Hydrogel wound dressing and preparation method thereof

Abstract

The invention discloses a hydrogel wound dressing and a preparation method thereof, and belongs to the technical field of medical wound dressing preparation. The preparation method comprises the following steps: S1, preparing chitosan-silver nanoparticles CS-Ag; s2, preparing aminated chitosan-silver nano particles (CS-Ag-NH2), and preparing the chitosan-silver nano particles, s3, a hydrogel wound dressing CNF / CS-Ag-NH2 is prepared; the CNF is a carboxylated cellulose nanofiber. According to the prepared CNF / CS-Ag-NH2 hydrogel wound dressing, through the synergistic effect of the carboxylated cellulose nanofibers and the aminated chitosan-silver nanoparticles, the organic combination of the antibacterial property and the healing promoting property is realized; the hydrogel wound dressing not only can effectively control wound infection, but also can promote wound healing, and has a wide application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of the preparation of medical wound dressings, and particularly relates to a hydrogel wound dressing and a preparation method thereof. Background Art

[0002] The skin is the largest organ of the human body. As a barrier between the body and the external environment, it has important functions such as protecting internal tissues, regulating body temperature, and sensing external stimuli. However, the skin is easily damaged by physical, chemical, or biological factors, resulting in wounds. When the wound is narrow and small, the skin can heal itself. However, large-area human skin wounds are prone to infection and difficult to heal. Therefore, in order to assist wound healing, appropriate wound treatment is necessary. To promote wound healing and prevent infection, the use of appropriate wound dressings is crucial. Traditional wound dressings, such as gauze, cotton wool, and bandages, although able to cover the wound and provide certain protection, have relatively single functions and cannot meet the high requirements of modern medicine for wound healing. For example, traditional dressings may not be able to effectively prevent bacterial infection. Therefore, the development of new wound dressings has become a hot topic in current research.

[0003] Hydrogel is a three-dimensional network structure formed by hydrophilic polymer materials through physical or chemical cross-linking, which can absorb and retain a large amount of water. Due to its unique physical and chemical properties, hydrogel shows great application potential in the field of wound dressings.

[0004] Compared with traditional dressings, hydrogel dressings have the following advantages: (1) Biocompatibility: Hydrogels are usually made of materials with good biocompatibility, which can reduce the irritation to the tissues around the wound; (2) Drug carrier: Hydrogels can be used as drug carriers to slowly release antibacterial agents, growth factors, or other therapeutic drugs to the wound site, enhancing the therapeutic effect; (3) Moist environment: Hydrogels can absorb wound exudate and keep the wound moist, promoting cell migration and proliferation, and accelerating wound healing. Although hydrogel dressings have many advantages, there are still some limitations in actual applications, such as limited antibacterial performance and poor effect of promoting wound healing. Summary of the Invention

[0005] The present invention provides a hydrogel wound dressing and a preparation method thereof, which can solve the problems of limited antibacterial performance and poor effect of promoting wound healing existing in the hydrogel wound dressing in the prior art.

[0006] A preparation method of a hydrogel wound dressing includes the following steps:

[0007] S1. Prepare chitosan-silver nanoparticles CS-Ag;

[0008] S2. Prepare amino-chitosan-silver nanoparticles CS-Ag-NH2;

[0009] S3. Prepare the hydrogel wound dressing CNF / CS-Ag-NH2;

[0010] The CNF is carboxylated cellulose nanofibers.

[0011] Furthermore, the specific steps of S1 are as follows:

[0012] Take chitosan CS powder, add it to distilled water, and add glacial acetic acid to adjust the pH value to 3-4 to completely dissolve CS; then add AgNO3 solution and stir well; then dropwise add NaBH4 solution and stir for reaction for 10-15 min; add ammonia water to adjust the pH value to alkaline to form a precipitate in the solution, centrifuge the solution to obtain a solid substance, wash the solid substance with distilled water, wash it with acetone, and dry it at room temperature for 10-12 h to obtain chitosan-silver nanoparticles, denoted as CS-Ag.

