A biomass hydrogel dressing based on broccoli stem pectin and its preparation method and application

Abstract

The present application 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, comprising the following steps: dissolving polyvinyl alcohol in deionized water, stirring uniformly to obtain a polyvinyl alcohol solution; adding broccoli stem pectin and adjusting pH to 2.0-3.0, stirring at 35-60 DEG C for 0.1-2h until the broccoli stem pectin is completely dissolved, obtaining a mixed solution, pouring the mixed solution into a mold, freezing and thawing, repeating 2-5 times, obtaining a hydrogel, packaging the hydrogel in a dialysis bag, dialyzing in neutral water for 3-6 times until the pH is 7.0, obtaining a hydrogel dressing. The biomass hydrogel dressing based on broccoli stem pectin and the preparation method and application thereof adopt the above steps, the hydrogel dressing prepared by repeatedly freezing and thawing after dissolving the broccoli stem pectin in the polyvinyl alcohol solution has excellent biocompatibility, mechanical properties, biological activity and good tissue repair function.

Description

TECHNICAL FIELD

[0001] The present application 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. BACKGROUND

[0002] The healing process of skin wounds usually includes three stages of inflammation, proliferation and remodeling, in which endogenous or exogenous factors can cause delay of the healing process, such as excessive inflammatory response, oxidative stress and bacterial infection, etc. 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 the ability to simulate the characteristics of extracellular matrix.

[0003] At present, many hydrogel materials have been improved in function by loading active ingredients such as anti-inflammatory and antioxidant, such as using 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 due to 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 problems can be reduced, and a more biomimetic healing microenvironment can be provided. However, traditional pectin has the problem of low gel strength in practical application, which limits its application in wound dressings. Therefore, it is an urgent problem to find a pectin biomass hydrogel that can guarantee biological activity and provide sufficient mechanical strength. SUMMARY

[0004] The purpose of the present application 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 purpose, the present application provides a preparation method of a biomass hydrogel dressing based on broccoli stem pectin, comprising the following steps,

[0006] S1, dissolving polyvinyl alcohol in deionized water and stirring uniformly to obtain a polyvinyl alcohol solution;

[0007] S2, adding broccoli stem pectin to the polyvinyl alcohol solution in S1 and adjusting the pH to 2.0-3.0, stirring at 35-60℃ for 0.1-2h until the broccoli stem pectin is completely dissolved, to obtain a mixed solution;

[0008] S3, pour the mixed solution obtained in S2 into a mold, freeze and thaw, repeat 2-5 times, to obtain a hydrogel;

[0009] S4, encapsulate the hydrogel in S3 in a dialysis bag, dialyze in neutral water for 3-6 times until the pH is 7.0 to obtain a hydrogel dressing.

[0010] Preferably, in S1, the molecular weight of polyvinyl alcohol is 89000-98000 Da, and the concentration of polyvinyl alcohol solution is 5-15wt%.

[0011] More preferably, the concentration of polyvinyl alcohol solution is 10wt%.

[0012] Preferably, in S2, the broccoli stem pectin is added in an amount of 0.1-1% of the mixed solution.

[0013] More preferably, the broccoli stem pectin is added in an amount of 0.5%.

[0014] 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%.

[0015] Preferably, in S2, one or more of hydrochloric acid and acetic acid is added when adjusting the pH.

[0016] Preferably, in S3, freezing is carried out at-30℃ to-15℃ for 2-6h.

[0017] Preferably, in S3, thawing is carried out at room temperature for 0.5-2h.

[0018] Preferably, in S4, the dialysis time is 3-5h, and the pH of the neutral water during dialysis is 6.8-7.5.

[0019] The hydrogel dressing prepared by the above-mentioned preparation method of the biomass hydrogel dressing based on broccoli stem pectin.

[0020] The application of the above-mentioned biomass hydrogel dressing based on broccoli stem pectin, the hydrogel dressing is used as a wound dressing to promote wound healing.

[0021] The mechanism of the present application is as follows:

[0022] The present application forms a large number of hydrogen bonds between polyvinyl alcohol PVA and carboxyl and carboxymethyl in broccoli stem pectin BSP through physical crosslinking, which enhances the mechanical properties of the hydrogel and avoids the toxicity problem of using chemical crosslinking agents. The hydrogel prepared based on physical interaction has excellent strength and elasticity, and can effectively withstand the stress of the wound site, while fully exerting the biological properties of broccoli stem pectin, significantly promoting wound healing.

