Medical transparent hydrogel dressing and preparation method thereof

Abstract

The invention belongs to the technical field of medical dressings, and particularly relates to a medical transparent hydrogel dressing and a preparation method thereof.The hydrogel dressing is prepared from, by weight, 4-6 parts of citric acid, 2-3 parts of L-cysteine, 4-5.5 parts of chitosan, 0.8-1.5 parts of hyaluronic acid, 0.08-0.1 part of MBA, 0.8-1.2 parts of modified PDA, 0.04 part of photoinitiator and 100 parts of PBS buffer solution with the pH being 6.5. Modified PDA nanoparticles based on a PCA / Fe < 3 + > coordination compound and DA are combined with carbon quantum dots to construct a dynamic interpenetrating network structure, a chitosan-hyaluronic acid-MBA gel cross-linking system forms micron-sized pores to maintain normal breathing of cells and promote wound healing while realizing visualization of an injured part, and a new solution is provided for complex wound treatment.

Description

Technical Field

[0001] The invention belongs to the technical field of medical dressings, and in particular relates to a medical transparent hydrogel dressing and a preparation method thereof. Background Art

[0002] As an important material for wound care, hydrogel dressings have been widely used in clinical practice. Their core advantages lie in the moist healing environment and local drug delivery capabilities brought by their high water content. However, existing products are mostly oriented towards single antibacterial, moisturizing and repair-promoting functions, which are difficult to meet the needs of adaptive regulation of complex wounds to dynamic pathological microenvironments. In addition, most traditional gel dressings cannot achieve visual monitoring of wounds due to poor material transmittance, so the timing of clinical dressing changes still depends on subjective judgment, increasing the risk of secondary injury. Based on this, transparent hydrogel dressings have gradually become a current research hotspot. Their high transmittance not only supports real-time observation of wounds, but also can integrate intelligent monitoring functions through optical means. However, this transparent hydrogel system brings about the difficult problem of balancing transparency and mechanical properties: high transparency often requires a uniform internal structure of the material, but low cross-linking density can easily lead to insufficient mechanical strength, making it difficult to resist exudate erosion or external friction; at the same time, a single response mechanism can hardly cover the complex microenvironment changes during wound healing, and the response accuracy and spatiotemporal controllability of drug release still need to be improved; in addition, although the low refractive index characteristics of the transparent matrix are beneficial to optical properties, they limit the stable loading of macromolecules or nanocarriers, resulting in low efficiency in the integration of multiple functions such as antibacterial, anti-inflammatory, and repair-promoting.

[0003] Therefore, there is an urgent need for a new type of transparent hydrogel dressing that can systematically solve the above-mentioned technical difficulties through structural innovation and component synergy, and achieve responsive drug controlled release, visualization of the transparent matrix and efficient repair methods. Summary of the invention

[0004] In view of the above situation, the present invention provides a medical transparent hydrogel dressing and a preparation method thereof. With "dynamic response-synergistic repair" as the core idea, the present invention aims to solve the problems of single function, insufficient environmental adaptability and difficulty in balancing mechanical and biological properties of traditional dressings. By synergistically constructing a dynamic three-dimensional network based on modified PDA nanoparticles copolymerized with PCA / Fe³⁺ coordination complex and GA-DA (gallic acid-dopamine) and nitrogen-sulfur co-doped carbon quantum dots, the dressing is endowed with responsive drug release ability, while taking into account high transparency, high air permeability and flexible adhesion, providing a new direction for the observation and repair of complex wounds.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is as follows: The invention provides a medical transparent hydrogel dressing. The hydrogel dressing comprises the following raw materials in parts by weight: 4-6 parts of citric acid, 2-3 parts of L-cysteine, 4-5.5 parts of chitosan, 0.8-1.5 parts of hyaluronic acid, 0.08-0.1 parts of MBA (methylenebisacrylamide), 0.8-1.2 parts of modified PDA (polydopamine), 0.04 parts of a photoinitiator and 100 parts of a pH 6.5 PBS (phosphate) buffer solution.

