Double-network hydrogel and preparation method thereof

Abstract

The invention relates to the technical field of biomedical materials, in particular to a dual-network hydrogel dressing and a preparation method thereof.The dual-network hydrogel dressing is prepared from, by weight, 0.1-0.3 part of methylacryloyl chitosan, 0.1-0.3 part of chitosan, 0.1-0.3 part of chitosan, 0.1-0.3 part of chitosan, 0.1-0.3 part of chitosan, 0.1-0.3 part of chitosan, 0.1-0.3 0.01 to 0.1 part of quaternary ammonium salt chitosan; 20 to 30 parts of acrylamide; 0.5 to 2 parts of sodium alginate; and 0.1 to 1 part of a photoinitiator. According to the double-network hydrogel dressing provided by the invention, the multifunctional double-network hydrogel dressing is constructed through photo-initiation covalent cross-linking, calcium ion physical cross-linking and biological function modification, the action mechanisms of all the components are clear and highly complementary, secondary injury of a wound surface is avoided while the mechanical property of the hydrogel is improved, and help is provided for wound repair.

Description

Technical Field

[0001] This invention relates to the field of biomedical materials technology, and in particular to a dual-network hydrogel and its preparation method. Background Technology

[0002] Diabetic skin ulcers, a serious complication of diabetes, not only have a high incidence rate but also easily lead to disability or even death. Burns, as a highly destructive type of skin trauma, especially large, irregular burns, present significant clinical challenges due to their slow healing process and difficulty in repair. Skin wounds are a prevalent global health problem, and their widespread occurrence not only significantly reduces patients' quality of life but also places a continuous and heavy burden on public health systems.

[0003] Against this clinical backdrop, the development of novel wound dressings with comprehensive advantages such as high-efficiency repair, reduced infection risk, and reduced patient suffering has become an urgent need in the field of wound repair. Currently, existing technologies for traditional dressings mainly include hydrocolloids, alginates, foams, and silver-containing dressings. While these dressings have improved exudate absorption and anti-infection properties, they still have shortcomings in regulating the wound microenvironment, promoting tissue regeneration, and adapting to complex wounds. Although bioactive dressings have better healing effects, they suffer from problems such as complex preparation, high cost, and difficulty in large-scale application, and still cannot completely solve the clinical challenges of chronic, non-healing wounds.

[0004] Hydrogel dressings, with their unique physicochemical and biological properties, have shown great potential in wound treatment, providing a new direction for solving clinical wound repair problems.

[0005] Although existing hydrogel dressings have excellent biocompatibility, they still have insufficient mechanical properties, which limits their application in the field of chronic and difficult-to-heal wounds. Summary of the Invention

[0006] To address the problem of insufficient mechanical properties in existing hydrogel dressings, this invention provides a dual-network hydrogel dressing. This dual-network hydrogel dressing achieves rapid molding and precise control through photocrosslinking, and strengthens structural properties through ionic crosslinking, thus constructing a mechanically adjustable, biosafe, and highly efficient wound repair dressing, solving the problem of insufficient mechanical properties in existing hydrogel dressings.

[0007] The technical solution adopted by this invention to solve its technical problem is: A dual-network hydrogel dressing, comprising the following components by weight: 0.1-0.3 parts of methacrylated chitosan; Quaternary ammonium salt chitosan, 0.01-0.1 parts; Acrylamide 20-30 parts; Sodium alginate 0.5-2 parts; Photoinitiator 0.1-1 part.

[0008] Optionally, the methacrylated chitosan is prepared by acylation reaction of methacrylic anhydride and chitosan.

[0009] Optionally, the preparation method of the methacrylated chitosan is as follows: after mixing deionized water, acetic acid and chitosan, methacrylic anhydride is added dropwise, and the mixture is reacted at 50-70°C. After dialysis and freeze-drying, methacrylated chitosan is obtained.

[0010] Optionally, the molar ratio of the amino group of the chitosan to the methacrylic anhydride is 1:4.

