An antibacterial dressing based on *Mammillaria mongholica* polysaccharide and its preparation method

Abstract

This invention relates to the field of antibacterial dressing technology, and discloses an antibacterial dressing based on *Mammillaria mongholica* polysaccharide and its preparation method. This antibacterial dressing based on *Mammillaria mongholica* polysaccharide includes the following raw materials: sodium alginate, hyaluronic acid, glycerin, *Mammillaria mongholica* polysaccharide sustained-release microcapsules, and deionized water. The *Mammillaria mongholica* polysaccharide sustained-release microcapsules are inclusion complexes composed of mussel adhesive protein and protocatechuic acid-modified cellulose as the wall material, and *Mammillaria mongholica* polysaccharide as the core material. The protocatechuic acid-modified cellulose is prepared by reacting protocatechuic acid with sodium carboxymethyl cellulose. The *Mammillaria mongholica* polysaccharide is obtained through multi-enzyme-assisted extraction. The antibacterial dressing prepared by this invention has excellent and long-lasting antibacterial effects and can significantly accelerate the healing process of skin wounds.

Description

Technical Field

[0001] This invention relates to the field of antibacterial dressing technology, specifically to an antibacterial dressing based on *Mammillaria mongholica* polysaccharide and its preparation method. Background Technology

[0002] As the largest organ in the human body, the skin is an important physical barrier against the invasion of external pathogens. Skin damage caused by trauma, surgery, or disease is prone to infection and inflammation, leading to slow wound healing and, in severe cases, threatening life. Traditional dressings, such as gauze and cotton pads, only provide physical coverage and absorb fluids for the wound, with relatively limited functions. They require frequent changes and can easily cause secondary damage to the wound. With the development of materials science, some functional dressings have been developed. Among them, natural polysaccharide dressings are widely used in wound repair due to their excellent biocompatibility and biodegradability. However, these polysaccharide dressings have limited antibacterial capabilities and are difficult to cope with the potential risk of bacterial infection in the wound.

[0003] Therefore, how to introduce antibacterial components into dressings and endow them with antibacterial effects has become a hot research topic at present. Patent CN113559311B discloses a medical antibacterial hemostatic gel dressing and its preparation method. It utilizes the fusion of components from silk fibroin, calcium alginate, active silver ions, chitosan, metronidazole, and traditional Chinese medicines such as dandelion extract, prunella vulgaris extract, Callicarpa japonica extract, elm bark extract, Artemisia argyi extract, and agave extract. The components of each raw material work synergistically to produce a combined antibacterial effect. This gel dressing has low irritation, good antibacterial effect and no toxic side effects. However, the antibacterial components in this gel dressing are easily lost and need to be replaced frequently. The durability of the antibacterial effect needs to be improved. Summary of the Invention

[0004] The purpose of this invention is to provide an antibacterial dressing based on *Mushroomia montana* polysaccharide and its preparation method, which solves the following technical problems: (1) ordinary antibacterial dressings have weak antibacterial ability and low durability, and need to be replaced frequently; (2) ordinary dressings have poor wound healing effect and are prone to causing wound inflammation.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] An antibacterial dressing based on *Mammillaria mongholica* polysaccharide comprises the following raw materials in parts by weight: 30-50 parts sodium alginate, 10-15 parts hyaluronic acid, 1-2 parts glycerin, 8-10 parts *Mammillaria mongholica* polysaccharide sustained-release microcapsules, and 100-200 parts deionized water; the *Mammillaria mongholica* polysaccharide sustained-release microcapsules are inclusion complexes composed of mussel adhesive protein and protocatechuic acid-modified cellulose as wall materials and *Mammillaria mongholica* polysaccharide as core material; the protocatechuic acid-modified cellulose is prepared by reacting protocatechuic acid with sodium carboxymethyl cellulose; and the *Mammillaria mongholica* polysaccharide is obtained through multi-enzyme-assisted extraction.

[0007] Furthermore, the preparation method of the *Mongoloides mongholicus* polysaccharide includes the following steps:

[0008] S1: Weigh Mongolian mushroom powder and mix it with petroleum ether. Stir continuously at room temperature for 18-20 hours. Then place the soaking liquid residue in an ethanol solution and stir continuously for 20-22 hours. After the soaking is completed, filter and dry to obtain pretreated Mongolian mushroom powder.

