Preparation method of bionic oriented bone material and bionic oriented bone material

Abstract

The invention discloses a bionic oriented bone material preparation method and a bionic oriented bone material.The method comprises the steps that hydroxyapatite, high-density polyethylene and ultra-high molecular weight polyethylene with the mass ratio being 1: 2: 2 are evenly mixed, a vinyl silane coupling agent dilute solution is prepared through absolute ethyl alcohol, and the mass ratio of a coupling agent to a solid mixture is 1: 100; a solid mixture is melted and extruded into a uniform wire rod with the diameter of about 1.75 mm through a screw extruder, hydroxyapatite is highly oriented through FDM printing oriented printing and printing nozzle shearing induction, a microstructure of a bone tissue structure is highly reduced, and the hot-melted material is subjected to pressing, grinding and irradiation crosslinking treatment, so that the bone tissue structure is obtained. Therefore, the mechanical property of the composite material is improved, a multi-layer complex directional structure of bone tissue is highly restored, and meanwhile, the composite material also has relatively high mechanical property and biological activity.

Description

Technical Field

[0001] The invention relates to the technical field of biomedical materials, and in particular to a preparation method of a bionic directional bone material and the bionic directional bone material. Background Art

[0002] With the accelerated pace of work and life, the increase in high-energy injuries caused by accidents such as car accidents and falls, as well as osteoporosis, fractures and bone defects caused by the aging population, have led to a growing clinical demand for bone repair treatment. Artificial bone repair materials have advantages in bone defect healing, guided bone fusion, bone function recovery, material degradation in vivo, reducing and avoiding secondary injuries to patients caused by autologous bone, and preventing the risk of disease transmission in allogeneic bone transplantation, and are gradually becoming a substitute for autologous bone and allogeneic bone.

[0003] The skeletal system is a complex hierarchical structure composed of biological components, mineralized bone salts, and aqueous substances. From a macroscopic perspective, bones can be divided into two main types: cortical bone and cancellous bone. At the microstructural level, the organization of collagen fibers occurs in lamellar lamellae, resulting in the formation of bone. At the nanoscale, collagen fibers are encapsulated and infiltrated by minerals, forming collagen fiber bundles. The presence of a hierarchical material structure enables bones to effectively perform their physical, chemical, and biological roles. These tasks include providing mechanical support, protecting cells from external stress or infection, and maintaining ionic balance in body tissues. There has been a lot of research on bionic bone materials in recent years, but it is still very difficult to replicate the complex multilayered structure of real bone while maintaining control over its morphology and composition. Summary of the invention

[0004] Technical purpose: In view of the shortcomings of existing simulated bone materials, the present invention discloses a method for preparing a bionic directional bone material and a bionic directional bone material that can highly restore the dense and ordered structure of natural bones and have good biocompatibility and mechanical support effects.

[0005] Technical solution: To achieve the above technical objectives, the present invention adopts the following technical solution: A method for preparing a bionic directional bone material comprises the following steps: S01, uniformly mixing hydroxyapatite powder, high-density polyethylene pellets and ultra-high molecular weight polyethylene pellets in a mass ratio of 1:1:2; S02, adding a coupling agent to chemically cross-link the mixture, and then using a screw extruder to melt-extrude the formed solid mixture to form a wire; S03, performing 3D printing according to the size of the three-dimensional model of the bone material, and forming the wire into a rectangular parallelepiped model; S04, performing heat-melting treatment on the rectangular parallelepiped model, and after the heat-melting treatment is completed, pressing and grinding according to the shape of the bone material; S05. Finally, electron beam irradiation and cross-linking treatment are performed to obtain a bone material sample.

[0006] Preferably, in step SS03 of the present invention, the printing path of the rectangular parallelepiped model is unidirectional printing.

[0007] Preferably, during the printing process of the present invention, the temperature of the print head is 210° C., the temperature of the printing platform is 80° C., the nozzle diameter of the printer metal nozzle is 0.1 mm, the filling rate is 100%, and the cross filling rate is 0%.

[0008] Preferably, in step S04 of the present invention, when performing the hot melt treatment, the rectangular parallelepiped model is placed in an oven for treatment, and tin foil is wrapped around the outside of the rectangular parallelepiped model.

[0009] Preferably, the temperature of the hot melt treatment of the present invention is 200° C., and the hot melt treatment time is 5-8 min.

[0010] Preferably, the coupling agent of the present invention is a vinyltrimethylsilane coupling agent, and the mass ratio of the coupling agent to the mixture is 1:100. The coupling agent is formed into a dilute coupling agent solution by adding anhydrous ethanol, and the solution is mixed with the mixture by spraying.

