A myrrh composite antibacterial dressing and a preparation method thereof

Abstract

The application discloses a Chinese gall complex antibacterial dressing and a preparation method thereof. The dressing is composed of 6-9% Chinese gall tannin extract (tannin≥95%), 10-14% chitosan, 12-16% gelatin, 4-5% glycerol, 0.8-1.2% genipin, 0.1-0.3% zinc nitrate source Zn²⁺ and the balance of deionized water, has a porous film structure, a pore size of 5-10 μm, a moisture permeation amount of ≥1800 g / (m²·24h) and a breaking strength of ≥35 MPa. The preparation method comprises the following steps: ultrasonic-assisted water extraction and alcohol precipitation of Chinese gall, preparation of component solutions, blending and stirring at 40 DEG C, constant-temperature crosslinking at 38-42 DEG C, casting, drying and ultraviolet sterilization. The dressing has excellent and stable antibacterial effect, good biocompatibility, good mechanical and moisture permeation properties, simple and green preparation process and easy scaling, is suitable for wound care of burns, wounds and the like, and solves many defects of traditional dressings.

Description

Technical Field

[0001] This invention belongs to the technical field of medical dressings, specifically relating to a gallnut composite antibacterial dressing and its preparation method. Background Technology

[0002] Medical dressings are essential medical supplies used in clinical treatment to cover and protect wounds, absorb wound exudate, and promote wound healing. They are widely used in the care of burns, trauma, ulcers, and other wounds. With the development of medical technology, traditional medical dressings (such as gauze and cotton pads) can no longer meet clinical needs. They have drawbacks such as poor antibacterial properties, poor moisture permeability, adhesion to the wound surface, and limited biocompatibility, which can easily lead to wound infection, delayed healing, and increased patient suffering and treatment costs.

[0003] To address these issues, various functional composite dressings have emerged, with antibacterial dressings becoming a research hotspot. Currently, the antibacterial components of antibacterial dressings are mainly divided into chemical antibacterial agents and natural antibacterial agents. Although chemical antibacterial agents have significant antibacterial effects, they suffer from poor biocompatibility, easy development of drug resistance, and potential toxic side effects on the human body. Natural antibacterial agents, on the other hand, have advantages such as wide availability, good biocompatibility, no drug resistance, and fewer toxic side effects, and are gradually becoming the preferred raw materials for antibacterial dressings.

[0004] Gallnut, a traditional Chinese medicine, primarily contains gallnut tannins, which possess excellent antibacterial, anti-inflammatory, and astringent properties. It exhibits significant inhibitory effects against common pathogenic bacteria such as Staphylococcus aureus and Escherichia coli, and demonstrates excellent biocompatibility, making it suitable for the preparation of medical dressings. Chitosan, a natural polysaccharide, possesses good biocompatibility, biodegradability, and antibacterial properties, and is widely used in the medical field. Gelatin, with its excellent film-forming properties and biocompatibility, can synergistically work with chitosan to improve the mechanical properties and adherence of dressings. Zn²⁺ ions have antibacterial, cell proliferation-promoting, and wound-healing effects, further enhancing the antibacterial efficacy and healing-promoting capacity of dressings.

[0005] Existing technologies include some research on composite antibacterial dressings based on gallnut or chitosan, but most suffer from the following drawbacks: First, the extraction purity of gallnut extract is low, with low tannin content, resulting in limited antibacterial effects; second, the proportions of the components are unreasonable, leading to insufficient synergistic effects and difficulty in simultaneously achieving antibacterial properties, mechanical properties, and moisture permeability; third, the preparation process is complex, requiring sophisticated equipment or toxic reagents, posing environmental pollution risks and hindering large-scale production; fourth, the pore structure of the dressing is unreasonable, resulting in poor moisture and air permeability, affecting wound healing efficiency. Furthermore, some composite dressings also suffer from uneven Zn²⁺ ion dispersion and easy aggregation, leading to unstable antibacterial effects, as well as insufficient cross-linking reactions, resulting in insufficient mechanical strength and easy breakage. Summary of the Invention

[0006] To address the aforementioned problems, the present invention aims to provide a gallnut composite antibacterial dressing and its preparation method that overcome the shortcomings of existing Chinese medicine antibacterial dressings, such as limited antibacterial effect, poor biocompatibility, insufficient mechanical properties, poor moisture permeability, and complex preparation process.

