基于3D打印羟基磷灰石支架的填充结构与力学性能研究

3D打印骨组织工程支架是近来的研究热点,而制备同时具有高孔隙率和足够力学性能的骨组织工程支架是研究的难点之一。在孔隙率相同条件下,探究不同填充角度结构对3D打印支架力学性能影响。首先用SolidWorks软件设计孔隙率相同的3种不同填充角度(45°、60°、90°)支架结构,以交点处结构作为支架的最小支撑单元,并用ABAQUS软件对其进行力学性能仿真,对仿真所得单元结构压缩模量进行累加,探究填充角度对支架力学性能的影响;进而通过3D打印制备3种填充结构的羟基磷灰石支架,测试支架的孔隙率和力学性能,对仿真结果进行验证。结果表明,仿真所得3种填充结构的压缩模量比为E_s(90°)∶E_s(60°)∶E_s(45°)=12.3∶10.9∶10.0。打印得到3种不同填充角度(90°,60°,45°)的羟基磷灰石支架孔隙率无显著性差异,其压缩模量比为E_s(90°)∶E_s(60°)∶E_s(45°)=15.4∶13.1∶10.0,与仿真结果趋势一致,90°填充的支架具有最高的抗压强度((7.36±0.63) MPa)和压缩模量((33.55 ± 2.49) MPa),与力学性能最低的45°填充支架相比,抗压强提高74.8%,压缩模量提高55.18%。在孔隙率相同的条件下,单个孔型面积越小,其压缩模量和抗压强度越高。该研究为制备最优填充结构的3D打印生物支架提供分析方法和理论依据。

Research on the Relationship Between Mechanical Properties of 3D Printed Hydroxyapatite Scaffolds and Inner Structures

3D printed bone tissue engineering scaffolds are becoming hotspot recently, and preparation of bone tissue engineering scaffolds with high porosity and sufficient mechanical properties is still one of the difficulties in current research. The purpose of this study was to investigate the effects of different filling angle structures on the mechanical properties of 3D printing scaffold with the same porosity. Firstly, three different filling angle (45°, 60°, 90°) scaffold structures with the same porosity were designed by SolidWorks software, the structure of the intersection point was used as the minimum support unit of the scaffold, and it′s mechanical properties were simulated by ABAQUS software. Next, the compression modulus of the structure unit was accumulated to investigate the effect of filling angle on the mechanical properties of the scaffold. Three kinds of hydroxyapatite scaffolds with inner structure were prepared by 3D printing, and the porosity and mechanical properties of the scaffolds were tested to verify the simulation results. Results showed that the compression modulus ratio of the three inner structures obtained by simulation was E_s(90°)∶E_s(60°)∶E_s (45°)=12.3:10.9:10.0. There were no significant differences in the porosity of the hydroxyapatite scaffolds among the three different filling angles (90°, 60°, 45°), and the compression modulus ratio was E_s(90°):E_s(60°):E_s(45°)=15.4:13.1:10.0, consistent with the simulation results. The 90° scaffold had the highest compressive strength (7.36 ± 0.63) MPa and compressive modulus (33.55 ± 2.49) MPa. Compared with the 45° scaffold, the compressive strength of 90° scaffold was increased by 74.8% and the compressive modulus was increased by 55.18%. With the same porosity, the scaffold with smaller area of single pore showed higher compressive modulus and compressive strength. This study provided an analytical method and theoretical basis for the preparation of 3D printed biological scaffolds with optimal inner structure.