[0011] Optionally, the photoinitiator is water-soluble TPO nanoparticles.

[0012] Optionally, the water-soluble TPO nanoparticles are prepared as follows: at room temperature, n-butyl acetate is mixed with sodium dodecyl sulfate, isopropanol and polyvinylpyrrolidone to form an oil phase, and then TPO is dissolved in the oil phase and poured into purified water to obtain a mixture; the mixture is stirred at room temperature to obtain an O / W microemulsion containing TPO; the microemulsion is freeze-dried to obtain water-soluble TPO nanoparticles.

[0013] Optionally, the concentration of TPO in the mixture is 1.7 wt%.

[0014] Optionally, the concentration of sodium dodecyl sulfate in the mixture is 7.5 wt%.

[0015] Optionally, the concentration of polyvinylpyrrolidone in the mixture is 7.5 wt%.

[0016] Another object of the present invention is to provide a method for preparing the dual-network hydrogel dressing as described above, comprising the following steps: S1: According to the formula, methacrylamide chitosan, quaternary ammonium salt chitosan, acrylamide, and sodium alginate are mixed at room temperature to obtain a mixed solution; S2: Add the photoinitiator to the mixed solution and stir under light-protected conditions to obtain a precursor solution for the hydrogel; S3: The precursor solution is ultrasonically dispersed and then cured by ultraviolet light to obtain a hydrogel; S4: The hydrogel is soaked in a supersaturated CaSO4 solution to obtain a double-network hydrogel.

[0017] The beneficial effects of this invention are: The dual-network hydrogel dressing provided by this invention is constructed through photo-initiated covalent crosslinking, calcium ion physical crosslinking, and biofunctional modification to synergistically create a dual-network multifunctional hydrogel dressing. The mechanisms of action of each component are clear and highly complementary. While improving the mechanical properties of the hydrogel, it avoids secondary damage to the wound surface and helps with wound healing. Detailed Implementation

[0018] The present invention will now be described in further detail. The embodiments described below are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0019] To address the insufficient mechanical properties of existing hydrogel dressings, this invention provides a dual-network hydrogel dressing, whose raw materials, by weight, comprise the following components: 0.1-0.3 parts of methacrylated chitosan; Quaternary ammonium salt chitosan, 0.01-0.1 parts; Acrylamide 20-30 parts; Sodium alginate 0.5-2 parts; Photoinitiator 0.1-1 part.

[0020] In the preparation process, the methacryloyl group of the side chain of methacrylamide chitosan (CSMA) is cleaved under UV / Vis light irradiation by a photoinitiator to generate free radicals, which copolymerize with acrylamide (AM) to form a stable three-dimensional covalent main network, providing the gel with core mechanical strength, excellent elasticity, and extensibility. Quaternary ammonium salt chitosan (QCS), as a long-lasting antibacterial enhancer, uses its positively charged quaternary ammonium salt groups to disrupt bacterial cell membranes through electrostatic interactions, achieving broad-spectrum antibacterial activity. It also further fine-tunes the charge density of the system to synergistically weaken non-specific binding, resulting in stable dispersion and no cytotoxicity. Sodium alginate (SA) in the system undergoes egg-box ionic crosslinking induced by the slow dissociation of supersaturated calcium sulfate (CaSO4), forming a secondary physical network interpenetrating with the covalent main network. By controlling the soaking time, the crosslinking density can be precisely controlled, significantly improving the toughness, anti-swelling properties, and structural stability of the hydrogel. Furthermore, SA can adsorb exudate and provide a scaffold for cell migration.

[0021] In addition, existing hydrogel dressings have shortcomings in terms of wound adhesion. Some natural polymers bind non-specifically to wound proteins, which can easily tear newly formed granulation tissue during dressing changes, causing secondary damage and delaying the healing process. In contrast, the CSMA in this invention retains the biocompatibility of chitosan, and the methacrylylation modification shields some amino groups, reducing electrostatic adsorption and hydrogen bonding with wound proteins at the molecular level, thereby reducing adhesion and preventing adhesion to the wound.