[0007] This invention is achieved through the following technical solution: A gallnut composite antibacterial dressing, by mass percentage, comprises the following components: 6-9% gallnut extract, 10-14% chitosan, 12-16% gelatin, 4-5% glycerin, 0.8-1.2% crosslinking agent, 0.1-0.3% Zn²⁺ ions, and the balance being deionized water; wherein the gallnut extract is a gallnut tannin extract with a tannin content ≥95%, purified by conventional ultrasonic treatment, and has a particle size ≤800nm.

[0008] Furthermore, the chitosan is conventional medical-grade chitosan with a degree of deacetylation ≥88% and a molecular weight of 60,000-90,000 Da.

[0009] Furthermore, the gelatin is conventional medical-grade gelatin with a molecular weight of 35,000-45,000 Da and an isoelectric point of 7.0-7.5.

[0010] Furthermore, the crosslinking agent is conventional genipin; the Zn²⁺ ions are derived from zinc nitrate.

[0011] Furthermore, the composite antibacterial dressing has a porous film structure with a pore size of 5-10 μm, a porosity of 40-50%, a moisture permeability of ≥1800 g / (m²·24h), a tensile strength of ≥35 MPa, and an elongation at break of ≥25%.

[0012] A method for preparing a gallnut composite antibacterial dressing includes the following steps: (1) Preparation of gallnut extract: Tannins in gallnut were extracted by conventional ultrasonic-assisted water extraction and alcohol precipitation. After ordinary filtration and purification and vacuum drying, gallnut extract powder was obtained for later use; purification; (2) Solution preparation: Chitosan is added to deionized water containing 0.5-1.0% acetic acid and stirred at room temperature until completely dissolved to obtain a chitosan solution; gelatin is added to deionized water at 45-50℃ and stirred until completely dissolved to obtain a gelatin solution; gallnut extract powder and zinc nitrate are added to a small amount of deionized water and ultrasonically dispersed until uniform to obtain a gallnut-Zn²⁺ dispersion; (3) Blending and stirring: Slowly add the gelatin solution to the chitosan solution, stir at a constant temperature of 40℃ for 20-30 minutes until uniform, then add the gallnut-Zn²⁺ dispersion and glycerol, and continue stirring for 40-50 minutes to obtain a mixed solution; (4) Crosslinking and curing: Add conventional genipin to the mixed solution, stir evenly, adjust the pH of the system to 6.8-7.2, and crosslink at a constant temperature of 38-42℃ for 1.2-1.8h; (5) Molding and drying: Pour the cross-linked mixed solution into a conventional plastic mold and cast it into a film with a thickness of 0.15-0.25 mm. Place it in a conventional oven and dry it at 55-60℃ for 2.2-2.8 h. After taking it out, cool it to room temperature, cut it, and sterilize it to obtain the gallnut composite antibacterial dressing.

[0013] Further, the specific steps of the ultrasonic-assisted water extraction and alcohol precipitation method described in step (1) are as follows: crush the gallnuts through a 40-mesh sieve, add 9-10 times the mass of deionized water, extract for 2.2-2.8 h at 85-90℃ and ultrasonic power of 250-300W, filter to obtain an aqueous extract; add ethanol to the aqueous extract to make the ethanol volume fraction reach 75-80%, let stand at room temperature for 18-22 h, filter, centrifuge, collect the precipitate, purify by ordinary filtration, and vacuum dry to a moisture content ≤5% to obtain gallnut extract powder.

[0014] Furthermore, the ultrasonic dispersion in step (2) is performed with a power of 250-300W, a dispersion time of 15-20min, and a dispersion temperature of 35-40℃ to ensure that the gallnut extract and Zn²⁺ ions are uniformly dispersed without agglomeration.

[0015] Furthermore, in step (4), no intermittent ultrasound assistance is required, and the crosslinking reaction is carried out by constant temperature stirring.

[0016] Furthermore, the sterilization method described in step (5) is conventional ultraviolet sterilization, and the sterilization time is 40-50 minutes.