[0013] Furthermore, the dosage ratio of CS, AgNO3 solution, and NaBH4 solution is 0.06-0.1 g: 6-10 mL: 0.6-1 mL; the concentration of AgNO3 solution is 10 mmol / L, and the concentration of NaBH4 solution is 100 mmol / L.

[0014] Furthermore, the specific steps of S2 are as follows:

[0015] Disperse CS-Ag in a methanol / water solution, carry out an amination reaction with KH550 at 60-70 °C for 10-12 h. After the reaction is completed, filter and wash with deionized water, and then vacuum dry at 30-40 °C for 12 h to obtain aminated chitosan-silver nanoparticles, denoted as CS-Ag-NH2.

[0016] Furthermore, the volume ratio of methanol to deionized water in the methanol / water solution is 9:1.

[0017] Furthermore, the dosage ratio of CS-Ag to the methanol / water solution is 1 g: 10 mL; the dosage of KH550 is 3-5% of the mass of CS-Ag.

[0018] Furthermore, the specific steps of S3 are as follows:

[0019] S31. Completely dissolve the carboxylated cellulose nanofibers CNF in deionized water, and ultrasonically treat it at room temperature for 15-20 min to obtain a uniform CNF hydrogel;

[0020] S32. Dissolve CS-Ag-NH2 in deionized water to form a CS-Ag-NH2 solution;

[0021] S33. Add the CS-Ag-NH2 solution to the CNF hydrogel, and vigorously stir at 25 °C for 2 h to form a non-covalently crosslinked hydrogel.

[0022] S34. Freeze-dry the non-covalently crosslinked hydrogel to obtain the CNF / CS-Ag-NH2 hydrogel wound dressing.

[0023] Furthermore, in step S31, the dosage ratio of CNF to deionized water is 200 mg: 15 mL; in step S32, the dosage ratio of CS-Ag-NH2 to deionized water is 0.2 mg: 5 mL.

[0024] Furthermore, in step S33, the mass ratio of CNF in the CNF hydrogel to CS-Ag-NH2 in the CS-Ag-NH2 solution is 100: 0.1 - 0.3.

[0025] A hydrogel wound dressing is prepared by the above preparation method.

[0026] Advantages of the present invention:

[0027] The CNF / CS-Ag-NH2 hydrogel wound dressing prepared by the present invention has excellent properties in many aspects, mainly reflected in its antibacterial property and the ability to promote wound healing.

[0028] (1) First, the carboxyl groups (-COOH) on the surface of carboxylated cellulose nanofibers and the amino groups (-NH2) on the surface of amino-functionalized chitosan-silver nanoparticles (CS-Ag-NH2) can form non-covalent crosslinks through electrostatic interactions or hydrogen bonding, thereby constructing a stable interpenetrating polymer network structure; this tight binding not only enhances the mechanical properties of the hydrogel but also endows the dressing with excellent antibacterial properties; silver nanoparticles (Ag NPs), as a broad-spectrum antibacterial agent, can destroy bacterial cell membranes by releasing silver ions (Ag + ) and inhibit bacterial growth, thus effectively preventing wound infection; in addition, chitosan (CS) itself also has certain antibacterial properties, which can further enhance the antibacterial effect of the dressing.

[0029] (2) Second, the CNF / CS-Ag-NH2 hydrogel wound dressing has excellent liquid absorption performance and moisture retention ability; the porous structure of the hydrogel can quickly absorb wound exudate, maintain a moist wound environment, and avoid excessive drying or excessive wetness of the wound; the moist wound environment is not only conducive to cell migration and proliferation but also can promote angiogenesis and tissue regeneration, thereby accelerating the wound healing process; at the same time, the breathability of the hydrogel allows the exchange of oxygen and carbon dioxide, further supporting the metabolism and repair of wound tissues; therefore, it can show a good effect in promoting wound healing.

