Novel artificial bone based on promoting neurovascular regeneration and preparation method

Abstract

Disclosed in the present invention are a novel artificial bone based on promoting neurovascular regeneration and a preparation method. The novel artificial bone comprises an artificial bone. The artificial bone is composed of β-tricalcium phosphate, polylactic acid-glycolic acid, a nano magnesium-based powder, and a piezoelectric polymer. The mass ratio of β-tricalcium phosphate to polylactic acid-glycolic acid in the artificial bone is 1:0-1:10. The nano magnesium-based powder and the piezoelectric polymer are mixed to form a piezoelectric composite solution, and the mass ratio of the nano magnesium-based powder to the piezoelectric polymer in the piezoelectric composite solution is 1:1-1:20, such that the surface of the artificial bone is modified by means of the piezoelectric composite solution, thereby forming a piezoelectric coating on the surface of the artificial bone; in this way, when the artificial bone is implanted into a bone defect site and is subject to stress, a charge and potential difference are generated. The present invention not only enhances the strength of the artificial bone, but also promotes the degradation of the artificial bone, stimulates local neurovascular regeneration, promotes the formation of new bone, and achieves the purpose of repairing osteonecrosis and bone defects.

Description

A new artificial bone based on promoting neurovascular regeneration and a preparation method thereof TECHNICAL FIELD

[0001] The present application relates to the technical field of biomedical materials, in particular to a new artificial bone based on promoting neurovascular regeneration and a preparation method thereof. BACKGROUND

[0002] Bone defects caused by trauma and bone diseases, especially large segment bone defects, are a difficult problem faced by orthopedic clinics. Traditional bone defect treatment methods include autologous bone transplantation, allogeneic bone, xenogeneic bone and artificial bone transplantation, but there are defects such as insufficient bone supply, rejection, related complications and poor osteogenesis effect. Bone tissue engineering technology is to plant cells with osteogenic differentiation potential to a biological material scaffold in vitro, and then implant it into the bone defect site in the body after induction by physical and chemical factors. With the proliferation and differentiation of cells and the degradation of the scaffold material, new bone tissue is formed. Bone tissue engineering technology overcomes the shortcomings of traditional bone defect transplantation technology and provides a new idea for the clinical treatment of bone defects. However, due to factors such as in vitro cell processing, induction factors, infection, poor differentiation and cell variation, its wide clinical application has been limited.

[0003] β-TCP is a commonly used bioceramic material in bone tissue engineering, which is similar to the inorganic components of human bone tissue, has good mechanical properties and biocompatibility, but its brittleness limits its single application. PLGA is randomly polymerized from two monomers, polylactic acid and glycolic acid, and has good biocompatibility and complete biodegradability, and has ideal flexibility and plasticity. Magnesium is an essential element for bone health. Recent studies have found that magnesium not only improves new bone formation by enhancing blood supply in bone necrosis lesions, but also stimulates new bone formation through neural regulation. Piezoelectric materials can generate a potential difference under appropriate stress. Studies have shown that the induced electric charge generated by the potential difference can promote the osteogenic differentiation of mesenchymal stem cells in bone tissue. Therefore, it is a bottleneck problem in this field to determine whether a multi-factor optimized artificial bone material can be directly implanted into bone defects or bone necrosis sites to improve the osteogenic efficiency of the artificial bone through the related mechanisms of different biological materials. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a new artificial bone based on promoting neurovascular regeneration, which not only strengthens the strength of the artificial bone, but also promotes the degradation of the artificial bone. Through the different components in the artificial bone, local neurovascular regeneration is stimulated, and new bone formation is promoted, achieving the purpose of repairing bone necrosis and bone defects.

[0005] To achieve the above object, the application discloses a new artificial bone based on promoting nerve and blood vessel regeneration, which comprises an artificial bone composed of beta-tricalcium phosphate (beta-TCP), polylactic acid-glycolic acid (PLGA), nano-magnesium-based powder and piezoelectric polymer, the mass ratio of beta-tricalcium phosphate and polylactic acid-glycolic acid in the artificial bone is 1:0-1:10, the nano-magnesium-based powder is mixed with the piezoelectric polymer to form a piezoelectric composite solution, and the mass ratio of the nano-magnesium-based powder and the piezoelectric polymer in the piezoelectric composite solution is 1:1-1:20, so that the surface of the artificial bone is modified by the piezoelectric composite solution to form a piezoelectric coating on the surface of the artificial bone, so that the artificial bone is implanted into a bone defect site and generates electric charge and potential difference under stress to promote new bone formation at the bone defect site.