[0006] Furthermore, the modified PDA comprises the following raw materials in parts by weight: 0.4-0.48 parts of PCA (protocatechuic acid), FeCl 3 6H 2 O 0.2-0.24 parts, DA (dopamine) 0.4-0.48 parts, GA (gallic acid) 0.2-0.24 parts, trehalose 0.1 parts and pH 7.8 PBS buffer 100 parts.

[0007] Furthermore, the photoinitiator is selected from any one of LAP (lithium phenyl-2,4,6-trimethylbenzoylphosphinate), curcumin and vitamin B2.

[0008] Furthermore, the chitosan has a deacetylation degree of 85%-90% and a molecular weight of 100-150 kDa.

[0009] Furthermore, the hyaluronic acid is composed of hyaluronic acid with a molecular weight of 100-1000 kDa and 10-100 kDa in a weight ratio of 3:1, and contains thiolated hyaluronic acid, the degree of substitution of thiol groups of which is 5-8%.

[0010] Furthermore, the DA is in the form of hydrochloride.

[0011] The preparation method of the modified PDA specifically comprises the following steps: S1: Weigh 0.4-0.48 parts PCA and 0.2-0.24 parts FeCl 3 6H 2 O, dissolved in 100 parts of pH 7.8 PBS buffer, stirred in an ice bath for 10-30 min to obtain a coordination complex; S2: Weigh 0.4-0.48 parts of DA and 0.2-0.24 parts of GA and add them to the coordination complex, stir at 4°C in the dark for 12 h to obtain GA-PDA polymer; S3: The GA-PDA polymer was dialyzed for 24 h using a 3 kDa dialysis membrane, and the solution was changed every 8 h to obtain a dialysate. 0.1 parts of trehalose was weighed and dissolved in the dialysate, and then freeze-dried to obtain modified PDA.

[0012] The present invention also provides a method for preparing a medical transparent hydrogel dressing, which specifically comprises the following steps: Step 1: Weigh 4-6 parts of citric acid and 2-3 parts of L-cysteine ​​and dissolve them in 100 mL of deionized water, perform hydrothermal reaction at 160°C for 4 h to obtain a reaction solution, dialyze the reaction solution with a 1 kDa dialysis bag and freeze-dry it to obtain N,S-CDs (nitrogen-sulfur co-doped carbon quantum dots); Step 2: Weigh 4-5.5 parts of chitosan, 0.8-1.5 parts of hyaluronic acid and 0.08-0.1 parts of MBA and dissolve them in 100 parts of pH 6.5 PBS buffer to obtain a gel matrix; Step 3: Weigh 0.8-1.2 parts of modified PDA and N,S-CDs and add them to the gel matrix, ultrasonically disperse them at 180 W for 10 minutes, then weigh 0.04 parts of photoinitiator and add them to dissolve, incubate at 37°C for 2 hours after UV curing, and obtain a medical transparent hydrogel dressing.

[0013] The beneficial effects achieved by the present invention are as follows: The medical transparent hydrogel dressing prepared by the present invention achieves comprehensive performance improvement that is difficult to achieve with a single material through the synergistic effect of multiple components: the composite system of modified PDA nanoparticles and N,S-CDs constitutes a dynamic response intelligent core: PCA / Fe 3+ The coordination network gives the material pH sensitivity, while the GA-DA copolymer structure provides enzyme response sites. The two form a dual drug release switch through the complementary dissociation mechanism of chemical bonds, so that the release of antibacterial and antioxidant ingredients can not only respond to changes in the acidity of the inflammatory microenvironment, but also be specifically activated by the overexpressed MMP-9 enzyme, which significantly improves the environmental adaptation accuracy compared to a single response mechanism; the rich functional groups on the surface of N,S-CDs can not only stabilize the dispersion state of the nanocarriers through the π-π stacking effect with PDA, but also avoid the transmittance loss caused by nanoparticle agglomeration while enhancing the photothermal conversion efficiency, and have a two-way gain of responsiveness and optical transparency.