[0030] In summary, the CNF / CS-Ag-NH2 hydrogel wound dressing prepared by the present invention realizes the organic combination of antibacterial and wound-healing promotion properties through the synergistic effect of carboxylated cellulose nanofibers and amino-functionalized chitosan-silver nanoparticles. This hydrogel wound dressing can not only effectively control wound infection but also promote wound healing, showing broad application prospects. Detailed Embodiments

[0031] The following describes the detailed embodiments of the present invention in detail, but it should be understood that the protection scope of the present invention is not limited by the detailed embodiments.

[0032] Example 1

[0033] This example provides a hydrogel wound dressing, which is prepared by the following steps:

[0034] S1. Preparation of chitosan-silver nanoparticles CS-Ag:

[0035] Take 0.06 g of CS powder, add it to distilled water, and add glacial acetic acid to adjust the pH value to 3 - 4 to completely dissolve CS. Then add 6 mL of a 10 mmol / L AgNO3 solution, stir and mix evenly. Next, dropwise add 0.6 mL of a 100 mmol / L NaBH4 solution, stir and react for 15 min. Add ammonia water to adjust the pH value to alkaline to form a precipitate in the solution. Centrifuge the solution to obtain a solid substance. The solid substance is washed with distilled water, washed with acetone, and dried at room temperature for 12 h to obtain chitosan-silver nanoparticles, denoted as CS-Ag.

[0036] S2. Preparation of amino-functionalized chitosan-silver nanoparticles CS-Ag-NH2:

[0037] Disperse 1 g of CS-Ag powder in a methanol / water solution with a volume ratio of methanol to deionized water of 9:1 (10 mL), carry out an amino-functionalization reaction with 0.03 g of KH550 at 70 °C for 12 h. After the reaction is completed, filter and wash with deionized water, and then vacuum dry at 35 °C for 12 h to obtain amino-functionalized chitosan-silver nanoparticles, denoted as CS-Ag-NH2.

[0038] S3. Preparation of the hydrogel wound dressing CNF / CS-Ag-NH2:

[0039] S31. Completely dissolve 200 mg of carboxylated cellulose nanofibers CNF in 15 mL of deionized water, and perform ultrasonic treatment at room temperature for 20 min to obtain a uniform CNF hydrogel.

[0040] S32. Dissolve 0.2 mg of CS-Ag-NH2 in 5 mL of deionized water to form a CS-Ag-NH2 solution.

[0041] S33. Add the above CS-Ag-NH2 solution to the CNF hydrogel and stir vigorously at 25 °C for 2 h to form a non-covalently crosslinked hydrogel;

[0042] S34. Pour the non-covalently crosslinked hydrogel into a petri dish and freeze-dry it to obtain a CNF / CS-Ag-NH2 hydrogel wound dressing.

[0043] Example 2

[0044] This example provides a hydrogel wound dressing, which is prepared by the following steps:

[0045] S1. Prepare chitosan-silver nanoparticles CS-Ag:

[0046] Take 0.08 g of CS powder, add it to distilled water, and add glacial acetic acid to adjust the pH value to 3-4 to completely dissolve CS; then add 8 mL of a 10 mmol / L AgNO3 solution, stir and mix well; then dropwise add 0.8 mL of a 100 mmol / L NaBH4 solution, stir and react for 15 min; add ammonia water to adjust the pH value to alkaline to form a precipitate in the solution, centrifuge the solution to obtain a solid substance, wash the solid substance with distilled water, wash it with acetone, and dry it at room temperature for 12 h to obtain chitosan-silver nanoparticles, denoted as CS-Ag;

[0047] S2. Prepare amino-functionalized chitosan-silver nanoparticles CS-Ag-NH2:

