Guar gum hydrogel with biological activity as well as preparation method and application of guar gum hydrogel

Abstract

The invention discloses guar gum hydrogel with biological activity and a preparation method and application thereof, and the preparation method comprises the following steps: adding tannic acid and a soluble ferric iron source into a guar gum solution, then adding a cross-linking agent, and carrying out a cross-linking reaction to obtain the guar gum hydrogel with biological activity. The hydrogel disclosed by the invention has good mechanical properties and self-repairing performance, can effectively prevent the hydrogel from being damaged and torn, avoids wound infection, is beneficial to providing a good repairing environment for wounds, and is beneficial to improving the healing effect of the wounds by integrating lysine with biological activity into guar gum hydrogel. The biocompatibility of the guar gum hydrogel is improved, and the capacity of promoting the healing of infected wounds is improved.

Description

Technical Field

[0001] The invention relates to the technical field of tissue engineering, and in particular to a guar gum hydrogel with biological activity and a preparation method and application thereof. Background Art

[0002] The skin is the largest organ in the human body and plays an important role in protecting the body from external aggression, regulating body temperature and sensing external stimuli. However, the skin is in direct contact with the external environment and is therefore particularly fragile. Once injured, the skin undergoes a complex and lengthy healing process. In addition, chronic wounds caused by burns, infections and diabetes often fail to heal properly, leading to long-term inflammation, insufficient angiogenesis, and ultimately amputation or even death. In order to promote wound repair, various wound dressings have been developed. Among them, hydrogels have great potential in the field of wound care due to their porous structure, excellent exudate absorption capacity, water retention capacity and oxygen permeability. In particular, polysaccharide hydrogels are often used as ideal wound dressings due to their good biocompatibility and wide availability. However, polysaccharide hydrogels have poor mechanical properties and are easily torn or damaged at the wound site, leading to serious infection. Therefore, there is an urgent need to develop a polysaccharide hydrogel wound dressing with good self-healing properties and mechanical properties to meet the needs.

[0003] Guar gum (GG) is a white-yellow natural water-soluble polysaccharide extracted from the seeds of the guar plant. It is rich in hydroxyl groups and can be used to construct self-healing hydrogels with dynamic networks. In addition, guar gum has good biocompatibility, hydrophilicity, biodegradability, easy availability and low cost, so it occupies a unique position among polysaccharides. However, guar gum hydrogels have weak mechanical properties and do not contain bioactive agents, which limits their application in the field of wound repair.

[0004] Therefore, it is necessary to provide a guar gum hydrogel with good wound repair effect as a medical antibacterial dressing. Summary of the invention

[0005] In view of this, the present application provides a guar gum hydrogel with biological activity and a preparation method and application thereof, which are used to solve the problem of how to improve the wound repair effect of guar gum hydrogel.

[0006] In order to achieve the above technical objectives, this application adopts the following technical solutions: In a first aspect, the present application provides a method for preparing a guar gum hydrogel having biological activity, comprising the following steps: adding tannic acid and a soluble trivalent iron source to a guar gum solution, and then adding a cross-linking agent and performing a cross-linking reaction to obtain a guar gum hydrogel having biological activity.

[0007] Preferably, the preparation method of the cross-linking agent is as follows: 4-formylphenylboronic acid is added to a lysine solution to obtain a clear solution, and then stirred for reaction to obtain the cross-linking agent.

[0008] Preferably, the soluble ferric iron source includes one or more of ferric chloride, ferric sulfate and ferric nitrate.

[0009] Preferably, the pH of the cross-linking reaction is 8-9, and the temperature of the cross-linking reaction is 20-40°C.

[0010] Preferably, the mass ratio of tannic acid to soluble ferric iron source is 5:0.15-0.45.

[0011] Preferably, the mass ratio of tannic acid to guar gum is 0.5:1-2.

[0012] Preferably, the stirring reaction temperature is 20-40°C.

[0013] Preferably, in the clear solution, the mass ratio of lysine to 4-formylphenylboronic acid is 15-20:30.

[0014] In a second aspect, the present application provides a guar gum hydrogel having biological activity.

[0015] In a third aspect, the present application provides a use of a bioactive guar gum hydrogel in the preparation of a biomedical antibacterial dressing.