[0014] At the matrix construction level, the antibacterial barrier formed by the cationic action of chitosan is connected with the cell migration promoting function of hyaluronic acid. It not only serves as a gel matrix, but also has antibacterial and anti-inflammatory effects. The existence of the MBA cross-linked network not only limits the excessive swelling of the polysaccharide chain, but also dissipates external stress through dynamic hydrogen bonds, so that the material forms invisible micro-pores to maintain the normal breathing of cells in the wound site and improve the oxygen permeability. This "rigid skeleton-flexible buffer" composite structure is further coupled with the nano-enhancement effect of the modified PDA, so that the hydrogel can still maintain structural integrity when encountering wound exudate, providing a stable carrier platform for long-term drug release. During the preparation process, ultraviolet light curing technology is used to precisely control the free radical polymerization rate to form a uniform cross-linked network within tens of seconds, avoiding the degradation of chitosan chains caused by traditional thermal initiation; and the low-temperature incubation stage repairs micro-defects through the relaxation and recombination of molecular chains, and the freeze-drying protection of PDA nanoparticles by trehalose improves the stability of the active ingredients.

[0015] The medical transparent hydrogel dressing provided by the present invention has the functions of dynamic drug release, controllable breathing micropores and transparent visibility, and provides a breakthrough material solution for complex wound management. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The scanning electron microscope characterization results of the transparent hydrogel dressing prepared in Example 4 and the gel appearance effect diagram; Figure 2 The results of the investigation on the skin adhesion of the transparent hydrogel dressings prepared in Examples 1-5 and Comparative Examples 1-2 are shown; Figure 3 The light transmittance test results of the transparent hydrogel dressings prepared in Examples 1-5 and Comparative Examples 1-2; Figure 4 The swelling performance test results of the transparent hydrogel dressings prepared in Examples 1-5 and Comparative Examples 1-2 are shown; Figure 5 The cumulative release rate results of the transparent hydrogel dressings prepared in Example 1 and Example 5 and Comparative Examples 1-2 in pH 5.5 and pH 7.4 media; Figure 6 The results of cell compatibility study of the transparent hydrogel dressings prepared in Examples 1-5 and Comparative Examples 1-2; Figure 7 These are the results of the cell migration scratch experiment of the transparent hydrogel dressings prepared in Example 4 and Comparative Example 2. DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0018] Unless otherwise defined, all professional and scientific terms used herein have the same meanings as those familiar to those skilled in the art. In addition, any methods and materials similar or equivalent to those described herein may be applied to the present invention. The preferred implementation methods and materials described herein are for demonstration purposes only and are not intended to limit the content of this application.

[0019] In the following examples, unless otherwise specified, conventional methods are used; the materials used in the following examples, unless otherwise specified, are all new materials purchased from the market.

[0020] Example 1: This example provides a medical transparent hydrogel dressing, which comprises the following raw materials in parts by weight: 4 parts of citric acid, 2 parts of L-cysteine, 4 parts of chitosan, 1.5 parts of hyaluronic acid, 0.1 parts of MBA, 0.8 parts of modified PDA, 0.04 parts of LAP and 100 parts of pH 6.5 PBS buffer, the molecular weight of chitosan is 100 kDa, the degree of deacetylation is 90%, and the degree of substitution of thiol groups in hyaluronic acid is 6%.

[0021] The modified PDA comprises the following raw materials in parts by weight: 0.4 parts of PCA, FeCl 3 6H 2 O 0.2 parts, DA 0.4 parts, GA 0.2 parts, trehalose 0.1 parts and pH 7.8 PBS buffer 100 parts, the specific preparation method is as follows: S1: Weigh 0.4 parts of PCA and 0.2 parts of FeCl 3 6H 2 O was dissolved in 100 parts of pH 7.8 PBS buffer and stirred in an ice bath for 10 min. The color of the solution was stable and transparent without any change and the particle size was detected to be 54.2 nm, thus obtaining a coordination complex. S2: Weigh 0.4 parts of DA and 0.2 parts of GA and add them to the coordination complex, stir at 4°C in the dark for 12 h to obtain GA-PDA polymer; S3: The GA-PDA polymer was dialyzed for 24 h using a 3 kDa dialysis membrane, and the solution was changed every 8 h to obtain a dialysate. 0.1 parts of trehalose was weighed and dissolved in the dialysate, and then freeze-dried to obtain modified PDA.