[0048] Disperse 1 g of CS-Ag powder in a methanol / water solution with a volume ratio of methanol to deionized water of 9:1 (10 mL), carry out an amino-functionalization reaction with 0.03 g of KH550 at 70 °C for 12 h. After the reaction, filter and wash with deionized water, and then vacuum dry at 35 °C for 12 h to obtain amino-functionalized chitosan-silver nanoparticles, denoted as CS-Ag-NH2;

[0049] S3. Prepare the hydrogel wound dressing CNF / CS-Ag-NH2:

[0050] S31. Completely dissolve 200 mg of carboxylated cellulose nanofibers CNF in 15 mL of deionized water, and ultrasonically treat it at room temperature for 20 min to obtain a uniform CNF hydrogel;

[0051] S32. Dissolve 0.2 mg of CS-Ag-NH2 in 5 mL of deionized water to form a CS-Ag-NH2 solution;

[0052] S33. Add the above CS-Ag-NH2 solution to the CNF hydrogel and stir vigorously at 25 °C for 2 h to form a non-covalently crosslinked hydrogel;

[0053] S34. Pour the non-covalently crosslinked hydrogel into a petri dish and freeze-dry it to obtain the CNF / CS-Ag-NH2 hydrogel wound dressing.

[0054] Example 3

[0055] This example provides a hydrogel wound dressing, which is prepared by the following steps:

[0056] S1. Prepare chitosan-silver nanoparticles CS-Ag:

[0057] Take 0.1 g of CS powder, add it to distilled water and add glacial acetic acid to adjust the pH value to 3-4 to completely dissolve CS; then add 10 mL of AgNO3 solution with a concentration of 10 mmol / L, stir and mix well; then dropwise add 1 mL of NaBH4 solution with a concentration of 100 mmol / L, stir and react for 15 min; add ammonia water to adjust the pH value to alkaline to form a precipitate in the solution, centrifuge the solution to obtain a solid substance, wash the solid substance with distilled water, wash it with acetone, and dry it at room temperature for 12 h to obtain chitosan-silver nanoparticles, denoted as CS-Ag;

[0058] S2. Prepare amino-functionalized chitosan-silver nanoparticles CS-Ag-NH2:

[0059] Disperse 1 g of CS-Ag powder in a methanol / water solution with a volume ratio of 9:1 of methanol and deionized water, carry out an amino-functionalization reaction with 0.03 g of KH550 at 70 °C for 12 h, after the reaction, filter and wash with deionized water, and then vacuum-dry at 35 °C for 12 h to obtain amino-functionalized chitosan-silver nanoparticles, denoted as CS-Ag-NH2;

[0060] S3. Prepare the hydrogel wound dressing CNF / CS-Ag-NH2:

[0061] S31. Completely dissolve 200 mg of carboxylated cellulose nanofibers CNF in 15 mL of deionized water, and ultrasonically treat it at room temperature for 20 min to obtain a uniform CNF hydrogel;

[0062] S32. Dissolve 0.2 mg of CS-Ag-NH2 in 5 mL of deionized water to form a CS-Ag-NH2 solution;

[0063] S33. Add the above CS-Ag-NH2 solution to the CNF hydrogel and stir vigorously at 25 °C for 2 h to form a non-covalently crosslinked hydrogel;

[0064] S34. Pour the non-covalently crosslinked hydrogel into a petri dish and freeze-dry it to obtain the CNF / CS-Ag-NH2 hydrogel wound dressing.

[0065] Example 4

[0066] This embodiment provides a hydrogel wound dressing, which is prepared by the following steps:

[0067] S1. Prepare chitosan-silver nanoparticles CS-Ag:

[0068] Take 0.1 g of CS powder, add it to distilled water, and add glacial acetic acid to adjust the pH value to 3-4 to completely dissolve CS; then add 10 mL of AgNO3 solution with a concentration of 10 mmol / L, stir and mix well; then dropwise add 1 mL of NaBH4 solution with a concentration of 100 mmol / L, stir and react for 15 min; add ammonia water to adjust the pH value to alkaline to form a precipitate in the solution, centrifuge the solution to obtain a solid substance, wash the solid substance with distilled water, wash it with acetone, and dry it at room temperature for 12 h to obtain chitosan-silver nanoparticles, denoted as CS-Ag;

