Solid hydrogel, bone implant and preparation method and application thereof

Abstract

The invention discloses solid hydrogel, a bone implant and a preparation method and application of the solid hydrogel, belongs to the technical field of biomedical materials, and solves the problem that in the prior art, when titanium alloy serves as an implant, modified hydrogel of the titanium alloy is insufficient in adhesion and prone to falling off. The method comprises the following steps: mixing and dissolving gulcomannan and oxidized gulcomannan in water to obtain a hydrogel precursor solution; mixing the hydrogel precursor solution and the sodium tetraborate solution, and stirring into gel to obtain a hydrogel precursor; and drying the hydrogel precursor to obtain the solid hydrogel. The solid hydrogel provided by the invention has good drug loading property and adhesion, and due to good in-situ gelling performance, the problem of falling of the solid hydrogel can be avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of biomedical materials, and more particularly to a solid hydrogel, a bone implant, and their preparation methods and applications. Background Art

[0002] Bone defects are usually caused by factors such as fractures, bone tumor resections, infections, or inflammations, which seriously affect the quality of life and functional recovery of patients. Titanium and its alloys have become ideal bone defect repair materials due to their good mechanical properties, biocompatibility, and corrosion resistance. Hydrogels have a three-dimensional cross-linked porous network structure, good water absorption and air permeability, flexible synthesis methods, adjustable structures, and good physical and chemical properties, which are conducive to the loading of bioactive substances such as drugs, cells, and cytokines. In order to overcome the limitations of titanium alloys as bone defect repair materials in promoting bone defect regeneration (such as insufficient bioactivity and poor integration with new bone), improve their bioactivity and bone integration ability, and endow them with functions such as osteogenic induction, targeted therapy, antibacterial sterilization, and immune microenvironment regulation, the surface modification of titanium alloy implants is often carried out by means of hydrogel coating.

[0003] Modifying titanium alloys with hydrogel coatings can not only increase their integration with surrounding tissues but also endow them with more functions to further regulate bone tissue repair. However, due to insufficient adhesion, the existing hydrogel-titanium alloy composite scaffolds have a risk of falling off when implanted into bone tissue. Summary of the Invention

[0004] The present invention provides a solid hydrogel, a bone implant, and their preparation methods and applications to solve the problem that when titanium alloys are used as implants in the prior art, the modified hydrogels have insufficient adhesion and are prone to falling off.

[0005] In a first aspect, the present invention provides a method for preparing a solid hydrogel, including the following steps: mixing glucomannan and oxidized glucomannan and dissolving them in water to obtain a hydrogel precursor solution; mixing the hydrogel precursor solution and a sodium tetraborate solution and stirring to form a gel to obtain a hydrogel precursor; drying the hydrogel precursor to obtain the solid hydrogel.

[0006] As a possible implementation, the mass ratio of the glucomannan to the oxidized glucomannan is 1-9:1; and / or, the solvent of the sodium tetraborate solution is water, and the mass concentration is 2%-5%; and / or, the volume ratio of the hydrogel precursor solution to the sodium tetraborate solution is 1-3:1; and / or, the temperature condition for drying is 45-75°C.

[0007] As a possible implementation, the mass ratio of the glucomannan and the oxidized glucomannan is 7:3; and / or, the solvent of the sodium tetraborate solution is water with a mass concentration of 3%; and / or, the volume ratio of the hydrogel precursor solution and the sodium tetraborate solution is 2:1; and / or, the drying temperature condition is 60 °C.

[0008] As a possible implementation, the preparation of the oxidized glucomannan includes the following steps: adding sodium periodate to the glucomannan solution, stirring and dissolving it under dark conditions at room temperature; adding ethylene glycol to remove the excessive sodium periodate to obtain a mixed solution; subjecting the mixed solution to dialysis and drying treatments in sequence to obtain the oxidized glucomannan.

[0009] As a possible implementation, the concentration of the glucomannan solution is 5 - 30 g / L; and / or, the addition amount of the sodium periodate and the mass ratio of the solute in the glucomannan solution is 1 - 3:1; and / or, the treatment duration of stirring under dark conditions at room temperature is 12 - 36 h; and / or, the treatment duration of dialysis is 3 - 6 d; the drying treatment is freeze-drying.

