CN115554462B

CN115554462B - Anti-swelling injectable hydrogel adhesive and preparation method thereof

Info

Publication number: CN115554462B
Application number: CN202211346260.5A
Authority: CN
Inventors: 李洁茹; 高扬; 卢同庆
Original assignee: Xian Jiaotong University
Current assignee: Xian Jiaotong University
Priority date: 2022-10-31
Filing date: 2022-10-31
Publication date: 2023-09-22
Anticipated expiration: 2042-10-31
Also published as: CN115554462A

Abstract

The invention discloses a preparation method of an anti-swelling injectable hydrogel adhesive, which comprises the following steps: 1. mixing a material A with amino groups, microsphere hydrogel C and PBS solution to obtain a first mixed solution; 2. mixing the material B with aldehyde groups with PBS solution to obtain a second mixed solution; 3. mixing the first mixed solution and the second mixed solution to obtain a hydrogel precursor solution; 4. standing and gelling to obtain the anti-swelling injectable hydrogel adhesive. The invention utilizes the Schiff base reaction of amino and aldehyde groups in the material to form hydrogel through in-situ crosslinking, the hydrogel and biological tissues form a tough bonding interface, the injectable function is realized, the excellent bonding performance and the good biocompatibility are achieved, the introduced microsphere hydrogel limits the hydrogel from absorbing water and swelling, the obvious anti-swelling effect is realized, the preparation process is simple, and the preparation method is suitable for the field of biological materials.

Description

Anti-swelling injectable hydrogel adhesive and preparation method thereof

Technical Field

The invention belongs to the technical field of biomedical materials, and particularly relates to an anti-swelling injectable hydrogel adhesive and a preparation method thereof.

Background

Hydrogels are three-dimensional network structure systems containing a large amount of water, and have physicochemical properties very similar to human tissues, such as higher water content, good biocompatibility and the like, so that the hydrogels are widely applied in biomedical fields such as health monitoring, wound closure, drug delivery, tissue repair and the like. These emerging fields of application often require hydrogels having adhesive properties.

In recent years, injectable hydrogels have received extensive attention from researchers. An injectable hydrogel refers to a hydrogel that is a fluid prior to injection, and after injection into muscle tissue or subcutaneously, forms a solid at the injection site. The formation mechanism is that under the induction of external stimulus, the macromolecular material and its polymer are changed in molecular conformation or state under physiological condition, so that it is converted from solution state into solid gel state, and the external stimulus is usually light, heat, PH, etc. Injectable hydrogels offer a great advantage over traditional preformed gels, namely in situ formation. The hydrogel precursor solution is injected into a body in a minimally invasive mode such as a needle, and hydrogel is formed in situ, so that the method has the following advantages: (1) the complex operation process is more convenient and quicker; (2) pain in the patient is reduced; (3) reduced risk and cost of treatment; (4) The fluidity is good, so that the defect part can be better fitted; (5) Can be used as carrier of medicine, cell and bioactive molecule, etc. to promote tissue regeneration.

Injectable hydrogels are commonly used in living organisms, which requires good bondability, biocompatibility and degradability characteristics. However, in an environment where the organism is composed of a large amount of liquid, the hydrogel will be in direct contact with water, and as a hydrophilic material, the hydrogel will readily absorb water to swell in aqueous solution, and absorption of a large amount of water by the polymer network will result in a decrease in mechanical properties, thereby impairing its ability to adhere to tissues and causing peeling. In addition, the large expansion of the hydrogel volume caused by swelling can compress surrounding tissue, potentially leading to serious complications. For example, there are potential complications in cranium and spinal surgery where post-operative cerebrospinal fluid leakage can lead to delayed healing, wound infection and meningitis, hydrogel sealant (Duraseal), a synthetic sealant approved by the FDA, is increasingly used for post-operative waterproof repair, however, it is reported in clinic that a patient develops spinal cord compression after Duraseal is used in cervical surgery, wherein expansion of Duraseal is believed to be the cause of spinal cord compression. Therefore, it is very important to control the swelling of hydrogels, and studies have shown that researchers chemically modify polymer molecular chains with hydrophobic moieties and polymerize these grafted macromolecular chains into hydrogels for the purpose of swelling resistance of hydrogels. However, the method has complex synthesis process and poor adhesive property, so that it is desired to develop an anti-swelling injectable hydrogel adhesive which is convenient and rapid and has universality, so that the method can be widely applied in the biomedical field.