[0069] S2. Prepare amino-functionalized chitosan-silver nanoparticles CS-Ag-NH2:

[0070] Disperse 1 g of CS-Ag powder in a methanol / water solution with a volume ratio of 9:1 of methanol and deionized water, carry out an amino-functionalization reaction with 0.04 g of KH550 at 70 °C for 12 h, after the reaction is completed, filter and wash with deionized water, and then vacuum dry at 35 °C for 12 h to obtain amino-functionalized chitosan-silver nanoparticles, denoted as CS-Ag-NH2;

[0071] S3. Prepare a hydrogel wound dressing CNF / CS-Ag-NH2:

[0072] S31. Completely dissolve 200 mg of carboxylated cellulose nanofibers CNF in 15 mL of deionized water, and ultrasonically treat it at room temperature for 20 min to obtain a uniform CNF hydrogel;

[0073] S32. Dissolve 0.2 mg of CS-Ag-NH2 in 5 mL of deionized water to form a CS-Ag-NH2 solution;

[0074] S33. Add the above CS-Ag-NH2 solution to the CNF hydrogel, and vigorously stir at 25 °C for 2 h to form a non-covalently crosslinked hydrogel;

[0075] S34. Pour the non-covalently crosslinked hydrogel into a petri dish, and freeze-dry it to obtain a CNF / CS-Ag-NH2 hydrogel wound dressing.

[0076] Example 5

[0077] This embodiment provides a hydrogel wound dressing, which is prepared by the following steps:

[0078] S1. Prepare chitosan-silver nanoparticles CS-Ag:

[0079] Take 0.1 g of CS powder, add it to distilled water, and add glacial acetic acid to adjust the pH value to 3 - 4 to completely dissolve CS; then add 10 mL of AgNO3 solution with a concentration of 10 mmol / L, stir and mix evenly; then dropwise add 1 mL of NaBH4 solution with a concentration of 100 mmol / L, stir and react for 15 min; add ammonia water to adjust the pH value to alkaline to form a precipitate in the solution, centrifuge the solution to obtain a solid substance, wash the solid substance with distilled water, wash it with acetone, and dry it at room temperature for 12 h to obtain chitosan-silver nanoparticles, denoted as CS-Ag;

[0080] S2. Preparation of amino-functionalized chitosan-silver nanoparticles CS-Ag-NH2:

[0081] Disperse 1 g of CS-Ag powder in a methanol / water solution with a volume ratio of methanol to deionized water of 9:1 (10 mL), carry out an amino-functionalization reaction with 0.05 g of KH550 at 70 °C for 12 h. After the reaction is completed, filter and wash with deionized water, and then vacuum dry at 35 °C for 12 h to obtain amino-functionalized chitosan-silver nanoparticles, denoted as CS-Ag-NH2;

[0082] S3. Preparation of hydrogel wound dressing CNF / CS-Ag-NH2:

[0083] S31. Completely dissolve 200 mg of carboxylated cellulose nanofibers CNF in 15 mL of deionized water, and ultrasonically treat it at room temperature for 20 min to obtain a uniform CNF hydrogel;

[0084] S32. Dissolve 0.2 mg of CS-Ag-NH2 in 5 mL of deionized water to form a CS-Ag-NH2 solution;

[0085] S33. Add the above CS-Ag-NH2 solution to the CNF hydrogel, and vigorously stir at 25 °C for 2 h to form a non-covalently crosslinked hydrogel;

[0086] S34. Pour the non-covalently crosslinked hydrogel into a petri dish, and freeze-dry it to obtain the CNF / CS-Ag-NH2 hydrogel wound dressing.