[0022] Therefore, this invention uses photocrosslinking to achieve rapid molding and precise control, uses ionic crosslinking to enhance structural performance, and uses chitosan-based functional components to achieve antibacterial, low adhesion and healing promotion, ultimately constructing a mechanically adjustable, highly moisturizing, non-adhesive wound dressing with long-lasting antibacterial and biosafety properties.

[0023] The dual-network hydrogel dressing provided by this invention is constructed through photo-initiated covalent crosslinking, calcium ion physical crosslinking, and biofunctional modification to synergistically create a dual-network multifunctional hydrogel dressing. The mechanisms of action of each component are clear and highly complementary. While improving the mechanical properties of the hydrogel, it avoids secondary damage to the wound surface and helps with wound healing.

[0024] The methacrylated chitosan in this invention is prepared by acylation reaction of methacrylic anhydride and chitosan. Specifically, it is obtained by acylation reaction of methacrylic anhydride with the -NH2 group on the side chain of chitosan.

[0025] The preferred preparation method of methacrylamide chitosan of the present invention is as follows: deionized water, acetic acid and chitosan are mixed, methacrylic anhydride is added dropwise, and the mixture is reacted at 50-70°C. After dialysis and freeze-drying, methacrylamide chitosan is obtained.

[0026] To balance biocompatibility and anti-adhesion properties, the present invention preferably uses a molar ratio of 1:4 for the amino group of chitosan to methacrylic anhydride.

[0027] The preferred quaternary ammonium salt chitosan of this invention is a cationic derivative obtained by nucleophilic reaction of the amino group (-NH2) of chitosan with a quaternizing agent. More preferably, the quaternary ammonium salt chitosan is purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. (grade and purity ≥80%, water soluble).

[0028] The preferred photoinitiator of this invention is water-soluble TPO nanoparticles, and the preparation method of water-soluble TPO nanoparticles is further preferred as follows: at room temperature, n-butyl acetate is mixed with sodium dodecyl sulfate, isopropanol and polyvinylpyrrolidone to form an oil phase, then TPO is dissolved in the oil phase and poured into purified water. The mixture is stirred at room temperature to obtain an O / W microemulsion containing TPO; the microemulsion is freeze-dried to obtain water-soluble TPO nanoparticles.

[0029] Furthermore, it is preferred that the concentration of TPO in the mixture is 1.7 wt%, the concentration of sodium dodecyl sulfate is 7.5 wt%, and the concentration of polyvinylpyrrolidone is 7.5 wt%.

[0030] This invention uses water-soluble TPO nanoparticles as a photoinitiator. The TPO nanoparticles prepared by freeze-drying have good water solubility and can be uniformly dispersed in the hydrogel precursor solution. Under ultraviolet light irradiation, they can efficiently initiate the cross-linking reaction between methacrylamide chitosan and acrylamide. The preparation process is simple and controllable.

[0031] In summary, this invention provides a covalent-ionic double crosslinked network type non-adhesive hydrogel dressing, which is constructed by building a covalent master network of methacryloyl chitosan (CSMA) / acrylamide (AM) + sodium alginate (SA)-Ca. 2+ The interpenetrating dual-network structure of the secondary network makes the prepared hydrogel soft and flexible, able to adhere closely to the skin surface, effectively preventing postoperative tissue adhesion and reducing the risk of secondary damage during dressing changes. The hydrogel can also be prepared according to the size and shape of the wound, which can effectively meet the actual needs of clinical postoperative protection and wound care, and has important application prospects in the field of wound repair and anti-adhesion materials.

[0032] In the hydrogel dressing system provided by this invention, sodium alginate can release calcium ions through ion exchange to activate platelets and accelerate the wound repair process, while chitosan provides a safe and friendly repair microenvironment for the wound with its advantages of broad-spectrum antibacterial, hemostatic, exudate absorption and tissue regeneration promotion. At the same time, the introduction of polyacrylamide for chemical cross-linking can significantly enhance the mechanical strength of the hydrogel, making the internal structure more uniform and dense, and effectively improving the defects of insufficient mechanical properties of traditional hydrogels.