Disclosure of Invention

The invention aims to solve the technical problem of providing a preparation method of an anti-swelling injectable hydrogel adhesive aiming at the defects of the prior art. According to the method, amino groups and aldehyde groups in the material are subjected to Schiff base reaction to form hydrogel in situ, the hydrogel and biological tissues form a tough bonding interface, an injectable function is realized, excellent bonding performance and good biocompatibility are achieved, meanwhile, the introduced microsphere hydrogel limits the hydrogel from swelling due to water absorption, a remarkable anti-swelling effect is achieved, the preparation process is simple, and the problems that the hydrogel is easy to swell due to water absorption and poor in bonding performance are solved.

In order to solve the technical problems, the invention adopts the following technical scheme: a method of preparing an anti-swelling injectable hydrogel adhesive, comprising the steps of:

mixing a material A with amino groups and microsphere hydrogel C with PBS solution to obtain a first mixed solution;

step two, mixing the material B with aldehyde groups with PBS solution to obtain a second mixed solution;

step three, mixing the first mixed solution obtained in the step one with the second mixed solution obtained in the step two to obtain a hydrogel precursor solution;

and fourthly, standing the hydrogel precursor solution obtained in the third step for gelation to obtain the swelling-resistant injectable hydrogel adhesive.

The invention utilizes amino in the material A with amino and aldehyde in the material B with aldehyde to generate Schiff base reaction to form imine bond, thus realizing injectability, in particular, hydrogel precursor solution obtained by mixing the amino and the aldehyde is liquid with better fluidity, when the hydrogel precursor solution is injected into biological tissues, the material A with amino and the material B with aldehyde quickly generate Schiff base reaction to carry out in-situ crosslinking, the hydrogel precursor solution is induced to gradually undergo sol-gel transition and gradually become viscous until gelation, and polymer network hydrogel is formed by in-situ crosslinking at the injection position of the biological tissues through covalent bond action; meanwhile, functional groups in the hydrogel precursor solution react with groups in biological tissues, wherein the reaction comprises Schiff base reaction between aldehyde groups in the material B and amino groups on the biological tissues to form imine bond covalent action, and hydrogen bond action is formed between amino groups in the material A and amino groups in the biological tissues, and the two actions cooperate with each other, so that good bonding performance is formed between the double-network hydrogel and the biological tissues, and the hydrogel and the biological tissues form a strong bonding interface with excellent bonding performance; in addition, the microsphere hydrogel C is led into the polymer network of the injectable hydrogel adhesive, so that the polymer network is limited to absorb water and swell in aqueous solution, the injectable hydrogel adhesive still maintains good mechanical property and adhesive property in the aqueous solution environment, and good anti-swelling property of the injectable hydrogel adhesive is realized.

The preparation method of the swelling-resistant injectable hydrogel adhesive is characterized in that the material A with amino groups in the first step is chitosan, gelatin or collagen. The natural product with amino group is beneficial to improving the biocompatibility of the injectable hydrogel adhesive, particularly, gelatin is selected as the material A with amino group, which is usually extracted from pigskin, has good compatibility with human tissues, can be reduced, has low cost, is easy to process and wide in source, and improves the practicability of the method.

The preparation method of the swelling-resistant injectable hydrogel adhesive is characterized in that the microsphere hydrogel C in the first step is prepared from hydroxyethyl methacrylate, N-dimethylacrylamide, methacryloyloxyethyl trimethyl ammonium chloride, 2-acrylamido-2-methylpropanesulfonic acid or sodium polystyrene sulfonate. The microsphere hydrogel C has wide sources of raw materials, is safe and nontoxic, and can control the mechanical properties of the microsphere hydrogel C by selecting the types of the raw materials so as to influence the anti-swelling performance of the microsphere hydrogel C.