[0009] S2: Weigh the pretreated Mongolian mushroom powder and mix it evenly with distilled water. Add cellulase and hydrolyze it for 50-60 minutes at pH 5-5.5 and temperature 50-53℃. Then add chitinase and hydrolyze it for 55-60 minutes at pH 5.5-6 and temperature 55-58℃. Finally, add neutral protease and hydrolyze it for 30-35 minutes at pH 6.5-6.8 and temperature 45-48℃. After the hydrolysis is complete, centrifuge the supernatant, concentrate it by rotary evaporation, and then precipitate it with alcohol. After centrifugation, collect the precipitate and freeze-dry it to obtain Mongolian mushroom polysaccharide.

[0010] Using the above technical solution, small molecule impurities such as monomers and pigments in *M. mongholicus* powder are removed by the action of petroleum ether and ethanol solution, and the powder is dried to obtain pretreated *M. mongholicus* powder. Then, cellulase, chitinase, and neutral protease are added sequentially for enzymatic hydrolysis. After completion, centrifugation, concentration, and alcohol precipitation are performed, followed by freeze-drying to obtain *M. mongholicus* polysaccharide. Cellulase can specifically hydrolyze the cellulose skeleton in the cell wall, chitinase can degrade chitin in the cell wall of *M. mongholicus* powder, and neutral protease can effectively hydrolyze protein components in the cell wall and cell membrane, disrupting the protein network and further disintegrating it, which helps to dissociate polysaccharides bound to proteins. This method, by adding the three enzymes sequentially, can synergistically decompose the complex cell wall structure of *M. mongholicus*, achieving targeted cell wall disruption and helping to improve the extraction rate of *M. mongholicus* polysaccharide.

[0011] Furthermore, in step S1, the mass fraction of the ethanol solution is 70-80%.

[0012] Furthermore, in step S2, the alcohol precipitation treatment is carried out at a temperature of 4-5°C for 18-20 hours.

[0013] Furthermore, the preparation method of the *Mongoloides mongholicus* polysaccharide sustained-release microcapsules includes the following steps:

[0014] SS1: Sodium carboxymethyl cellulose was mixed with deionized water and stirred. 0.1-0.2 mol / L hydrochloric acid solution was added to adjust the pH to 3-4.5. After precipitation, the mixture was filtered and washed with anhydrous ethanol. The vacuum-dried product was mixed with protocatechuic acid in N,N-dimethylformamide and stirred. Nitrogen gas was introduced and a composite catalyst was added. The mixture was stirred at room temperature for 24-28 h and then purified and dried. The product was collected to obtain protocatechuic acid modified cellulose.

[0015] SS2: Place mussel adhesive protein powder in phosphate buffer and stir thoroughly to obtain a positive wall material solution; place protocatechuic acid modified cellulose and Mongolian mushroom polysaccharide in deionized water and mix thoroughly to obtain a mixed solution of negative wall material and core material;

[0016] SS3: Add positive wall material solution dropwise to the mixed solution of negative wall material and core material, stir continuously at 300-350 rpm for 50-55 min, add cross-linking agent, continue stirring at room temperature for 5-6 h, collect the suspension, collect the product after centrifugation, and freeze-dry to obtain Mongolian mushroom polysaccharide sustained-release microcapsules.

[0017] Through the above technical solution, sodium carboxymethyl cellulose and protocatechuic acid undergo esterification reaction under the action of composite catalyst to obtain protocatechuic acid modified cellulose. Mussel adhesive protein carries a positive charge in solution, while protocatechuic acid modified cellulose carries a negative charge. It is used as the wall material of Mongolian mushroom polysaccharide sustained-release microcapsules by complex coagulation method, and Mongolian mushroom polysaccharide is used as the core material for encapsulation treatment to obtain Mongolian mushroom polysaccharide sustained-release microcapsules. Sodium carboxymethyl cellulose, as an anionic polysaccharide backbone, possesses excellent biocompatibility and biodegradability. Furthermore, the abundant hydroxyl groups in its molecular chain provide active sites for grafting reactions of protocatechuic acid. Protocatechuic acid exhibits broad-spectrum antibacterial and anti-inflammatory capabilities. Anchoring it to the molecular chain of carboxymethyl cellulose enables the microcapsules to possess durable and non-leaching antibacterial properties. Mussel adhesive protein, rich in dopa and possessing a unique amino acid structure, exhibits excellent adhesion properties, enabling it to form adhesion anchors with biological tissues such as skin or mucous membranes. This significantly enhances the residence time of active ingredients on the wound surface, forming a physical barrier while also possessing antibacterial effects. It can also form a dual antibacterial defense with protocatechuic acid. Mongolian mushroom polysaccharide, as a core material, can enhance the body's ability to recognize pathogenic microorganisms by activating immune cells such as macrophages, thus promoting cell proliferation and accelerating wound healing.