[0016] The beneficial effects of this application are as follows: The hydrogel of the present application has good mechanical properties and self-repairing properties, which can effectively prevent the hydrogel from being damaged and torn, avoid wound infection, and help provide a good repair environment for the wound; This application combines TA and Fe 3+ The formed chelate is introduced into the guar gum hydrogel, so that the hydrogel can produce excellent photothermal effect under near-infrared irradiation, thereby greatly improving the antibacterial property of the hydrogel, which can not only avoid the drug resistance problem caused by the abuse of antibiotics, but also has the advantages of remote controllability and little damage to normal tissues; The present application integrates bioactive lysine into guar gum hydrogel, thereby improving the biocompatibility of the guar gum hydrogel and the ability to promote healing of infected wounds. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a scanning electron micrograph of the biologically active guar gum hydrogel obtained in Example 1; Figure 2 This is a scanning electron micrograph of the biologically active guar gum hydrogel obtained in Example 2; Figure 3 This is a scanning electron micrograph of the biologically active guar gum hydrogel obtained in Example 3; Figure 4 Compressed histograms of bioactive guar gum hydrogels prepared for different examples; Figure 5 This is the effect diagram of hydrogel on Escherichia coli and Staphylococcus aureus; Figure 6 A bar graph showing the efficiency of hydrogels in promoting healing of infected wounds. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0019] Bacterial infection is a major factor that hinders wound healing. Therefore, it is crucial to improve the antibacterial properties of hydrogels. Photothermal therapy (PTT) is an antibacterial method with broad-spectrum efficacy, remote controllability, non-invasiveness and high selectivity.

[0020] Based on this, this application was created.

[0021] The present application provides a method for preparing a guar gum hydrogel with biological activity, comprising the following steps: adding tannic acid and a soluble trivalent iron source to a guar gum solution, and then adding a cross-linking agent and performing a cross-linking reaction to obtain a guar gum hydrogel with biological activity.

[0022] In this application, tannic acid / iron chelate (TA / Fe 3+ ) can be used as a photothermal agent, which has good biocompatibility and high near-infrared light absorption capacity. Tannic acid / iron chelate (TA / Fe 3+ ) is introduced into guar gum to give the guar gum hydrogel excellent photothermal antibacterial properties. At the same time, the bioactive guar gum hydrogel of the present application has adjustable mechanical properties, photothermal properties, good self-healing properties and biocompatibility, which enable the bioactive guar gum hydrogel to provide a good healing environment for wounds and accelerate the rapid healing of bacterial-infected wounds.

[0023] In some embodiments, the preparation method of the cross-linking agent is as follows: 4-formylphenylboronic acid is added to a lysine solution to obtain a clear solution, and then stirred for reaction to obtain a cross-linking agent (FLF).

[0024] In the present application, lysine (Lys) contains two amino groups, which can form a dynamic Schiff base with the aldehyde group in 4-formylphenylboronic acid (FPBA), thereby forming a small molecule crosslinker (FLF). The phenylboronic acid group of the small molecule crosslinker (FLF) can form a borate ester bond with the hydroxyl group in guar gum, thereby establishing a dynamic crosslinking network through the Schiff base and the borate ester bond, which has the effect of giving the guar gum hydrogel self-healing properties; at the same time, the addition of lysine enhances the ability of the hydrogel to promote wound repair and improves the biocompatibility of the guar gum hydrogel; furthermore, the hydrogel of the present application contains an aromatic Schiff base and also has antibacterial properties. The aromatic Schiff base is combined with the photothermal effect to further enhance the antibacterial properties of the guar gum hydrogel.

[0025] In some embodiments, the soluble ferric iron source includes one or more of ferric chloride, ferric sulfate, and ferric nitrate.

[0026] In some embodiments, the pH of the cross-linking reaction is 8-9, and the temperature of the cross-linking reaction is 20-40°C.

[0027] In some embodiments, the mass ratio of tannic acid to soluble ferric iron source is 5:0.15-0.45.

[0028] In the present application, the increase or decrease of the iron source content affects the mechanical properties of the finished hydrogel.

[0029] In some embodiments, the mass ratio of tannic acid to guar gum is 0.5:1-2.

[0030] In some embodiments, the temperature of the stirred reaction is 20-40°C.

[0031] In some embodiments, in the clear solution, the mass ratio of lysine to 4-formylphenylboronic acid is 15-20:30.

