Preparation method of surface-modified 3D printing artificial bone, artificial bone composite material and application of surface-modified 3D printing artificial bone composite material

Abstract

The invention provides a preparation method of a surface-modified 3D printing artificial bone as well as an artificial bone composite material and application thereof, and relates to the field of artificial bones. The preparation method of the surface modified 3D printed artificial bone comprises the following steps: mixing beta-TCP with photosensitive resin, and carrying out DLP printing, sintering and cleaning to obtain a beta-TCP scaffold; immersing the beta-TCP stent into a degradable high-molecular polymer solution, soaking and drying to obtain a high-molecular polymer coated stent; putting the high-molecular polymer coated scaffold into a Tris-HCl buffer solution of dopamine hydrochloride, and reacting to obtain a polydopamine modified scaffold; the polydopamine modified scaffold is placed in a collagen solution, collagen is adsorbed on the surface of the polydopamine modified scaffold, and the surface modified 3D printing artificial bone is obtained. The mechanical property of the 3D printed artificial bone is remarkably improved through a simple modification method. Under the condition that the mechanical property is not reduced, the biocompatibility of the stent is further improved, and bone defect repair is more facilitated.

Description

Technical Field

[0001] This invention relates to the field of artificial bone, and particularly to a method for preparing surface-modified 3D-printed artificial bone, its artificial bone composite materials, and their applications. Background Technology

[0002] Skeleton is the basic structure of the human body, playing an indispensable role in supporting the torso, protecting internal organs, and driving movement. The main components of bone include an organic matrix and inorganic mineral salts. The organic matrix, primarily composed of type I collagen fibers, accounts for 90% of the organic portion and gives bone tissue tensile strength and flexibility. The inorganic portion consists of hydroxyapatite, magnesium, sodium, and potassium, which not only provide rigidity and compressive strength but also contribute to overall ion balance.

[0003] Bone injury is one of the most common problems in orthopedics. Clinically used autologous and allogeneic transplants have drawbacks such as postoperative complications like infection, high costs, limited donor availability, immunogenicity, and transplant rejection. To overcome these problems and limitations, bone tissue engineering has gained widespread attention as an alternative method for repairing and reconstructing fractures.

[0004] Bone tissue engineering has three basic components: scaffolds, growth factors, and cells. Scaffolds used in bone tissue engineering are typically constructed from natural polymers, synthetic polymers, bioceramics, and metallic materials. The surface properties of the scaffold are one of the most important characteristics, influencing the interaction between the scaffold and cells and the reconstruction of damaged tissue. Surface modification of the scaffold can improve several properties, such as biocompatibility, biodegradability, and mechanical properties. Currently used modification methods include physical adsorption, chemical surface modification, and layer-by-layer assembly. These techniques help control the deposition of materials onto the scaffold surface, giving them tailored properties and creating scaffolds that are very similar to the natural bone matrix, thereby promoting better integration and regeneration.

[0005] Surface modification techniques based on physical adsorption primarily adhere polymer coatings to substrate surfaces through weak intermolecular forces, including hydrogen bonds, van der Waals forces, electrostatic or hydrophobic interactions. These methods mainly include dip coating, spin coating, and spray coating, and are a general and direct approach. In dip coating, the substrate is immersed in a solution containing the desired coating material and then extracted at a controlled rate to form a thin film on the substrate surface. Spin coating involves depositing a liquid polymer solution onto the substrate and then rotating it at high speed to obtain a uniform polymer film. Spray coating atomizes the polymer solution into fine droplets on the substrate surface; as the solvent evaporates, these droplets form a uniform polymer layer. This technique is well-suited for coating substrates with complex geometries because the droplets can uniformly cover irregular surfaces. The main drawback of this method is the weak adhesion between the coating and the substrate, relying solely on physical forces, resulting in poor coating stability. The coating is prone to detachment and failure under mechanical friction, liquid erosion, or long-term use, and precise control of coating thickness and uniformity is often difficult.