[0018] Further, in step SS1, the composite catalyst is a mixture of dicyclohexylcarbodiimide and 4-dimethylaminopyridine in a mass ratio of 0.3-0.4:0.1-0.15.

[0019] Further, in step SS2, the concentration of the phosphate buffer solution is 0.01-0.02 mol / L, and the pH is 7.2-7.6.

[0020] Furthermore, in step SS3, the crosslinking agent is genipin.

[0021] A method for preparing an antibacterial dressing based on *Flammulina montana* polysaccharide includes the following steps:

[0022] Step 1: Place sodium alginate, hyaluronic acid and glycerin in deionized water and stir magnetically until fully mixed to obtain a composite colloid;

[0023] Step 2: Add Mongolian mushroom polysaccharide sustained-release microcapsules to the composite colloid, stir evenly, and collect the product to obtain the dressing.

[0024] The beneficial effects of this invention are:

[0025] Adding Mongolian mushroom polysaccharide sustained-release microcapsules to the dressing preparation process can effectively maintain the moisture level of the wound. At the same time, the synergistic antibacterial and adhesive effects between the wall materials create an excellent wound healing environment, which can effectively prevent inflammatory reactions caused by bacterial invasion. Meanwhile, the Mongolian mushroom polysaccharide as the core material can stimulate cell growth and regeneration, actively and continuously repair the wound, so that the prepared dressing has excellent and sustained antibacterial effects and the ability to promote the wound repair process.

[0026] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 The UV spectrum of sodium carboxymethyl cellulose and protocatechuic acid-modified cellulose in this embodiment of the invention is shown below.

[0029] Figure 2 This is a diagram illustrating the wound healing process in rats during the performance testing of this invention. Detailed Implementation

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

[0031] Example 1

[0032] I. Preparation of Polysaccharides from *Mongoloides mongholicus*

[0033] S1: Weigh 5g of Mongolian mushroom powder and mix it with 60ml of petroleum ether. Stir continuously at room temperature for 18h. Then place the residue of the soaking solution into 50ml of 75% ethanol solution and stir continuously for 20h. After the end of the process, filter and dry to obtain pretreated Mongolian mushroom powder.

[0034] S2: Weigh 3.5g of pretreated Mongolian mushroom powder and mix it evenly with 40ml of distilled water. Add 0.8g of cellulase and hydrolyze it for 55min at pH 5.3 and 52℃. Then add 0.2g of chitinase and hydrolyze it for 58min at pH 5.7 and 56℃. Finally, add 0.1g of neutral protease and hydrolyze it for 32min at pH 6.6 and 46℃. After the hydrolysis, centrifuge the solution, collect the supernatant, concentrate it by rotary evaporation, and then precipitate it with alcohol at 4℃ for 19h. After centrifugation, collect the precipitate and freeze-dry it to obtain Mongolian mushroom polysaccharide.

[0035] The yield of *Mongoloides mongholicus* polysaccharide was calculated using the following formula: *Mongoloides mongholicus* polysaccharide yield (%) = *Mongoloides mongholicus* polysaccharide mass (g) / pretreated *Mongoloides mongholicus* powder (g); the calculated yield of *Mongoloides mongholicus* polysaccharide was 17.37%.

[0036] II. Preparation of sustained-release microcapsules of *Morchella montana* polysaccharide

[0037] SS1: Mix 1g of sodium carboxymethyl cellulose with 20ml of deionized water and stir. Add 0.1mol / L hydrochloric acid solution to adjust the pH to 4. After precipitation, filter and wash with anhydrous ethanol. Place the vacuum-dried product with 0.8g of protocatechuic acid in 100ml of N,N-dimethylformamide and stir. Purge with nitrogen gas, add 0.3g of dicyclohexylcarbodiimide and 0.1g of 4-dimethylaminopyridine. Stir at room temperature for 24h and then purify and dry. Collect the product to obtain protocatechuic acid modified cellulose.