[0023] Therefore, the application adopts the above-mentioned biomass hydrogel dressing based on broccoli stem pectin and its preparation method and application, which has the beneficial effects of:

[0024] 1、The mechanical property of the hydrogel dressing PVA / BSP provided by the application is significantly improved, the introduction of broccoli stem pectin enhances the strength and elasticity of the hydrogel system, and the biological properties of pectin are fully exerted, which significantly promotes wound healing and meets the use requirements of the hydrogel dressing in different environments;

[0025] 2、The hydrogel dressing PVA / BSP provided by the application has excellent biocompatibility, which not only promotes cell proliferation but also does not cause hemolysis, has excellent effect in promoting wound healing, has good tissue repair function, and is suitable for clinical application;

[0026] 3、The preparation method of the hydrogel dressing PVA / BSP provided by the application is simple in operation, short in time consumption, low in raw material cost, and high in biocompatibility, and has large-scale application development prospects in industrial production.

[0027] The technical solutions of the application will be further described in detail below with the help of the drawings and examples. DESCRIPTION OF DRAWINGS

[0028] Figure 1 is the FT-IR spectrum of broccoli stem pectin in the application, the FT-IR spectrum of the hydrogel dressing in Example 1 and Comparative Example 1,

[0029] wherein, Figure 1 the FT-IR spectrum of the broccoli stem pectin in the application, Figure 1 the FT-IR spectrum of the hydrogel dressing in Example 1 and Comparative Example 1;

[0030] Figure 2 is the scanning electron microscope image of the hydrogel dressing in Example 1 and Comparative Example 1 in the application,

[0031] wherein, Figure 2 the scanning electron microscope image of the hydrogel dressing in Comparative Example 1, Figure 2 the scanning electron microscope image of the hydrogel dressing in Example 1;

[0032] Figure 3 is the mechanical property combination diagram of the hydrogel dressing in Example 1 and Comparative Example 1 in the application,

[0033] wherein, Figure 3 the tensile stress-strain curve, Figure 3 the compression stress-strain curve;

[0034] Figure 4is a combination chart of biocompatibility performance of the hydrogel dressing in Example 1 and Comparative Example 1 of the present application,

[0035] wherein, Figure 4 a in is a column chart of L929 cell survival rate, Figure 4 b in is a hemolysis schematic diagram of hydrogel dressing PVA and hydrogel dressing PVA / BSP;

[0036] Figure 5 is a combination chart of the test of promoting wound healing in the present application;

[0037] Figure 6 is a flowchart schematic diagram of the preparation method in the present application. DETAILED DESCRIPTION

[0038] The present application is further described below in conjunction with the accompanying drawings and examples. Unless otherwise defined, the technical terms or scientific terms used in the present application shall be understood as the usual meaning understood by those skilled in the art in the field of the present application. The features mentioned above or the features mentioned in the specific examples can be combined in any manner, and these specific examples are only used to illustrate the present application and not to limit the scope of the present application.

[0039] 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. The reagents used are:

[0040] Polyvinyl alcohol (PVA): purchased from Sigma-Aldrich Trading Co., Ltd.

[0041] Broccoli stem pectin (BSP): provided by the Chinese Academy of Agricultural Sciences, Institute of Vegetables and Flowers.

[0042] Example 1

[0043] As shown in Figure 6 S1, 2g of polyvinyl alcohol was dissolved in 18ml of deionized water preheated to 90℃, the molecular weight of polyvinyl alcohol was 89000-98000Da, and the mixture was stirred uniformly to obtain a 10wt% polyvinyl alcohol solution.

[0044] S2, 0.1g of broccoli stem pectin was added to the polyvinyl alcohol solution in S1, and acetic acid was added to adjust the pH to 2.0-3.0, and the mixture was stirred at 45℃ for 0.5h until the broccoli stem pectin was completely dissolved, to obtain a mixed solution.

[0045] In S2, the broccoli stem pectin was separated and purified from broccoli stems, and the degree of esterification of the broccoli stem pectin was 51%.