[0006] Chemical surface modification methods can be categorized into wet chemical modification, plasma surface modification, and various chemical binders. Wet chemical methods primarily generate functional groups on the surface through amino decomposition and hydrolysis, increasing surface hydrophilicity; however, the use of solvents and harmful substances can lead to toxicity. Plasma surface modification uses plasma treatment with different gases to introduce polar groups onto the scaffold surface, improving its hydrophilicity and porosity, as well as cell adhesion and proliferation. It poses no risk of toxicity or pollution, but the functional groups formed on the surface are rapidly destroyed. Commonly used chemical binders include dopamine derivatives, silane coupling agents, and 1,6-hexamethylenediamine. Dopamine is widely used primarily because it imparts inherent adhesive properties to the scaffold, allowing various materials to adhere to the scaffold surface and improving the possibility of cell adhesion, proliferation, and differentiation.

[0007] Layer-by-layer assembly is a simple method for constructing polyelectrolyte multilayers by sequentially adsorbing polyanions and polycations onto a charged substrate. This technique utilizes electrostatic interactions to achieve rapid polymer adsorption and surface charge reversal, followed by a rinsing step to remove unbound material, thus forming customized films layer by layer. While this method allows for precise control of the film structure, its main drawbacks are the time-consuming and cumbersome process, requiring multiple adsorption and rinsing cycles to obtain films of sufficient thickness, resulting in low production efficiency. Furthermore, the stability of the final polyelectrolyte multilayer film is challenged when exposed to solutions with extreme pH values ​​or high ionic strengths, potentially leading to desorption.

[0008] The core innovation of this invention lies in proposing a composite surface modification method for 3D-printed β-TCP artificial bone scaffolds. By combining synthetic polymers, a bioactive intermediate layer, and functionalization of natural proteins, the mechanical properties of the scaffold are significantly improved while its hydrophilicity and biocompatibility are effectively enhanced, achieving synergistic optimization of mechanical support and bioactivity. The entire modification process retains the enhancement of the scaffold's mechanical properties by the synthetic polymer, and through the gradual modification with PDA and collagen, it addresses the shortcomings of traditional polymer coatings in terms of bioactivity. This provides a generalizable composite surface engineering strategy for constructing bone repair scaffolds with both high mechanical strength and excellent osteogenic activity. Summary of the Invention

[0009] In view of this, the present invention proposes a method for preparing surface-modified 3D printed artificial bone, as well as its artificial bone composite material and its application.

[0010] The technical solution of this invention is implemented as follows: A method for preparing surface-modified 3D-printed artificial bone includes the following steps: (1) β-TCP is mixed with photosensitive resin, and then printed by DLP, sintered, and cleaned to obtain a β-TCP scaffold; (2) Immerse the β-TCP scaffold from step (1) in a biodegradable polymer solution for 10-60 min, then dry to obtain a polymer-coated scaffold. (3) The polymer-coated scaffold from step (2) is placed in Tris-HCl buffer solution of dopamine hydrochloride and reacted for 4-16 hours to obtain a polydopamine-modified scaffold; the preferred reaction time is 4-8 hours. (4) The polydopamine-modified scaffold was placed in a collagen solution, and collagen was adsorbed onto the surface of the polydopamine-modified scaffold to obtain surface-modified 3D printed artificial bone.

[0011] Furthermore, the collagen is at least one of animal-derived collagen, recombinant collagen, or their hydrolysate.

[0012] To further enhance the biological activity of the scaffold, collagen was adsorbed onto the surface of the polydopamine-modified scaffold. The catechol structure of dopamine is a key component of mussel adhesion protein, enabling it to interact with various materials. Without affecting its mechanical properties, this significantly improves the scaffold's activity and is more conducive to bone defect repair after scaffold implantation.

[0013] Further, in step (1), the mass ratio of β-TCP to photosensitive resin is 53-58:42-47, preferably 55:45; the monomer of the photosensitive resin is a medical-grade photosensitive resin monomer, and the photosensitive resin monomer is at least one of acrylic acid, acrylamide or methacrylate.

