AU2021100755A4

AU2021100755A4 - Silver Nanocluster-based Chitosan Hydrogel Dressing and Its Preparation Method and Application

Info

Publication number: AU2021100755A4
Application number: AU2021100755A
Authority: AU
Inventors: Xiangyu Wang; Xun YUAN
Original assignee: Qingdao University of Science and Technology
Current assignee: Qingdao University of Science and Technology
Priority date: 2021-02-07
Filing date: 2021-02-07
Publication date: 2021-04-22
Anticipated expiration: 2029-02-07

Abstract

The present invention belongs to the field of silver nanocluster-based chitosan hydrogel dressing technology, disclosing the silver nanocluster-based chitosan hydrogel dressing and its preparation methods and applications. Silver nanoclusters solution (Ag NCs) and mangiferin liposome solution (MF-Lip) are mixed and stirred, then 0.15-3mL of 1% (w/v) chitosan solution, 0.1-3mL of 3% (w/v) polyethylene glycol solution are added and mixed and stirred. Finally, 0.01-0.3mL of 2% (w/v) glutaric dialdehyde is added and stirred for 5-200 minutes, and the gel is formed to obtain Ag NCs@CH-MF hydrogel dressing after incubation of 30-180 minutes. The Ag NCs@CH-MF hydrogel provided by the invention can effectively avoid wound infection, reduce tissue necrosis, promote tissue repair and regeneration, which makes it effective on promoting the wound healing. 1 /3 Gelation Ag NCs MF-Lip PEG Chitosan Ag NCs@Chitosan-PEG loaded MF-Lip hydrogel Figure 1. The schematic diagram of the synthesis of the hydrogel Ag NCs@CH-MF provided by the present invention 1%CH 4- -Ag NCs@CH Ag NCs@CH-MF 3 .0 M I I 0-7 200 300 400 500 600 700 800 Wavelength (nm) Figure 2. The ultraviolet-visible absorption spectrum of the hydrogel Ag NCs@CH MF provided by the present invention

Description

1 /3

Gelation

Ag NCs MF-Lip PEG Chitosan

Ag NCs@Chitosan-PEG loaded MF-Lip hydrogel

Figure 1. The schematic diagram of the synthesis of the hydrogel Ag NCs@CH-MF

provided by the present invention

1%CH 4- -Ag NCs@CH Ag NCs@CH-MF 3

.0

M I I 0-7

200 300 400 500 600 700 800 Wavelength (nm)

Figure 2. The ultraviolet-visible absorption spectrum of the hydrogel Ag NCs@CH

MF provided by the present invention

Silver Nanocluster-based Chitosan Hydrogel Dressing and Its Preparation

Method and Application

TECHNICAL FIELD

[01] The present invention relates to silver nanocluster-based chitosan hydrogel dressings, particularly to silver nanocluster-based chitosan hydrogel dressings and their preparation methods and applications.

BACKGROUND

[02] In recent years, according to the statistics of World Health Organization (WTO), bacterial infection has been listed as one of health killers with the highest mortality in developing countries and regions. The antibiotics, which are mainly used for sterilization and antibacterial, have induced the increasing resistance of bacteria due to their excessive use, posing a serious threat to human health. Although more and more antibacterial studies of natural antibacterial compounds have gradually replaced those frequently used synthetic antibiotics, such as chitosan antimicrobials, vaccines, and phage therapy, the low antibacterial activity of natural compounds hinders their practical use in replacing synthetic antibiotics.

[03] Hydrogel is an emerging polymeric biomaterial with unique properties, which can maintain a certain shape and absorb a large amount of water. Hydrogels can do various kinds of drug carriers, such as chitosan hydrogel materials that are now largely reported, which have good solubility, high biocompatibility and biodegradability, flexibility, water absorption and air permeability, they are more acceptable to human body, basically without allergy or irritation adverse reactions. However, the existing hydrogels only have three-dimensional structure and water absorption effect by themselves, and do not have the functions of highly efficient antibacterial, antioxidant, and promoting tissue repair and regeneration.

[04] With the development of novel functional nanomaterials, a large group of antibacterial nanomaterials have emerged. It is documented that silver nanoparticles can effectively control the growth of bacteria in wounds. However, silver nanoparticles have large sizes, poor physical stability, easy aggregation and agglomeration, and certain toxicity, which limits their clinical application.