The preparation method of the swelling-resistant injectable hydrogel adhesive is characterized in that the microsphere hydrogel C is prepared from hydroxyethyl methacrylate, and the specific preparation process is as follows: and mixing the hydroxyethyl methacrylate monomer with deionized water to obtain a first mixed solution, mixing the first mixed solution with a cross-linking agent N, N' -methylene bisacrylamide to obtain a second mixed solution, mixing the second mixed solution with an initiator ammonium persulfate to obtain a precursor solution, and performing freeze drying, grinding and screening on the precursor solution after gelation to obtain the hydroxyethyl methacrylate microsphere hydrogel. The microsphere hydrogel C prepared by the hydroxyethyl methacrylate has the advantages of simple preparation process, safety and no toxicity, and is convenient to control the crosslinking density of the microsphere hydrogel C by controlling the concentration of raw material liquid, and the swelling resistance of the microsphere hydrogel C is influenced by combining the speed and time parameters of grinding.

The preparation method of the swelling-resistant injectable hydrogel adhesive is characterized in that the material B with the aldehyde group in the second step is a product with the aldehyde group, which is obtained by modifying dextran, hyaluronic acid, alginate, cellulose or chondroitin. The product with aldehyde groups obtained by modifying the natural material has good biocompatibility with biological tissues, is safe and nontoxic, is degradable, and is favorable for improving the biocompatibility of the injectable hydrogel adhesive; meanwhile, aldehyde groups in the modified product with aldehyde groups can react with amino groups in the material A to crosslink and solidify to form hydrogel on one hand, and can react with active amino groups on the surface of biological tissues on the other hand, so that the tissue adhesion performance of a hydrogel system is improved.

The preparation method of the swelling-resistant injectable hydrogel adhesive is characterized in that the material B with aldehyde groups is oxidized glucose obtained by oxidizing and modifying dextran, and the specific preparation process comprises the following steps: glucose and oxidant are evenly mixed and then are placed in deionized water for dialysis, and freeze drying is carried out. The oxidized glucose is used as a cross-linking agent for forming a polymer network, has the advantages of good biocompatibility, no toxicity, degradability and the like, and improves the biocompatibility and safety of the injectable hydrogel adhesive; meanwhile, the preparation process of the oxidized glucose is simple, the addition of a toxic cross-linking agent is avoided, and the use safety is further improved.

The preparation method of the swelling-resistant injectable hydrogel adhesive is characterized in that the mass ratio of the material A with the amino group to the microsphere hydrogel C in the first step is 15:1-5, the mass ratio of the material A with the amino group to the material B with the aldehyde group in the second step is 100:1, and the size of the microsphere hydrogel C is 23-100 mu m. Preferably, the mass ratio of the material A with amino groups to the microsphere hydrogel C is 15:1, 15:2, 15:3, 15:4 or 15:5, and the size of the microsphere hydrogel C is 23-48 μm, 48-80 μm and 80-100 μm.

In addition, the invention also discloses an anti-swelling injectable hydrogel adhesive prepared by the method.

Compared with the prior art, the invention has the following advantages:

1. the invention provides the idea of utilizing microsphere hydrogel to resist swelling, and the microsphere hydrogel C is introduced into the hydrogel adhesive and is absorbed by the hydrogel precursor solution containing the polymer chains in advance to reach swelling balance, and the swelling of the polymer hydrogel in the hydrogel adhesive is limited due to the physical winding and other actions of the microsphere hydrogel C and the polymer chain segments in the process, so that the hydrogel adhesive can still keep excellent mechanical property and adhesive property in an aqueous solution environment, and has good swelling resistance.

2. The invention provides the idea of toughening by using a long-chain network, and compared with a short-chain network hydrogel, the long-chain network hydrogel has higher fracture toughness and interface bonding energy, but the long-chain network hydrogel is easier to absorb water and swell, so that the mechanical property and the bonding property of the long-chain network hydrogel are greatly reduced.

3. The hydrogel adhesive provided by the invention realizes an injectable function, the amino group in the material A with the amino group and the aldehyde group in the material B with the aldehyde group are subjected to Schiff base reaction to perform in-situ crosslinking, a long-chain hydrogel network polymer is formed at an injection position, the volume of the microsphere hydrogel C is tiny, and the introduction of the microsphere hydrogel C does not influence the whole injectability of the hydrogel adhesive.

4. The hydrogel adhesive has the characteristic of degradability, raw materials for crosslinking to form a high-molecular long-chain network can be selected from natural materials, the high-molecular long-chain network has good biocompatibility and degradability, and the microsphere hydrogel C can be degraded through material selection, so that the hydrogel is not required to be removed after being applied to biological tissues, and secondary injury is avoided.