[0017] The beneficial effects of this invention are: 1. Excellent and stable antibacterial effect: This invention uses high-purity gallnut tannin extract as the main antibacterial component, with a tannin content ≥95%. Combined with the synergistic antibacterial effect of Zn²⁺ ions, it has a significant inhibitory effect on common pathogenic bacteria such as Staphylococcus aureus and Escherichia coli, with a broad antibacterial range and long-lasting effect. At the same time, Zn²⁺ ions are evenly distributed in the dressing system through ultrasonic dispersion to avoid agglomeration, further ensuring the stability of the antibacterial effect and making it less likely to induce drug resistance.

[0018] 2. Excellent biocompatibility: The gallnut extract, chitosan, gelatin, genipin, and other components used in this invention all exhibit excellent biocompatibility, are non-toxic and non-irritating, will not produce toxic side effects on the human body, and will not adhere to the wound surface, reducing patient discomfort during dressing changes and lowering the risk of wound infection. Among these, gallnut tannins, as a natural plant extract, also possess anti-inflammatory and astringent properties, further promoting wound healing.

[0019] 3. Excellent mechanical properties and moisture permeability: Through a reasonable ratio of chitosan, gelatin, and cross-linking agents, combined with an optimized cross-linking process, the dressing possesses excellent mechanical properties, with a tensile strength ≥35MPa and an elongation at break ≥25%, making it resistant to breakage and easy to use. The porous membrane structure (pore size 5-10μm, porosity 40-50%) achieves good moisture permeability, with a moisture permeability ≥1800g / (m²·24h), which can promptly drain wound exudate, keep the wound dry and clean, provide a suitable microenvironment for wound healing, and accelerate the wound healing process.

[0020] 4. Simple and environmentally friendly preparation process: The preparation method of this invention requires no complex equipment, is simple in steps, easy to operate, and can be mass-produced, reducing production costs. No toxic or harmful reagents are used in the preparation process; a natural cross-linking agent, genipin, is employed, and the ultrasound-assisted extraction and dispersion processes are environmentally friendly, causing no pollution and meeting the environmental requirements of modern medical products. Furthermore, this preparation method solves technical problems such as low purity of gallnut tannin extraction, uneven component dispersion, and insufficient cross-linking reaction, ensuring stable dressing performance. Detailed Implementation

[0021] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0022] It should be noted that the terms “comprising,” “including,” or any other variations are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Example 1

[0023] The Gallnut Compound Antibacterial Dressing, with a total mass of 100g, comprises the following ingredients: 7.5% Gallnut Tannin Extract, 12% Medical-grade Chitosan, 14% Medical-grade Gelatin, 4.5% Glycerin, 1.0% Genipin, 0.2% Zn²⁺ Ions, and 60.8% Deionized Water. Specifically, the Gallnut Tannin Extract contains 96.2% tannin with a particle size of 620nm; the Chitosan has a degree of deacetylation of 90% and a molecular weight of 75,000 Da; the Gelatin has a molecular weight of 40,000 Da and an isoelectric point of 7.2; and the Zn²⁺ ions are derived from zinc nitrate hexahydrate, with a calculated addition of 0.91g of zinc nitrate hexahydrate.

[0024] Preparation method (1) Preparation of gallnut extract: Gallnut is crushed and passed through a 40-mesh sieve, and 10 times the mass of deionized water is added. Extraction is carried out at 88℃ and ultrasonic power of 280W for 2.5h. The aqueous extract is obtained by filtration. Anhydrous ethanol is added to the aqueous extract to make the ethanol volume fraction reach 78%. The mixture is allowed to stand at room temperature for 20h, filtered, centrifuged at 3000r / min for 10min, the precipitate is collected, purified by microporous membrane, and vacuum dried to a moisture content of 3.2% to obtain gallnut extract powder for later use.

[0025] (2) Solution preparation: Chitosan was added to deionized water containing 0.8% acetic acid and stirred at room temperature until completely dissolved to obtain a chitosan solution with a mass fraction of 2%; gelatin was added to deionized water at 48℃ and stirred until completely dissolved to obtain a gelatin solution with a mass fraction of 5%; gallnut extract powder and zinc nitrate hexahydrate were added to a small amount of deionized water and ultrasonically dispersed at 280W and 38℃ for 18 minutes to obtain a uniform gallnut-Zn²⁺ dispersion without agglomeration.