[05] Ultra-small sized silver nanoclusters (Ag NCs, <3nm) have attracted much attention as a new class of functional nanomaterials. At present, researchers have tried to introduce novel Ag NCs with broad-spectrum yet high antibacterial properties into biomedical materials for the preparation of highly antibacterial Ag NC-based hybrid materials. However, these attempts are not aimed at promoting the process of biological wound repair and tissue regeneration. In summary, providing a composite dressing that can not only ensure excellent antibacterial properties, but also reduce inflammation and improve wound healing is of great significance for medical clinics.

SUMMARY

[06] To solve the technical problems of poor sterilization and wound healing improvement of silver cluster-based composite materials in the prior art, the present invention provides a method for preparing a silver nanocluster-based chitosan hydrogel dressing.

[07] To solve the above technical problems, the present invention adopts the following technical solutions:

[08] The preparation method of silver nano cluster-based chitosan hydrogel dressing is as follows. Mix the silver nanocluster (Ag NCs) solution and the mangiferin liposome solution (MF-Lip), then add and mix 0.15-3mL of1% (w/v) chitosan solution and 0.1-3mL of 3% (w/v) polyethylene glycol solution. Finally, 0.01-0.3mL of 2% (w/v) glutaric dialdehyde is added and stirred for 5-200 minutes, and then left for 30 180 minutes to form a gel to obtain an Ag NCs@CH-MF hydrogel dressing.

[09] The total volume of the silver nanocluster (Ag NCs) solution and the mangiferin liposome solution (MF-Lip) is 0.01-3mL.

[010] The silver content of the silver nanoclusters (Ag NCs) is 4.723mg/L, and the mangiferin liposome solution (MF-Lip) contains 1 to 500mg of mangiferin.

[011] Chitosan shows anti-inflammatory, anti-bacterial and skin repairing effects in medical and health care. It has super adsorption capacity and has been used in wound care. But to replace antibiotics with chitosan, a natural polycationic polysaccharide, there is still a disadvantage of insufficient antibacterial property, and high efficiency sustained broad-spectrum antibacterial cannot be achieved. Therefore, the present invention uses chitosan hydrogel as a carrier to load silver nanoclusters and mangiferin. Because chitosan is a polycationic substance, and silver nanoclusters and liposomes are negatively charged substances, the composite hydrogel dressing prepared by the combination of static electricity has the properties of the three, and also has synergistic, efficient sterilization and anti-inflammatory effects. And, the resulting composite hydrogel dressing is not only injectable and can target to a variety of complex therapeutic environments, but also the mechanical properties are in accordance with the requirements, which can effectively avoid wound infection, reduce tissue necrosis, promote tissue repair and regeneration, and have a positive effect on wound healing. In addition, the prepared composite hydrogel dressing is not only injectable, suitable for a variety of complex treatment environments, but also meets the requirements of mechanical properties, can effectively avoid wound infection, reduce tissue necrosis, promote tissue repair and regeneration, and have a positive effect on wound healing. The present silver nanocluster-based chitosan hydrogel dressing thus has potential applications in the treatment of burns, scalds, skin wounds, chronic wounds, such as diabetes and immune function defects.

[012] The 1% (w/v) chitosan solution of the present invention is not specifically limited, it can be prepared by conventional methods in the art, or commercially available. Preferably, the present invention is obtained by dissolving Ig of chitosan in 1OOmL of 2% (w/v) acetic acid solution by heating, and then adding sodium hydroxide solution for neutralization. The chitosan is a chitosan with a degree of deacetylation of %.

[013] The preparation method of the silver nanoclusters of the present invention is as follows: 50mmol/L lipoic acid methanol solution 1-5mL, ultrapure water 3.3 33mL, 20mmol/L silver nitrate solution 0.2-2OmL, 100mmol/L 0.05-5mL of sodium borohydride solution, all of them are mixed and stirred, reacted for 3 hours, and centrifuged to obtain silver nanoclusters (Ag NCs).

[014] Silver nanoclusters (Ag NCs) are composed of a silver core and an outer layer ligand, with a size of less than 2nm, and have the characteristics of broad-spectrum sterilization and biocompatibility, and their physical and chemical properties are related to the surface ligands. Lipoic acid is an all-round nutrient that can be dissolved in water and fat. It participates in the energy release of each cell, so the present invention selects lipoic acid (DHLA) as the ligand. However, the silver nanoclusters protected by lipoic acid have poor stability in complex organisms and are prone to decomposition, which is not conducive to long-term drug effects. The chitosan hydrogel provided by the present invention is a carrier with a three-dimensional cross-linked network structure, chitosan is a polycationic substance, silver nanoclusters are electronegative substances, and the chitosan hydrogel is loaded with silver nanoclusters. Through electrostatic combination, the stability of lipoic acid-protected silver nanoclusters in complex organisms is poor, and the technical problem that they are prone to decomposition is solved, and the effect of drugs can be fully exerted.

