Polyethyleneimine / polyacrylic acid-based hydrogel for wound repair and preparation method of polyethyleneimine / polyacrylic acid-based hydrogel

Abstract

The invention relates to the field of biomedical materials, in particular to polyethyleneimine / polyacrylic acid-based hydrogel for wound repair and a preparation method of the polyethyleneimine / polyacrylic acid-based hydrogel. The hydrogel is prepared by the following steps: dissolving polyacrylic acid with a specific polymerization degree, reacting with a cross-linking agent and an initiator, treating to obtain a polyacrylic acid group, and mixing and stirring with a polyethyleneimine aqueous solution. In the preparation process, the raw material proportion, reaction conditions and other parameters are accurately controlled. The hydrogel has a unique microstructure and physicochemical properties, such as appropriate swelling ratio, mechanical strength and surface charge density, and has good tissue adhesion and antibacterial property in wound repair, and degradation products are harmless. The method can also be used for preparing medical dressings, and has a wide application prospect in the field of wound repair of skin, mucous membranes and the like.

Description

Technical Field

[0001] The invention relates to the field of biomedical materials, and in particular to a polyethyleneimine / polyacrylic acid-based hydrogel for wound repair and a preparation method thereof. Background Art

[0002] A wound is an injury that causes the skin, tissues and mucous membranes to lose continuity. Since wounds are usually directly exposed to a complex environment, they are susceptible to bacterial infection, which in turn causes a persistent inflammatory response at the site of infection, resulting in delayed wound healing and, in some special cases, even serious complications.

[0003] In the field of wound repair, the demand for efficient and multifunctional biomaterials is growing. Traditional wound repair materials often fail to meet the requirements in terms of tissue adhesion, antifouling properties, hemostasis and antibacterial properties. Polyethyleneimine has good biocompatibility and amino functional groups, and can react with a variety of substances, while polyacrylic acid has abundant carboxyl groups. The combination of the two is expected to prepare hydrogel materials with excellent performance for wound repair. However, the existing methods for preparing related materials have problems such as complex processes and difficulty in performance regulation.

[0004] In view of this, the present application provides a simple and performance-controllable polyethyleneimine / polyacrylic acid-based hydrogel for wound repair and a preparation method to solve the above-mentioned technical problems. Summary of the invention

[0005] In view of the above problems in the prior art, the present application proposes a polyethyleneimine / polyacrylic acid-based hydrogel for wound repair and a preparation method thereof.

[0006] A method for preparing a polyethyleneimine / polyacrylic acid-based hydrogel for wound repair comprises the following steps:

[0007] S1. Dissolving polyacrylic acid in a buffer solution to obtain a polyacrylic acid solution.

[0008] S2. Add a crosslinking agent and an initiator to the polyacrylic acid solution, and carry out a crosslinking polymerization reaction at a specific temperature and reaction time.

[0009] S3. Filter, wash and dry the reaction product to obtain polyacrylic acid.

[0010] S4, mixing the polyacrylic acid-based aqueous solution and the polyethyleneimine aqueous solution in a certain volume ratio, and stirring to obtain the polyacrylic acid-based / polyethyleneimine hydrogel.

[0011] As a preferred solution, the initiator in the step is N,N-dicyclohexylcarbodiimide (DCC), and the cross-linking agent is N-hydroxysuccinimide (NHS).

[0012] As a preferred solution, the reaction conditions in the step are an ice bath environment, and the reaction time is 2h to 24h.

[0013] As a preferred solution, the slow-release solvent in the step is a mixed solution of dichloromethane (DCM) and N,N-dimethylformamide (DMF) in a volume ratio of 1:1.

[0014] As a preferred solution, the degree of polymerization of the polyacrylic acid in the step is 100 kDa to 450 kDa, and the degree of polymerization of the polyethyleneimine is 20 to 120 kDa.

[0015] As a preferred solution, in the step, DCC is used as a coupling mediator, and the molar ratio of DCC to NHS is maintained at 1:1; the mass ratio of NHS to PAA is between 2.5:1 and 1:1.

[0016] As a preferred solution, the concentration of the polyacrylic acid aqueous solution in the step is 10-30%, the concentration of the polyethyleneimine aqueous solution is 10%-30%, and the volume ratio of the polyacrylic acid aqueous solution and the polyethyleneimine aqueous solution is between 1:3 and 3:1.

[0017] As a preferred solution, the mass fraction of the silicone liquid in the step is 30% to 50%, the mass fraction of the lubricating fluid is 50% to 70%, and the mass fraction of the silane coupling agent is 0.1% to 0.2%.

[0018] As a preferred solution, in step S5, the mass fraction of the siloxane liquid is 30% to 50%, the mass fraction of the lubricating fluid is 50% to 70%, and the mass fraction of the silane coupling agent is 0.1 to 0.2%.

[0019] The above technical features can be combined in a suitable manner or replaced by equivalent technical features as long as the purpose of the present invention can be achieved.