[0033] Another object of the present invention is to provide a method for preparing the dual-network hydrogel dressing as described above, the method comprising the following steps: S1: According to the formula, methacrylamide chitosan, quaternary ammonium salt chitosan, acrylamide, and sodium alginate are mixed at room temperature to obtain a mixed solution; Specifically, this step can be performed as follows: At room temperature, CSMA, QCS, AM, and SA in different proportions were added to beakers and stirred until completely dissolved to obtain a homogeneous and stable mixed solution. S2: Add the photoinitiator to the mixed solution and stir under light-protected conditions to obtain the precursor solution of the hydrogel; S3: After ultrasonic dispersion of the precursor solution, it is cured by ultraviolet light to obtain a hydrogel; Specifically, this step can be performed as follows: The precursor solution was ultrasonically dispersed in an ultrasonic instrument for 15 minutes; the solution was then injected into a mold, and the mold was cured under ultraviolet light. After curing, a hydrogel was obtained. S4: The hydrogel was soaked in a supersaturated CaSO4 solution to obtain a double-network hydrogel; The preferred soaking time is 30 min to 10 h. During the soaking process, the SA in the hydrogel reacts with Ca. 2+ The reaction occurs, forming a double-network hydrogel containing ionic crosslinking and covalent crosslinking entanglements.

[0034] The method for preparing a dual-network hydrogel dressing provided by this invention constructs a dual-network structure through physical and chemical cross-linking. The preparation process is simple, the reaction conditions are mild and controllable, the raw materials are widely available, and the solvent system is low-toxicity and environmentally friendly. It features low cost, biodegradability, and sustainable application. The prepared dual-network hydrogel dressing synergistically constructs a dual-network multifunctional hydrogel dressing through photo-initiated covalent cross-linking, calcium ion physical cross-linking, and biofunctional modification. The mechanisms of action of each component are clear and highly complementary, improving the mechanical properties of the hydrogel while avoiding secondary damage to the wound surface, thus aiding in wound healing.

[0035] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below.

[0036] Unless otherwise specified, the methacrylamide chitosan in the embodiments and comparative examples of this invention was prepared according to the following method: First, 87 parts by weight of deionized water, 3 parts by weight of acetic acid, and 2 parts by weight of chitosan were added to a round-bottom three-necked flask. The flask was then placed in an oil bath at 60°C and continuously stirred until the chitosan gradually and completely dissolved. After the chitosan was completely dissolved, methacrylic anhydride was slowly added dropwise at a molar ratio of 1:4 (amino group of chitosan to methacrylic anhydride (MA)). The mixture was then magnetically stirred at 60°C for 6 hours. After the reaction was complete, the mixture was dialyzed using a 5 kDa molecular weight cutoff membrane for 7 days. Dialysis effectively removed unreacted substances and impurities such as byproducts generated during the reaction. After dialysis, the resulting solution was freeze-dried to obtain the white product CSMA.

[0037] Unless otherwise specified, the water-soluble TPO nanoparticles in the embodiments and comparative examples of this invention were prepared according to the following method: At room temperature, n-butyl acetate (nBuAc) was mixed with sodium dodecyl sulfate (SDS), isopropanol (IPA), and polyvinylpyrrolidone (PVP) to form an oil phase. TPO was then dissolved in the oil phase and poured into purified water to obtain a mixture. The mixture contained 22.3 wt% n-butyl acetate (nBuAc), 7.5 wt% SDS, 21 wt% IPA, 7.5 wt% PVP, and 1.7 wt% TPO. The mixture was magnetically stirred at room temperature until a transparent system was formed, yielding an O / W microemulsion containing TPO. The microemulsion was freeze-dried at approximately -50°C to obtain dried TPO nanoparticles. The theoretical composition of the freeze-dried powder was 10.18 wt% TPO, 44.91 wt% SDS, and 44.91 wt% PVP.