[015] The method for the synthesis of mangiferin liposome solution (MF-lip) in the present work is synthesized by the film dispersion method, and the specific procedures are as follows: 4-20 parts by weight of lecithin, 1-15 parts by weight of cholesterol, 0.1-10 parts by weight of mangiferin (MF) are dissolved in a solvent to react, and filtered after the reaction. The filtrate is mangiferin liposome solution (MF Lip).

[016] Preferably, the solvent is a mixture of chloroform and methanol, and the volume ratio of chloroform and methanol is 1:1.

[017] Another object of the present invention is to provide a silver nanocluster based chitosan hydrogel dressing prepared by the above preparation method.

[018] Finally, the present invention provides applications of the silver nanocluster-based chitosan hydrogel dressing in the preparation of bactericidal, anti inflammatory as well as promoting wound healing and tissue repair regeneration composites.

[019] It can be seen from the above technical solutions that the present invention provides a silver nanocluster-based chitosan hydrogel dressing and its preparation method and application. The silver nanocluster-based chitosan hydrogel dressing plays a synergistic and efficient sterilization and anti-inflammatory effect. The silver nanocluster-based chitosan hydrogel dressing is not only injectable for a variety of complex therapeutic environments, but also has the required mechanical properties to effectively avoid wound infection, reduce tissue necrosis, promote tissue repair and regeneration, and have a positive effect on wound healing.

DESCRIPTION OF THE FIGURES

[020] Figure 1 is the schematic diagram of the synthesis of the hydrogel Ag NCs@CH-MF provided by the present invention.

[021] Figure 2 is the ultraviolet-visible absorption spectrum of the hydrogel Ag NCs@CH-MF provided by the present invention.

[022] Figure 3 is the scanning electron microscope image of the hydrogel Ag NCs@CH-MF provided by the present invention.

[023] Figure 4 is the view of wound healing and section observation of rats provided by the present invention.

[024] Figure 5 is the bacterial plate diagram of the broad-spectrum antibacterial performance test of the hydrogel Ag NCs@CH-MF provided by the invention.

[025] Figure 6 is the injection performance test diagram of the hydrogel Ag NCs@CH-MF provided by the present invention.

DESCRIPTION OF THE INVENTION

[026] The present invention discloses silver nanocluster-based chitosan hydrogel dressings and their preparation methods and applications. Those skilled in the art can learn from the content of this article and appropriately improve the process parameters. Particularly, what should be pointed out is that all similar substitutions and modifications are obvious to those skilled in the art, and they are all considered to be included in the present invention. The methods and applications of the present invention have been described by means of preferred embodiments and it is obvious that the person concerned is able to implement and apply the techniques of the present invention by making changes or appropriate variations and combinations to the methods and applications described herein without departing from the content, spirit and scope of the present invention.

[027] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below in conjunction with specific embodiments.

[028] Comparative example 1

[029] O.4mL of 0.04mmol/L Ag NCs solution (silver content 4.723mg/L), 1.6mL of ultrapure water, were mixed to obtain Ag NCs with a volume fraction of 0.2 (defined as 0.2 Ag NCs, the number before the cluster represents the volume fraction, the same below).

[030] Comparative example 2

[031] 0.73mL of ultrapure water, 0.25mL of 3% polyethylene glycol solution, 1mL of 1% chitosan solution, stir for 30min and 0.015mL of 2% glutaric dialdehyde solution were mixed for 5min at room temperature. The solution stands for 100min to form a gel and obtain 1% chitosan hydrogel with 1% CH.

[032] Comparative example 3

[033] 0.73mL of ultrapure water, 0.25mL of 3% polyethylene glycol solution, 1mL of 2% chitosan solution, stir for 30min, and 0.015mL of 2% glutaric dialdehyde solution 0.015mL were mixed for 5min at room temperature, and stand for 100min to form a gel to obtain 2% chitosan hydrogel with 2% CH.