[0010] As a possible implementation, the concentration of the glucomannan solution is 10 g / L; and / or, the addition amount of the sodium periodate and the mass ratio of the solute in the glucomannan solution is 1 - 1.5:1; and / or, the treatment duration of stirring under dark conditions at room temperature is 24 h; and / or, the treatment duration of dialysis is 3 d.

[0011] In a second aspect, the present invention provides a solid hydrogel prepared by the preparation method according to any one of the possible implementations in the first aspect.

[0012] In a third aspect, the present invention provides a powdered hydrogel, obtained by grinding the solid hydrogel prepared by the preparation method according to any one of the possible implementations in the first aspect or the solid hydrogel according to any one of the possible implementations in the second aspect.

[0013] In a fourth aspect, the present invention provides the application of the solid hydrogel prepared by the preparation method according to any one of the possible implementations in the first aspect, or the solid hydrogel according to any one of the possible implementations in the second aspect, or the powdered hydrogel according to any one of the possible implementations in the third aspect in the preparation of bone implants.

[0014] As a possible implementation, the bone implant includes a matrix and a coating; the matrix is metallic titanium or acid-etched metallic titanium; the coating is the solid hydrogel / the powdered hydrogel.

[0015] As a possible implementation, the solid hydrogel / the powder hydrogel is disposed on the surface of the substrate in a manner of in-situ gelation.

[0016] As a possible implementation, the solid hydrogel / the powder hydrogel has antibacterial property and / or has anti-inflammatory property.

[0017] In a fifth aspect, the present invention provides a bone implant, which is the bone implant according to any possible implementation of the fourth aspect.

[0018] The present invention discloses a preparation method of a solid hydrogel. This hydrogel can rapidly form a gel in-situ when encountering a solution, and can achieve the loading of drugs and exogenous bioactive substances. In the application of bone repair, first sprinkle the solid hydrogel into the defect site, and then implant the stent. Due to the presence of hydrogen bonds and borate bonds in this solid hydrogel, it can form a hydrogel in-situ after absorbing tissue fluid; due to the good adhesion property of this solid hydrogel, it can form a connecting interlayer between the tissue and the implant to promote the integration ability of the implant and the surrounding tissue. At the same time, this method of in-situ gelation can well avoid the problem of the coating on the surface of the implant falling off during implantation. Description of the Drawings

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0020] Figure 1 It is the FTIR characterization result diagram of GM and OGM provided by the embodiment of the present invention.

[0021] Figure 2 It is the in-situ gelation experiment result of the powder hydrogel provided by the embodiment of the present invention.

[0022] Figure 3 It is the SEM characterization result of the powder hydrogel provided by the embodiment of the present invention. Among them, A is the hydrogel precursor, B is the powder hydrogel, and C is the restored hydrogel.

[0023] Figure 4 It is the drug loading experiment result of the powder hydrogel provided by the embodiment of the present invention. Among them, A is the mixture of methyl orange (drug) and powder hydrogel, and B is the drug-loaded restored hydrogel.

[0024] Figure 5The experimental process of the hydrogel adhesion performance test provided by the embodiments of the present invention, where Mini gel represents micro gel, Water represents water, press represents pressure, and Adhesion represents adhesion.

[0025] Figure 6 The experimental results of the adhesion performance of the powder hydrogel provided by the embodiments of the present invention.

[0026] Figure 7 Provided by the embodiments of the present invention Figure 6 Quantitative statistical results.

[0027] Figure 8 The experimental results of the antibacterial performance of the powder hydrogel provided by the embodiments of the present invention.

[0028] Figure 9 The in vivo antibacterial performance results of the powder hydrogel provided by the embodiments of the present invention.

[0029] Figure 10 The H&E staining and Masson staining results of the in vivo experiment of the powder hydrogel provided by the embodiments of the present invention. Detailed implementation manners

[0030] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0031] To solve the problem that in the prior art, when a titanium alloy is used as an implant, the insufficient adhesion of its modified hydrogel leads to easy detachment, this embodiment provides a solid hydrogel, a bone implant, and their preparation methods and applications.