[0011] Preferably, in step S02 of the present invention, the wire diameter is 1.75±0.1 mm, the extrusion chamber temperature of the screw extruder is 210-220° C., and the screw speed is 80 r / min.

[0012] Preferably, in step S05 of the present invention, the irradiation dose of electron beam irradiation cross-linking is 20 KGy and 40 KGy.

[0013] Preferably, in step S01 of the present invention, the hydroxyapatite is micrometer-sized, synthesized by a hydrothermal method, and has a hexagonal rod shape, with an edge length of about 0.5-2 μm and a total prism length of about 20-50 μm.

[0014] The invention also discloses a bionic directional bone material, which is manufactured using the above-mentioned preparation method.

[0015] Beneficial effects: The method for preparing a bionic directional bone material and the bionic directional bone material provided by the present invention have the following beneficial effects: 1. The present invention controls the 3D printing path through G-code, performs unidirectional printing on bone materials, and induces orientation through the shear stress inside the melt inside the gradually shrinking nozzle of the printer during printing, and finally realizes the directional arrangement of long rod-shaped hydroxyapatite inside the formed wire composite material. This directional structure not only improves the mechanical support effect of the bionic bone composite material, but also makes the material have a certain anisotropy. At the same time, the bionic bone has good biocompatibility, greatly reducing the probability of complications at the bone defect.

[0016] 2. The present invention improves the surface hardness, flexural strength and poor processing performance of ultra-high molecular weight polyethylene by adding a coupling agent to chemically cross-link the mixture, and simulates bone tissue by cross-linking hydroxyapatite powder, high-density polyethylene granules and ultra-high molecular weight polyethylene granules, so that the bionic bone has superior performance.

[0017] 3. The present invention adds high-density polyethylene granules to significantly improve the processing fluidity of ultra-high molecular weight polyethylene and further improve the tensile strength of the formed bone material.

[0018] 4. The present invention uses a vinyl silane coupling agent (KH-171) to chemically crosslink the blending system of the mixture. The molecular structure of vinyl silane has a vinyl functional group containing an unsaturated double bond structure and three hydrolyzed methoxy groups. The hydrolyzed silicone hydroxyl formed by the methoxy group will condense with the hydroxyl group on the surface of hydroxyapatite to form a chemical bond. In the high-density polyethylene and ultra-high molecular weight polyethylene blending system, the vinyl group can be grafted onto the molecular chain of the polymer through the unsaturated double bond addition reaction. Through the above-mentioned two-way reaction, the coupling connection between the inorganic filler and the organic polymer material is realized, thereby improving the combination between the two, improving the dispersion and reinforcement effect of the inorganic filler, and then improving the mechanical properties of the composite material.

[0019] 5. The present invention eliminates the warping and gap problems caused by the one-way printing process through hot melt treatment and pressing. At the same time, tin foil wrapping is to prevent excessive oxidation and shaping.

[0020] 6. The present invention performs electron beam irradiation cross-linking treatment on the bone material after the hot melt treatment, which can further improve the various properties of the bionic bone material. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below.

[0022] Figure 1 The actual object and scanning electron microscope image of micron-sized prismatic hydroxyapatite prepared by the water method of the present invention; Figure 2This is a physical picture of the wire material processed by the screw extruder of the present invention; Figure 3 A rectangular parallelepiped model diagram of the bionic directional bone material printed by the present invention; Figure 4 A rectangular parallelepiped model diagram of the bionic directional bone material after hot-melt treatment of the present invention; Figure 5 This is a scanning electron microscope image of the bionic directional bone material of the present invention; Figure 6 The WAXS one-dimensional and two-dimensional images of the bionic directional bone material of the present invention; Figure 7 The WAXS azimuth angle curve diagram of the matrix phase and the filling phase of the bionic directional bone material of the present invention; Figure 8 This is a modulus diagram of the bionic directional bone material of the present invention measured under an atomic force microscope. DETAILED DESCRIPTION

[0023] Reference will now be made in detail to embodiments of the present disclosure, one or more examples of which are set forth herein below. Each embodiment and example is provided by explaining the apparatus, composition and materials of the present disclosure, rather than limiting. On the contrary, the following description provides a convenient illustration of an exemplary embodiment for implementing the present disclosure. In fact, it will be clear to those skilled in the art that various modifications and variations can be made in the teachings of the present disclosure without departing from the scope or spirit of the present disclosure. For example, a feature shown or described as a part of an embodiment can be used in conjunction with another embodiment to produce yet another embodiment. It is expected that the present disclosure covers such modifications and variations within the scope of the appended claims and their equivalents. Other objects, features and aspects of the present disclosure are disclosed in or clear from the following detailed description. It will be understood by those of ordinary skill in the art that this discussion is only a description of exemplary embodiments and is not intended to limit the wider aspects of the present disclosure.

