A method for preparing a hydrogel composite

Abstract

The present invention belongs to the technical field of hydrogel biomaterials. Aiming at the problem that the post-treatment method of the existing hydrogel membrane material cannot effectively reduce the pore size of the hydrogel, the present invention provides a method for preparing a hydrogel composite, which is used to reduce the pore size of the biohydrogel material, and the biohydrogel is used as a substrate, immersed in a prepolymer solution containing methyl methacrylate, 2-hydroxyethyl methacrylate and ethylene glycol dimethacrylate, and a free radical polymerization reaction occurs to generate a composite hydrogel material with a smaller pore size or no pores. The method is simple to operate and quick to prepare; by adjusting the concentration of the prepolymer solution, the hydrogel and the acrylate polymer in the prepared composite hydrogel are interspersed with each other, and the pore size of the composite hydrogel can be adjusted.

Description

Technical Field

[0001] The invention belongs to the technical field of hydrogel biomaterials, and particularly relates to a method for preparing a hydrogel composite. Background Art

[0002] Hydrogel is a material composed of natural or synthetic polymers that can form a three-dimensional network structure in water. Biohydrogels are widely used in biomedical fields such as tissue engineering, drug delivery, wound healing, and biosensors. In these applications, the physical and chemical properties of hydrogels, especially the pore size, have an important impact on their functions and effects. If the pore size of the hydrogel is too large, the drug may be released too quickly, causing the effective concentration of the drug to drop rapidly in a short period of time, and it is impossible to maintain sustained efficacy. In tissue engineering, if the pore size of the hydrogel is too large, cells may not be able to effectively attach to the hydrogel, or due to the lack of sufficient cell-cell contact, cell differentiation is affected. Hydrogels with too large pores may have poor mechanical properties and cannot maintain their morphology and function in applications that need to withstand a certain degree of mechanical stress. For cell growth and differentiation, appropriate nutrient and oxygen transmission rates are necessary. Too large pores may cause these substances to pass through the hydrogel too quickly, unable to form an appropriate concentration gradient in the hydrogel, and the hydrogel may be more easily eroded by body fluids or cells, resulting in a decrease in its stability in the body, which is not conducive to use as an implantable material in the body. Therefore, hydrogels with pores that are too large may face many challenges in practical applications.

[0003] The key factor in the development and application of polymer membranes is the control of their polymer morphology, and membrane pore size and membrane porosity are the control factors of membrane morphology. The control methods of the pore size of polymer membrane materials mainly include control in the polymer preparation process, control in the film forming process, and control after film forming. For example, studies have shown that the polymer pore size and pore size distribution can be adjusted by controlling the amount of crosslinking agent. As the amount of crosslinking agent increases, the number of micropores increases. When the amount of crosslinking agent continues to increase to a certain extent, the number of micropores on the polymer surface is significantly reduced (Journal of Petroleum (Petroleum Processing) 2012 No. 3, pp. 470-474). CN108499361A patent document discloses a method for preparing a nanoporous polymer membrane with adjustable pore size, wherein a molecular-based coordination compound is dissolved in a solvent as a pore-forming agent so that it can be uniformly dispersed in a polymer casting solution, and then the obtained casting solution is prepared into a film, and the pore-forming agent is removed by using an appropriate solvent, i.e., a polymer membrane with adjustable pore size is obtained, and the pore size can be further adjusted by adjusting the concentration, the type of pore-forming agent, etc. However, the pore size control range of the membrane surface by the porogen is relatively small. Post-treatment is one of the treatment methods to control the membrane morphology, including heat treatment, plasma treatment, chemical etching, etc. These methods are used to increase the porosity and pore size, but cannot reduce the pore size of the hydrogel material. Summary of the invention

[0004] In view of the above-mentioned problem that the post-treatment method of the existing hydrogel membrane material cannot effectively reduce the pore size of the hydrogel, the present invention provides a method for preparing a hydrogel composite, which uses a biological hydrogel as a substrate, is immersed in a prepolymer solution containing methyl methacrylate, 2-hydroxyethyl methacrylate and ethylene glycol dimethacrylate, and undergoes a free radical polymerization reaction to generate a composite hydrogel material with a small pore size or no pores. The method is simple to operate and quick to prepare; by adjusting the concentration of the prepolymer solution, the hydrogel and the acrylate polymer in the prepared composite hydrogel are interspersed with each other, and the pore size of the composite hydrogel can be adjusted.

