Biomass hydrogel dressing based on broccoli stem pectin as well as preparation method and application of biomass hydrogel dressing

Abstract

The invention relates to the technical field of biomedical materials, in particular to a biomass hydrogel dressing based on broccoli stem pectin and a preparation method and application thereof.The preparation method comprises the following steps that polyvinyl alcohol is dissolved in deionized water and stirred to be uniform, and a polyvinyl alcohol solution is obtained; and adding the broccoli stem pectin, adjusting the pH value to 2.0-3.0, stirring at 35-60 DEG C for 0.1-2 hours until the broccoli stem pectin is completely dissolved, pouring the obtained mixed solution into a mold, freezing, unfreezing, repeating for 2-5 times, packaging the obtained hydrogel in a dialysis bag, and dialyzing in neutral water for 3-6 times until the pH value is 7.0 to obtain the hydrogel dressing. According to the broccoli stem pectin-based biomass hydrogel dressing as well as the preparation method and the application thereof, the broccoli stem pectin is dissolved in the polyvinyl alcohol solution to be repeatedly frozen and thawed to prepare the hydrogel dressing, and the hydrogel dressing has excellent biocompatibility, mechanical property and biological activity and a good tissue repair function.

Description

Technical Field

[0001] The invention relates to the technical field of biomedical materials, and in particular to a biomass hydrogel dressing based on broccoli stem pectin, and a preparation method and application thereof. Background Art

[0002] The healing process of skin wounds usually includes three stages: inflammation, proliferation, and remodeling. During these stages, endogenous or exogenous factors may delay the healing process, such as excessive inflammatory response, oxidative stress, and bacterial infection. In order to solve these problems, a variety of biomedical materials have been developed and applied to wound dressings, especially hydrogel materials. Hydrogels have become the research focus of wound dressings due to their excellent three-dimensional structure, good biocompatibility, and ability to simulate the properties of extracellular matrix.

[0003] At present, many hydrogel materials have been loaded with anti-inflammatory, antioxidant and other active ingredients to improve their functions, such as antibiotics, curcumin, polydopamine, etc., but these systems usually require complex drug loading and release control, which may cause side effects. Natural polymers are more popular for their excellent biocompatibility and biodegradability. Natural polysaccharides, including pectin, have been widely studied for wound healing due to their biocompatibility and immunomodulatory properties. When natural active materials are integrated into hydrogel systems, the preparation process can be simplified, potential toxicity issues can be reduced, and a more biomimetic healing microenvironment can be provided. However, traditional pectin has the problem of low gel strength in practical applications, which limits its application in wound dressings. Therefore, finding a pectin biomass hydrogel that can both ensure biological activity and provide sufficient mechanical strength is an urgent problem to be solved. Summary of the invention

[0004] The purpose of the present invention is to provide a biomass hydrogel dressing based on broccoli stem pectin, and a preparation method and application thereof. The hydrogel dressing prepared by dissolving broccoli stem pectin in a polyvinyl alcohol solution and repeatedly freezing and thawing has excellent biocompatibility, mechanical properties, biological activity and good tissue repair function.

[0005] To achieve the above object, the present invention provides a method for preparing a biomass hydrogel dressing based on broccoli stem pectin, comprising the following steps: S1, dissolving polyvinyl alcohol in deionized water, and stirring to obtain a polyvinyl alcohol solution; S2, adding broccoli stem pectin to the polyvinyl alcohol solution in S1, adjusting the pH to 2.0-3.0, stirring at 35-60° C. for 0.1-2 h until the broccoli stem pectin is completely dissolved, to obtain a mixed solution; S3, pouring the mixed solution obtained in S2 into a mold, freezing and then thawing, repeating 2-5 times to obtain a hydrogel; S4. Encapsulate the hydrogel in S3 in a dialysis bag, and dialyze in neutral water for 3-6 times until the pH reaches 7.0 to obtain a hydrogel dressing.