[0022] This embodiment also provides a method for preparing a medical transparent hydrogel dressing, which specifically comprises the following steps: Step 1: Weigh 4 parts of citric acid and 2 parts of L-cysteine ​​and dissolve them in 100 mL of deionized water. Perform hydrothermal reaction at 160°C for 4 h to obtain a reaction solution. The reaction solution is dialyzed with a 1 kDa dialysis bag and then freeze-dried to obtain N,S-CDs. Step 2: Weigh 4 parts of chitosan, 1.5 parts of hyaluronic acid and 0.1 parts of MBA and dissolve them in 100 parts of pH 6.5 PBS buffer to obtain a gel matrix; Step 3: Weigh 0.8 parts of modified PDA and N,S-CDs and add them to the gel matrix, disperse them ultrasonically at 180 W for 10 min, then weigh 0.04 parts of LAP and add them to dissolve, cure them under 405 nm UV light, and incubate them at 37 °C for 2 h to obtain a medical transparent hydrogel dressing.

[0023] Example 2: This example provides a medical transparent hydrogel dressing, which comprises the following raw materials in parts by weight: 5 parts of citric acid, 2.5 parts of L-cysteine, 4.5 parts of chitosan, 0.8 parts of hyaluronic acid, 0.08 parts of MBA, 1.2 parts of modified PDA, 0.04 parts of curcumin and 100 parts of pH 6.5 PBS buffer solution, the molecular weight of chitosan is 120 kDa, the degree of deacetylation is 85%, and the degree of substitution of thiol groups in hyaluronic acid is 5%.

[0024] The modified PDA comprises the following raw materials in parts by weight: 0.48 parts of PCA, FeCl 3 6H 2 O 0.22 parts, DA 0.48 parts, GA 0.22 parts, trehalose 0.1 parts and pH 7.8 PBS buffer 100 parts, the specific preparation method is as follows: S1: Weigh 0.48 parts of PCA and 0.22 parts of FeCl 3 6H 2 O was dissolved in 100 parts of pH 7.8 PBS buffer and stirred in an ice bath for 20 min. The color of the solution was stable and transparent without change and the particle size was detected to be 45.5 nm, thus obtaining a coordination complex; S2: Weigh 0.48 parts of DA and 0.22 parts of GA and add them to the coordination complex, stir at 4°C in the dark for 12 h to obtain GA-PDA polymer; S3: The GA-PDA polymer was dialyzed for 24 h using a 3 kDa dialysis membrane, and the solution was changed every 8 h to obtain a dialysate. 0.1 parts of trehalose was weighed and dissolved in the dialysate, and then freeze-dried to obtain modified PDA.

[0025] This embodiment also provides a method for preparing a medical transparent hydrogel dressing, which specifically comprises the following steps: Step 1: Weigh 5 parts of citric acid and 2.5 parts of L-cysteine ​​and dissolve them in 100 mL of deionized water. Perform hydrothermal reaction at 160°C for 4 h to obtain a reaction solution. The reaction solution is dialyzed with a 1 kDa dialysis bag and then freeze-dried to obtain N,S-CDs. Step 2: Weigh 4.5 parts of chitosan, 0.8 parts of hyaluronic acid and 0.08 parts of MBA and dissolve them in 100 parts of pH 6.5 PBS buffer to obtain a gel matrix; Step 3: Weigh 1.2 parts of modified PDA and N,S-CDs and add them to the gel matrix. Ultrasonic dispersion is performed at 180 W for 10 min. Then, 0.04 parts of curcumin is dissolved in 1 mL of ethanol and slowly transferred to the gel matrix. After UV curing at 510 nm, the mixture is incubated at 37 °C for 2 h to obtain a medical transparent hydrogel dressing.

[0026] Example 3: This example provides a medical transparent hydrogel dressing, which comprises the following raw materials in parts by weight: 6 parts of citric acid, 3 parts of L-cysteine, 5.5 parts of chitosan, 1 part of hyaluronic acid, 0.09 parts of MBA, 1 part of modified PDA, 0.04 parts of vitamin B2 and 100 parts of pH 6.5 PBS buffer, and 0.01 parts of triethanolamine are additionally added as a co-initiator. The molecular weight of chitosan is 150 kDa, the degree of deacetylation is 95%, and the degree of substitution of thiol groups in hyaluronic acid is 8%.