[034] Example 1

[035] 0.16mL of Ag NCs solution (silver content 4.723mg/L) and 0.57mL of ultrapure water were mixed for 20min. 0.25mL of 3% polyethylene glycol solution, 1mL of 1% chitosan solution were mixed for 30min, then adding 0.015mL of 2% glutaric dialdehyde solution to stirring at room temperature for 5min, standing for 100min to form a gel so as to obtain Ag NCs@CH.

[036] Example 2

[037] 0.32mL of Ag NCs solution (silver content of 4.723mg/L) and 0.4lmL of ultrapure water were mixed for 20min. 0.25mL of 3% polyethylene glycol solution, 1mL of 1% chitosan solution were mixed for 30min, then adding 0.015mL of 2% glutaric dialdehyde solution while stirring at room temperature for 5min, standing for 100min to form a gel, so as to obtain Ag NCs@CH.

[038] Example 3

[039] 0.4mL of Ag NCs solution (silver content 4.723mg/L) and 0.33mL of ultrapure water were mixed for 20min. 0.25mL of 3% polyethylene glycol solution, and 1mL of 1% chitosan solutionwere mixed for 30min, then adding 0.015mL of 2% glutaric dialdehyde solution, stirring at room temperature for 5min, and standing for 100min to form a gel to obtain Ag NCs@CH.

[040] Example 4

[041] 0.4mL of Ag NCs solution (silver content 4.723mg/L), 0.33mL of ultrapure water, were mixed for 20min.0.25m Lof 3% polyethylene glycol solution, 1mL of 2% chitosan solution were mixed 30min, then adding 0.015mL of 2% glutaric dialdehyde solution, which was stirred at room temperature for 5min, standing for 100min to form a gel and obtain Ag NCs@2%CH.

[042] Example 5

[043] 0.4mL of Ag NCs solution (silver content 4.723mg/L), 0.33mL of mangiferin liposome solution containing 10mg of mangiferin were mixed for 20min. 0.25 mL of 3% polyethylene glycol solution and 1mL of 1% chitosan solution are stirred for 30min. Adding 0.015mL of 2% glutaric dialdehyde solution ti stir the solution at room temperature for 5 minutes, and allowed to stand for 100 minutes to form a gel to obtain a composite hydrogel Ag NCs@CH-MF.

[044] The schematic diagram of the above reaction is shown in Figure 1.

[045] The composition of the obtained hydrogel Ag NCs@CH-MF is analyzed with an ultraviolet-visible spectrophotometer, as shown in Figure 2. The 1% blank chitosan hydrogel shows a characteristic absorption peak around 255nm, and the hydrogel Ag NCs@CH with silver nanoclusters added to the chitosan has an extra 430nm characteristic absorption peak of Ag NCs. On the other hand, Ag NCs@CH-MF loaded with mangiferin on the silver nanocluster-based hydrogel has an additional

367nm characteristic absorption peak of MF. Figure 2 shows that the prepared Ag NCs@ CH-MF hydrogel does exist in Ag NCs and MF.

[046] The hydrogel Ag NCs@CH-MF is also scanned by electron microscopy and the scans are shown in Figure 3. Figure 3 (a) shows the micro morphology of the blank chitosan hydrogel, Figure 3 (b) shows the micro morphology of the chitosan hydrogel loaded with silver nanoclusters, Figure 3(c) shows the microscopic morphology of chitosan hydrogel loaded with silver nanoclusters and mangiferin. As can be seen from Figure 3, the addition of hydrophilic silver nanoclusters makes the hydrogel more porous with visible pores. The addition of hydrophobic mannoprotein liposomes results in denser voids, which appears as pores and folds.

[047] Example 6

[048] 1.5mL of Ag NCs solution (silver content 4.723mg/L), 1.5mL of mangiferin liposome solution containing 1mg of mangiferin were mixed stir for 20min. 3mL of 3% polyethylene glycol solution and 3mL of 1% chitosan solution are stirred for 30 minutes. Then 0.3mL of 2% glutaric dialdehyde solution is stirred at room temperature for 100 minutes, standing for 30 minutes to form a gel to obtain a composite hydrogel Ag NCs@CH-MF.

[049] Example 7

[050] 0.07mL of Ag NCs solution (silver content of 4.723mg/L) and 0.08mL of mangiferin liposome solution containing 1mg of mangiferin were mixed for 20min. 0.1mL of 3% polyethylene glycol solution, 0.15mL of 1% chitosan solution were mixed for 30min.0.0lmL of 2% glutaric dialdehyde solution is stirred at room temperature for 200 minutes, and allowed to stand for 120 minutes to form a gel to obtain a composite hydrogel Ag NCs@CH-MF.