The technical scheme of the invention is further described in detail through the drawings and the embodiments.

Drawings

FIG. 1 is a schematic diagram showing the adhesive power test of the hydrogel adhesive of the present invention with biological tissue.

FIG. 2 is a graph showing the comparison of the anti-swelling effect of the hydrogel adhesives prepared in example 2 and comparative example 1 of the present invention.

Detailed Description

Example 1

The preparation method of the embodiment comprises the following steps:

step one, dissolving 15g of gelatin and 1g of hydroxyethyl methacrylate microsphere hydrogel with the size of 48-80 mu m in 50mL of PBS solution with the pH value of 7.4 to obtain a first mixed solution;

the specific preparation process of the hydroxyethyl methacrylate microsphere hydrogel comprises the following steps: mixing 13.5562g of hydroxyethyl methacrylate monomer with 86.4438g of deionized water to obtain a first mixed solution with the concentration of 1mol/L, mixing the first mixed solution with 0.6165g of cross-linking agent N, N' -methylene bisacrylamide to obtain a second mixed solution, mixing the second mixed solution with 0.0145g of initiator ammonium persulfate to obtain a precursor solution, gelling the precursor solution, and freeze-drying, grinding, sieving and sieving to obtain hydroxyethyl methacrylate microspheres with the size of 48-80 mu m;

step two, dissolving 1.5g of oxidized glucose with the molecular weight Mw=20000 in 5mL of PBS solution with the pH value of 7.4 to obtain a second mixed solution; the specific preparation process of the oxidized glucose comprises the following steps: uniformly mixing glucose solution with the mass fraction of 10% and sodium periodate solution with the mass fraction of 10% according to the molar ratio of glucose to sodium periodate of 1:1.5, fully reacting, then placing into deionized water for dialysis, and then freeze-drying;

step three, adopting two syringes to respectively absorb the first mixed liquid obtained in the step one and the second mixed liquid obtained in the step two, and then connecting the two syringes by an adapter and pushing the two syringes back and forth for five times to ensure that the first mixed liquid and the second mixed liquid are uniformly mixed to obtain a hydrogel precursor solution; the mass ratio of the first mixed solution to the second mixed solution is 100:1;

injecting the hydrogel precursor solution obtained in the step three on fresh pigskin, standing for gelation to form an anti-swelling injectable hydrogel adhesive, and then testing the adhesion energy between the injectable hydrogel adhesive and the fresh pigskin of biological tissues by adopting a 180-degree peeling experiment, wherein the adhesion energy is shown in figure 1; and simultaneously, injecting the hydrogel precursor solution obtained in the step three on a glass die, standing for gelation to form an anti-swelling injectable hydrogel adhesive, cutting into a cylinder by using a round cutter, soaking in deionized water at 37 ℃, observing the dynamic swelling process, and recording the swelling mass ratio at 24 hours.

In the first embodiment, the material A with amino group can be replaced by chitosan or collagen, and the microsphere hydrogel C can be prepared from N, N-dimethylacrylamide, methacryloyloxyethyl trimethyl ammonium chloride, 2-acrylamido-2-methylpropanesulfonic acid or sodium polystyrene sulfonate; the material B with aldehyde group in the second step can also be a product with aldehyde group obtained by modifying hyaluronic acid, alginate, cellulose or chondroitin.

Example 2

This embodiment differs from embodiment 1 in that: the mass of the hydroxyethyl methacrylate microsphere hydrogel in the first step is 3g.

Example 3

This embodiment differs from embodiment 1 in that: the mass of the hydroxyethyl methacrylate microsphere hydrogel in the first step is 5g.

Example 4

This embodiment differs from embodiment 1 in that: in the first step, the mass of the hydroxyethyl methacrylate microsphere hydrogel is 3g, and the size of the hydroxyethyl methacrylate microsphere hydrogel is 23-48 mu m.

Example 5

This embodiment differs from embodiment 1 in that: in the first step, the mass of the hydroxyethyl methacrylate microsphere hydrogel is 3g, and the size of the hydroxyethyl methacrylate microsphere hydrogel is 80-100 mu m.