[0038] Sodium carboxymethyl cellulose and protocatechuic acid-modified cellulose were analyzed using a UV spectrophotometer. The results are as follows: Figure 1As shown, the UV spectrum of carboxymethyl cellulose shows no obvious absorption peak in the 200-400 nm range, while the protocatechuic acid-modified cellulose shows a strong absorption peak at 260 nm, which is a characteristic absorption peak of the benzene ring. The appearance of this absorption peak indicates that sodium carboxymethyl cellulose reacted with protocatechuic acid.

[0039] SS2: Place 0.2g of mussel adhesive protein powder in 200ml of phosphate buffer solution with a concentration of 0.01mol / L and a pH of 7.4, and stir thoroughly to obtain a positive wall material solution; place 0.2g of protocatechuic acid modified cellulose and 0.5g of Mongolian mushroom polysaccharide in 200ml of deionized water, and mix thoroughly to obtain a mixed solution of negative wall material and core material;

[0040] SS3: Add positive wall material solution dropwise to the mixed solution of negative wall material and core material, stir continuously at 320 rpm for 52 min, add 0.2 g genipin, continue stirring at room temperature for 5.5 h, collect the suspension, collect the product after centrifugation, and freeze-dry to obtain Mongolian mushroom polysaccharide sustained-release microcapsules.

[0041] Take 10 ml of the suspension from step SS3, centrifuge, and collect the supernatant (8 ml volume). Determine the concentration of *Mongoloides mongholicus* polysaccharide in the supernatant using the phenol-sulfuric acid method; the concentration is 0.55 mg / ml. Calculate the total free sugar mass using the following formula: Total free sugar mass (mg) = *Mongoloides mongholicus* polysaccharide concentration (mg / ml) × Supernatant volume (ml) × 40. The calculated total free sugar mass is 176 mg. Calculate the encapsulation efficiency of the *Mongoloides mongholicus* polysaccharide sustained-release microcapsules using the following formula.

[0042]

[0043] The encapsulation rate of *Mammillaria mongholica* polysaccharide was calculated to be 64.8%.

[0044] III. Preparation of Dressing

[0045] Step 1: Place 30 parts sodium alginate, 10 parts hyaluronic acid and 1 part glycerin in 100 parts deionized water and stir magnetically until fully mixed to obtain a composite colloid;

[0046] Step 2: Add 8 parts of Mongolian mushroom polysaccharide sustained-release microcapsules to the composite colloid, stir evenly, and collect the product to obtain the dressing.

[0047] Example 2

[0048] Preparation of dressings

[0049] Step 1: Place 40 parts sodium alginate, 12 parts hyaluronic acid and 1.5 parts glycerin in 150 parts deionized water and stir magnetically until fully mixed to obtain a composite colloid;

[0050] Step 2: Add 9 parts of Mongolian mushroom polysaccharide sustained-release microcapsules to the composite colloid, stir evenly, and collect the product to obtain the dressing.

[0051] Example 3

[0052] Preparation of dressings

[0053] Step 1: Place 50 parts sodium alginate, 15 parts hyaluronic acid and 2 parts glycerin in 200 parts deionized water and stir magnetically until fully mixed to obtain a composite colloid.

[0054] Step 2: Add 10 parts of Mongolian mushroom polysaccharide sustained-release microcapsules to the composite colloid, stir evenly, and collect the product to obtain the dressing.

[0055] Comparative Example 1

[0056] Preparation of dressings

[0057] Step 1: Place 40 parts sodium alginate, 12 parts hyaluronic acid and 1.5 parts glycerin in 150 parts deionized water and stir magnetically until fully mixed to obtain a composite colloid;

[0058] Step 2: Add 9 parts of Mongolian mushroom polysaccharide to the composite colloid, stir well, and collect the product to obtain the dressing.

[0059] The preparation method of the Mongolian mushroom polysaccharide is the same as that in Example 1.