[051] Note: The preparation method of the 1% (w/v) chitosan solution used in the examples is as follows: Ig chitosan (with a degree of deacetylation of 90%) is dissolved by heating in 100mL of 2% (w/v) acetic acid solution, and then sodium hydroxide solution is added to neutralize the obtained solution. The synthetic method of the mangiferin liposome solution is to dissolve 12 parts by weight of lecithin, 8 parts by weight of cholesterol, and 5 parts by weight of mangiferin (MF) in a solvent (a mixture of chloroform and methanol with a volume ratio of 1:1). After the reaction and filtration, the filtrate is a mannoside liposome solution (MF-Lip). The method for preparing the silver nanoclusters is to mix 3mL of 50mmol/L lipoic acid methanol solution, 22mL of ultrapure water, 10mL of 20mmol/L silver nitrate solution, and 2mL of 100mmol/L sodium borohydride solution, and stir and react for 3 hours. The silver nanoclusters (Ag NCs) are obtained by centrifugation.

[052] The products obtained in Examples 1-5 and Comparative Examples 1-3 are tested for performance, and the test results are shown in Table 1 and Table 2.

[053] Table 1 Product antibacterial test results

Sterilizatio Experime Experime Experime Experime Compari Compari Compari n ntal ntal ntal ntal son 1 son 2 son 3 performance example 1 example 2 example 3 example 4 e Killing rate 99.996% 99.998% 99.999% 99.950 74.882% 72.877% 76.432% of Staphyloco ccus aureus

[054] The data in Table 1 shows that for the products Ag NCs@CH in Experimental Example 3 and Experimental Example 4, when the concentration of silver ions in the gel is the same, the concentration of the chitosan solution increases, resulting in a dense gel network and slower silver release. And the sterilization is reduced. Therefore, the present invention found that the concentration of chitosan is 1% (w/v), and Ag NCs@CH has the best bactericidal effect. The data of Experimental Example 3 and Comparative Examples 1 and 2 show that the bactericidal properties of individual silver nanoclusters and individual chitosan are not high. When the two are integrated, the synergistic bactericidal effect is significantly improved, which indicates that the adsorption of chitosan adsorbs bacteria to the hydrogel, and then the silver nanoclusters release bactericidal substances (Ag t and active oxygen groups), which effectively integrates sterilization. Through Comparative Example 2 and Example 3, the bactericidal properties are improved as the concentration of chitosan increases and the ammonium group in the gel becomes more adsorptive for negatively charged bacteria.

[055] Table 2 Other performance tests of products

Other properties Experimental Experimental Comparison 2 example 3 example 5 Killing rate of 99.996% 99.999% 72.877% Staphylococcus aureus Murine fibroblast 82.47% 94.34% 78.43% survival rate Porosity 82.89% 74.2% 82.94% Swelling rate 1800% 1200% 1400%

[056] The data in Table 2 shows that by comparing the properties of Comparative Example 2 and Experimental Example 3, it can be seen that when silver nanoclusters are added, the bactericidal performance of chitosan hydrogel is significantly improved, and with the addition of lipoic acid-protected clusters, the biocompatibility of the hydrogel is improved, and the swelling rate is increased. The addition of silver nanoclusters increases the hydrophilicity of the hydrogel, and the movement of water molecules in the gel network. The swelling capacity and the cell protection effect is enhanced. However, if the swelling rate is too high, it will affect the tightness of the network, the stability of the product in complex organisms will be affected, as well as the mechanical properties. The mangiferin liposome added in the present invention is a hydrophobic substance, and the movement of water molecules is hindered, which reduces the porosity and swelling rate of the product. In this way, the swelling rate of the product obtained in Example 5 of the present invention reached the best. At the same time, the addition of mangiferin improves the biosafety of the gel, reduces its toxicity to cells, and inhibits cell apoptosis. By recording the wound healing of rats on different days, as shown in Figure 4(a), it is found that the present invention can better promote wound healing compared with the control group. Furthermore, through the tissue section of the rat on the fourth day, it was found that the hydrogel of Example 5 did not have obvious inflammatory reaction and necrosis in the rat wound after 4 days, and produced new hair follicles and capillaries. For details, see Figure 4(b) (circle: area of inflammation. Straight line: area of necrosis. Box: new hair follicle. Arrow: new capillary). The untreated blank group showed inflammation and necrosis.