[0006] Preferably, in S1, the molecular weight of polyvinyl alcohol is 89000-98000 Da, and the concentration of polyvinyl alcohol solution is 5-15 wt %.

[0007] More preferably, the concentration of the polyvinyl alcohol solution is 10 wt %.

[0008] Preferably, in S2, the mass of broccoli stem pectin added is 0.1-1% of the mixed solution.

[0009] More preferably, the added mass of broccoli stem pectin is 0.5%.

[0010] Preferably, in S2, the broccoli stem pectin is separated and purified from broccoli stems, and the degree of esterification of the broccoli stem pectin is 51%.

[0011] Preferably, in S2, one or more of hydrochloric acid and acetic acid are added when adjusting the pH.

[0012] Preferably, in S3, the freezing is performed at -30°C to -15°C for 2-6 hours.

[0013] Preferably, in S3, thawing is thawing at room temperature for 0.5-2 h.

[0014] Preferably, in S4, the dialysis time is 3-5 hours, and the pH of neutral water during dialysis is 6.8-7.5.

[0015] The hydrogel dressing is prepared by the above-mentioned method for preparing a biomass hydrogel dressing based on broccoli stem pectin.

[0016] The above-mentioned application of the biomass hydrogel dressing based on broccoli stem pectin is used as a wound dressing to promote wound healing.

[0017] Mechanism of the present invention: The present invention forms abundant hydrogen bonds between polyvinyl alcohol (PVA) and carboxyl and carboxylmethyl groups in broccoli stem pectin (BSP) by physical crosslinking, thereby enhancing the mechanical properties of the hydrogel and avoiding the toxicity problem of using chemical crosslinking agents. The hydrogel prepared based on physical interaction has excellent strength and elasticity, can effectively withstand the stress of the wound site, and at the same time gives full play to the biological properties of broccoli stem pectin, significantly promoting wound healing.

[0018] Therefore, the present invention adopts the above-mentioned broccoli stem pectin-based biomass hydrogel dressing and its preparation method and application, and its beneficial effects are: 1. The mechanical properties of the PVA / BSP hydrogel dressing provided by the present invention are significantly improved. The introduction of broccoli stem pectin enhances the strength and elasticity of the hydrogel system, while giving full play to the biological properties of pectin, significantly promoting wound healing, and meeting the use requirements of the hydrogel dressing in different environments; 2. The hydrogel dressing PVA / BSP provided by the present invention has excellent biocompatibility, not only promotes cell proliferation, but also does not cause hemolytic reaction. It has excellent effect in promoting wound healing, has good tissue repair function, and is suitable for clinical application; 3. The preparation method of the hydrogel dressing PVA / BSP provided by the present invention is simple to operate, short in time, and has low raw material cost and high biocompatibility, and has a development prospect of large-scale application in industrial production.

[0019] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is the FT-IR spectra of the broccoli stem pectin of the present invention, the hydrogel dressing of Example 1 and Comparative Example 1, in, Figure 1 a in the figure is the FT-IR spectrum of broccoli stem pectin. Figure 1 b is the FT-IR spectra of the hydrogel dressings in Example 1 and Comparative Example 1; Figure 2 is a scanning electron microscope image of the hydrogel dressing in Example 1 and Comparative Example 1 of the present invention, in, Figure 2 a in the figure is a scanning electron microscope image of the hydrogel dressing in Comparative Example 1, Figure 2 b is a scanning electron microscope image of the hydrogel dressing in Example 1; Figure 3 is a combined diagram of the mechanical properties of the hydrogel dressings in Example 1 and Comparative Example 1 of the present invention, in, Figure 3 a in the figure is the tensile stress-strain curve. Figure 3 b in the figure is the compressive stress-strain curve; Figure 4 is a combined graph of the biocompatibility performance of the hydrogel dressings in Example 1 and Comparative Example 1 of the present invention, in, Figure 4 a in the figure is the L929 cell survival rate bar graph, Figure 4 b is a schematic diagram of hemolysis of hydrogel dressing PVA and hydrogel dressing PVA / BSP; Figure 5 It is a wound healing promotion test combination diagram of the present invention; Figure 6It is a schematic flow diagram of the preparation method of the present invention. DETAILED DESCRIPTION