[0024] like Figure 1-Figure 8 As shown, the present invention discloses a method for preparing a bionic directional bone material, comprising the steps of: S01, uniformly mixing hydroxyapatite powder, high-density polyethylene pellets and ultra-high molecular weight polyethylene pellets in a mass ratio of 1:1:2; The hydroxyapatite powder is micrometer-sized and synthesized by hydrothermal method, such as Figure 1 As shown, the left side is a real product picture, and the scanning electron microscope picture on the right side shows that the shape is a hexagonal prism rod with an edge length of about 0.5-2μm and a total prism length of about 20-50μm.

[0025] The specific synthesis process is as follows. The mass of each component can be adjusted according to the actual synthesis amount: weigh 0.9922g Ca(NO3)2·4H2O, 0.3291g (NH4)2HPO4, 1.4g C2H5NO, and 0.2911g HNO3, add them into 60ml deionized water and stir for 4h. Pour the mixed solution into a polytetrafluoroethylene inner tank, put it into a high-temperature and high-pressure reactor, and place it in a 190℃ electric heating constant temperature air drying oven for drying for 24 hours. After cooling naturally to room temperature, filter the bottom precipitate, wash it three times with deionized water and ethanol respectively, and finally dry it at 80℃ to make a prismatic hydroxyapatite sample.

[0026] S02, adding a coupling agent to chemically crosslink the mixture, and then using a screw extruder to melt and extrude the solid mixture to form a wire. The extrusion chamber temperature of the screw extruder is 210 ~ 220 ° C, the screw speed is 80r / min, and the wire is as follows Figure 3 As shown, the wire diameter is 1.75 ± 0.1 mm; The coupling agent is vinyltrimethylsilane coupling agent, and the mass ratio of the coupling agent to the mixture is 1:100. The coupling agent is formed into a dilute coupling agent solution by adding anhydrous ethanol, and is mixed with the mixture by spraying. The mass ratio of anhydrous ethanol to vinyltrimethylsilane coupling agent is 4:1.

[0027] S03. Use wire to perform 3D printing according to the size of the three-dimensional model of the bone material, and form the wire into a rectangular parallelepiped model. The structure of the formed rectangular parallelepiped model is as follows Figure 4 As shown, during the printing process, due to the stress caused by temperature changes and the influence of the printer's own printing movement path, gaps will be formed in the rectangular model and the ends will warp, etc., which requires post-processing to eliminate defects in order to ensure the performance of the bone material; The present invention uses an FDM printer for printing. During the printing process, the temperature of the printing nozzle is controlled to be 210° C., the temperature of the printing platform is controlled to be 80° C., the nozzle diameter of the metal nozzle is 0.1 mm, the filling rate is 100%, the cross filling rate is 0%, and the printing path is unidirectional printing. During this process, the 3D printing path is controlled by G-code, and the bone material is printed unidirectionally. During printing, the shear stress inside the melt is used to induce orientation inside the gradually shrinking nozzle of the printer, and finally the directional arrangement of the long rod-shaped hydroxyapatite inside the formed wire composite material is achieved. This directional structure not only improves the mechanical support effect of the bionic bone composite material, but also makes the material have a certain anisotropy, thereby enhancing the performance of the formed bionic directional bone material.

[0028] S04, performing heat-melting treatment on the rectangular parallelepiped model, and after the heat-melting treatment is completed, pressing and grinding according to the shape of the bone material; When performing hot melt treatment, place the rectangular model in an oven for treatment, wrap tin foil around the outside of the rectangular model, and use a hot melt treatment temperature of 200°C for 5-8 minutes. This method can eliminate the warping and gap problems caused by printing.

[0029] S05. Finally, electron beam irradiation and cross-linking treatment was performed, and the irradiation dose was 20 KGy and 40 KGy to obtain bone material samples. The present invention also tested and compared the mechanical properties of the unirradiated bionic bone samples and the irradiated bionic bone samples. Under 40 KGy electron beam irradiation, the modulus of the bionic bone reached 6.3 GPa and the hardness was about 63 HV. Under 20 KGy electron beam irradiation, the modulus of the bionic bone reached 6.4 GPa and the hardness was about 60 HV. The modulus of the bionic bone that had not been cross-linked by irradiation reached 3.8 GPa and the hardness was about 55 HV. Irradiation cross-linking has a certain improvement on the elastic modulus and hardness of the bionic bone composite material.