[057] Comparing Example 5 with Experimental Example 3, when an effective dose of mangiferin is added to the hydrogel containing silver clusters, the bactericidal rate of the hydrogel is further increased and extended to Gram-negative and Gram positive bacteria, and the product we prepared achieved 99 .99% bactericidal rates against Bacillus subtilis (B. subtilis), Escherichia coli (E. coli), Pseudomonas aeruginosa(P. aeruginosa)and Staphylococcus aureus (S. aureus), as shown in Figure 5.

[058] Thus, the present invention provides chitosan hydrogel loaded silver nanoclusters and mangiferin composite hydrogel, synergistic with chitosan, silver nanoclusters and mangiferin, with multifunctional functions such as efficient broad spectrum bactericidal ability, promotion of tissue repair and regeneration ability, anti inflammation and necrosis, and good biocompatibility.

[059] The injectability of the composite hydrogel Ag NCs@CH-MF obtained in Example 5 was tested, and the test result is shown in Figure 6. Figure 6 shows a picture of Ag NCs@CH-MF hydrogel injected into a glass plate and water. It can be seen from the figure that the upper part of Fig. 6 is the photo of the injected hydrogel, and the lower part of Fig. 6 is the image of the water-infused hydrogel, showing that the hydrogel Ag NCs@CH-MF obtained in Example 5 is injectable and has good injectability. And it keeps the shape of the glue after being injected into water, so that it can treat wounds in various complicated situations to maximize sterilization and promote wound healing.

[060] Although the invention has been described with reference to specific examples, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms, in keeping with the broad principles and the spirit of the invention described herein.

[061] The present invention and the described embodiments specifically include the best method known to the applicant of performing the invention. The present invention and the described preferred embodiments specifically include at least one feature that is industrially applicable

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. Preparation method of silver nanocluster-based chitosan hydrogel dressing,

which is characterized by mixing and stirring silver nanocluster solution (Ag NCs) and

mangiferin liposome solution (MF-Lip), then 0.15-3mL of 1% (w/v) chitosan solution

and 0.1-3mL of 3% (w/v) polyethylene glycol solution are added, mixed and stirred.

Finally, 0.01-0.3mL of 2% (w/v) glutaric dialdehyde is added and stirred for 5-200

minutes, and after being left for 30-180 minutes, the gel is formed to obtain Ag

NCs@CH-MF hydrogel dressing.

The total volume of the silver nanocluster (Ag NCs) solution and the mangiferin

liposome solution (MF-Lip) is 0.01-3mL.

The silver content of the silver nanoclusters (Ag NCs) is 4.723mg/L, and the

mangiferin liposome solution (MF-Lip) contains 1 to 500mg of mangiferin.

2. The preparation method as mentioned in claim 1, characterized in that1% (w/v)

chitosan solution is obtained by dissolving lg of chitosan in1OOmL of 2% (w/v) acetic

acid solution by heating and then adding sodium hydroxide solution to neutralize. The

chitosan is a chitosan with a degree of deacetylation of 90%.

3. The preparation method according to claim 1, characterized in that the

preparation method of the silver nanoclusters is as follows: 50mmol/L lipoic acid

methanol solution 1-5mL, ultrapure water 3.3-33mL, 20mmol/L nitric acid Silver

solution 0.2-2OmL, 100mmol/L sodium borohydride solution 0.05-5mL, all of them are

mixed and stirred, reacted for 3h, and centrifuged to obtain silver nanocluster solution

(Ag NCs).

4. The method of preparation as mentioned in claim 1, characterised in that the

synthesis of mangiferin liposome solution is carried out by dissolving 4-20 weight of

lecithin, 1-15 weight of cholesterol and 0.1-10 weight of mangiferin (MF) in a solvent and filtering the filtrate after the reaction to form a mangiferin liposome solution (MF

Lip).

5. The preparation method according to claim 4, wherein the solvent is a mixture

of chloroform and methanol, and the volume ratio of chloroform and methanol is 1:1.

6. The silver nanocluster-based chitosan hydrogel dressing is prepared by the

preparation method of any one of claims 1-5.

7. The application of the silver nanocluster-based chitosan hydrogel dressing

according to claim 6 is in the preparation of a composite material for sterilization, anti

inflammation, and promotion of wound healing and tissue repair and regeneration.