[0005] The present invention is achieved through the following technical solutions:

[0006] A method for preparing a hydrogel composite comprises the following steps:

[0007] (1) Methyl methacrylate, 2-hydroxyethyl methacrylate and ethylene glycol dimethacrylate are mixed in a volume ratio of (25-35): (160-240): (0.8-1.2), and then mixed with deionized water, wherein the mass fraction of the total monomers in the mixed solution is 20%-100%, and then 0.005%-0.01% of the total monomer volume of DMPA ethanol solution is added to obtain a prepolymer solution;

[0008] (2) soaking the bio-hydrogel to be treated in the prepolymer solution, leaving it to stand for 1-3 hours and then taking it out;

[0009] (3) Exposing the biohydrogel to ultraviolet light to initiate free radical polymerization to obtain a composite hydrogel;

[0010] (4) Take out the composite hydrogel, wash it with deionized water, and freeze-dry it.

[0011] The biohydrogel is a medical hydrogel of any origin, preferably a methacrylylated heparin / methacrylylated glucose photoinitiated copolymer hydrogel or a polyether F127 hydrogel or a gelatin hydrogel.

[0012] In the step (1), the three monomers of methyl methacrylate, 2-hydroxyethyl methacrylate and ethylene glycol dimethacrylate are mixed in a volume ratio of (28-32): (180-220): (0.8-1.2).

[0013] The mass fraction of total monomers in the mixed solution of step (1) is 20%-80%, preferably 60%.

[0014] In the step (3), ultraviolet light is irradiated for 20-30 minutes.

[0015] The preparation method of the methacryloylated heparin / methacryloylated glucose photoinitiated copolymer hydrogel comprises the following steps: dissolving methacryloylated heparin and methacryloylated glucose in a 50% ethanol aqueous solution, adding a photoinitiator, mixing evenly, and irradiating with ultraviolet light to obtain the methacryloylated heparin / methacryloylated glucose photoinitiated copolymer hydrogel.

[0016] Preferably, the mass ratio of methacryloylated heparin to methacryloylated glucose is (4-6):(2-3); preferably, their mass concentrations in the mixed solution are 4%-6% and 2%-3%, respectively.

[0017] The preparation method of the polyether F127 hydrogel comprises the following steps: dissolving methacrylated polyether F127 in water, adding a photoinitiator, mixing evenly, and irradiating with ultraviolet light to obtain the polyether F127 hydrogel.

[0018] The preparation method of the gelatin hydrogel comprises the following steps: dissolving gelatin in water, adding sodium carboxymethyl cellulose (CMC) and N-hydroxysuccinimide (NHS), mixing evenly, and placing at room temperature for 1-3 hours to obtain the gelatin hydrogel.

[0019] The mass ratio of the gelatin, sodium carboxymethyl cellulose and N-hydroxysuccinimide is (80-120): (4.0-5.0): (1.6-2.2).

[0020] In the preparation of the above biohydrogel, the photoinitiator is preferably DMPA. DMPA is preferably dissolved in ethanol and then added to the reaction system, and the mass fraction of the DMPA ethanol solution is 10%. Preferably, ultrasonic mixing is used. The ultraviolet irradiation time is preferably 25-35 minutes.

[0021] The present invention has the following beneficial effects:

[0022] The composite hydrogel provided by the present invention solves the disadvantage of the large pore size of the traditional hydrogel. After the hydrogel is combined with the acrylic ester polymer, the composite hydrogel material becomes a material with a small pore size or no pore size, which can be synthesized on a large scale in vitro, greatly reducing the use cost, thereby providing a new solution to the shortage of implant materials.

[0023] The invention is simple to operate and quick to prepare; the pore size of the composite material hydrogel can be adjusted by adjusting the concentration of the prepolymer solution.