[0021] The present invention is further described below in conjunction with the accompanying drawings and embodiments. Unless otherwise defined, the technical terms or scientific terms used in the present invention should be the common meanings understood by people with ordinary skills in the field to which the present invention belongs. The above-mentioned features or features mentioned in the specific examples mentioned in the present invention can be combined arbitrarily, and these specific embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0022] In the following examples, unless otherwise specified, the experimental methods used are conventional methods, and the reagents used can be purchased from chemical or biological reagent companies. Reagents used: Polyvinyl alcohol (PVA): purchased from Sigma-Aldrich Trading Co., Ltd.

[0023] Broccoli stem pectin (BSP): provided by Vegetable and Floriculture Research Institute, Chinese Academy of Agricultural Sciences.

[0024] Example 1 like Figure 6 As shown, S1, dissolve 2 g of polyvinyl alcohol in 18 ml of deionized water preheated to 90° C., the molecular weight of the polyvinyl alcohol is 89000-98000 Da, and stir evenly to obtain a 10 wt % polyvinyl alcohol solution.

[0025] S2. Add 0.1 g of broccoli stem pectin to the polyvinyl alcohol solution in S1, add acetic acid to adjust the pH to 2.0-3.0, and stir at 45° C. for 0.5 h until the broccoli stem pectin is completely dissolved to obtain a mixed solution.

[0026] In S2, broccoli stem pectin is separated and purified from broccoli stems, and the degree of esterification of the broccoli stem pectin is 51%.

[0027] S3. Pour the mixed solution obtained in S2 into a mold, freeze it at -20°C for 4 hours, thaw it at room temperature for 1 hour, and repeat the freezing and thawing for 3 times to obtain a hydrogel.

[0028] S4. Encapsulate the hydrogel in S3 in a dialysis bag, and dialyze in neutral water for 5 times to remove low molecular weight impurities in the solution until the pH reaches 7.0 to obtain the hydrogel dressing PVA / BSP.

[0029] Comparative Example 1 S1. Dissolve 2 g of polyvinyl alcohol in 18 ml of deionized water preheated to 90° C. The molecular weight of the polyvinyl alcohol is 89,000-98,000 Da. Stir evenly to obtain a 10 wt % polyvinyl alcohol solution.

[0030] S2. Pour the polyvinyl alcohol solution obtained in S1 into a mold, freeze it at -20°C for 4 hours, thaw it at room temperature for 1 hour, repeat the freezing and thawing process 3 times to obtain a hydrogel dressing PVA.

[0031] Test Example 1 a. FT-IR spectrum test FT-IR spectrum test was performed on the broccoli stem pectin, the hydrogel dressing obtained in Example 1 and Comparative Example 1. The results are as follows: Figure 1 shown. Figure 1 a in the figure is the FT-IR spectrum of broccoli stem pectin, at 1740 cm -1 and 1620cm -1 The absorption peaks at 1020cm and 1020cm correspond to the stretching vibrations of the esterified carbonyl (COO) and carboxyl (COOH) groups. -1 The absorption peaks at are attributed to the stretching vibrations of the CO and CC bonds of the C2-C3, C2-O2 and C1-O1 skeletons in the galacturonic acid unit, and the presence of these functional groups is the key to the antioxidant activity of pectin. Figure 1 b is the FT-IR spectra of the hydrogel dressings obtained in Example 1 and Comparative Example 1, both of which have a wavelength of 1086 cm -1 and 1328cm -1 The absorption peaks of CO and CH-OH appeared near 1740 cm-1, indicating that the hydroxyl group (-OH) of PVA participated in the formation of the hydrogel network. -1 and 1020cm -1 The stretching vibration peaks corresponding to C=O and COO in pectin appeared at , which confirmed that BSP was successfully introduced into the hydrogel system.