[0026] (3) Blending and stirring: The gelatin solution is slowly added dropwise to the chitosan solution, and the mixture is stirred at a constant temperature of 40°C for 25 minutes until the system is homogeneous. Then, the gallnut-Zn²⁺ dispersion and glycerol are added, and the mixture is stirred at a constant temperature for 45 minutes to obtain a homogeneous and transparent mixed solution.

[0027] (4) Crosslinking and curing: Add genipin to the mixed solution, stir evenly, adjust the pH of the system to 7.0 with dilute acetic acid and dilute sodium hydroxide solution, and crosslink at a constant temperature of 40°C for 1.5 h.

[0028] (5) Molding and drying: Pour the cross-linked mixed solution into a horizontally placed polytetrafluoroethylene mold, cast into a wet film with a thickness of 0.2 mm, put it in a forced-air drying oven, dry it at 58°C for 2.5 h, take it out and let it cool naturally to room temperature, cut it according to specifications, and sterilize it in an ultraviolet sterilization box for 45 min to obtain the finished product of gallnut composite antibacterial dressing.

[0029] The dressing prepared in this embodiment has a uniform porous film structure with a pore size of 6-8 μm and a porosity of 46%; a moisture permeability of 2150 g / (m²·24h), a tensile strength of 42 MPa, and an elongation at break of 32%; it has an inhibition rate of 99.8% against Staphylococcus aureus and 99.6% against Escherichia coli, is non-cytotoxic, has a skin irritation rating of 0, and its biocompatibility meets the national standards for medical dressings. Example 2

[0030] The Gallnut Compound Antibacterial Dressing, with a total mass of 100g, comprises the following ingredients: 6% Gallnut Tannin Extract, 10% Medical-grade Chitosan, 12% Medical-grade Gelatin, 4% Glycerin, 0.8% Genipin, 0.1% Zn²⁺ Ions, and 67.1% Deionized Water. Specifically, the Gallnut Tannin Extract contains 95.3% tannin with a particle size of 780nm; the Chitosan has a degree of deacetylation of 88% and a molecular weight of 60,000 Da; the Gelatin has a molecular weight of 35,000 Da and an isoelectric point of 7.0; and the Zn²⁺ ions are derived from zinc nitrate hexahydrate, with a calculated addition of 0.46g of zinc nitrate hexahydrate.

[0031] Preparation method (1) Preparation of gallnut extract: Gallnut is crushed and passed through a 40-mesh sieve, and 9 times the mass of deionized water is added. Extraction is carried out at 85℃ and ultrasonic power of 250W for 2.2h. The aqueous extract is obtained by filtration. Anhydrous ethanol is added to the aqueous extract to make the ethanol volume fraction reach 75%. The mixture is allowed to stand at room temperature for 18h, filtered, centrifuged at 3000r / min for 10min, the precipitate is collected, purified by microporous filter membrane, and vacuum dried to a moisture content of 4.5% to obtain gallnut extract powder for later use.

[0032] (2) Solution preparation: Chitosan was added to deionized water containing 0.5% acetic acid and stirred at room temperature until completely dissolved to obtain a chitosan solution with a mass fraction of 2%; gelatin was added to deionized water at 45℃ and stirred until completely dissolved to obtain a gelatin solution with a mass fraction of 5%; gallnut extract powder and zinc nitrate hexahydrate were added to a small amount of deionized water and ultrasonically dispersed at 250W and 35℃ for 15 minutes to obtain a uniform gallnut-Zn²⁺ dispersion without agglomeration.

[0033] (3) Blending and stirring: The gelatin solution is slowly added dropwise to the chitosan solution, and stirred at a constant temperature of 40°C for 20 minutes until the system is uniform. Then, the gallnut-Zn²⁺ dispersion and glycerol are added, and the mixture is stirred at a constant temperature for 40 minutes to obtain a uniform and transparent mixed solution.

[0034] (4) Crosslinking and curing: Add genipin to the mixed solution, stir evenly, adjust the pH of the system to 6.8 with dilute acetic acid and dilute sodium hydroxide solution, and crosslink at a constant temperature of 38℃ for 1.2h. (5) Molding and drying: Pour the crosslinked mixed solution into a horizontally placed polytetrafluoroethylene mold, cast into a wet film with a thickness of 0.15mm, place it in a forced-air drying oven, dry at 55℃ for 2.2h, take it out and let it cool naturally to room temperature, cut it according to specifications, and sterilize it in an ultraviolet sterilization box for 40min to obtain the finished product of gallnut composite antibacterial dressing.