[0024] The composite hydrogel prepared by the invention is transparent, soft and has good biocompatibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1This is an optical microscope image of the methacryloyl heparin / methacryloyl glucose photoinitiated copolymer hydrogel and its composite hydrogel (heparin-glucose-acrylate composite hydrogel) in Example 1. They are divided into three groups according to the mass fraction of the total monomers in the prepolymer solution, A 0%; B 20%; C 60%.

[0026] Figure 2 This is an optical microscope image of the photoinitiated polyether F127 hydrogel and its composite hydrogel (F127-acrylate composite hydrogel) in Example 2. They are divided into three groups according to the total monomer mass fraction in the prepolymer solution, A 0%; B 20%; C 60%.

[0027] Figure 3 This is an optical microscope image of the photo-initiated gelatin hydrogel and its composite hydrogel (gelatin-acrylate composite hydrogel) of Example 3. They are divided into three groups according to the mass fraction of the total monomers in the prepolymer solution, A 0%; B 20%; C 60%. DETAILED DESCRIPTION

[0028] The present invention is further described in detail below with reference to specific embodiments and accompanying drawings.

[0029] If no specific techniques or conditions are specified in the examples, the techniques or conditions described in the literature in the field or the product instructions are used. If no manufacturer is specified for the reagents or instruments used, they are all conventional products that can be purchased through regular channels. Example 1

[0030] (1) 100.0 mg of methacryloylated heparin and 50.0 mg of methacryloylated glucose were dissolved in 2.0 mL of 50% ethanol aqueous solution, and then 3.0 µL of 10% DMPA ethanol solution was added. The mixed solution was sonicated for 3 min and then irradiated with UV light for 30 min to obtain methacryloylated heparin / methacryloylated glucose photoinitiated copolymer hydrogel.

[0031] (2) 30.0 µL of methyl methacrylate, 200.0 µL of 2-hydroxyethyl methacrylate and 1.0 µL of ethylene glycol dimethacrylate were fully mixed and then mixed with water to obtain two mixed solutions with total monomer mass fractions of 20% and 60%, respectively. 1.5 µL of 10% DMPA solution was added to each of the mixed solutions to prepare a prepolymer solution.

[0032] (3) 4.0 mg of methacryloylated heparin / methacryloylated glucose photoinitiated copolymer hydrogel was placed in 500.0 µL of prepolymerization solution. After standing for 2.0 hours, the hydrogel was taken out.

[0033] (4) Expose the hydrogel to ultraviolet light for 20-30 minutes to obtain a composite hydrogel.

[0034] (5) The composite hydrogel was taken out, washed with deionized water three times, and then freeze-dried. Example 2

[0035] (1) Dissolve 100.0 mg of methacryloyl polyether F127 in 1.0 mL of water, and then add 1.5 µL of 10% DMPA ethanol solution. Ultrasonicate the mixture for 3 min and irradiate it with ultraviolet light for 30 min to obtain polyether F127 hydrogel.

[0036] (2) 30.0 µL of methyl methacrylate, 200.0 µL of 2-hydroxyethyl methacrylate and 1.0 µL of ethylene glycol dimethacrylate were fully mixed, and then fully mixed with water to obtain two mixed solutions with total monomer mass fractions of 20% and 60%, respectively. 1.5 µL of 10% DMPA solution was added to each of the mixed solutions to prepare a prepolymer solution.

[0037] (3) Place 6.0 mg of polyether F127 hydrogel in the prepolymerization solution, let it stand for 2.0 hours, and then take out the hydrogel.

[0038] (4) Expose the hydrogel prepared in (3) to ultraviolet light for 20-30 minutes to obtain a composite hydrogel.

[0039] (5) Take out the composite hydrogel in (4), wash it three times with deionized water, and then freeze-dry it. Example 3

[0040] (1) Dissolve 100.0 mg of gelatin in 1.0 mL of water, then add 4.5 mg of sodium carboxymethyl cellulose (CMC) and 1.8 mg of N-hydroxysuccinimide (NHS). Ultrasonicate for 3 min and place at room temperature for 2 h to obtain gelatin hydrogel.

[0041] (2) 30.0 µL of methyl methacrylate, 200.0 µL of 2-hydroxyethyl methacrylate and 1.0 µL of ethylene glycol dimethacrylate were fully mixed, and then fully mixed with water to obtain two mixed solutions with total monomer mass fractions of 20% and 60%, respectively. 1.5 µL of 10% DMPA solution was added to each of the mixed solutions to prepare a prepolymer solution.