[0020] The polyethyleneimine / polyacrylic acid-based hydrogel for wound repair and the preparation method provided by the present invention have at least the following beneficial effects compared with the prior art:

[0021] The hydrogel has a unique microstructure, with a porous cross-linked polymer network and specific physical and chemical properties. For example, at 37°C and pH 7.4, its swelling rate is 500%-1000%, its mechanical strength is 10-50 kPa, and its surface charge density is 5-20 mC / m 2 .

[0022] The polyethyleneimine / polyacrylic acid-based hydrogel for wound repair can be used in the preparation of adhesive biomaterials, and the application includes but is not limited to being used as an adhesive in wound repair of skin, mucous membrane and other wound types. The adhesion between the hydrogel and the wound tissue is measured to be 25-45 kPa under a tensile test method and a simulated physiological environment, and the hydrogel can form chemical bonds with active groups on the tissue surface through amino groups during the adhesion process. At the same time, the degradation rate of the hydrogel as an adhesive biomaterial in the body is 10%-30% / week, and the degradation products are non-toxic and can be metabolized by the body, and will not cause inflammation, allergies and other adverse effects on human tissues. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention will be described in more detail below based on embodiments and with reference to the accompanying drawings, wherein:

[0024] Figure 1 The test results of the adhesion strength between Examples 1-3 of the present invention and pig skin tissue are shown;

[0025] Figure 2 The FTIR infrared spectrum test diagrams of Examples 1-3 of the present invention are shown;

[0026] Figure 3 An electron microscope image of the hydrogel microstructure of Example 3 of the present invention is shown;

[0027] Figure 4 The chemical principle diagram of the modification of polyacrylic acid with N-hydroxysuccinimide (NHS) in Examples 2 and 3 of the present invention is shown. DETAILED DESCRIPTION

[0028] The present invention will be further described below in conjunction with the accompanying drawings.

[0029] The invention provides a polyethyleneimine / polyacrylic acid-based hydrogel for wound repair and a preparation method thereof.

[0030] Example 1

[0031] 10 g of 10 wt% PEI aqueous solution (Mv, ca. 70,000) and 20 g of 10 wt% PAA aqueous solution (Mv, ca. 240,000) were mixed with stirring under a sterile environment, and the mixture was poured into liquid nitrogen for freezing, ground, and freeze-dried in a freeze dryer for 48 h to obtain PAA / PEI hydrogel powder.

[0032] Example 2

[0033] Under ice bath conditions, 2 g of polyacrylic acid (PAA) (Mv, ca. 240,000), 4.13 g of N,N-dicyclohexylcarbodiimide (DCC) and 2.30 g of N-hydroxysuccinimide (NHS) were fully dissolved in a 1:1 mixed solution of dichloromethane (DCM) and N,N-dimethylformamide (DMF). The DCC pre-solution was added dropwise to the polyacrylic acid solution. After 5 minutes, the NHS pre-solution was added dropwise to the reaction solution in the same manner. The chemical principle is as follows: Figure 4 As shown. After stirring for 1 hour under ice bath conditions, continue stirring at 22°C for 12 hours. During the reaction, DCC will be converted into N,N-dicyclohexylurea (DCU) which is insoluble in organic reagents. After filtering, the filtrate is dried at low temperature. The obtained product is washed with ammonia water and dichloromethane, and then dried in a vacuum to obtain the modified PAA-NHS powder, which is dissolved in water to prepare 20g of PAA-NHS solution.

[0034] 10 g of 10 wt% polyethyleneimine (PEI) (Mv, ca. 70,000) solution and 20 g of the polyacrylate (PAA-NHS) solution prepared above were mixed with stirring in a sterile, light-proof environment. The mixture was poured into liquid nitrogen for freezing, ground, and freeze-dried in a freeze dryer for 48 h to obtain PEI / PAA-NHS hydrogel powder, which was stored in a low-temperature dry environment.

[0035] Example 3

[0036] Under ice bath conditions, 2 g of polyacrylic acid (PAA), 8.26 g of N,N-dicyclohexylcarbodiimide (DCC) and 4.60 g of N-hydroxysuccinimide (NHS) were fully dissolved in a 1:1 mixed solution of dichloromethane (DCM) and N,N-dimethylformamide (DMF). The DCC pre-solution was added dropwise to the polyacrylic acid solution. After 5 minutes, the NHS pre-solution was added dropwise to the reaction solution in the same manner. After stirring for 1 hour under ice bath conditions, stirring was continued at 22°C for 12 hours. During the reaction, DCC will be converted into N,N-dicyclohexylurea (DCU) which is insoluble in organic reagents. After filtering it, the filtrate is dried at low temperature. The obtained product is washed with ammonia water and dichloromethane, and then dried in a vacuum to obtain the modified PAA-NHS powder, which is dissolved in water to prepare 20 g of PAA-NHS solution.

[0037] 10 g of 10 wt% polyethyleneimine (PEI) solution and 20 g of the polyacrylate (PAA-NHS) solution prepared above were mixed with stirring in a sterile, light-proof environment. The mixture was poured into liquid nitrogen for freezing, ground, and freeze-dried in a freeze dryer for 48 h to obtain PEI / PAA-NHS hydrogel powder, which was stored in a low-temperature dry environment.