[0035] The dressing prepared in this embodiment has a uniform porous film structure with a pore size of 5-7 μm and a porosity of 41%; a moisture permeability of 1860 g / (m²·24h), a tensile strength of 36 MPa, and an elongation at break of 26%; it has an inhibition rate of 99.2% against Staphylococcus aureus and 99.0% against Escherichia coli, is non-cytotoxic, has a skin irritation rating of 0, and its biocompatibility meets the national standards for medical dressings. Example 3

[0036] The Gallnut Compound Antibacterial Dressing, with a total mass of 100g, comprises the following ingredients: 9% Gallnut Tannin Extract, 14% Medical-grade Chitosan, 16% Medical-grade Gelatin, 5% Glycerin, 1.2% Genipin, 0.3% Zn²⁺ Ions, and 54.5% Deionized Water. Specifically, the Gallnut Tannin Extract contains 95.8% tannin with a particle size of 550nm; the Chitosan has a degree of deacetylation of 92% and a molecular weight of 90,000 Da; the Gelatin has a molecular weight of 45,000 Da and an isoelectric point of 7.5; and the Zn²⁺ ions are derived from zinc nitrate hexahydrate, with a calculated addition of 1.37g of zinc nitrate hexahydrate.

[0037] Preparation method (1) Preparation of gallnut extract: Gallnut is crushed and passed through a 40-mesh sieve, and 10 times the mass of deionized water is added. Extraction is carried out at 90℃ and ultrasonic power of 300W for 2.8h. The aqueous extract is obtained by filtration. Anhydrous ethanol is added to the aqueous extract to make the ethanol volume fraction reach 80%. The mixture is allowed to stand at room temperature for 22h, filtered, centrifuged at 3000r / min for 10min, the precipitate is collected, purified by microporous membrane, and vacuum dried to a moisture content of 2.8% to obtain gallnut extract powder for later use.

[0038] (2) Solution preparation: Chitosan was added to deionized water containing 1.0% acetic acid and stirred at room temperature until completely dissolved to obtain a chitosan solution with a mass fraction of 2%; gelatin was added to deionized water at 50℃ and stirred until completely dissolved to obtain a gelatin solution with a mass fraction of 5%; gallnut extract powder and zinc nitrate hexahydrate were added to a small amount of deionized water and ultrasonically dispersed at 300W and 40℃ for 20 minutes to obtain a uniform gallnut-Zn²⁺ dispersion without agglomeration.

[0039] (3) Blending and stirring: The gelatin solution is slowly added dropwise to the chitosan solution, and the mixture is stirred at a constant temperature of 40°C for 30 minutes until the system is homogeneous. Then, the gallnut-Zn²⁺ dispersion and glycerol are added, and the mixture is stirred at a constant temperature for 50 minutes to obtain a homogeneous and transparent mixed solution.

[0040] (4) Crosslinking and curing: Add genipin to the mixed solution, stir evenly, adjust the pH of the system to 7.2 with dilute acetic acid and dilute sodium hydroxide solution, and crosslink at a constant temperature of 42℃ for 1.8h.

[0041] (5) Molding and drying: Pour the cross-linked mixed solution into a horizontally placed polytetrafluoroethylene mold, cast into a wet film with a thickness of 0.25 mm, put it in a forced-air drying oven, dry it at 60°C for 2.8 h, take it out and let it cool naturally to room temperature, cut it according to specifications, and sterilize it in an ultraviolet sterilization box for 50 min to obtain the finished product of gallnut composite antibacterial dressing.

[0042] The dressing prepared in this embodiment has a uniform porous film structure with a pore size of 8-10 μm and a porosity of 49%; a moisture permeability of 1980 g / (m²·24h), a tensile strength of 39 MPa, and an elongation at break of 29%; it has an inhibition rate of 99.9% against Staphylococcus aureus and 99.8% against Escherichia coli, is non-cytotoxic, has a skin irritation rating of 0, and its biocompatibility meets the national standards for medical dressings.

[0043] The scope of protection of this invention is not limited to the technical solutions disclosed in the specific embodiments. Any modifications, equivalent substitutions, improvements, etc., made to the above embodiments based on the technical essence of this invention shall fall within the scope of protection of this invention.