[0042] (3) Place 1.0 mg of gelatin hydrogel in 500.0 µL of prepolymer solution, let it stand for 2.0 hours, and then take out the hydrogel.

[0043] (4) Expose the hydrogel to ultraviolet light for 20-30 minutes to obtain a composite hydrogel.

[0044] (5) Take out the composite hydrogel prepared in (4), wash it three times with deionized water, and freeze-dry it.

[0045] Comparative Example 1

[0046] The method of Example 1 was used to prepare methacrylylated heparin / methacrylylated glucose photoinitiated copolymer hydrogel.

[0047] 200.0 μL of methyl methacrylate, 30.0 μL of 2-hydroxyethyl methacrylate and 1.0 μL of ethylene glycol dimethacrylate were fully mixed with water to obtain two mixed solutions with total monomer mass fractions of 20% and 60%, respectively, and 1.5 μL of 10% DMPA solution was added to the mixed solutions to prepare prepolymer solutions.

[0048] The remaining steps are carried out with reference to Example 1.

[0049] Comparative Example 2

[0050] The gelatin hydrogel was prepared according to the method of Example 3.

[0051] 30.0 µL of methyl methacrylate, 200.0 µL of 2-hydroxyethyl methacrylate and 1.0 µL of diethylene glycol diacrylate were fully mixed with water to obtain two mixed solutions with total monomer mass fractions of 20% and 60%, respectively, and 1.5 µL of 10% DMPA solution was added to the mixed solutions to prepare prepolymer solutions.

[0052] The remaining steps are carried out according to Example 3.

[0053] The pore size of the hydrogels before and after treatment in the dry state was evaluated by scanning electron microscopy.

[0054] like Figure 1 As shown, the heparin-glucose-acrylate composite hydrogel prepared in Example 1, when the total monomer mass fraction in the prepolymer solution is 0, shows that the hydrogel material has pores with a pore size of 100 microns or even hundreds of microns ( Figure 1 HD); when the total monomer mass fraction in the prepolymer solution is 20%, it is shown that most of the pores in the hydrogel material are about 40-60 microns ( Figure 1 H20); when the total monomer mass fraction in the prepolymer solution is 60%, it shows that most of the pores in the hydrogel material are less than 20 microns ( Figure 1 H60), the pores are evenly distributed, the pore size is uniform, and the pore shape is circular. The above shows that the hydrogel is immersed in a prepolymer solution containing methyl methacrylate, 2-hydroxyethyl methacrylate and ethylene glycol dimethacrylate, and a free radical polymerization reaction occurs to generate a composite hydrogel material with a small pore size or no pores.

[0055] like Figure 2As shown, the polyether F127-acrylate composite hydrogel prepared in Example 2, when the total monomer mass fraction in the prepolymer solution is 0, shows that the hydrogel material may have too large pores and does not have sufficient mechanical properties to form a pore morphology ( Figure 2 PD); when the total monomer mass fraction in the prepolymer solution is 20% and 60%, the pores in the hydrogel material are significantly reduced ( Figure 2 P20, P60). Figure 2 As shown in P20, the pores on the surface of the hydrogel material are oval, shallow, and closed at the bottom; Figure 2 As shown in P60, most of the elliptical pores on the surface of the hydrogel material disappeared. The above shows that the hydrogel is immersed in a prepolymer solution containing methyl methacrylate, 2-hydroxyethyl methacrylate and ethylene glycol dimethacrylate, and a free radical polymerization reaction occurs to generate a composite hydrogel material with small pores or no pores.

[0056] like Figure 3 As shown, the gelatin-acrylate composite hydrogel material prepared in Example 3, when the total monomer mass fraction in the prepolymer solution is 0, shows that the hydrogel material has many pores with a pore size of more than 100 microns ( Figure 3 MD); when the total monomer mass fraction in the prepolymer solution is 20%, it is shown that most of the pores in the hydrogel material are smaller than 50 microns ( Figure 3 M20); when the total monomer mass fraction in the prepolymer solution is 60%, it shows that there are no obvious micron-scale pores in the hydrogel material ( Figure 3 M60). The above description shows that the hydrogel is immersed in a prepolymer solution containing methyl methacrylate, 2-hydroxyethyl methacrylate and ethylene glycol dimethacrylate, and a free radical polymerization reaction occurs to generate a composite hydrogel material with a small pore size or no pores.