[0038] Unless otherwise specified, the product information for quaternary ammonium chitosan (QSA) in the various embodiments and comparative examples of this invention is as follows: The test methods in the embodiments and comparative examples of this invention are as follows: Tensile Properties: The mechanical properties of the hydrogel material were tested using an Instron 4505 universal testing machine. All tests were performed at room temperature. A 100N sensor was selected and fixed, and both the displacement and mechanical sensors were zeroed. The probe rise speed of the Instron tester was 50 mm / min. The test sample was 2 mm thick, 4 mm wide, and had a gauge length of 25 mm. Tensile strength σ t The calculation formula is as follows: In the formula, F represents the maximum tensile stress on the gel, expressed in nanometers (N). B -- Spline width, in mm D -- Spline thickness, in mm.

[0039] Rheological properties: The rheological properties of the hydrogel were determined using a HAAKE MARS rotational rheometer. A 20mm parallel plate fixture was used, and dynamic frequency scanning tests (1-10Hz) were conducted at a test temperature of 35℃ and a strain amplitude of 1.0% (linear deformation region). The test sample was a cylindrical gel with a diameter of 10.5mm and a thickness of 1.2mm, ensuring that the geometric dimensions met the standard test specifications.

[0040] Swelling performance: The water absorption performance of the hydrogel was characterized using a swelling kinetics test method. After determining the initial mass (W0) of the cylindrical gel sample, it was placed in excess deionized water for swelling at room temperature. Samples were removed at preset time intervals (5-hour intervals), surface free water was removed, and the swollen mass (W1) was measured and recorded. The swelling ratio was calculated using the mass change rate. The formula for calculating the swelling ratio SR is as follows: In the formula, W0 -- initial mass, in grams. W1 -- Mass after swelling, in grams.

[0041] Peel strength: Peel strength was tested using an Instron 4505 universal testing machine. A sample approximately 400 mm long × 25 mm wide was cut and placed in the center of a stainless steel plate, with both sides of the sample parallel to the two long sides of the steel plate. Pressure was applied to the bonded portion of the sample using a roller at a speed of approximately 60 cm / min along the length of the sample, rolling four times. The sample was then left to stand for 10 minutes under standard atmospheric pressure. Using a suitable force measuring instrument with a force reading range of 15%-85% of full scale, the force required to peel the sample from the steel plate was determined [force angle 180°, peel speed (300±30) mm / min]. The force applied at the first 25 mm length was observed, and the force was observed every 30 mm. The average of six readings was taken. Example 1

[0042] This embodiment provides a dual-network hydrogel dressing, the preparation method of which is as follows: S1: Weigh 0.1 parts by weight of methacrylamide chitosan (CSMA), 0.01 parts by weight of quaternary ammonium chitosan (QCS), 20 parts by weight of acrylamide (AM), and 0.5 parts by weight of sodium alginate (SA) using an electronic balance, and add them to a beaker in sequence. Add the remaining purified water (total weight is 100 parts). Stir with a magnetic stirrer at room temperature for 2 hours until all solid raw materials are completely dissolved to obtain a homogeneous and stable mixed solution. S2: Add 0.1 parts of water-soluble TPO photoinitiator to the above mixed solution, immediately wrap the beaker with aluminum foil to protect it from light, and continue stirring at room temperature for 30 minutes to ensure uniform dispersion of the photoinitiator and prepare a precursor solution for the hydrogel. S3: The precursor solution is ultrasonically dispersed for 15 minutes to remove tiny air bubbles inside the solution; then the solution is slowly injected into a polytetrafluoroethylene mold, and the mold is irradiated with ultraviolet light (wavelength 365nm, cured for 1 minute to complete covalent cross-linking and obtain a preliminary hydrogel. S4: Completely immerse the initially obtained hydrogel in a supersaturated CaSO4 solution and allow it to stand at room temperature for 30 minutes. 2+ It diffuses into the hydrogel network, undergoes ionic cross-linking reaction with SA, and becomes entangled with the covalent cross-linking network to form a double-network hydrogel, thus obtaining the final sample; The prepared hydrogel was subjected to tensile, rheological, and swelling property tests, and the tensile strength was 291 kPa, storage modulus was 15726 Pa, swelling ratio was 8.90 g / g, and peel strength was 0.043 N / cm. Example 2