Claims

1. A gallnut composite antibacterial dressing, characterized in that: The product is composed of the following components by mass percentage: 6-9% gallnut extract, 10-14% chitosan, 12-16% gelatin, 4-5% glycerol, 0.8-1.2% crosslinking agent, 0.1-0.3% Zn²⁺ ions, and the balance being deionized water; the gallnut extract is a gallnut tannin extract with a tannin content ≥95%, purified by conventional ultrasonic treatment, and has a particle size ≤800nm.

2. The gallnut composite antibacterial dressing according to claim 1, characterized in that: The chitosan is conventional medical-grade chitosan with a degree of deacetylation ≥88% and a molecular weight of 60,000-90,000 Da.

3. The gallnut composite antibacterial dressing according to claim 1, characterized in that: The gelatin is conventional medical-grade gelatin with a molecular weight of 35,000-45,000 Da and an isoelectric point of 7.0-7.

5.

4. The gallnut composite antibacterial dressing according to claim 1, characterized in that: The crosslinking agent is conventional genipin; the Zn²⁺ ions are derived from zinc nitrate.

5. The gallnut composite antibacterial dressing according to claim 1, characterized in that: The composite antibacterial dressing has a porous film structure with a pore size of 5-10 μm, a porosity of 40-50%, a moisture permeability of ≥1800 g / (m²·24h), a tensile strength of ≥35 MPa, and an elongation at break of ≥25%.

6. The method for preparing the gallnut composite antibacterial dressing according to any one of claims 1-5, characterized in that: Includes the following steps: (1) Preparation of gallnut extract: Tannins in gallnut were extracted by conventional ultrasonic-assisted water extraction and alcohol precipitation. After ordinary filtration and purification and vacuum drying, gallnut extract powder was obtained for later use; purification; (2) Solution preparation: Chitosan is added to deionized water containing 0.5-1.0% acetic acid and stirred at room temperature until completely dissolved to obtain a chitosan solution; gelatin is added to deionized water at 45-50℃ and stirred until completely dissolved to obtain a gelatin solution; gallnut extract powder and zinc nitrate are added to a small amount of deionized water and ultrasonically dispersed until uniform to obtain a gallnut-Zn²⁺ dispersion; (3) Blending and stirring: Slowly add the gelatin solution to the chitosan solution, stir at a constant temperature of 40℃ for 20-30 minutes until uniform, then add the gallnut-Zn²⁺ dispersion and glycerol, and continue stirring for 40-50 minutes to obtain a mixed solution; (4) Crosslinking and curing: Add conventional genipin to the mixed solution, stir evenly, adjust the pH of the system to 6.8-7.2, and crosslink at a constant temperature of 38-42℃ for 1.2-1.8h; (5) Molding and drying: Pour the cross-linked mixed solution into a conventional plastic mold and cast it into a film with a thickness of 0.15-0.25 mm. Place it in a conventional oven and dry it at 55-60℃ for 2.2-2.8 h. After taking it out, cool it to room temperature, cut it, and sterilize it to obtain the gallnut composite antibacterial dressing.

7. The preparation method according to claim 6, characterized in that: The specific steps of the ultrasonic-assisted water extraction and alcohol precipitation method described in step (1) are as follows: crush the gallnuts through a 40-mesh sieve, add 9-10 times the mass of deionized water, extract for 2.2-2.8 h at 85-90℃ and ultrasonic power of 250-300W, filter to obtain an aqueous extract; add ethanol to the aqueous extract to make the ethanol volume fraction reach 75-80%, let stand at room temperature for 18-22 h, filter, centrifuge, collect the precipitate, purify by ordinary filtration, and vacuum dry to a moisture content ≤5% to obtain gallnut extract powder.

8. The preparation method according to claim 6, characterized in that: The ultrasonic dispersion in step (2) uses a power of 250-300W, a dispersion time of 15-20min, and a dispersion temperature of 35-40℃ to ensure that the gallnut extract and Zn²⁺ ions are uniformly dispersed without agglomeration.

9. The preparation method according to claim 6, characterized in that: In step (4), no intermittent ultrasound assistance is required; the cross-linking reaction is carried out by constant-temperature stirring.

10. The preparation method according to claim 6, characterized in that: The sterilization method described in step (5) is conventional ultraviolet sterilization, and the sterilization time is 40-50 minutes.