[0006] Further, the piezoelectric polymer comprises at least one of polyvinylidene fluoride, polyvinylidene fluoride-trifluoroethylene, poly-3-hydroxybutyric acid-3-hydroxyvaleric acid ester, polyamide or levorotatory polylactic acid.

[0007] Further, the nano-magnesium-based powder comprises at least one of pure magnesium powder, magnesium oxide powder, magnesium chloride powder, magnesium silicate powder or magnesium sulfate powder.

[0008] Further, the shape of the artificial bone is at least one of cylindrical, granular, cubic and strip-shaped.

[0009] Further, the pore size of the surface of the artificial bone is 200-500 mu m, and the porosity is 70%-80%.

[0010] A preparation method of the new artificial bone based on promoting nerve and blood vessel regeneration comprises the following steps:

[0011] S1, dissolving: dissolve beta-TCP and PLGA in 1, 4-dioxane at room temperature in proportion, and the volume-mass ratio of beta-TCP, PLGA and 1, 4-dioxane is 0.25g:(0-1.015g):10mL;

[0012] S2, stirring: stir at room temperature with a magnetic stirrer for 12h;

[0013] S3, printing: design the printing mode in advance, and the printer is used for spinning printing at-30 DEG C (the function is the same as CLRF-200-II), the wire diameter is set to 240 mu m, and the wire spacing is set to 600 mu m;

[0014] S4, freeze-drying: freeze-dry the printed artificial bone in a freeze-drying environment at-30 DEG C and 30Pa for 24h;

[0015] S5, 4.5 g piezoelectric polymer is weighed after freeze-drying and added to 50 mL N, N-dimethylformamide (DMF), after stirring for 0.5 h under the condition of heating at 80℃ water bath until the piezoelectric polymer is completely dissolved, 0.2-4.5 g nano-magnesium-based powder is added to the solution, and a uniformly dispersed piezoelectric composite solution is obtained after ultrasonic dispersion for 10 min;

[0016] S6, the artificial bone is soaked in a piezoelectric composite solution with a mass concentration of 10% for 2 min, the artificial bone is drained after being taken out, conductive adhesive tape is pasted on both sides of the artificial bone, and the artificial bone is placed in 100℃ silicone oil and polarized for 15-30 min, so that piezoelectric artificial bone is prepared and sealed.

[0017] Further, the volume-mass ratio of the beta-tricalcium phosphate, polylactic acid-glycolic acid and 1, 4-dioxane in step S1 is 0.25 g:1.015 g:10 ml.

[0018] Compared with the prior art, the application has the beneficial effects that:

[0019] (1) The important component of the artificial bone, nano-magnesium-based powder, has good effects of promoting nerve and blood vessel regeneration, and further promoting new bone formation. (2) The artificial bone after surface modification in the application can form a piezoelectric coating, can transmit induced electric charges generated by mechanical movement, and can better promote local osteogenesis and tissue repair. (3) The piezoelectric polymer particles used for surface modification of the artificial bone in the application are uniformly dispersed, have good piezoelectric effect, form an electric charge transmission channel on the outside of the artificial bone, are beneficial to the growth and differentiation of osteoblasts, and promote osteogenesis. (4) The artificial bone is printed according to the shape of the bone defect site in the application, individualized customization is realized, and the artificial bone can well fit the defect site. (5) The artificial bone with different shapes is designed according to different diseases, so that the adaptability of the artificial bone is wider, and the application of the artificial bone is not limited to one disease. BRIEF DESCRIPTION OF DRAWINGS

[0020] Fig. 1 is a structural schematic diagram of a cylindrical artificial bone of the application;

[0021] Fig. 2 is a structural schematic diagram of a granular artificial bone of the application;

[0022] Fig. 3 is a structural schematic diagram of a cubic artificial bone of the application;

[0023] Fig. 4 is a structural schematic diagram of a long strip-shaped artificial bone of the application;

[0024] Fig. 5 is a schematic diagram of the new artificial bone treating femoral head necrosis;

[0025] Fig. 6 is a schematic diagram of the new artificial bone treating femoral fracture;

[0026] Fig. 7 is a schematic diagram of the new artificial bone treating bone defects caused by bone diseases;

[0027] Figure 8 is a schematic diagram of personalized 3D printing of a new artificial bone for treating bone defects. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings.