[0057] The morphologies of the hydrogels of Comparative Example 1 and Comparative Example 2 before and after compounding were observed under an optical microscope, and no significant changes in the pore size on the surface of the materials were observed.

[0058] The present invention achieves the adjustment (reduction) of the pore size through intercalation polymerization of hydrogel and acrylate material. The higher the total monomer concentration in the prepolymer solution, the smaller the pore size. The treated composite hydrogel material is expected to improve the mechanical strength of the hydrogel and reduce the degradation rate.

[0059] The embodiments described above are only descriptions of the preferred implementation modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for preparing a hydrogel composite, characterized in that: The following steps are involved: (1) Methyl methacrylate, 2-hydroxyethyl methacrylate and ethylene glycol dimethacrylate are mixed in a volume ratio of (25-35): (160-240): (0.8-1.2), and then mixed with deionized water, wherein the mass fraction of the total monomers in the mixed solution is 20%-80%, and then 0.005%-0.01% of the total monomer volume of DMPA ethanol solution is added to obtain a prepolymer solution; (2) soaking the bio-hydrogel to be treated in the prepolymer solution, leaving it to stand for 1-3 hours and then taking it out; the bio-hydrogel is a methacrylylated heparin / methacrylylated glucose photoinitiated copolymer hydrogel, polyether F127 hydrogel or gelatin hydrogel; (3) Exposing the biohydrogel to ultraviolet light to initiate free radical polymerization to obtain a composite hydrogel; (4) Take out the composite hydrogel, wash it with deionized water, and freeze-dry it.

2. The preparation method according to claim 1, characterized in that: In the step (1), the three monomers of methyl methacrylate, 2-hydroxyethyl methacrylate and ethylene glycol dimethacrylate are mixed in a volume ratio of (28-32): (180-220): (0.8-1.2).

3. The preparation method according to claim 1, characterized in that: In the step (3), ultraviolet light is irradiated for 20-30 minutes.

4. The preparation method according to claim 1, characterized in that: The preparation method of the methacryloylated heparin / methacryloylated glucose photoinitiated copolymer hydrogel in step (2) comprises the following steps: dissolving methacryloylated heparin and methacryloylated glucose in a 50% ethanol aqueous solution, adding a photoinitiator, mixing well, and irradiating with ultraviolet light to obtain the methacryloylated heparin / methacryloylated glucose photoinitiated copolymer hydrogel; The preparation method of the polyether F127 hydrogel comprises the following steps: dissolving methacrylated polyether F127 in water, adding a photoinitiator, mixing evenly, and irradiating with ultraviolet light to obtain the polyether F127 hydrogel; The preparation method of the gelatin hydrogel comprises the following steps: dissolving gelatin in water, adding sodium carboxymethyl cellulose and N-hydroxysuccinimide, mixing evenly, and placing at room temperature for 1-3 hours to obtain the gelatin hydrogel.

5. The preparation method according to claim 4, characterized in that: The mass ratio of the methacryloyl heparin to the methacryloyl glucose is (4-6): (2-3); the mass concentration of the methacryloyl polyether F127 is 5%-15%; the mass ratio of the gelatin, sodium carboxymethyl cellulose and N-hydroxysuccinimide is (80-120): (4.0-5.0): (1.6-2.2).

6. The preparation method according to claim 4, characterized in that: In the preparation of the biohydrogel in step (2), the photoinitiator is DMPA, which is dissolved in ethanol and then added to the reaction system, and the mass fraction of the DMPA ethanol solution is 10%.

7. The preparation method according to claim 4, characterized in that: In the preparation of the biohydrogel in step (2), ultrasonic mixing is adopted.

8. The preparation method according to claim 4, characterized in that: The step (2) uses an ultrasonic method to mix the ultraviolet light for 25-35 minutes.

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