[0087] Example 6

[0088] This example provides a hydrogel wound dressing, which is prepared by the following steps:

[0089] S1. Preparation of chitosan-silver nanoparticles CS-Ag:

[0090] Take 0.1 g of CS powder, add it to distilled water, and add glacial acetic acid to adjust the pH value to 3 - 4 to completely dissolve CS; then add 10 mL of AgNO3 solution with a concentration of 10 mmol / L, stir and mix well; then dropwise add 1 mL of NaBH4 solution with a concentration of 100 mmol / L, stir and react for 15 min; add ammonia water to adjust the pH value to alkaline to form a precipitate in the solution, centrifuge the solution to obtain a solid substance, wash the solid substance with distilled water, wash it with acetone, and dry it at room temperature for 12 h to obtain chitosan-silver nanoparticles, denoted as CS-Ag;

[0091] S2. Preparation of amino-functionalized chitosan-silver nanoparticles CS-Ag-NH2:

[0092] Disperse 1 g of CS-Ag powder in a methanol / water solution with a volume ratio of methanol to deionized water of 9:1 (10 mL), carry out an amino-functionalization reaction with 0.05 g of KH550 at 70 °C for 12 h. After the reaction is completed, filter and wash with deionized water, and then vacuum dry at 35 °C for 12 h to obtain amino-functionalized chitosan-silver nanoparticles, denoted as CS-Ag-NH2;

[0093] S3. Preparation of hydrogel wound dressing CNF / CS-Ag-NH2:

[0094] S31. Completely dissolve 200 mg of carboxylated cellulose nanofibers CNF in 15 mL of deionized water, and ultrasonically treat it at room temperature for 20 min to obtain a uniform CNF hydrogel;

[0095] S32. Dissolve 0.4 mg of CS-Ag-NH2 in 10 mL of deionized water to form a CS-Ag-NH2 solution;

[0096] S33. Add the above CS-Ag-NH2 solution to the CNF hydrogel and stir vigorously at 25 °C for 2 h to form a non-covalently crosslinked hydrogel;

[0097] S34. Pour the non-covalently crosslinked hydrogel into a petri dish and freeze-dry it to obtain the CNF / CS-Ag-NH2 hydrogel wound dressing.

[0098] Example 7

[0099] This example provides a hydrogel wound dressing, which is prepared by the following steps:

[0100] S1. Preparation of chitosan-silver nanoparticles CS-Ag:

[0101] Take 0.1 g of CS powder, add it to distilled water, and add glacial acetic acid to adjust the pH value to 3 - 4 to completely dissolve CS. Then add 10 mL of AgNO3 solution with a concentration of 10 mmol / L, stir and mix well. Next, dropwise add 1 mL of NaBH4 solution with a concentration of 100 mmol / L, stir and react for 15 min. Add ammonia water to adjust the pH value to alkaline to form a precipitate in the solution. Centrifuge the solution to obtain a solid substance. The solid substance is washed with distilled water, washed with acetone, and dried at room temperature for 12 h to obtain chitosan-silver nanoparticles, denoted as CS-Ag;

[0102] S2. Preparation of amino-functionalized chitosan-silver nanoparticles CS-Ag-NH2:

[0103] Disperse 1 g of CS-Ag powder in a methanol / water solution with a volume ratio of 9:1 of methanol and deionized water, and carry out an amino-functionalization reaction with 0.05 g of KH550 at 70 °C for 12 h. After the reaction is completed, filter and wash with deionized water, and then vacuum dry at 35 °C for 12 h to obtain amino-functionalized chitosan-silver nanoparticles, denoted as CS-Ag-NH2;

[0104] S3. Preparation of hydrogel wound dressing CNF / CS-Ag-NH2:

[0105] S31. Completely dissolve 200 mg of carboxylated cellulose nanofibers CNF in 15 mL of deionized water, and ultrasonically treat it at room temperature for 20 min to obtain a uniform CNF hydrogel;

[0106] S32. Dissolve 0.6 mg of CS-Ag-NH2 in 15 mL of deionized water to form a CS-Ag-NH2 solution;

[0107] S33. Add the above CS-Ag-NH2 solution to the CNF hydrogel, and stir vigorously at 25 °C for 2 h to form a non-covalently crosslinked hydrogel;

[0108] S34. Pour the non-covalently crosslinked hydrogel into a petri dish and freeze-dry to obtain the CNF / CS-Ag-NH2 hydrogel wound dressing.