[0027] The modified PDA comprises the following raw materials in parts by weight: 0.44 parts of PCA, FeCl 3 6H 2 O 0.24 parts, DA 0.44 parts, GA 0.24 parts, trehalose 0.1 parts and pH 7.8 PBS buffer 100 parts, the specific preparation method is as follows: S1: Weigh 0.44 parts of PCA and 0.24 parts of FeCl 3 6H 2 O was dissolved in 100 parts of pH 7.8 PBS buffer and stirred in an ice bath for 30 min. The color of the solution was stable and transparent without change and the particle size was detected to be 71.8 nm, thus obtaining a coordination complex; S2: Weigh 0.44 parts of DA and 0.24 parts of GA and add them to the coordination complex, stir at 4°C in the dark for 12 h to obtain GA-PDA polymer; S3: The GA-PDA polymer was dialyzed for 24 h using a 3 kDa dialysis membrane, and the solution was changed every 8 h to obtain a dialysate. 0.1 parts of trehalose was weighed and dissolved in the dialysate, and then freeze-dried to obtain modified PDA.

[0028] This embodiment also provides a method for preparing a medical transparent hydrogel dressing, which specifically comprises the following steps: Step 1: Weigh 6 parts of citric acid and 3 parts of L-cysteine ​​and dissolve them in 100 mL of deionized water. Perform hydrothermal reaction at 160°C for 4 h to obtain a reaction solution. The reaction solution is dialyzed with a 1 kDa dialysis bag and then freeze-dried to obtain N,S-CDs. Step 2: Weigh 5.5 parts of chitosan, 1 part of hyaluronic acid and 0.09 parts of MBA and dissolve them in 100 parts of pH 6.5 PBS buffer to obtain a gel matrix; Step 3: Weigh 1 part of modified PDA and N,S-CDs and add them to the gel matrix, ultrasonically disperse them at 180 W for 10 min, then weigh 0.04 part of vitamin B2 and 0.01 part of triethanolamine and add them to the gel matrix. After 337 nm UV curing, incubate at 37 °C for 2 h to obtain a medical transparent hydrogel dressing.

[0029] Example 4: This example provides a medical transparent hydrogel dressing, which comprises the following raw materials in parts by weight: 5 parts of citric acid, 3 parts of L-cysteine, 5 parts of chitosan, 1 part of hyaluronic acid, 0.1 parts of MBA, 1 part of modified PDA, 0.04 parts of LAP and 100 parts of pH 6.5 PBS buffer, the molecular weight of chitosan is 150 kDa, the degree of deacetylation is 90%, and the degree of substitution of thiol groups in hyaluronic acid is 6%.

[0030] The modified PDA comprises the following raw materials in parts by weight: 0.4 parts of PCA, FeCl 3 6H 2 O 0.24 parts, DA 0.45 parts, GA 0.2 parts, trehalose 0.1 parts and pH 7.8 PBS buffer 100 parts, the specific preparation method is as follows: S1: Weigh 0.4 parts of PCA and 0.24 parts of FeCl 3 6H 2 O was dissolved in 100 parts of pH 7.8 PBS buffer and stirred in an ice bath for 20 min. The color of the solution was stable and transparent without any change and the particle size was detected to be 36.4 nm, thus obtaining a coordination complex. S2: Weigh 0.45 parts of DA and 0.2 parts of GA and add them to the coordination complex, stir at 4°C in the dark for 12 h to obtain GA-PDA polymer; S3: The GA-PDA polymer was dialyzed for 24 h using a 3 kDa dialysis membrane, and the solution was changed every 8 h to obtain a dialysate. 0.1 parts of trehalose was weighed and dissolved in the dialysate, and then freeze-dried to obtain modified PDA.