[0032] b. Scanning electron microscope test The hydrogel dressings obtained in Example 1 and Comparative Example 1 were subjected to scanning electron microscopy testing, and the obtained scanning electron microscopy images are as follows: Figure 2 shown. Figure 2 a in the figure is a scanning electron microscope image of the hydrogel dressing in Comparative Example 1, Figure 2 b is a scanning electron microscope image of the hydrogel dressing in Example 1. Figure 2 As can be seen in a, during the freeze-thaw cycle of the hydrogel dressing PVA, water molecules form ice crystals, and the PVA molecular chains are repelled into the liquid microphase between the ice crystals. This volume expansion forces the PVA molecular chains to be arranged more closely, increasing the interaction between molecules, especially the formation of hydrogen bonds. These hydrogen bonds are retained during the thawing process, thus forming a stable three-dimensional network structure. Figure 2As can be seen from b, more hydrophilic carboxyl (-COOH) groups and hydroxyl (-OH) groups are introduced into the hydrogel dressing PVA / BSP. These groups simultaneously form a large number of hydrogen bonds with PVA, increasing the cross-linking degree of the hydrogel dressing PVA / BSP and thus reducing the pore size of the hydrogel dressing PVA / BSP.

[0033] c. Mechanical properties test The tensile and compression tests were conducted using a BPN-50CH universal testing machine, and all experiments were conducted at room temperature (25°C). The hydrogel dressings obtained in Example 1 and Comparative Example 1 were made into a spindle-shaped (central deformation area, length: 20 mm, width: 4 mm, thickness: 2 mm) for tensile testing, and the test tensile rate was fixed at 5 mm / min. The hydrogel dressings for compression testing were made into a cylinder with a diameter of 15 mm and a height of 10 mm, and the compression rate was fixed at 5 mm / min.

[0034] The test results are as follows Figure 3 As shown, Figure 3 a in the figure is the tensile stress-strain curve. Figure 3 b in the figure is the compressive stress-strain curve. Figure 3 As can be seen from a in the figure, compared with the hydrogel dressing PVA, the hydrogel dressing PVA / BSP achieved a significant improvement in tensile stress, reaching 0.95MPa. The 376% strain capacity of the hydrogel dressing PVA / BSP still meets the flexibility and compliance requirements in clinical applications.

[0035] Depend on Figure 3 As can be seen from b, in the compression test, the hydrogel dressing PVA / BSP exhibited a compressive stress of 1.24 MPa at a deformation of 80%, and also showed significant mechanical enhancement compared to the hydrogel dressing PVA.

[0036] d. Biocompatibility test Determination method: MTT colorimetry was used for the experiment. The hydrogel dressing PVA and hydrogel dressing PVA / BSP were incubated with L929 cells for 24 hours and 48 hours. Figure 4 As shown, Figure 4 a in the figure is the L929 cell survival rate bar graph, Figure 4 b in the figure is a schematic diagram of hemolysis of hydrogel dressing PVA and hydrogel dressing PVA / BSP.

[0037] Depend on Figure 4As can be seen from a, both hydrogel dressing PVA and hydrogel dressing PVA / BSP were non-toxic to L929 cells and significantly promoted cell proliferation, among which hydrogel dressing PVA / BSP had a significantly better effect on promoting cell proliferation than hydrogel dressing PVA. The cell survival rate of cells co-cultured with hydrogel dressing PVA / BSP for 48 hours reached 167.37±7.19% (with ordinary culture medium as the control group, the cell survival rate was 100%).

[0038] Wound dressings are inevitably in contact with blood during actual use, and the ideal hemolysis rate of clinical wound dressings should be kept below 5%. Figure 4 As can be seen from b, when the hydrogel dressing PVA and the hydrogel dressing PVA / BSP were in contact with whole blood red blood cells at 37°C for 60 minutes, the hemolysis rates were less than 5%, and neither showed obvious hemolysis.