[0109] Comparative Example 1

[0110] This comparative example provides a hydrogel wound dressing, which is prepared by the following steps:

[0111] S1. Preparation of chitosan-silver nanoparticles CS-Ag:

[0112] Take 0.06 g of CS powder, add it to distilled water, and add glacial acetic acid to adjust the pH value to 3 - 4 to completely dissolve CS; then add 6 mL of AgNO3 solution with a concentration of 10 mmol / L, stir and mix evenly; then dropwise add 0.6 mL of NaBH4 solution with a concentration of 100 mmol / L, stir and react for 15 min; add ammonia water to adjust the pH value to alkaline to form a precipitate in the solution, centrifuge the solution to obtain solid substances, wash the solid substances with distilled water, wash with acetone, and dry at room temperature for 12 h to obtain chitosan-silver nanoparticles, denoted as CS-Ag;

[0113] S2. Preparation of hydrogel wound dressing CNF / CS-Ag:

[0114] S21. Completely dissolve 200 mg of carboxylated cellulose nanofibers CNF in 15 mL of deionized water, and ultrasonically treat it at room temperature for 20 min to obtain a uniform CNF hydrogel;

[0115] S22. Dissolve 0.2 mg of CS-Ag in 5 mL of deionized water to form a CS-Ag solution;

[0116] S23. Add the above CS-Ag solution to the CNF hydrogel, and vigorously stir at 25 °C for 2 h to form a non-covalently crosslinked hydrogel;

[0117] S24. Pour the non-covalently crosslinked hydrogel into a petri dish and freeze-dry to obtain the CNF / CS-Ag hydrogel wound dressing.

[0118] Comparative Example 2

[0119] This comparative example provides a hydrogel wound dressing, which is prepared by the following steps:

[0120] Completely dissolve 200 mg of carboxylated cellulose nanofibers CNF in 15 mL of deionized water, and ultrasonically treat it at room temperature for 20 min to obtain a uniform CNF hydrogel; pour the CNF hydrogel into a petri dish and freeze-dry to obtain the CNF hydrogel wound dressing.

[0121] Perform antibacterial tests and wound healing ability tests on the hydrogel wound dressings prepared in Examples 1 - 7 and Comparative Examples 1 - 2. The test methods are as follows:

[0122] Antibacterial test method: Use the agar diffusion method to test the antibacterial rate of the hydrogel wound dressing against Staphylococcus aureus and Escherichia coli;

[0123] Wound healing ability test method: Prepare 7 adult male mice weighing 18 - 22 g. Make a skin wound with a diameter of 8 mm on the back of each mouse, and tightly cover it with the hydrogel wound dressings prepared in Examples 1 - 5 and Comparative Examples 1 - 2. After 10 days, measure the wound size of the mice. The wound healing rate is calculated by the following formula, where S1 represents the wound area size on the first day and S10 represents the wound area size on the tenth day.

[0124]

[0125] The test results are shown in Table 1.

[0126] Table 1

[0127]

[0128] As can be seen from Table 1, the CNF / CS-Ag-NH2 hydrogel wound dressings prepared in Examples 1 - 7 have excellent antibacterial properties and the ability to promote wound healing.

[0129] Compared with Example 1, Comparative Example 1 prepared a CNF / CS-Ag hydrogel wound dressing, and both the antibacterial property and the wound healing rate decreased, indicating that the amination modification of CS-Ag can improve the antibacterial property and the ability to promote wound healing of the hydrogel wound dressing; compared with Example 1, Comparative Example 2 did not add aminated chitosan-silver nanoparticles CS-Ag-NH2 and prepared a CNF hydrogel wound dressing, which has no antibacterial property and poor ability to promote wound healing.