[0032] Sodium periodate was added to an aqueous solution of glucomannan with a concentration of 5 - 30 g / mL, and stirred and dissolved for 12 - 36 h under dark conditions at room temperature; wherein, the mass ratio of the added amount of sodium periodate to the mass of the solute in the aqueous solution of glucomannan was 1 - 3:1; ethylene glycol was added to remove the excessive sodium periodate to obtain a mixed solution; the mixed solution was dialyzed for 3 - 6 d and then freeze-dried to obtain oxidized glucomannan (OGM). Glucomannan powder and the prepared OGM powder were added to water at a mass ratio of 1 - 9:1 to prepare a hydrogel precursor solution. Sodium tetraborate was dissolved in water to prepare a sodium tetraborate solution with a concentration of 2% - 5% (w / w). The hydrogel precursor solution and the sodium tetraborate solution were mixed at a volume ratio of 1 - 3:1 and quickly stirred into a gel to obtain a hydrogel. The hydrogel was dried in a forced-air drying oven at 45 - 75 °C and ground with a mortar to obtain a powdered hydrogel. In the examples of the present invention, a hydrogel was successfully prepared under the above preparation conditions, and the prepared solid hydrogel could be synthesized in-situ without affecting its structure.

[0033] In the examples of the present invention, the products prepared under the following preparation conditions were taken as examples for relevant tests: 10 g of glucomannan (GM) powder was added to 1000 mL of water, stirred evenly, 12 g of sodium periodate was added, and continuously stirred under dark conditions at room temperature for 24 h; 2 mL of ethylene glycol was added and stirring was continued for 2 h to remove the excessive sodium periodate; the obtained mixed solution was dialyzed in deionized water for 3 d and then freeze-dried to obtain oxidized glucomannan. Glucomannan powder and the prepared OGM powder were added to water at a mass ratio of 7:3 to prepare a hydrogel precursor solution with a concentration of 20%. Sodium tetraborate was dissolved in water to prepare a sodium tetraborate solution with a concentration of 3% (w / w). The hydrogel precursor solution and the sodium tetraborate solution were mixed at a volume ratio of 2:1 and quickly stirred into a gel to obtain a hydrogel. The hydrogel was dried in a forced-air drying oven at 60 °C and ground with a mortar to obtain a powdered hydrogel.

[0034] The examples of the present invention provided drug loading experiments and adhesion performance test experiments of the above solid hydrogel, which proved that it had good drug loading ability and verified that it had good adhesion performance with titanium substrates treated differently.

[0035] Furthermore, the examples of the present invention provided antibacterial performance experiments of the above solid hydrogel, which verified that it had good resistance to Escherichia coli and Staphylococcus aureus.

[0036] Furthermore, the examples of the present invention provided in-vivo action experiments of the above solid hydrogel, which verified that it had good in-vivo antibacterial properties, and had a certain inhibitory / repair effect on in-vivo inflammation, tissue infection and other injuries, and had a certain ability to promote cell renewal and growth.

[0037] The technical solution of the present invention will be further described below in conjunction with specific embodiments.

[0038] Example 1

[0039] This example provides a preparation and verification experiment of a solid hydrogel.

[0040] Add 10 g of glucomannan (GM) powder to 1000 mL of water, stir evenly, add 12 g of sodium periodate, and continuously stir in the dark at room temperature for 24 h; add 2 mL of ethylene glycol and continue to stir for 2 h to remove the excess sodium periodate; dialyze the obtained mixed solution in deionized water for 3 d and freeze-dry to obtain oxidized glucomannan (OGM). Add the glucomannan powder and the prepared OGM powder to water at a mass ratio of 7:3 to prepare a hydrogel precursor solution with a concentration of 20%. Dissolve sodium tetraborate in water to prepare a sodium tetraborate solution with a concentration of 3% (w / w). Mix the hydrogel precursor solution and the sodium tetraborate solution according to a volume ratio of 2:1 and quickly stir to form a gel to obtain a hydrogel. Dry the hydrogel in a forced-air drying oven at 60 °C and grind it with a mortar to obtain a powdered hydrogel.