[0046] S3, pour the mixed solution obtained in S2 into a mold, freeze at -20°C for 4 h, thaw at room temperature for 1 h, repeat freezing and thawing for 3 times, and obtain a hydrogel.

[0047] S4, encapsulate the hydrogel in S3 in a dialysis bag, dialyze in neutral water for 5 times to remove low molecular impurities in the solution, and obtain a hydrogel dressing PVA / BSP after the pH is 7.0.

[0048] Comparative Example 1

[0049] 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, and stir uniformly to obtain a 10 wt% polyvinyl alcohol solution.

[0050] S2, pour the polyvinyl alcohol solution obtained in S1 into a mold, freeze at -20°C for 4 h, thaw at room temperature for 1 h, repeat freezing and thawing for 3 times, and obtain a hydrogel dressing PVA.

[0051] Test Example 1

[0052] a, FT-IR spectrum test

[0053] The hydrogel dressings obtained in broccoli stem pectin, Example 1 and Comparative Example 1 were all subjected to FT-IR spectrum test, and the results are shown in Figure 1 Figure 1 The FT-IR spectrum of the broccoli stem pectin in a is shown in Figure 1. The absorption peaks at 1740 cm -1 and 1620 cm -1 correspond to the stretching vibration of esterified carbonyl (COO) and carboxyl (COOH), respectively. The absorption peak at 1020 cm -1 is attributed to the stretching vibration of C-O and C-C bonds of C2-C3, C2-O2 and C1-O1 skeleton in galacturonic acid units, and the presence of these functional groups is the key to the antioxidant activity of pectin. Figure 1 The FT-IR spectra of the hydrogel dressings obtained in Example 1 and Comparative Example 1 are shown in b. Both of them have absorption peaks of C-O and CH-OH near 1086 cm -1 and 1328 cm -1 , which indicates that the hydroxyl groups (-OH) of PVA participate in the formation of the hydrogel network. Compared with PVA, PVA / BSP has stretching vibration peaks corresponding to C=O and COO in pectin at 1740 cm -1 and 1020 cm -1 , which confirms that BSP is successfully introduced into the hydrogel system.

[0054] b, scanning electron microscope test

[0055] ​The hydrogel dressings obtained in Example 1 and Comparative Example 1 were subjected to scanning electron microscopy (SEM) analysis, and the resulting SEM images are shown below. Figure 2 As shown. Figure 2 In the image, 'a' is a scanning electron microscope image of the hydrogel dressing in Comparative Example 1. Figure 2 In the image, b is a scanning electron microscope image of the hydrogel dressing from Example 1. Figure 2 As shown in 'a', during the freeze-thaw cycle of the PVA hydrogel dressing, water molecules form ice crystals, while the PVA molecular chains are repelled into the liquid microphase between the ice crystals. This volume expansion forces the PVA molecular chains to arrange themselves more tightly, increasing intermolecular interactions, especially the formation of hydrogen bonds. These hydrogen bonds are retained during thawing, thus forming a stable three-dimensional network structure. Figure 2 As can be seen from b, more hydrophilic carboxyl (-COOH) groups and hydroxyl (-OH) groups are introduced into the PVA / BSP hydrogel dressing. These groups form a large number of hydrogen bonds with PVA, which increases the crosslinking degree of the PVA / BSP hydrogel dressing and thus reduces the pore size of the PVA / BSP hydrogel dressing.

[0056] c. Mechanical property testing

[0057] Tensile and compression tests were conducted using a BPN-50CH universal testing machine, and all tests were performed at room temperature (25°C). The hydrogel dressings obtained in Example 1 and Comparative Example 1 were prepared into spindle shapes (central deformation region, length: 20 mm, width: 4 mm, thickness: 2 mm) specifically for tensile testing, with a tensile rate fixed at 5 mm / min. For compression testing, the hydrogel dressings were prepared into cylinders with a diameter of 15 mm and a height of 10 mm, with a compression rate fixed at 5 mm / min.