[0031] This embodiment also provides a method for preparing a medical transparent hydrogel dressing, which specifically comprises the following steps: Step 1: Weigh 5 parts of citric acid and 3 parts of L-cysteine ​​and dissolve them in 100 mL of deionized water. Perform hydrothermal reaction at 160°C for 4 h to obtain a reaction solution. The reaction solution is dialyzed with a 1 kDa dialysis bag and then freeze-dried to obtain N,S-CDs. Step 2: Weigh 5 parts of chitosan, 1 part of hyaluronic acid and 0.1 part of MBA and dissolve them in 100 parts of pH 6.5 PBS buffer to obtain a gel matrix; Step 3: Weigh 1 part of modified PDA and N,S-CDs and add them to the gel matrix, disperse them ultrasonically at 180 W for 10 min, then weigh 0.04 part of LAP and add it to dissolve, cure it with 405 nm UV light, and incubate it at 37 °C for 2 h to obtain a medical transparent hydrogel dressing.

[0032] Example 5: This example provides a medical transparent hydrogel dressing, which comprises the following raw materials in parts by weight: 4 parts of citric acid, 2 parts of L-cysteine, 4 parts of chitosan, 0.8 parts of hyaluronic acid, 0.1 parts of MBA, 1 part of modified PDA, 0.04 parts of LAP and 100 parts of pH 6.5 PBS buffer, the molecular weight of chitosan is 140 kDa, the degree of deacetylation is 90%, and the degree of substitution of thiol groups in hyaluronic acid is 7%.

[0033] The modified PDA comprises the following raw materials in parts by weight: 0.4 parts of PCA, FeCl 3 6H 2 O 0.2 parts, DA 0.48 parts, GA 0.24 parts, trehalose 0.1 parts and pH 7.8 PBS buffer 100 parts, the specific preparation method is as follows: S1: Weigh 0.4 parts of PCA and 0.2 parts of FeCl 3 6H 2 O was dissolved in 100 parts of pH 7.8 PBS buffer and stirred in an ice bath for 20 min. The color of the solution was stable and transparent without change and the particle size was detected to be 53.9 nm, thus obtaining a coordination complex; S2: Weigh 0.48 parts of DA and 0.24 parts of GA and add them to the coordination complex, stir at 4°C in the dark for 12 h to obtain GA-PDA polymer; S3: The GA-PDA polymer was dialyzed for 24 h using a 3 kDa dialysis membrane, and the solution was changed every 8 h to obtain a dialysate. 0.1 parts of trehalose was weighed and dissolved in the dialysate, and then freeze-dried to obtain modified PDA.

[0034] This embodiment also provides a method for preparing a medical transparent hydrogel dressing, which specifically comprises the following steps: Step 1: Weigh 4 parts of citric acid and 2 parts of L-cysteine ​​and dissolve them in 100 mL of deionized water. Perform hydrothermal reaction at 160°C for 4 h to obtain a reaction solution. The reaction solution is dialyzed with a 1 kDa dialysis bag and then freeze-dried to obtain N,S-CDs. Step 2: Weigh 4 parts of chitosan, 0.8 parts of hyaluronic acid and 0.1 parts of MBA and dissolve them in 100 parts of pH 6.5 PBS buffer to obtain a gel matrix; Step 3: Weigh 1 part of modified PDA and N,S-CDs and add them to the gel matrix, disperse them ultrasonically at 180 W for 10 min, then weigh 0.04 part of LAP and add it to dissolve, cure it with 405 nm UV light, and incubate it at 37 °C for 2 h to obtain a medical transparent hydrogel dressing.

[0035] The difference between Comparative Example 1 and Example 4 is that no modified PDA is added, and the other parts are the same as Example 4.

[0036] The difference between Comparative Example 2 and Example 4 is that no citric acid and L-cysteine ​​are added, that is, no N,S-CDs are added, and the rest is the same as Example 4.

[0037] Morphology inspection The transparent hydrogel dressing prepared in Example 4 was dispersed on a silicon wafer, and after being sprayed with gold, the gel morphology was observed under a cryo-scanning electron microscope (SEM). The gel appearance and SEM results are shown in Figure 1 .