[0130] The above only discloses several specific embodiments of the present invention. However, the embodiments of the present invention are not limited thereto, and any changes that can be conceived by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. A preparation method of a hydrogel wound dressing, characterized in that, It includes the following steps: S1. Prepare chitosan-silver nanoparticles CS-Ag; S2. Prepare amino-functionalized chitosan-silver nanoparticles CS-Ag-NH2; S3. Prepare a hydrogel wound dressing CNF / CS-Ag-NH2; The CNF is carboxylated cellulose nanofibers.

2. The preparation method of a hydrogel wound dressing according to claim 1, characterized in that, The specific steps of S1 are as follows: Take chitosan CS powder, add it to distilled water, and add glacial acetic acid to adjust the pH value to 3-4 to completely dissolve CS; then add AgNO3 solution and stir well; then dropwise add NaBH4 solution and stir for reaction for 10-15 min; add ammonia water to adjust the pH value to alkaline to form a precipitate in the solution, centrifuge the solution to obtain a solid substance, wash the solid substance with distilled water, wash it with acetone, and dry it at room temperature for 10-12 h to obtain chitosan-silver nanoparticles, denoted as CS-Ag.

3. The preparation method of a hydrogel wound dressing according to claim 2, characterized in that, The dosage ratio of CS, AgNO3 solution and NaBH4 solution is 0.06-0.1 g: 6-10 mL: 0.6-1 mL; the concentration of AgNO3 solution is 10 mmol / L, and the concentration of NaBH4 solution is 100 mmol / L.

4. The preparation method of a hydrogel wound dressing according to claim 1, characterized in that, The specific steps of S2 are as follows: Disperse CS-Ag in a methanol / water solution, carry out an amino-functionalization reaction with KH550 at 60-70 °C for 10-12 h. After the reaction is completed, filter and wash with deionized water, and then vacuum dry at 30-40 °C for 12 h to obtain amino-functionalized chitosan-silver nanoparticles, denoted as CS-Ag-NH2.

5. The preparation method of a hydrogel wound dressing according to claim 4, characterized in that, The volume ratio of methanol to deionized water in the methanol / water solution is 9:

1.

6. The preparation method of a hydrogel wound dressing according to claim 4, wherein, The dosage ratio of CS-Ag to the methanol / water solution is 1 g: 10 mL; the dosage of KH550 is 3-5% of the mass of CS-Ag.

7. The preparation method of a hydrogel wound dressing according to claim 1, characterized in that, The specific steps of S3 are as follows: S31. Completely dissolve carboxylated cellulose nanofibers CNF in deionized water, and ultrasonically treat it at room temperature for 15-20 min to obtain a uniform CNF hydrogel; S32. Dissolve CS-Ag-NH2 in deionized water to form a CS-Ag-NH2 solution; S33. Add the CS-Ag-NH2 solution to the CNF hydrogel and stir vigorously at 25 °C for 2 h to form a non-covalently crosslinked hydrogel; S34. Freeze-dry the non-covalently crosslinked hydrogel to obtain a CNF / CS-Ag-NH2 hydrogel wound dressing.

8. The preparation method of a hydrogel wound dressing according to claim 7, characterized in that, In step S31, the dosage ratio of CNF to deionized water is 200 mg: 15 mL; in step S32, the dosage ratio of CS-Ag-NH2 to deionized water is 0.2 mg: 5 mL.

9. The preparation method of a hydrogel wound dressing according to claim 7, characterized in that, In step S33, the mass ratio of CNF in the CNF hydrogel to CS-Ag-NH2 in the CS-Ag-NH2 solution is 100: 0.1-0.

3.

10. A hydrogel wound dressing, characterized in that, Prepared by the preparation method according to any one of claims 1-9.

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