[0029] Referring to Figures 1-4, a new artificial bone based on promoting neurovascular regeneration includes an artificial bone 10, which is composed of β-tricalcium phosphate (β-TCP), polylactic acid-glycolic acid (PLGA), nano-magnesium-based powder and piezoelectric polymer. The β-tricalcium phosphate and polylactic acid-glycolic acid are used to make the artificial bone 10 that fits the defect site by 3D printing, and the mass ratio of β-tricalcium phosphate to polylactic acid-glycolic acid in the artificial bone 10 is 1:0-1:5. The nano-magnesium-based powder is mixed with the piezoelectric polymer to form a piezoelectric composite solution, and the mass ratio of the nano-magnesium-based powder to the piezoelectric polymer in the piezoelectric composite solution is 1:1-1:20. The surface of the artificial bone 10 is modified by the piezoelectric composite solution to form a piezoelectric coating on the surface of the artificial bone.

[0030] The piezoelectric polymer in this embodiment includes at least one of polyvinylidene fluoride, polyvinylidene fluoride-trifluoroethylene, poly-3-hydroxybutyric acid-3-hydroxyvalerate, polyamide or levorotatory polylactic acid. Polyvinylidene fluoride is preferably used in this embodiment. The nano-magnesium-based powder includes at least one of pure magnesium powder, magnesium oxide powder, magnesium chloride powder, magnesium silicate powder or magnesium sulfate powder. Magnesium chloride powder is preferably used in this embodiment.

[0031] Magnesium element is one of the important components of bone in this embodiment. As a biodegradable metal with mechanical properties similar to natural bone, it directly affects the crystallization and formation of minerals in the newly formed bone. It has been confirmed that magnesium metal and magnesium alloy biomaterials have the effect of promoting osteogenesis. More importantly, compared with other metals or polymeric materials, magnesium ions can also improve local blood perfusion. However, pure magnesium degrades rapidly in the body, cannot provide long-term mechanical support in the body, and can trigger acute inflammatory reactions, which limit the clinical application of magnesium metal.

[0032] In the embodiment, the polylactic acid-glycolic acid (PLGA) is randomly polymerized from lactic acid and glycolic acid, has good biological safety and biodegradability, and has been approved by the US Food and Drug Administration (FDA) for clinical use. However, its main defects as a biomaterial are low mechanical strength, weak bone binding force, and the formation of acidic products after degradation of the polylactic acid-glycolic acid (PLGA) which can cause inflammation of surrounding organs and tissues. The beta-tricalcium phosphate (β-TCP) is a commonly used bioceramic material in tissue engineering, which is similar to the inorganic composition in natural bone, has sufficient mechanical strength, good biocompatibility, and certain bone conduction effect. At the same time, the beta-tricalcium phosphate (β-TCP) has high solubility in acidic environment, and the solubility is greatly reduced in neutral and alkaline environment. In the body, calcium and phosphate ions are gradually dissolved to provide raw materials for the formation of new bone in situ, and the beta-tricalcium phosphate (β-TCP) has the ability to induce bone formation. At the same time, the mixture of beta-tricalcium phosphate (β-TCP) and polylactic acid-glycolic acid (PLGA) can well solve the problem of acidic environment formed after the degradation of polylactic acid-glycolic acid (PLGA). The beta-tricalcium phosphate (β-TCP) is a weak acid and strong base salt, which releases calcium ions and phosphate after degradation, and the solution is alkaline, which can undergo neutralization reaction to solve the problem of excessive acid in local tissues. Under physiological conditions, the degradation rate of beta-tricalcium phosphate (β-TCP) in the body is significantly slower than that of magnesium metal. In addition, the beta-tricalcium phosphate (β-TCP) extract has good bone immune regulation reaction, which can change the phenotype of macrophages to M2 type and release BMP2, thereby enhancing the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). In order to better promote osteogenesis and tissue regeneration and repair, the piezoelectric polymer is used to modify the surface of the artificial bone in the embodiment, so that a piezoelectric coating is formed on the surface of the modified artificial bone. After the artificial bone is implanted into the bone defect site, electric charge and potential difference are generated under stress, which is beneficial to the ingrowth and differentiation of osteoblasts and promotes osteogenesis, so that the new artificial bone has ideal biocompatibility, mechanical strength, degradability, and new bone formation efficiency of promoting nerve and blood vessel regeneration.

[0033] In the embodiment, the pore size of the artificial bone surface is 200-500 μm, and the porosity is 70%-80%, which is beneficial to the migration of cells and new nerve vessels into the artificial bone pores and mineralization into bone after the artificial bone is implanted into the treatment site.