[0060] Comparative Example 2

[0061] I. Preparation of sustained-release microcapsules of *Morchella montmorillonite* polysaccharide using sodium carboxymethyl cellulose as an anion exchange wall material

[0062] (1) Place 0.2g of mussel adhesive protein powder in 200ml of phosphate buffer solution with a concentration of 0.01mol / L and a pH of 7.4, and stir thoroughly to obtain a positive wall material solution; place 0.2g of sodium carboxymethyl cellulose and 0.5g of Mongolian mushroom polysaccharide in 200ml of deionized water, and mix thoroughly to obtain a mixed solution of negative wall material and core material;

[0063] (2) Add positive wall material solution dropwise to the mixed solution of negative wall material and core material, stir continuously at 320 rpm for 52 min, add 0.2 g genipin, continue stirring at room temperature for 5.5 h, collect the suspension, collect the product after centrifugation, freeze dry to obtain Mongolian mushroom polysaccharide sustained-release microcapsules.

[0064] II. Preparation of Dressing

[0065] Step 1: Place 40 parts sodium alginate, 12 parts hyaluronic acid and 1.5 parts glycerin in 150 parts deionized water and stir magnetically until fully mixed to obtain a composite colloid;

[0066] Step 2: Add 9 parts of Mongolian mushroom polysaccharide sustained-release microcapsules to the composite colloid, stir evenly, collect the product, and obtain the dressing;

[0067] The preparation method of the Mongolian mushroom polysaccharide is the same as that in Example 1.

[0068] Performance testing

[0069] ① Fifty rats weighing 230-250g were selected and divided into 5 groups of 10 each. Under anesthesia, a circular wound with a diameter of 1.5cm and a depth of 2mm was made on the back of each rat. The wound was covered with dressings prepared in Examples 1-3 and Comparative Examples 1-2. The wound healing was observed on days 1, 3, 7, and 12. The wound healing rate was calculated using the following formula: Wound healing rate (%) = (Initial wound area - Wound area after treatment) × 100% / Initial wound area; The specific test results are shown in Table 1 below:

[0070] Table 1: Results of wound healing rate test in rats

[0071]

[0072] As shown in Table 1 above, the dressings prepared in Examples 1-3 all exhibit excellent wound healing capabilities, with a healing rate exceeding 90% by the 7th day after wound formation. In Comparative Example 1, the dressing directly incorporated *Morchella mongholica* polysaccharide without any encapsulation treatment, resulting in a significantly lower wound healing rate, and the wound was still not fully healed by the 12th day. Comparative Example 2 used sodium carboxymethyl cellulose directly as the wall material without modification, achieving a good wound healing effect, with a healing rate of 98.9% by the 12th day. However, its wound healing effect was not as good as the examples, likely because the antibacterial and anti-inflammatory properties of the *Morchella mongholica* polysaccharide sustained-release microcapsules made from sodium carboxymethyl cellulose without protocatechuic acid modification were inferior to those in the examples, and the wound healing environment was also less favorable.

[0073] ② Inoculate Staphylococcus aureus and Escherichia coli strains into nutrient broth, incubate at 37°C for 18 hours, and adjust the bacterial concentration to 1×10⁻⁶. 6CFU / ml, 0.5g of the dressings prepared in Examples 1-3 and Comparative Examples 1-2 were taken as samples and placed in Erlenmeyer flasks. 20ml of bacterial suspension was added to the corresponding Erlenmeyer flask, sealed, and cultured with shaking at 37℃ and 150rpm for 24h. After the culture, 100μL of bacterial suspension was taken from each flask, serially diluted, and 30μL was taken from each flask and evenly spread on solid culture medium. The flasks were then incubated at 37℃ for 48h. The number of colonies on the culture medium was counted, and a blank experiment was performed simultaneously. The antibacterial rate was calculated using the following formula: Antibacterial rate (%) = (Number of colonies on culture medium in the blank experiment - Number of colonies on culture medium in the sample) × 100% / Number of colonies on culture medium in the blank experiment. The specific test results are shown in Table 2 below.

[0074] Table 2: Results of Antibacterial Performance Tests for Dressings

[0075]

[0076] As shown in Table 2 above, the dressings prepared in Examples 1-3 and Comparative Examples 1-2 all have excellent antibacterial effects. The dressing sample prepared in Comparative Example 1 directly added Mongolian mushroom polysaccharide without encapsulation treatment, resulting in poor antibacterial and anti-inflammatory effects. The sample prepared in Comparative Example 2 directly used sodium carboxymethyl cellulose as the wall material of the microcapsules without introducing protocatechuic acid as an antibacterial enhancing component, so its antibacterial effect was not as good as that of the examples.

[0077] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0078] The above content is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the scope defined by the inventive concept, they should all fall within the protection scope of the present invention.