[0041] Perform Fourier transform infrared spectroscopy (FTIR) characterization on GM and the prepared OGM to obtain the results as shown in Figure 1 As can be seen from Figure 1 OGM has a new absorption peak at 1728.92 cm -1 which is the absorption peak of the aldehyde group, proving the occurrence of the oxidation reaction and successfully synthesizing OGM.

[0042] Perform an in-situ gelation experiment on the prepared powdered hydrogel to obtain the results as shown in Figure 2 As can be seen from Figure 2 the powdered hydrogel can form a stable hydrogel morphology after absorbing the liquid.

[0043] Perform scanning electron microscopy (SEM) characterization on the prepared powdered hydrogel to obtain the results as shown in Figure 3 As can be seen from Figure 3 the hydrogel has a porous network structure, and the hydrogel formed by grinding and adding to the aqueous solution and in-situ gelation still has a porous network structure.

[0044] Mix 2 mg of the drug (methyl orange) with 18 mg of the powdered hydrogel prepared in Example 1, add 80 μL of water, and mix evenly to obtain the drug-loaded hydrogel as shown in Figure 4 As can be seen from Figure 4 the powdered hydrogel prepared in Example 1 has good drug-loading properties.

[0045] Example 2

[0046] This example provides a test experiment on the adhesion performance of hydrogels.

[0047] Prepare titanium sheets (Ti) with a length of 40 mm and a width of 10 mm, and acid-etched titanium sheets (Acid-Ti). Wet the surface of the titanium sheet with water (10 mm × 10 mm), sprinkle powdered hydrogel on the wet surface of the titanium sheet, and cover the powdered hydrogel side with another titanium sheet, ensuring that the coverage area is 10 mm × 10 mm. Press the titanium sheet under a 200 g weight for a period of time, and then use a universal mechanical testing machine to perform tests at a constant shear speed of 1 mm / s. Shear adhesion strength = maximum stress / area (for the experimental process, see Figure 5 ). The results are as shown in Figure 6 and Figure 7 . As can be seen from Figure 6 and Figure 7 , the powdered hydrogel in-situ forms a new hydrogel by absorbing the aqueous solution on the surface of the titanium implant, and has good adhesion performance with the substrate surface, showing good adhesion performance on both the surface of untreated titanium (Ti) and acid-etched titanium (Ti-acid).

[0048] Example 3

[0049] This example provides an experiment on the antibacterial performance of hydrogels.

[0050] Co-culture the powdered hydrogel prepared in Example 1 with Escherichia coli (E.coil) and Staphylococcus aureus (S.aureus) at a dose of 0.1 g / mL for 24 h respectively as the treatment group (Hydrogel), and use the absence of powdered hydrogel as the control group (Control). The colony numbers are counted by the method of plate coating, and the results are as shown in Figure 8 .

[0051] As can be seen from Figure 8 , the colony numbers in the treatment group are significantly less than those in the control group. It can be seen that the powdered hydrogel has good resistance to both E.coil and S.aureus.

[0052] Example 4

[0053] This example provides an in-vivo experiment on hydrogels.

[0054] Use Staphylococcus aureus to construct a bone tissue infection model to explore the anti-infection ability and bone integration promotion ability of titanium implants modified with powdered hydrogel.

[0055] By drilling a hole with a diameter of 1.2 mm near the tibial knee joint of SD rats and injecting 10 μL of Staphylococcus aureus (1ⅹ10 7A rat model of bone defect infection was constructed by the method of [[CFU / mL]]. Fifteen rats with bone defect infection models were selected and randomly divided into 3 groups on average, namely the control group (Control), the scaffold group (Ti-acid), and the treatment group (Ti-acid / Hydrogel). The surface of the titanium scaffold was acid-etched and implanted into the Ti-acid group; the titanium scaffold with an acid-etched surface modified by powder hydrogel was implanted into the rats in the Ti-acid / Hydrogel group; no implantation treatment was given to the Control group.