Example 6

This embodiment differs from embodiment 1 in that: in the first step, the mass of the hydroxyethyl methacrylate microsphere hydrogel is 3g, and the hydrogel is soaked in physiological saline at 37 ℃ to record the swelling mass ratio at 24 hours.

Comparative example 1

This comparative example differs from example 1 in that: in step one, 15g of gelatin was dissolved in 50mL of PBS solution having a pH of 7.4 to obtain a first mixed solution.

Fig. 2 is a graph showing the comparative swelling resistance of the hydrogel adhesives prepared in example 2 and comparative example 1 according to the present invention, including a graph showing the apparent volume ratio when immersed in deionized water for 0h, 1h, 2h, 4h, 8h, 12h, and 24h, and it is understood from fig. 2 that the volume ratio of the hydrogel adhesive prepared in example 2 according to the present invention is substantially maintained as the immersion time increases, compared to the hydrogel adhesive prepared in comparative example 1, which shows that the hydrogel adhesive prepared by adding hydroxyethyl methacrylate microsphere hydrogel according to the present invention has excellent swelling resistance.

Comparative example 2

This comparative example differs from example 1 in that: in the first step, 15g of gelatin and 3g of hydroxyethyl methacrylate microsphere hydrogel with the size larger than 500 mu m are dissolved in 50mL of PBS solution with the pH value of 7.4 to obtain a first mixed solution.

Comparative example 3

This comparative example differs from example 1 in that: in the first step, 15g of gelatin and 3g of hydroxyethyl methacrylate monomer were dissolved in 50mL of PBS solution having a pH of 7.4 to obtain a first mixed solution.

The results of the adhesive energy of the injectable hydrogel adhesives prepared in examples 1 to 6 and comparative examples 1 to 3 of the present invention to fresh pig skin of biological tissue and the swelling mass ratio at 24 hours (mass of the sample after soaking for 24 hours divided by the initial mass) are shown in table 1 below.

TABLE 1

As can be seen from the adhesive energy results of Table 1, the injectable hydrogel adhesives prepared in examples 1 to 6 and comparative examples 1 to 3 of the present invention have adhesive energy of up to 100J/m with fresh pig skin of biological tissue ² The hydrogel adhesive prepared by the method has good tissue adhesive property. Because the adhesion between the injectable hydrogel adhesive prepared by the invention and biological tissues depends on two aspects, mainly the covalent action of imine bond formed by aldehyde groups on oxidized dextran and amino groups on biological tissues and the hydrogen bond action of amino groups on gelatin and amino groups on biological tissues, the good adhesion changing energy between the hydrogel adhesive and biological tissues is not affected by changing the addition amount of the microsphere hydrogel in examples 1-6 and the addition of no microsphere hydrogel in comparative examples 1-3, changing the size of the microsphere hydrogel and adding hydroxyethyl methacrylate monomer instead of the microsphere hydrogel.

From the results of the swelling mass ratio at 24 hours in Table 1, it is understood that the injectable hydrogel adhesives prepared by adding the microsphere hydrogels in examples 1 to 6 of the present invention have excellent anti-swelling effect. It is known from examples 1 to 3 and comparative example 1 that, compared with the injectable hydrogel adhesive prepared without adding the microsphere hydrogel in comparative example 1, the swelling mass ratio is as high as 14.64 at 24 hours, the swelling mass ratio of the injectable hydrogel adhesive prepared with adding the microsphere hydrogel in examples 1 to 3 is only 1.09 to 1.93, i.e., hardly swells, and at the same time, the more the addition amount of the non-adding microsphere hydrogel is, the better the anti-swelling effect is, the anti-swelling effect of the injectable hydrogel adhesive prepared in example 2 is, and it is known from analysis that when the addition amount of the microsphere hydrogel is small, part of gelatin long chains are not wrapped inside the microsphere hydrogel, and when the hydrogel is immersed in deionized water at 37 ℃, the first layer gelatin-oxidized dextran long chain network absorbs water to swell, and when the amount of the microsphere hydrogel is too large, the water in the precursor solution cannot make the microsphere hydrogel swell in advance, and when the injectable hydrogel is immersed in deionized water, the microsphere hydrogel is expanded, and therefore, the anti-swelling effect of the hydrogel adhesive prepared in example 2 is continued to reach the optimal quality of the anti-swelling effect of the microsphere hydrogel.