[0043] This embodiment provides a dual-network hydrogel dressing, the preparation method of which is as follows: S1: Weigh 0.2 parts by weight of methacrylamide chitosan (CSMA), 0.04 parts by weight of quaternary ammonium chitosan (QCS), 25 parts by weight of acrylamide (AM), and 1.25 parts by weight of sodium alginate (SA) using an electronic balance, and add them to a beaker in sequence. Add the remaining purified water (total weight is 100 parts). Stir with a magnetic stirrer at room temperature for 2 hours until all solid raw materials are completely dissolved to obtain a homogeneous and stable mixed solution. S2: Add 0.5 parts of water-soluble TPO photoinitiator to the above mixed solution, immediately wrap the beaker with aluminum foil to protect it from light, and continue stirring at room temperature for 30 minutes to ensure uniform dispersion of the photoinitiator and prepare a precursor solution for the hydrogel. S3: The precursor solution is ultrasonically dispersed for 15 minutes to remove tiny air bubbles inside the solution; then the solution is slowly injected into a polytetrafluoroethylene mold, and the mold is irradiated with ultraviolet light (wavelength 365nm, cured for 1 minute to complete covalent cross-linking and obtain a preliminary hydrogel. S4: Completely immerse the initially obtained hydrogel in a supersaturated CaSO4 solution and allow it to soak at room temperature for 2 hours. 2+ The substance diffuses into the hydrogel network, undergoes ionic cross-linking with SA, and becomes entangled with the covalent cross-linking network to form a double-network hydrogel, thus obtaining the final sample.

[0044] The prepared hydrogel was subjected to tensile, rheological, and swelling property tests, and the tensile strength was 3.98 MPa, storage modulus was 29762 Pa, swelling ratio was 12.92 g / g, and peel strength was 0.023 N / cm. Example 3

[0045] This embodiment provides a dual-network hydrogel dressing, the preparation method of which is as follows: S1: Weigh 0.3 parts by weight of methacrylamide chitosan (CSMA), 0.1 parts by weight of quaternary ammonium chitosan (QCS), 30 parts by weight of acrylamide (AM), and 2 parts by weight of sodium alginate (SA) using an electronic balance, and add them to a beaker in sequence. Add the remaining purified water (total weight is 100 parts). Stir with a magnetic stirrer at room temperature for 2 hours until all solid raw materials are completely dissolved to obtain a homogeneous and stable mixed solution. S2: Add 1 part of water-soluble TPO photoinitiator to the above mixed solution, immediately wrap the beaker with aluminum foil to protect it from light, and continue stirring at room temperature for 30 minutes to make the photoinitiator evenly dispersed, thus preparing a precursor solution for the hydrogel; S3: The precursor solution is ultrasonically dispersed for 15 minutes to remove tiny air bubbles inside the solution; then the solution is slowly injected into a polytetrafluoroethylene mold, and the mold is irradiated with ultraviolet light (wavelength 365nm, cured for 1 minute to complete covalent cross-linking and obtain a preliminary hydrogel. S4: Completely immerse the pre-formed hydrogel in a supersaturated CaSO4 solution and allow it to soak at room temperature for 10 hours. 2+ The substance diffuses into the hydrogel network, undergoes ionic cross-linking with SA, and becomes entangled with the covalent cross-linking network to form a double-network hydrogel, thus obtaining the final sample.

[0046] The prepared hydrogel was subjected to tensile, rheological, and swelling property tests, and the tensile strength was 1.73 MPa, storage modulus was 18374 Pa, swelling ratio was 13.87 g / g, and peel strength was 0.018 N / cm.

[0047] Each comparative example in this invention is compared with Example 1.