[0014] Further, in step (1), the sintering process begins at 25-30°C with a 6-fold speed. The temperature was gradually increased to 390-410℃ at a heating rate of 7℃ / h, and then gradually increased to 1250-1350℃ at a heating rate of 24-26℃ / h, followed by sintering at that temperature for 2 hours. 3 hours.

[0015] Preferably, the sintering process starts at 25°C and proceeds at 6... The temperature was gradually increased to 400℃ at a heating rate of 7℃ / h, and then gradually increased to 1300℃ at a heating rate of 25℃ / h from 400℃; sintering was carried out at 1300℃ for 2 hours. 3 hours; Further, in step (2), the concentration of the polymer solution is 2%-5% w / w; the polymer is at least one of PLLA, PCL, and PLCL.

[0016] Further, in step (2), the drying temperature is 37-40℃ and the drying time is 20-28h. Preferably, the drying temperature is 37℃ and the drying time is 24h.

[0017] Further, in step (3), the pH value of the Tris-HCl buffer solution is 8.0-8.8.

[0018] Further, in step (4), the mass concentration of the collagen solution is 1%-5%, and the adsorption time is 20-24h.

[0019] A surface-modified 3D-printed artificial bone composite material, prepared by any one of the methods described in this invention.

[0020] The present invention relates to the application of surface-modified 3D-printed artificial bone composite material in the preparation of artificial bone.

[0021] Compared with the prior art, the beneficial effects of the present invention are: (1) The present invention significantly improves the mechanical properties of 3D printed artificial bone through a simple modification method.

[0022] (2) Without reducing mechanical properties, the present invention further improves the biocompatibility of the scaffold, which is more conducive to the repair of bone defects.

[0023] (3) In this invention, collagen is adsorbed onto the surface of the polydopamine-modified scaffold, which allows it to interact with various materials. Without affecting its mechanical properties, the activity of the scaffold can be significantly improved, which is more conducive to the repair of bone defects after scaffold implantation.

[0024] (3) Moreover, the raw materials and final products of the surface-modified artificial bone prepared by the present invention are all free from cytotoxicity and have good safety. Attached Figure Description

[0025] Figure 1 The present invention describes the preparation process of surface-modified 3D-printed artificial bone; Figure 2 Images showing the effects of impregnating the stent with different concentrations of PLLA. Figure 3 Hydrophilicity and hydrophobicity of the PLLA-impregnated stent; Figure 4 Products prepared by different dopamine polymerization times; Figure 5 The effect of different dopamine polymerization times on hydrophilicity / hydrophobicity and mechanical properties; Figure 6 SEM images of the surface before and after modification according to this invention; Figure 7 The infrared spectrum of the modified stent of this invention. In the figure, Wavenumber: wavenumber.

[0026] Figure 8 Image showing the effect of impregnating a stent with 20% wt% PCL; Figure 9 Products prepared by impregnation with PCL of different concentrations; Figure 10 Hydrophilicity / hydrophobicity and mechanical properties after impregnation with PCL of different concentrations.

[0027] Figure 11 This invention relates to the detection of cytotoxicity in the preparation of raw materials and final products for surface-modified artificial bone. In the figure, CellViability refers to cell viability. Detailed Implementation

[0028] Unless otherwise specified, the experimental methods used in the embodiments of this invention are conventional methods; Unless otherwise specified, all materials and reagents used in the embodiments of this invention are commercially available.

[0029] Table 1. Chinese meanings or explanations of the English / abbreviations

[0030] The preparation process of the surface-modified 3D printed artificial bone of this invention is as follows: Figure 1 As shown.

[0031] The collagen used in this invention is animal-derived collagen, recombinant collagen or its hydrolysate, with a molecular weight of 1-200 kDa.

[0032] The collagen used in Examples 1-4 of this invention is gelatin.