As is clear from examples 2, 4, 5 and comparative example 2, the swelling mass ratio at 24 hours of the injectable hydrogel adhesives prepared by using the hydroxyethyl methacrylate microsphere hydrogels of 48 μm to 80 μm, 23 μm to 48 μm, 80 μm to 100 μm respectively in examples 2, 4, 5 of the present invention was about 1.1, indicating that the size of the added hydroxyethyl methacrylate microsphere hydrogels had little effect on the anti-swelling effect of the injectable hydrogel adhesives in the size range of 23 μm to 100 μm; when the hydroxyethyl methacrylate microsphere hydrogel with the size larger than 500 μm is adopted in comparative example 2, the swelling mass ratio of the prepared injectable hydrogel adhesive at 24 hours is as high as 10.25, and the swelling resistance effect is poor, but the injectable hydrogel adhesive still has a certain swelling resistance effect compared with the hydroxyethyl methacrylate microsphere hydrogel not added in comparative example 1.

From examples 2 and 6, the swelling mass ratio of the injectable hydrogel adhesive prepared by the invention is basically unchanged at 24 hours in deionized water and physiological saline, which indicates that the injectable hydrogel adhesive still has excellent anti-swelling effect in physiological saline, and the feasibility of the injectable hydrogel adhesive in application in body fluid environment is verified.

As is clear from example 2 and comparative example 3, the swelling mass ratio at 24 hours of the injectable hydrogel adhesive prepared by directly adding the hydroxyethyl methacrylate monomer in comparative example 3 was much higher than that at 24 hours of the injectable hydrogel adhesive prepared by adding the hydroxyethyl methacrylate microsphere hydrogel in example 2, which is similar to that at 24 hours of the injectable hydrogel adhesive prepared by not adding the microsphere hydrogel in comparative example 1, indicating that the hydroxyethyl methacrylate monomer itself does not have an anti-swelling effect, and that an excellent anti-swelling effect can be achieved only by making it into a microsphere hydrogel.

The above description is only of the preferred embodiments of the present invention, and is not intended to limit the present invention. Any simple modification, variation and equivalent variation of the above embodiments according to the technical substance of the invention still fall within the scope of the technical solution of the invention.

Claims

1. A method of preparing an anti-swelling injectable hydrogel adhesive, comprising the steps of:

mixing a material A with amino groups and microsphere hydrogel C with PBS solution to obtain a first mixed solution; the microsphere hydrogel C is prepared from hydroxyethyl methacrylate, and the specific preparation process comprises the following steps: mixing hydroxyethyl methacrylate monomer with deionized water to obtain a first mixed solution, and then mixing the first mixed solution with a cross-linking agent N, N'Mixing methylene bisacrylamide to obtain a second mixed solution, mixing the second mixed solution with an initiator ammonium persulfate to obtain a precursor solution, and performing freeze drying, grinding and screening on the precursor solution after gelation to obtain hydroxyethyl methacrylate microsphere hydrogel;

the mass ratio of the material A with amino to the microsphere hydrogel C is 15:1-5, and the size of the microsphere hydrogel C is 23-100 mu m;

step three, mixing the first mixed solution obtained in the step one with the second mixed solution obtained in the step two to obtain a hydrogel precursor solution; the mass ratio of the first mixed solution of the material A with the amino group to the second mixed solution of the material B with the aldehyde group is 100:1;

2. The method for preparing an anti-swelling injectable hydrogel adhesive according to claim 1, wherein the amino group-containing material a in the first step is chitosan, gelatin or collagen.

3. The method for preparing the swelling-resistant injectable hydrogel adhesive according to claim 1, wherein the material B with aldehyde groups in the second step is a modified product of dextran, hyaluronic acid, alginate, cellulose or chondroitin with aldehyde groups.

4. The method for preparing the swelling-resistant injectable hydrogel adhesive according to claim 3, wherein the material B with aldehyde groups is oxidized dextran obtained by oxidizing and modifying dextran, and the specific preparation process comprises the following steps: and uniformly mixing glucan and an oxidant, dialyzing in deionized water, and freeze-drying.

5. An anti-swelling injectable hydrogel adhesive prepared by the method of any one of claims 1 to 4.