[0038] Skin Adhesion Test Take 2.0 g of each of the transparent hydrogel dressings prepared in Examples 1-5 and Comparative Examples 1-2, shape them in a 25 mm × 25 mm mold, adhere them to the simulated skin surface, let them stand for 5 min to eliminate the preload stress, and test the adhesion of the hydrogel under the conditions of 10 mm / min, preload force 0.1 N, and 25.0°C. The adhesion strength σ=F max / bonding area, apply shear load in the vertical direction of the sample, the shear rate is 5 mm / min, and the shear strength is tested; take the transparent hydrogel dressings prepared in Examples 1-5 and Comparative Examples 1-2, shape the mold into a size of 25 mm×100 mm×2 mm, adhere to the simulated skin surface, and test the sample peeling force (F) under the conditions of peeling rate 300 mm / min and peeling angle 180°. Each group is tested 5 times, and the results are shown in Figure 2 .

[0039] Light transmittance test The transparent hydrogel dressings prepared in Examples 1-5 and Comparative Examples 1-2 were made into smooth sheets with a thickness of 2 mm. The transmittance (T%) and haze (H%) at 550 nm were measured using a UV-visible spectrophotometer. The measurement was repeated 3 times. The results are shown in Table 1. Figure 3 .

[0040] Swelling rate test After the transparent hydrogel dressings prepared in Examples 1-5 and Comparative Examples 1-2 were freeze-dried, 0.50 g of the dried gel (W 0 ), immersed in PBS at 37℃ for 24 h, taken out, dried and weighed (W 1 ), calculate the swelling ratio = (W 1 -W 0 ) / W 0 ×100%, see the results Figure 4 .

[0041] Drug dissolution testing Weigh 2.00 g of each of the transparent hydrogel dressings prepared in Example 1 and Example 4 and Comparative Examples 1-2, evenly apply them on medical gauze, place them in a dissolution tester, and detect the dissolution of GA in pH 5.5 and pH 7.4 PBS media. The dissolution medium is 900 mL, the temperature is 37±0.5°C, and samples are taken at 5 min, 30 min, 1 h, and 2 h. The paddle speed is 50 rpm, and the GA cumulative release rate is detected by high performance liquid chromatography. The results are shown in Table 1. Figure 5 .

[0042] Cell biocompatibility testing The transparent hydrogel dressings prepared in Examples 1-5 and Comparative Examples 1-2 were extracted at 37°C for 24 h, and the extracts were added to HSF human skin fibroblasts. The absorbance (OD) of the cells at 450 nm was determined by CCK-8 method. The control group was HSF cells without extracts, and the blank group was a blank culture dish without cells inoculated. The cell survival rate (%) was (OD 实验 -OD 空白 ) / (OD 对照 -OD 空白 )×100%, see the results Figure 6 .

[0043] Cell scratch assay HUVEC human umbilical vein endothelial cells were seeded in a 12-well plate, and scratches were made on the cells after the cells adhered to the wall. The transparent hydrogel dressings prepared in Example 4 and Comparative Example 2 were extracted at 37°C for 24 h, and the extract was added to the cell well plate with scratches, and incubated in an incubator for 12 h. The growth of the scratched cells was observed under a microscope, and the cell well plate without extract was used as the control group. The results are shown in FIG. Figure 7 .

[0044] Figure 1 The SEM results of the transparent hydrogel dressing showed that there were a large number of micron-sized pores in the gel, which was beneficial to the gas exchange of the skin or wound tissues. The qualitative hydrogel was transparent and had strong formability.

[0045] Figure 2 The results of the adhesion test showed that the transparent hydrogel dressing prepared in Example 4 had high adhesion strength and low peeling force, and was convenient for replacement and cleaning.

[0046] Figure 3 The light transmittance results show that the hydrogel dressings prepared in Examples 1-5 and Comparative Examples 1-2 have strong light transmittance effects, with a light transmittance of more than 80%, among which the hydrogel dressing prepared in Example 4 has the highest light transmittance.

[0047] Figure 4 The results of the gel swelling test showed that the hydrogel dressing prepared in Example 4 had the highest cross-linking density, limited the penetration of water molecules, and had the lowest swelling rate, while the hydrogel dressing prepared in Comparative Example 1 without adding modified PDA had a swelling rate of 480%. Its high water absorption easily caused the collapse of the three-dimensional network structure of the gel, resulting in reduced performance.