Claims

1. An antibacterial dressing based on *Flammulina montana* polysaccharide, characterized in that, The raw materials include the following parts by weight: 30-50 parts sodium alginate, 10-15 parts hyaluronic acid, 1-2 parts glycerin, 8-10 parts Mongolian mushroom polysaccharide sustained-release microcapsules, and 100-200 parts deionized water; wherein the Mongolian mushroom polysaccharide is obtained by multi-enzyme-assisted extraction; The preparation method of the Mongolian mushroom polysaccharide sustained-release microcapsules includes the following steps: SS1: Sodium carboxymethyl cellulose was mixed with deionized water and stirred. 0.1-0.2 mol / L hydrochloric acid solution was added to adjust the pH to 3-4.

5. After precipitation, the mixture was filtered and washed with anhydrous ethanol. The vacuum-dried product was mixed with protocatechuic acid in N,N-dimethylformamide and stirred. Nitrogen gas was introduced and a composite catalyst was added. The mixture was stirred at room temperature for 24-28 h and then purified and dried. The product was collected to obtain protocatechuic acid modified cellulose. SS2: Place mussel adhesive protein powder in phosphate buffer and stir thoroughly to obtain a positive wall material solution; place protocatechuic acid modified cellulose and Mongolian mushroom polysaccharide in deionized water and mix thoroughly to obtain a mixed solution of negative wall material and core material; SS3: Add positive wall material solution dropwise to the mixed solution of negative wall material and core material, stir continuously at 300-350 rpm for 50-55 min, add cross-linking agent, continue stirring at room temperature for 5-6 h, collect the suspension, collect the product after centrifugation, and freeze-dry to obtain Mongolian mushroom polysaccharide sustained-release microcapsules.

2. The antibacterial dressing based on *Flammulina montana* polysaccharide according to claim 1, characterized in that, The preparation method of the *Mongoloides mongholicus* polysaccharide includes the following steps: S1: Weigh Mongolian mushroom powder and mix it with petroleum ether. Stir continuously at room temperature for 18-20 hours. Then place the soaking liquid residue in an ethanol solution and stir continuously for 20-22 hours. After the soaking is completed, filter and dry to obtain pretreated Mongolian mushroom powder. S2: Weigh the pretreated Mongolian mushroom powder and mix it evenly with distilled water. Add cellulase and hydrolyze it for 50-60 minutes at pH 5-5.5 and temperature 50-53℃. Then add chitinase and hydrolyze it for 55-60 minutes at pH 5.5-6 and temperature 55-58℃. Finally, add neutral protease and hydrolyze it for 30-35 minutes at pH 6.5-6.8 and temperature 45-48℃. After the hydrolysis is complete, centrifuge the supernatant, concentrate it by rotary evaporation, and then precipitate it with alcohol. After centrifugation, collect the precipitate and freeze-dry it to obtain Mongolian mushroom polysaccharide.

3. The antibacterial dressing based on *Mammillaria mongholica* polysaccharide according to claim 2, characterized in that, In step S1, the ethanol solution has a mass fraction of 70-80%.

4. The antibacterial dressing based on *Flammulina montana* polysaccharide according to claim 2, characterized in that, In step S2, the alcohol precipitation treatment is carried out at a temperature of 4-5°C for 18-20 hours.

5. The antibacterial dressing based on *Flammulina montana* polysaccharide according to claim 1, characterized in that, In step SS1, the composite catalyst is a mixture of dicyclohexylcarbodiimide and 4-dimethylaminopyridine in a mass ratio of 0.3-0.4:0.1-0.

15.

6. The antibacterial dressing based on *Mammillaria mongholica* polysaccharide according to claim 1, characterized in that, In step SS2, the concentration of the phosphate buffer solution is 0.01-0.02 mol / L, and the pH is 7.2-7.

6.

7. The antibacterial dressing based on *Flammulina montana* polysaccharide according to claim 1, characterized in that, In step SS3, the crosslinking agent is genipin.

8. The method for preparing an antibacterial dressing based on *Mammillaria mongholica* polysaccharide as described in claim 1, characterized in that, Includes the following steps: Step 1: Place sodium alginate, hyaluronic acid and glycerin in deionized water and stir magnetically until fully mixed to obtain a composite colloid; Step 2: Add Mongolian mushroom polysaccharide sustained-release microcapsules to the composite colloid, stir evenly, and collect the product to obtain the dressing.

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