment in sequence to obtain FePS3 nanosheets; The FePS3 nanosheets were formulated into an aqueous dispersion of FePS3 nanosheets. (2) After mixing the aqueous dispersion of FePS3 nanosheets obtained in step (1) with polyvinylpyrrolidone, HAuCl4·3H2O and NaBH4 are added, and the second ultrasonic treatment and the second post-treatment are performed in sequence to obtain Au-FePS3 nanosheets. (3) Add sodium periodate solution to dextran solution and carry out redox reaction at room temperature in the dark. Then, perform dialysis, low temperature standing and freeze drying in sequence to obtain oxidized dextran. (4) Prepare an aqueous solution of Au-FePS3 nanosheets from the Au-FePS3 nanosheets obtained in step (2); The oxidized dextran obtained in step (3) is prepared into an aqueous solution of oxidized dextran; An aqueous solution of Au-FePS3 nanosheets, an aqueous solution of oxidized dextran, an aqueous solution of quaternary ammonium salt chitosan, and water were mixed and stirred and allowed to stand in sequence to obtain an antibacterial hydrogel loaded with gold-iron-phosphorus trisulfide nanosheets. In step (4), the concentration of quaternary ammonium salt chitosan-oxidized dextran hydrogel in the antibacterial hydrogel loaded with gold-iron-phosphorus trisulfide nanosheets is 3~7wt%.

2. The preparation method according to claim 1, characterized in that, In step (1), the concentration of the aqueous dispersion of FePS3 nanosheets is 0.1~0.5 mg / mL.

3. The preparation method according to claim 1, characterized in that, In step (2), the volume ratio of the aqueous dispersion of FePS3 nanosheets to the mass ratio of polyvinylpyrrolidone is 10 mL: (0.3~1) g.

4. The preparation method according to claim 1, characterized in that, In step (2), the mass ratio of FePS3 nanosheets in the aqueous dispersion to the molar amounts of HAuCl4·3H2O and NaBH4 is 1 mg: (2 × 10⁻⁶) / ( ... -3 ~8×10 -3 mmol: (2×10 -3 ~8×10 -3 0.05 mmol.

5. The preparation method according to claim 1, characterized in that, In step (3), the molar ratio of dextran monomer in the dextran solution to sodium periodate in the sodium periodate solution is 1:(1~2).

6. The preparation method according to claim 1, characterized in that, In step (4), the concentration of Au-FePS3 nanosheets in the aqueous solution is 0.5~2 mg / mL; the concentration of quaternary ammonium salt chitosan in the aqueous solution is 5~10 wt%.

7. The preparation method according to claim 1, characterized in that, In step (4), the temperature for standing is 25~37℃ and the time for standing is 2~10 min.

8. An antibacterial hydrogel loaded with gold-iron-phosphorus trisulfide nanosheets prepared by the preparation method according to any one of claims 1 to 7.

9. The antibacterial hydrogel loaded with gold-iron-phosphorus trisulfide nanosheets as described in claim 8 is used in the preparation of a drug for treating diabetic wounds.

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