[0033] Example 1 A method for preparing surface-modified 3D-printed artificial bone specifically includes the following steps: (1) β-TCP is mixed with photosensitive resin and printed by DLP, starting at 25°C at 6 The temperature was gradually increased to 400℃ at a heating rate of 7℃ / h, and then gradually increased to 1300℃ at a heating rate of 25℃ / h from 400℃; sintering was carried out at 1300℃ for 2 hours. After 3 hours of cleaning, the β-TCP stent was obtained. The mass ratio of the above-mentioned β-TCP to photosensitive resin is 55:45.

[0034] The photosensitive resin mentioned above is at least one of acrylic acid, acrylamide, or methacrylate. In this example, the photosensitive resin used is acrylamide. (2) Immerse the β-TCP scaffold from step (1) in a 5%wt PLLA solution for 10 min, remove it, and dry it at 37℃ for 24 h to obtain a PLLA-impregnated scaffold (abbreviation: β-TCP+PLLA). (3) The PLLA-impregnated scaffold from step (2) was placed in Tris-HCl (pH=8.5) buffer solution of dopamine hydrochloride and reacted for 4 hours to obtain a polydopamine-modified scaffold. (4) The polydopamine-modified scaffold was placed in a collagen solution, and collagen was adsorbed onto the surface of the polydopamine-modified scaffold to obtain surface-modified 3D printed artificial bone (abbreviation: β-TCP+PLLA+COL); the mass concentration of the collagen solution was 2%, and the adsorption time was 24h.

[0035] After the composite surface modification was completed, the morphology and chemical composition of the material surface were analyzed by scanning electron microscopy and infrared spectroscopy, respectively.

[0036] Material 1 (β-TCP): β-TCP scaffold; Material 2 (β-TCP+PLLA): β-TCP scaffold modified with PLLA; Material 3 (β-TCP+PLLA+COL): β-TCP scaffold modified with polydopamine and collagen; Compared to the β-TCP scaffold, the composite-modified scaffold exhibits a noticeable coating adhesion on the surface of the crystalline particles. The fine pores observed after PLLA modification are likely due to rapid solvent evaporation, but these were significantly improved after modification with polydopamine and collagen. Figure 6 As shown.

[0037] The adhesion of the layer, in which the small pores that appeared after PLLA modification may be due to the rapid evaporation of the solvent, was significantly improved after modification with polydopamine and collagen.

[0038] like Figure 7 The infrared spectrum is shown at 10¹² cm⁻¹. -1 The location is PO4 -3 The asymmetric stretching vibration of the group, at 1755 cm⁻¹ -1 The presence of PLLA at the C=O stretching vibration indicates its existence. Compared to PLLA coating, the presence of PLLA at 3100-3500 cm⁻¹ is observed in β-TCP+PLLA+COL. -1 A relatively broad peak appeared at the point, which was caused by the stretching of NH in collagen, indicating the successful adsorption of collagen.

[0039] Example 2 The effect of different concentrations of PLLA solution was studied. Based on Example 1, in step (2), the concentration of PLLA solution was adjusted to 0%, 2%, 5%, and 10%, w / w.

[0040] The results showed that immersing the sintered and cleaned β-TCP scaffold in PLLA solutions of different concentrations (0%, 2%, 5%, 10%, w / w) enhanced the mechanical properties of the scaffold. However, excessively high concentrations would clog the scaffold pores, preventing cell ingrowth and nutrient transport. The preferred PLLA solution concentration in this invention is 2%-5%. The effects of immersing the scaffold in PLLA solutions of different concentrations are shown in the figures below. Figure 2 As shown.

[0041] from Figure 3 The scaffold can be seen to change from a hydrophilic to a hydrophobic state, which proves the successful impregnation of PLLA. However, the hydrophobic scaffold is not conducive to the subsequent adhesion and growth of cells.

[0042] Example 3 The effect of polymerization time on the surface modification results of polydopamine was studied. Based on Example 1, step (3) was performed by adjusting the reaction time to 4 h, 8 h, and 16 h.