[0034] Referring to Figs. 1-4, further, the shape of the artificial bone is at least one of granular, cubic, strip-shaped and cylindrical, and in the present embodiment, different shapes of artificial bone can be designed according to different diseases, for example, the cylindrical artificial bone can be implanted into the necrotic site of the bone, so that the artificial bone locally supports and fills the necrotic site of the bone, and new bone is formed by the artificial bone promoting the regeneration of nerves and blood vessels, as shown in Fig. 5, or the strip-shaped or granular artificial bone can be applied to support and fill the long bone defect caused by trauma, as shown in Fig. 6, or the granular artificial bone can be applied to support and fill the bone defect caused by bone disease, as shown in Fig. 7, so that the adaptability of the artificial bone is wider and is not limited to the application of one disease.

[0035] Or as shown in Fig. 8, the required bone defect site is implanted by 3D printing to achieve personalized customization, which can well fit the defect site.

[0036] The preparation method of the artificial bone in the present application comprises the following steps:

[0037] S1, dissolving: dissolve β-tricalcium phosphate, polylactic acid-glycolic acid at room temperature in 1, 4-dioxane in proportion, the volume mass ratio of β-tricalcium phosphate, polylactic acid-glycolic acid, 1, 4-dioxane is 0.25g:(0-1.015g):10mL;

[0038] S2, stirring: stirring at room temperature with a magnetic stirrer for 12h;

[0039] S3, printing: the printing mode is designed in advance, the printer is used for spinning printing at-30℃ (the function is the same as CLRF-200-II), the filament diameter is set to 240μm, and the filament spacing is 600μm;

[0040] S4, freeze-drying: the printed artificial bone is placed in a freeze-drying environment at-30℃ and 30Pa for 24h;

[0041] S5, after freeze-drying, 4.5g of piezoelectric polymer is weighed and added to 50mL of N,N-dimethylformamide (DMF), and after stirring for 0.5h under the condition of 80℃ water bath heating until the piezoelectric polymer is completely dissolved, 0.2-4.5g of nano-magnesium-based powder is added to the solution, and after ultrasonic dispersion for 10 minutes, a uniformly dispersed piezoelectric composite solution is obtained;

[0042] S6, the artificial bone is soaked in a piezoelectric composite solution with a mass concentration of 10% for 2 minutes, the artificial bone is taken out and drained, conductive adhesive tape is pasted on both sides of the artificial bone, and the artificial bone is placed in 100℃ silicone oil for polarization for 15-30 minutes, the polarization voltage is 5kV, and the piezoelectric artificial bone is prepared and sealed.

[0043] Since the component ratio between the beta-tricalcium phosphate (β-TCP), polylactic acid-glycolic acid (PLGA) and nano-magnesium-based powder in the embodiment needs to consider multiple aspects such as osteogenesis effect, mechanical property, biocompatibility and feasibility, a balance point needs to be found among various requirements. If the content of the beta-tricalcium phosphate is too low, the compressive strength and Young's modulus of the artificial bone cannot be improved, resulting in that the artificial bone cannot bear normal physiological load, stress shielding effect is caused, the artificial bone is deformed and displaced, and the acidic product generated by the degradation of polylactic acid-glycolic acid cannot be neutralized. If the content of the beta-tricalcium phosphate is too high, on the one hand, the degradation period of the artificial bone is greatly prolonged, which cannot match the growth process of the new bone, and on the other hand, the solubility of the beta-tricalcium phosphate in 1, 4-dioxane is limited and cannot be dissolved in a large mass. The mass of polylactic acid-glycolic acid as the main component of the artificial bone needs to be adapted to the mass of the beta-tricalcium phosphate to adjust the elastic modulus of the artificial bone scaffold. If the acidic product generated by the degradation is excessive, inflammation of the local tissue is caused and the generation of the new bone in the defect site is affected. Therefore, in step S1 of the embodiment, the volume-mass ratio of the beta-tricalcium phosphate, polylactic acid-glycolic acid and 1, 4-dioxane is preferably 0.25 g:1.015 g:10 mL. By dissolving 0.25 g of beta-tricalcium phosphate and 1.015 g of polylactic acid-glycolic acid in 10 mL of 1, 4-dioxane at room temperature, then stirring at room temperature for 12 H, and then printing into an artificial bone with a shape matching the bone defect part by a 3D printer, the strength of the artificial bone is greatly improved, the degradation of the artificial bone is promoted, and the artificial bone has better osteogenesis effect.

[0044] In addition, the magnesium atoms in the nano-magnesium-based powder are the main substances for promoting the generation of new bone and new blood vessels. If the content is too low, the effect cannot be guaranteed, and if the content is too high, biocompatibility problems may be caused. Therefore, the content of magnesium atoms that can promote the best effect of osteogenesis and angiogenesis under the premise of safety needs to be determined. In step S5 of the embodiment, the nano-magnesium-based powder is preferably 0.3 g, so that the artificial bone can better promote the regeneration of nerves and blood vessels and the formation of new bone.