[0048] Comparative Example 1 The specific implementation method is the same as in Example 1, except that the initially formed hydrogel does not undergo the process of soaking in a supersaturated CaSO4 solution, and the hydrogel sample only has covalent cross-linking and no ionic cross-linking.

[0049] The prepared hydrogel was subjected to tensile, rheological, and swelling property tests, and the tensile strength was 183 kPa, storage modulus was 12539 Pa, swelling ratio was 10.18 g / g, and peel strength was 0.09 N / cm.

[0050] Comparative Example 2 The specific implementation method is the same as in Example 1, except that it is completely immersed in a supersaturated CaSO4 solution and soaked for 24 hours.

[0051] The prepared hydrogel was subjected to tensile, rheological, and swelling property tests. When soaked for 24 hours, the tensile properties of the hydrogel were poor, making it impossible to conduct experiments. Storage modulus: 9823 Pa, swelling rate: 7.31 g / g, peel strength: 0.029 N / cm.

[0052] Comparative Example 3 The specific implementation method is the same as in Example 1, except that chitosan is used instead of methacrylated chitosan.

[0053] The prepared hydrogel was subjected to tensile, rheological, and swelling property tests, and the tensile strength was 1.28 kPa, storage modulus was 13462 Pa, swelling ratio was 9.83 g / g, and peel strength was 0.072 N / cm.

[0054] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A dual-network hydrogel dressing, characterized in that, The raw materials, by weight, include the following components: 0.1-0.3 parts of methacrylated chitosan; Quaternary ammonium salt chitosan, 0.01-0.1 parts; Acrylamide 20-30 parts; Sodium alginate 0.5-2 parts; Photoinitiator 0.1-1 part.

2. The dual-network hydrogel dressing as described in claim 1, characterized in that, The methacrylated chitosan is prepared by acylation reaction of methacrylic anhydride and chitosan.

3. The dual-network hydrogel dressing as described in claim 2, characterized in that, The preparation method of the methacrylamide chitosan is as follows: deionized water, acetic acid and chitosan are mixed, methacrylic anhydride is added dropwise, and the mixture is reacted at 50-70℃. After dialysis and freeze-drying, methacrylamide chitosan is obtained.

4. The dual-network hydrogel dressing as described in claim 3, characterized in that, The molar ratio of the amino group of the chitosan to the methacrylic anhydride is 1:

4.

5. The dual-network hydrogel dressing according to any one of claims 1-4, characterized in that, The photoinitiator is water-soluble TPO nanoparticles.

6. The dual-network hydrogel dressing as described in claim 5, characterized in that, The preparation method of the water-soluble TPO nanoparticles is as follows: at room temperature, n-butyl acetate is mixed with sodium dodecyl sulfate, isopropanol and polyvinylpyrrolidone to form an oil phase, and then TPO is dissolved in the oil phase and poured into purified water to obtain a mixture; the mixture is stirred at room temperature to obtain an O / W microemulsion containing TPO; the microemulsion is freeze-dried to obtain water-soluble TPO nanoparticles.

7. The dual-network hydrogel dressing as described in claim 6, characterized in that, The concentration of TPO in the mixture is 1.7 wt%.

8. The dual-network hydrogel dressing as described in claim 6, characterized in that, The concentration of sodium dodecyl sulfate in the mixture is 7.5 wt%.

9. The dual-network hydrogel dressing as described in claim 6, characterized in that, The concentration of polyvinylpyrrolidone in the mixture is 7.5 wt%.

10. A method for preparing a dual-network hydrogel dressing as described in any one of claims 1-9, characterized in that, Includes the following steps: S1: According to the formula, methacrylamide chitosan, quaternary ammonium salt chitosan, acrylamide, and sodium alginate are mixed at room temperature to obtain a mixed solution; S2: Add the photoinitiator to the mixed solution and stir under light-protected conditions to obtain a precursor solution for the hydrogel; S3: The precursor solution is ultrasonically dispersed and then cured by ultraviolet light to obtain a hydrogel; S4: The hydrogel is soaked in a supersaturated CaSO4 solution to obtain a double-network hydrogel.

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