[0048] Figure 5 The cumulative release rate results show that in the pH 5.5 environment, the GA release of the hydrogel dressing prepared in Example 4 is the slowest and the content is the lowest, which is beneficial to the slow release of the drug in the skin microenvironment and has a sustained release effect. In the pH 7.4 medium, the cumulative release rate of GA in Example 1 and Example 4 is higher and the release rate is faster, which is beneficial to the rapid antibacterial and absorption of tissue fluid in the wound or skin defect site, and the use of active substances in the gel to accelerate wound healing. The prepared hydrogel dressing has pH responsiveness.

[0049] Figure 6 The cell survival rate results showed that the hydrogel dressings prepared in Examples 1-5 had good cell compatibility, while the hydrogel dressings prepared in Comparative Examples 1-2 lacked the deep cross-linking structure or the antioxidant protection of N,S-CDs and showed certain cytotoxicity.

[0050] Figure 7 The results of the cell scratch experiment showed that compared with the control group, the hydrogel dressing prepared in Example 4 could promote HUVEC cell migration and accelerate angiogenesis at the wound site.

[0051] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

[0052] The present invention and its implementation methods are described above, which is not restrictive. The drawings are only one of the implementation methods of the present invention, and the actual application is not limited thereto. In short, if ordinary technicians in the field are inspired by it and design methods and embodiments similar to the technical solution without creativity without departing from the purpose of the invention, they should all fall within the protection scope of the present invention.

Claims

1. A medical transparent hydrogel dressing, characterized in that: The invention comprises the following raw materials in parts by weight: 4-6 parts of citric acid, 2-3 parts of L-cysteine, 4-5.5 parts of chitosan, 0.8-1.5 parts of hyaluronic acid, 0.08-0.1 parts of MBA, 0.8-1.2 parts of modified PDA, 0.04 parts of photoinitiator and 100 parts of pH 6.5 PBS buffer solution; The modified PDA comprises the following raw materials in parts by weight: 0.4-0.48 parts of PCA, 0.2-0.24 parts of FeCl3·6H2O, 0.4-0.48 parts of DA, 0.2-0.24 parts of GA, 0.1 parts of trehalose and 100 parts of pH 7.8 PBS buffer. The specific preparation method of the modified PDA comprises the following steps: S1: Weigh PCA and FeCl3·6H2O and dissolve them in pH 7.8 PBS buffer to obtain a coordination complex; S2: Weigh DA and GA and add them to the coordination complex to react and obtain GA-PDA polymer; S3: The GA-PDA polymer is dialyzed, trehalose is added and freeze-dried to obtain modified PDA.

2. A medical transparent hydrogel dressing according to claim 1, characterized in that: The DA is in the form of hydrochloride; In step S2, the reaction process is carried out at 4° C. in the dark; In step S3, the dialysis time is 24 hours, and the solution is changed every 8 hours.

3. A medical transparent hydrogel dressing according to claim 1, characterized in that: The photoinitiator is selected from any one of LAP, curcumin and vitamin B2.

4. The medical transparent hydrogel dressing according to claim 1, characterized in that: The chitosan has a deacetylation degree of 85%-90% and a molecular weight of 100-150 kDa.

5. The medical transparent hydrogel dressing according to claim 1, characterized in that: The hyaluronic acid comprises thiolated hyaluronic acid, and the degree of substitution of thiol groups thereof is 5-8%.

6. A method for preparing a medical transparent hydrogel dressing according to any one of claims 1 to 5, characterized in that: The specific preparation method is as follows: Step 1: Weigh citric acid and L-cysteine, dissolve, react, dialyze and freeze-dry to obtain N,S-CDs; Step 2: weigh chitosan, hyaluronic acid and MBA and dissolve them in pH 6.5 PBS buffer to obtain a gel matrix; Step 3: Weigh the modified PDA and N,S-CDs and add them into the gel matrix for dispersion treatment, then add a photoinitiator for curing to obtain a medical transparent hydrogel dressing.

7. The method for preparing a medical transparent hydrogel dressing according to claim 6, characterized in that: In step 1, the reaction process is a hydrothermal reaction at 160° C. for 4 h; In step 3, the dispersion treatment process uses ultrasound, and after the solidification is completed, the mixture is incubated at 37° C. for 2 h.

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