[0032] In a second aspect, the present application provides a guar gum hydrogel having biological activity.

[0033] In a third aspect, the present application provides a use of a bioactive guar gum hydrogel in the preparation of a biomedical antibacterial dressing.

[0034] The present solution is further described below through specific embodiments.

[0035] Example 1 A method for preparing a biologically active guar gum hydrogel comprises the following steps: 0.03g lysine and 0.06g 4-formylphenylboronic acid were dissolved in deionized water, and the pH was adjusted until the solution was clear and transparent to obtain a clear solution, which was then stirred at 25°C for 0.5h to obtain 2ml of FLF solution, which was the cross-linking agent; then 8ml of deionized water, 0.05g of tannic acid, 0.01ml of ferric chloride solution (300mg / ml) and 0.2g of guar gum powder were added to another beaker and stirred at 25°C for 2 hours, 2ml of FLF solution was added to the guar gum solution containing tannic acid / iron chelate, and the pH was adjusted to 8.5 to obtain a guar gum hydrogel with biological activity.

[0036] Example 2 A method for preparing a biologically active guar gum hydrogel comprises the following steps: Dissolve 0.03g of lysine and 0.06g of 4-formylphenylboronic acid in deionized water, adjust the pH until the solution is clear and transparent to obtain a clear solution, and then stir at 25°C for 0.5h to obtain 2ml of FLF solution, which is the cross-linking agent; then add 8ml of deionized water, 0.05g of tannic acid, 0.02ml of ferric chloride solution (300mg / ml) and 0.2g of guar gum powder into another beaker, and stir at 25°C for 2 hours. Add 2ml of FLF solution to the guar gum solution containing tannic acid / iron chelate, and adjust the pH to 8.5 to obtain a guar gum hydrogel with biological activity.

[0037] Example 3 A method for preparing a biologically active guar gum hydrogel comprises the following steps: Dissolve 0.03g of lysine and 0.06g of 4-formylphenylboronic acid in deionized water, adjust the pH until the solution is clear and transparent to obtain a clear solution, and then stir at 25°C for 0.5h to obtain 2ml of FLF solution, which is the cross-linking agent; then add 8ml of deionized water, 0.05g of tannic acid, 0.03ml of ferric chloride solution (300mg / ml) and 0.2g of guar gum powder into another beaker, and stir at 25°C for 2 hours. Add 2ml of FLF solution to the guar gum solution containing tannic acid / iron chelate, and adjust the pH to 8.5 to obtain a guar gum hydrogel with biological activity.

[0038] Comparative Example 1 A method for preparing a guar gum hydrogel, the other contents of which are the same as those of Example 1, except that lysine is not added.

[0039] Comparative Example 2 A method for preparing a guar gum hydrogel, the other contents of which are the same as those of Example 1, except that 4-formylphenylboronic acid is not added.

[0040] Comparative Example 3 A method for preparing a guar gum hydrogel, the other contents of which are the same as those of Example 1, except that tannic acid is not added.

[0041] Comparative Example 4 A method for preparing a guar gum hydrogel, the other contents of which are the same as those of Example 1, except that ferric chloride is not added.

[0042] Test and Evaluation The guar gum hydrogel obtained in Examples 1-3 was subjected to electron microscopy scanning, and the results were as follows: Figure 1-3 The scanning electron microscope image of the product obtained in Example 1 is shown in Figure 1 , indicating that a biologically active guar gum hydrogel with a three-dimensional network structure, microporous characteristics, and high porosity was obtained. Figure 4 The compression modulus bar graph shows that the hydrogel has good mechanical properties (~1.06 kPa). Figure 2 , indicating that a biologically active guar gum hydrogel with a three-dimensional network structure, microporous characteristics, and high porosity was obtained. Figure 4 The compression bar graph shows that the hydrogel has good mechanical properties (~0.67 kPa). Figure 3 , indicating that a biologically active guar gum hydrogel with a three-dimensional network structure, microporous characteristics, and high porosity was obtained. Figure 4 The compression bar graph shows that the hydrogel has good mechanical properties (~0.46 kPa).