[0058] Test results are as follows Figure 3 As shown, Figure 3 In the figure, 'a' represents the tensile stress-strain curve. Figure 3 In the diagram, 'b' represents the compressive stress-strain curve. (From...) Figure 3 As can be seen from 'a', compared with PVA hydrogel dressing, PVA / BSP hydrogel dressing achieved a significant improvement in tensile stress, reaching 0.95 MPa. The 376% strain capacity of PVA / BSP hydrogel dressing still meets the flexibility and compliance requirements in clinical applications.

[0059] 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 80% deformation, which also showed a significant mechanical enhancement compared to the hydrogel dressing PVA.

[0060] d. Biocompatibility testing

[0061] Measurement method: MTT colorimetric method 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, and the results are shown in Figure 4 Figure 4 a in which is the L929 cell survival rate column chart, Figure 4 b in which is the hemolysis diagram of hydrogel dressing PVA and hydrogel dressing PVA / BSP.

[0062] As can be seen from a in Figure 4 , the hydrogel dressing PVA and hydrogel dressing PVA / BSP have no toxicity to L929 cells and significantly promote cell proliferation, and the hydrogel dressing PVA / BSP has a better effect on promoting cell proliferation than the hydrogel dressing PVA. The cell survival rate after co-culturing with the hydrogel dressing PVA / BSP for 48 hours reaches 167.37±7.19% (with the ordinary culture medium as the control group, and the cell survival rate is 100%).

[0063] The wound dressing inevitably contacts with blood in actual use, and the hemolysis rate of the ideal clinical wound dressing should be kept below 5%. As can be seen from b in Figure 4 , the hydrogel dressing PVA and hydrogel dressing PVA / BSP are contacted with whole blood red blood cells at 37°C for 60 minutes, and the results show that the hemolysis rate is less than 5%, and no obvious hemolysis phenomenon is shown.

[0064] e. Promote wound healing test

[0065] Measurement method: The full-thickness skin defect model of SD rats (male, 180-200g) was used to simulate acute wounds in animal experiments. The rats were randomly divided into 3 groups, including the control group (gauze), the PVA group and the PVA / BSP group.

[0066] After the SD rats were anesthetized, the back was depilated and cleaned, and after alcohol disinfection, two full-thickness skin wounds were made on the back using an 8 mm round punch. The control group was covered with gauze and polyurethane film, and the PVA group and the PVA / BSP group were covered with the corresponding hydrogel dressing on the wound, and then covered and fixed with gauze and polyurethane film. After the treatment on the 0th, 3rd, 7th and 14th day, the wound was photographed, as shown in Figure 5 . The PVA / BSP hydrogel dressing showed better healing-promoting ability than the control group and the PVA hydrogel dressing.

[0067] ​Therefore, the application adopts the above-mentioned broccoli stem pectin-based biomass hydrogel dressing, preparation method and application, the hydrogel dressing prepared by repeatedly freezing and thawing after dissolving the broccoli stem pectin in a polyvinyl alcohol solution, has excellent biocompatibility, mechanical properties, biological activity and good tissue repair function.

[0068] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application rather than limiting them, although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that: its still can modify or equivalent replacement of the technical solutions of the present application, and these modifications or equivalent replacement also can not make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present application.

Claims

1. A method for preparing a biomass hydrogel dressing based on broccoli stem pectin, characterized in that: Includes the following steps, S1. Dissolve polyvinyl alcohol in deionized water and stir until homogeneous to obtain a polyvinyl alcohol solution; S2. Add broccoli stem pectin to the polyvinyl alcohol solution in S1, adjust the pH to 2.0-3.0, and stir at 35-60℃ for 0.1-2 hours until the broccoli stem pectin is completely dissolved to obtain a mixed solution. S3. Pour the mixed solution obtained in S2 into a mold, freeze and then thaw, repeat 2-5 times to obtain a hydrogel; S4. Seal the hydrogel from S3 in a dialysis bag and dialyze it in neutral water 3-6 times until the pH reaches 7.0 to obtain the 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 89,000-98,000 Da, and the concentration of polyvinyl alcohol solution is 5-15 wt%.

3. 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 added at a mass of 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 was isolated and purified from broccoli stems, and the degree of esterification of broccoli stem pectin was 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 when adjusting 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 hours.

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 hours, and the pH of the neutral water during dialysis is 6.8-7.

5.

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

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

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