[0056] Three days after the implantation operation, the femurs with implants were taken out, and the number of bacteria remaining on the surface of the implants and in the bone marrow of each group was evaluated by the plate coating experiment, and the results were obtained as Figure 9 shown. It can be seen from Figure 9 that, compared with the Control group and the Ti-acid group, the number of colonies in the Ti-acid / Hydrogel group was significantly less, indicating that the powder hydrogel has good antibacterial properties.

[0057] Seven days after the implantation operation, the tissues around the treatment sites of rats in different treatment groups were stained with H&E and Masson to evaluate their promoting effect on tissue regeneration, and the results were obtained as Figure 10 shown. The H&E staining images showed obvious acute inflammation and neutrophil infiltration in the tissues around the Ti-acid group, indicating tissue infection, while no obvious tissue damage was observed in the tissues around the Ti-acid / Hydrogel group, showing a reduction in inflammation, indicating that bacteria may be completely removed by the powder hydrogel on the surface of the titanium alloy scaffold. In addition, Masson trichrome staining showed that higher collagen deposition could be detected in the tissues around the Ti-acid / Hydrogel group 7 days after the operation, which was significantly higher than that in the Control group and the Ti-acid group. The above experimental results show that the powder hydrogel exhibits good antibacterial properties and can effectively solve the problem of tissue infection around implants.

[0058] Although the preferred embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications to these embodiments once they learn the basic creative concept. Therefore, the appended claims are intended to be construed to include the preferred embodiments as well as all changes and modifications falling within the scope of the present invention.

[0059] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims

1. A method for preparing a solid hydrogel, characterized in that: The following steps are involved: Mixing and dissolving glucomannan and oxidized glucomannan in water to obtain a hydrogel precursor solution; The hydrogel precursor solution and the sodium tetraborate solution are mixed and stirred into a gel to obtain a hydrogel precursor; The hydrogel precursor is dried to obtain the solid hydrogel.

2. The preparation method according to claim 1, characterized in that: The mass ratio of the glucomannan to the oxidized glucomannan is 1 to 9:1; And / or, the solvent of the sodium tetraborate solution is water, and the mass concentration is 2% to 5%; and / or, the volume ratio of the hydrogel precursor solution to the sodium tetraborate solution is 1 to 3:1; And / or, the drying temperature condition is 45-75°C.

3. The preparation method according to claim 1, characterized in that: The preparation of the oxidized glucomannan comprises the following steps: Add sodium periodate to the glucomannan solution and stir to dissolve at room temperature in the dark; adding ethylene glycol to remove excess sodium periodate to obtain a mixed solution; The mixed solution is dialyzed and dried in sequence to obtain the oxidized glucomannan.

4. The preparation method according to claim 3, characterized in that: The concentration of the glucomannan solution is 5 to 30 g / L; and / or, the mass ratio of the amount of sodium periodate added to the solute in the glucomannan solution is 1 to 3:1; And / or, the stirring treatment time at room temperature and in the dark is 12 to 36 hours; And / or, the dialysis treatment duration is 3 to 6 days; The drying process is freeze drying.

5. A solid hydrogel prepared by the preparation method according to any one of claims 1 to 4.

6. A powdered hydrogel, characterized in that: The solid hydrogel prepared by the preparation method according to any one of claims 1 to 4 or the solid hydrogel according to claim 5 is ground to obtain the powdered hydrogel.

7. Use of the solid hydrogel prepared by the preparation method according to any one of claims 1 to 4, the solid hydrogel according to claim 5, or the powdered hydrogel according to claim 6 in the preparation of bone implants.

8. The use according to claim 7, characterized in that: The bone implant comprises a matrix and a coating; The substrate is metal titanium or metal titanium treated with acid etching; The coating layer is the solid hydrogel / the powder hydrogel.

9. The use according to claim 7, characterized in that: The solid hydrogel / the powdered hydrogel is arranged on the surface of the substrate in an in-situ gelling manner.

10. A bone implant, characterized in that: The bone implant according to any one of claims 7 to 9.

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