[0038] Take the samples prepared in the above experimental example and conduct the following experiment:

[0039] 1. The application of the hydrogel powder prepared in Experimental Examples 1-3 in the preparation of adhesive biomaterials includes but is not limited to being used as an adhesive in wound repair of wounds of the skin, mucous membranes and other types. The adhesion between the hydrogel powder and the wound tissue is measured to be 25-45 kPa under a tensile test method and a simulated physiological environment, and the hydrogel can form chemical bonds with the active groups on the surface of the tissue through the amino group during the adhesion process. At the same time, the hydrogel as an adhesive biomaterial has a degradation rate of 10%-30% / week in vivo, and the degradation products are non-toxic and can be metabolized by the body, and will not cause inflammation, allergies and other adverse effects on human tissues.

[0040] Figure 1 It is the adhesion strength test result of each sample. As can be seen from the figure, the adhesion strength of the hydrogel adhesion powder obtained by NHS modification has been significantly improved, and it increases with the increase of NHS content.

[0041] 2. The hydrogel powders prepared in Experimental Examples 1 to 3 were tested by FTIR infrared spectroscopy. The results are as follows: Figure 2 As shown. Figure 2 It can be seen that through NHS modification, the original carboxyl group of PAA and the free amino group form an amide bond polymerized NHS ester, which is also the reason why the adhesion of the modified hydrogel powder is improved.

[0042] 3. The sample prepared in Experimental Example 3 has a unique microstructure. Its microstructure is observed under an electron microscope. Figure 3 It can be seen from the electron microscope image that the polymer inside the hydrogel prepared by the present invention presents a porous cross-linked morphology.

[0043] 4. The physicochemical properties of the hydrogel powder prepared in Experimental Examples 1-3 were tested. Under the conditions of 37°C and pH 7.4, the swelling rate was 500%-1000%, the mechanical strength was 20-50 kPa, and the surface charge density was 5-20 mC / m 2 .

[0044] 5. Animal experiments. The digestive system of pigs is similar to that of humans, and their special environment is most suitable for experimental research on complex wound repair. Therefore, the inventors created two ulcer surfaces with a diameter of 0.8 cm in the stomach of living pigs, and treated the wounds with either no treatment or polyethyleneimine / polyacrylic acid-based hydrogel.

[0045] Experiments show that the polyethyleneimine / polyacrylic acid-based hydrogel of the present invention has a significant effect on promoting the repair of tissue damage under complex conditions.

[0046] Although the present invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the present invention. It should therefore be understood that many modifications may be made to the exemplary embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that the various dependent claims and features described herein may be combined in a manner different from that described in the original claims. It should also be understood that features described in conjunction with individual embodiments may be used in other described embodiments.

Claims

1. A method for preparing a polyethyleneimine / polyacrylic acid-based hydrogel for wound repair, characterized in that: The following steps are involved: Step S1, dissolving polyacrylic acid in a slow-release solvent to obtain a polyacrylic acid solution; Step S2, adding a crosslinking agent and an initiator to the polyacrylic acid solution to carry out a crosslinking polymerization reaction; Step S3, filtering, washing and drying the reaction product to obtain polyacrylic acid; Step S4: mixing the polyacrylic acid aqueous solution and the polyethyleneimine aqueous solution, and stirring to obtain the polyacrylic acid / polyethyleneimine hydrogel.

2. The preparation method according to claim 1, characterized in that: The initiator is N,N-dicyclohexylcarbodiimide, potassium persulfate or ammonium persulfate, and the cross-linking agent is N-hydroxysuccinimide, N,N'-methylenebisacrylamide, chitosan, graphene oxide or nanocellulose.

3. The preparation method according to claim 1, characterized in that: The reaction temperature of step S2 is -10°C-37°C, and the reaction time is 2h-24h.

4. The preparation method according to claim 1, characterized in that: The slow-release solvent is a mixed solution of dichloromethane and N,N-dimethylformamide in a volume ratio of 1:

1.

5. The preparation method according to claim 1, characterized in that: The polymerization degree of the polyacrylic acid is 100 kDa to 450 kDa, and the polymerization degree of the polyethylene imine is 20 to 120 kDa.

6. The preparation method according to claim 1, characterized in that: The molar ratio of N,N-dicyclohexylcarbodiimide as a coupling mediator to N-hydroxysuccinimide is maintained at 1:1; the mass ratio of N-hydroxysuccinimide to polyacrylic acid is between 2.5:1 and 1:

1.

7. The preparation method according to claim 1, characterized in that: The concentration of the polyacrylic acid-based aqueous solution is 10-30%, the concentration of the polyethyleneimine aqueous solution is 10%-30%, and the volume ratio of the polyacrylic acid-based aqueous solution and the polyethyleneimine aqueous solution is between 1:3 and 3:

1.

8. The polyethyleneimine / polyacrylic acid-based hydrogel for wound repair prepared by the preparation method according to any one of claims 1 to 7.

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