[0045] Further, after the artificial bone is soaked in a piezoelectric composite solution with a mass concentration of 10%, the artificial bone is taken out and drained, and then polarization treatment is performed, so that a piezoelectric coating is formed on the surface of the artificial bone. The modified artificial bone generates electric charge and potential difference under stress, that is, after the modified artificial bone is implanted into the bone defect site, the magnesium elements in the artificial bone can promote the regulation of osteogenesis by promoting the generation of new blood vessels and nerves. At the same time, during the contraction and relaxation process of human muscles, the implanted artificial bone can be deformed and vibrated. Since the particles in the piezoelectric polymer used for modification are uniformly dispersed and move along the outer surface of the artificial bone, the artificial bone has good piezoelectric effect, which is beneficial to the growth and differentiation of osteoblasts, so as to achieve the purpose of osteogenesis and tissue repair and reconstruction.

[0046] Of course, the above embodiments are only for illustrating the technical concept and characteristics of the present application, and the purpose is to enable those skilled in the art to understand the content of the present application and to implement it, and cannot limit the protection scope of the present application. Any modification made according to the content of the main technical solution of the present application should be covered within the protection scope of the present application.

Claims

1. A novel artificial bone based on promoting neurovascular regeneration, characterized in that, The invention includes artificial bone, which is composed of β-tricalcium phosphate (β-TCP), polylactic-co-glycolic acid (PLGA), nano-magnesium-based powder, and a piezoelectric polymer. The mass ratio of β-tricalcium phosphate to PLGA in the artificial bone is 1:0 to 1:10, but the mass ratio of β-tricalcium phosphate to PLGA is not 1:

0. The nano-magnesium-based powder and the piezoelectric polymer are mixed to form a piezoelectric composite solution, and the mass ratio of the nano-magnesium-based powder to the piezoelectric polymer in the piezoelectric composite solution is 1:1 to 1:

20. The piezoelectric composite solution is used to modify the surface of the artificial bone to form a piezoelectric coating on the surface of the artificial bone. This allows the artificial bone to be implanted into a bone defect site and generate charge and potential difference under stress, thereby promoting new bone formation in the bone defect site. The piezoelectric polymer includes at least one of polyvinylidene fluoride, polyvinylidene fluoride-trifluoroethylene, poly-3-hydroxybutyrate-3-hydroxyvalerate, polyamide, or L-polylactic acid; The nano-magnesium-based powder includes at least one of pure magnesium powder, magnesium oxide powder, magnesium chloride powder, magnesium silicate powder, or magnesium sulfate powder.

2. The novel artificial bone based on promoting neurovascular regeneration according to claim 1, characterized in that, The artificial bone is in the shape of at least one of granular, cubic, strip, and cylindrical.

3. The novel artificial bone based on promoting neurovascular regeneration according to claim 1, characterized in that, The artificial bone surface has a pore size of 200-500 μm and a porosity of 70%-80%.

4. A method for preparing a novel artificial bone based on promoting neurovascular regeneration as described in any one of claims 1-3, comprising the following steps: S1. Dissolution: Dissolve β-tricalcium phosphate and polylactic-co-glycolic acid in 1,4-dioxane at room temperature in the following proportions: β-tricalcium phosphate, polylactic-co-glycolic acid, and 1,4-dioxane in a volume-to-mass ratio of 0.25 g: 1.015 g: 10 mL. S2. Stirring: Stir with a magnetic stirrer at room temperature for 12 hours; S3. Printing: Design the printing mode in advance. The printer spins and prints at -30℃. Set the filament diameter to 240μm and the filament spacing to 600μm. S4. Freeze-drying: Place the printed artificial bone in a freeze-drying environment of -30℃ and 30Pa for 24 hours; S5. After freeze-drying, weigh 4.5g of piezoelectric polymer and add it to 50mL of N,N-dimethylformamide (DMF). Stir for 0.5h under 80℃ water bath heating conditions until the piezoelectric polymer is completely dissolved. Then add 0.3g of nano-magnesium-based powder to the solution and ultrasonically disperse for 10 minutes to obtain a uniformly dispersed piezoelectric composite solution. S6. Immerse the artificial bone in a 10% piezoelectric composite solution for 2 minutes. After removing the artificial bone and draining it, attach conductive tape to both sides of the artificial bone and place it in silicone oil at 100℃ for 15-30 minutes to polarize it. The polarization voltage is 5kV. The piezoelectric artificial bone is then obtained and sealed for storage.

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