[0039] e. Wound healing test Measurement method: Animal experiments used a full-thickness skin defect model of SD rats (male, 180–200 g) to simulate acute wounds. The rats were randomly divided into three groups, including a control group (gauze), a PVA group, and a PVA / BSP group.

[0040] After SD rats were anesthetized, their backs were depilated and cleaned. After disinfection with alcohol, two full-thickness skin wounds were made on the backs using an 8 mm round puncture punch. The control group was covered with gauze and polyurethane film, while the PVA group and PVA / BSP group were covered with the corresponding hydrogel dressings, and then covered and fixed with gauze and polyurethane film. Photos of the wounds were taken on the 0th, 3rd, 7th, and 14th days of treatment. Figure 5 As shown in Figure 2, PVA / BSP hydrogel dressing showed better healing ability compared with the control group and PVA hydrogel dressing.

[0041] Therefore, the present invention adopts the above-mentioned biomass hydrogel dressing based on broccoli stem pectin and its preparation method and application, and the hydrogel dressing prepared by dissolving broccoli stem pectin in a polyvinyl alcohol solution and repeatedly freezing and thawing has excellent biocompatibility, mechanical properties, biological activity and good tissue repair function.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for preparing a biomass hydrogel dressing based on broccoli stem pectin, characterized in that: The following steps are included: S1, dissolving polyvinyl alcohol in deionized water, and stirring to obtain a polyvinyl alcohol solution; S2, adding broccoli stem pectin to the polyvinyl alcohol solution in S1, adjusting the pH to 2.0-3.0, stirring at 35-60° C. for 0.1-2 h until the broccoli stem pectin is completely dissolved, to obtain a mixed solution; S3, pouring the mixed solution obtained in S2 into a mold, freezing and then thawing, repeating 2-5 times to obtain a hydrogel; S4. Encapsulate the hydrogel in S3 in a dialysis bag, and dialyze in neutral water for 3-6 times until the pH reaches 7.0 to obtain a hydrogel dressing.

2. The method for preparing a biomass hydrogel dressing based on broccoli stem pectin according to claim 1, characterized in that: In S1, the molecular weight of polyvinyl alcohol is 89000-98000Da, and the concentration of polyvinyl alcohol solution is 5-15wt%.

3. The method for preparing a biomass hydrogel dressing based on broccoli stem pectin according to claim 1, characterized in that: In S2, the mass of broccoli stem pectin added is 0.1-1% of the mixed solution.

4. The method for preparing a biomass hydrogel dressing based on broccoli stem pectin according to claim 1, characterized in that: In S2, broccoli stem pectin is separated and purified from broccoli stems, and the degree of esterification of the broccoli stem pectin is 51%.

5. The method for preparing a biomass hydrogel dressing based on broccoli stem pectin according to claim 1, characterized in that: In S2, one or more of hydrochloric acid and acetic acid are added to adjust the pH.

6. The method for preparing a biomass hydrogel dressing based on broccoli stem pectin according to claim 1, characterized in that: In S3, freezing is performed at -30°C to -15°C for 2-6 hours.

7. The method for preparing a biomass hydrogel dressing based on broccoli stem pectin according to claim 1, characterized in that: In S3, thawing is performed at room temperature for 0.5-2 h.

8. The method for preparing a biomass hydrogel dressing based on broccoli stem pectin according to claim 1, characterized in that: In S4, the dialysis time is 3-5 h, and the pH of neutral water during dialysis is 6.8-7.

5.

9. A hydrogel dressing prepared according to the method for preparing a biomass hydrogel dressing based on broccoli stem pectin according to any one of claims 1 to 8.

10. The use of a biomass hydrogel dressing based on broccoli stem pectin according to claim 9, characterized in that: Hydrogel dressings are used as wound dressings to promote wound healing.

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