[0043] To modify the hydrophobicity of the scaffold caused by polymer impregnation, the self-polymerization ability of dopamine hydrochloride was used to modify the scaffold surface, altering its hydrophilicity and hydrophobicity without significantly reducing the scaffold's mechanical properties. PLLA-impregnated and dried scaffolds were placed in a Tris-HCl (pH=8.5) buffer solution containing dopamine hydrochloride. However, considering that a weak base might accelerate the hydrolysis of PLLA, the reaction time was adjusted (4h, 8h, and 16h) for testing, as shown in the table below. Figure 4 , Figure 5 As shown, the hydrophobicity of the scaffold was improved after polydopamine surface modification, and the mechanical properties of the scaffold did not decrease significantly after 4 hours of reaction.

[0044] Table 2

[0045] Example 4 Based on Example 1, the PLLA solution was replaced with a PCL solution, and the PCL solution concentrations were 0%, 5%, 10%, and 15% w / w. Preferably, the PCL solution concentration in this invention is 5%-15%.

[0046] like Figure 8 , Figure 9 , Figure 10 As shown in the table below, impregnation with PCL polymer can achieve the same effect, altering hydrophilicity and hydrophobicity and improving the mechanical properties of the scaffold.

[0047] Table 3

[0048] Example 5 Materials 1, 2, and 3 from Example 1 were subjected to cytotoxicity testing. The results showed that neither the raw materials nor the final product of the surface-modified artificial bone of this invention exhibited cytotoxicity. Figure 11 As shown, it possesses the biocompatibility basis for use as a bone repair material.

[0049] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the scope of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing surface-modified 3D-printed artificial bone, characterized in that, Includes the following steps: (1) β-TCP is mixed with photosensitive resin, and then printed by DLP, sintered, and cleaned to obtain a β-TCP scaffold; (2) Immerse the β-TCP scaffold from step (1) in a biodegradable polymer solution for 10-60 min, then dry to obtain a polymer-coated scaffold. (3) Place the polymer-coated scaffold from step (2) into Tris-HCl buffer solution of dopamine hydrochloride and react for 4-16 hours to obtain a polydopamine-modified scaffold. (4) The polydopamine-modified scaffold was placed in a collagen solution, and collagen was adsorbed onto the surface of the polydopamine-modified scaffold to obtain surface-modified 3D printed artificial bone.

2. The method for preparing surface-modified 3D-printed artificial bone according to claim 1, characterized in that, In step (1), the mass ratio of β-TCP to photosensitive resin is 53-58:42-47; the monomer of the photosensitive resin is at least one of acrylic acid, acrylamide or methacrylate.

3. The method for preparing surface-modified 3D-printed artificial bone according to claim 1 or 2, characterized in that, Step (1), the sintering process starts at 25-30℃ and proceeds at 6... The temperature was gradually increased to 390-410℃ at a heating rate of 7℃ / h, and then gradually increased to 1250-1350℃ at a heating rate of 24-26℃ / h, followed by sintering at that temperature for 2 hours. 3 hours.

4. The method for preparing surface-modified 3D-printed artificial bone according to claim 1, characterized in that, In step (2), the concentration of the polymer solution is 2%-5% w / w; the polymer is at least one of PLLA, PCL, and PLCL.

5. The method for preparing surface-modified 3D-printed artificial bone according to claim 1 or 4, characterized in that, In step (2), the drying temperature is 37-40℃ and the drying time is 20-28h.

6. The method for preparing surface-modified 3D-printed artificial bone according to claim 1, characterized in that, In step (3), the pH value of the Tris-HCl buffer solution is 8.0-8.

8.

7. The method for preparing surface-modified 3D-printed artificial bone according to claim 1 or 6, characterized in that, Step (3), the reaction time is 4-8 hours.

8. The method for preparing surface-modified 3D-printed artificial bone according to claim 1, characterized in that, In step (4), the mass concentration of the collagen solution is 1%-5%, and the adsorption time is 20-24h.

9. A surface-modified 3D-printed artificial bone composite material, characterized in that, It is prepared by the method described in any one of claims 1-8.

10. The application of the surface-modified 3D-printed artificial bone composite material according to claim 9 in the preparation of artificial bone.

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