[0030] The present invention also discloses a bionic directional bone material, which is prepared by the above-mentioned preparation method. The bionic directional aggregate prepared by the preparation method of the present invention is Figure 5 The results of scanning electron microscopy show that the present invention successfully replicates this complex ordered structure through directional printing and shear induction. It can be seen that the long rod-shaped hydroxyapatite synthesized by the hydrothermal method is directional in the composite material. Figure 6-Figure 7 As shown, the WAXS spectrum integral curves of natural bone and bionic composite materials are compared. Except for the two characteristic peaks of polyethylene crystals, the curves of natural bone and bionic bone are highly similar. In addition, we also observed that the peak value corresponding to the characteristic peak in the bionic bone curve is significantly higher than that of natural bone, indicating that compared with natural bone, the crystallization performance of bionic bone materials is better, the grain size is larger, and the corresponding crystal plane growth is more orderly. The WAXS spectrum integral curve of the bionic bone composite material clearly shows four characteristic peaks at 2θ=21.2°, 23.4°, 26° and 32°, representing the (110) and (200) crystal planes of polyethylene crystals and the (002) and (211) crystal planes of HAp crystals, respectively. The anisotropic structure inside the composite material was observed in the WAXS two-dimensional spectrum, and the scattering halos representing the (110) and (002) crystal planes showed significant differences in qx (radial)-qy (axial), indicating that there is a clear orientation arrangement between the PE matrix phase and the filling phase HAp crystals. Figure 7 For the filling phase HAp crystals and PE matrix phase, the intensity-azimuth curves on the WAXS spectrum show a trend of trigonometric function direction change, indicating that they have a highly directional arrangement structure. Figure 8 Force curves of six samples examined using atomic force microscopy are shown. The boundary area between the contact curve and the withdrawal curve represents the viscosity of the sample. The viscosity of the bionic bone is generally higher than that of the natural bone, which shows superior performance.

Claims

1. A method for preparing a bionic directional bone material, characterized in that: Includes steps: S01, uniformly mixing hydroxyapatite powder, high-density polyethylene pellets and ultra-high molecular weight polyethylene pellets in a mass ratio of 1:1:2; S02, adding a coupling agent to chemically cross-link the mixture, and then using a screw extruder to melt-extrude the formed solid mixture to form a wire; S03, performing 3D printing according to the size of the three-dimensional model of the bone material, and forming the wire into a rectangular parallelepiped model; S04, performing heat-melting treatment on the rectangular parallelepiped model, and after the heat-melting treatment is completed, pressing and grinding according to the shape of the bone material; S05. Finally, electron beam irradiation and cross-linking treatment are performed to obtain a bone material sample.

2. The method for preparing a bionic directional bone material according to claim 1, characterized in that: In step SS03, the printing path of the rectangular parallelepiped model is unidirectional printing.

3. The method for preparing a bionic directional bone material according to claim 2, characterized in that: During the printing process, the temperature of the print head was 210°C, the temperature of the printing platform was 80°C, the nozzle diameter of the printer's metal nozzle was 0.1mm, the filling rate was 100%, and the cross filling rate was 0%.

4. The method for preparing a bionic directional bone material according to claim 1, characterized in that: In step S04, during the hot melt treatment, the rectangular parallelepiped model is placed in an oven for treatment, and tin foil is wrapped around the outside of the rectangular parallelepiped model.

5. The method for preparing a bionic directional bone material according to claim 4, characterized in that: The temperature of the hot melt treatment is 200° C., and the hot melt treatment time is 5-8 minutes.

6. The method for preparing a bionic directional bone material according to claim 1, characterized in that: The coupling agent is vinyltrimethylsilane coupling agent, and the mass ratio of the coupling agent to the mixture is 1:

100. The coupling agent is formed into a dilute coupling agent solution by adding anhydrous ethanol, and is mixed with the mixture by spraying.

7. The method for preparing a bionic directional bone material according to claim 1, characterized in that: In step S02, the wire diameter is 1.75±0.1 mm, the extrusion chamber temperature of the screw extruder is 210-220°C, and the screw speed is 80 r / min.

8. The method for preparing a bionic directional bone material according to claim 1, characterized in that: In step S05 , the irradiation dose of electron beam irradiation cross-linking is 20 KGy and 40 KGy.

9. The method for preparing a bionic directional bone material according to claim 1, characterized in that: In step S01, the hydroxyapatite is micrometer-sized and synthesized by a hydrothermal method. The shape is a hexagonal rod, the edge length is about 0.5-2 μm, and the total length of the prism is about 20-50 μm.

10. A bionic directional bone material, characterized in that: The preparation method according to any one of claims 1 to 9 is used for preparation.

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