[0043] The antibacterial and photothermal antibacterial efficiency of the guar gum hydrogel obtained in Example 2 against Escherichia coli and Staphylococcus aureus were tested: the hydrogel precursor prepared in Example 2 was added to a 48-well cell culture plate in two groups. After standing for complete gelation, it was sterilized with ultraviolet light for 24 hours. One group (Example 2 group) added 1000 μL of diluted bacterial suspension (108 CFU / mL) to the sterilized hydrogel, and the other group (Example 2 + light irradiation group) added 1000 μL of diluted bacterial suspension (108 CFU / mL) to the sterilized hydrogel, and the near-infrared laser (808 nm, 1.2 W / cm 2) for 5 minutes; at the same time, two control groups were set up: one group (control group) added 1000μL of diluted bacterial suspension to the 48 cell culture plates without hydrogel, and the other group (control group + light group) added 1000μL of bacterial suspension to the 48 cell culture plates without hydrogel and irradiated with near-infrared laser (808 nm, 1.2 W / cm2) for 5 minutes. Then, the above 4 groups of culture dishes were cultured in an oscillating incubator at 100 rpm / min and 37°C for 12 hours, and each group of bacterial liquid was diluted with sterile PBS, and then 100μL of bacterial suspension was evenly dispersed on the agar plate and cultured in a constant temperature oscillating incubator for 12 hours. Finally, the antibacterial properties of the material were analyzed by taking pictures and counting the colonies on the agar plates. The number of colonies on the agar plates is shown in Figure 5 This indicates that the bioactive guar gum hydrogel prepared in the present application has excellent antibacterial properties.

[0044] The wound healing effect of the guar gum hydrogel obtained in Example 2 was tested: a wound healing experiment was conducted using a bacterial infection wound model of Kunming mice (female, 35-40 g). The back hair of the anesthetized mice was shaved, and then two full-thickness wounds with a diameter of about 8 mm were prepared on both sides of the back of the mice. In addition, 30 μL of Staphylococcus aureus (1×10 8 CFU / mL) to establish an infected wound model. The experiment was divided into three groups. The first group was a PBS group as a control group, the second group was a 3M commercial dressing group, the third group was the hydrogel prepared in Example 2 without 808nm laser irradiation, and the third group was the hydrogel prepared in Example 2 irradiated with 808nm laser for 5 minutes. Photos of mouse wounds were taken on days 0, 3, 7, and 12, and the wound healing rate was calculated. The wound healing rate of mice is shown in Figure 6 , indicating that the bioactive guar gum hydrogel prepared in this application can effectively promote the healing of bacterially infected wounds.

[0045] The above are only preferred specific implementations of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for preparing a biologically active guar gum hydrogel, characterized in that: The method comprises the following steps: adding tannic acid and a soluble trivalent iron source into a guar gum solution, and then adding a cross-linking agent and performing a cross-linking reaction to obtain the guar gum hydrogel with biological activity.

2. The method for preparing the biologically active guar gum hydrogel according to claim 1, characterized in that: The preparation method of the cross-linking agent is as follows: 4-formylphenylboronic acid is added to a lysine solution to obtain a clear solution, and then stirred for reaction to obtain the cross-linking agent.

3. The method for preparing the biologically active guar gum hydrogel according to claim 1, characterized in that: The soluble ferric iron source includes one or more of ferric chloride, ferric sulfate and ferric nitrate.

4. The method for preparing the biologically active guar gum hydrogel according to claim 1, characterized in that: The pH of the cross-linking reaction is 8-9, and the temperature of the cross-linking reaction is 20-40°C.

5. The method for preparing the biologically active guar gum hydrogel according to claim 1, characterized in that: The mass ratio of the tannic acid to the soluble ferric iron source is 6.25:0.375-1.

125.

6. The method for preparing the biologically active guar gum hydrogel according to claim 1, characterized in that: The mass ratio of the tannic acid to the guar gum is 0.5:1-2.

7. The method for preparing the biologically active guar gum hydrogel according to claim 2, characterized in that: The temperature of the stirring reaction is 20-40°C.

8. The method for preparing the biologically active guar gum hydrogel according to claim 2, characterized in that: In the clear solution, the mass ratio of lysine to the 4-formylphenylboronic acid is 15-20:

30.

9. A guar gum hydrogel having biological activity obtained by the preparation method according to any one of claims 1 to 8.

10. Use of the biologically active guar gum hydrogel according to claim 9 in preparing a biomedical antibacterial dressing.

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