基于力学支撑与稳定活性构建的新型3D打印生物活性类骨材料的研究

骨科植入材料需求量大，新材料、新技术快速发展。模拟人体骨组织的纳米羟基磷灰石/聚酰胺非降解生物材料在临床上逐渐应用，但体内外研究显示植入材料在骨长入、血管化以及材料-骨界面愈合方面仍存在不足。为改善非降解材料与自身骨组织的愈合界面，我们前期研究了表面改性对复合材料生物活性的影响，发现激光打孔制备的表面微孔能提高材料与骨组织之间的界面成骨；但内部微孔结构才能使细胞和血管长入，最终实现骨修复和替代。设计梯度微孔结构可在同一材料体系中调节孔隙大小、形态和分布，实现力学性能和细胞、液体流动的平衡，满足材料对生物活性和力学性能的要求。相比传统方法，3D打印技术可对骨植入材料进行内部复杂结构和精确尺度的设计与调控。本项目首次提出3D打印具有梯度微孔体系的纤维增强纳米羟基磷灰石/聚酰胺类骨生物材料，制备基于力学支撑的兼具稳定生物活性的复合材料，探讨3D打印类骨生物材料在骨组织修复和替代中的应用价值。

The increasing demand for orthopaedic implants is leading to a rapid development of new materials and technologies. Biomimetic nano-hydroxyapatite/polyamide composites have been used in clinical practice for more than 10 years. However, in vivo and in vitro studies have shown that the implants still have shortcomings in the bone ingrowth, vascularization and interface healing between non-degradable implants and bone tissues. In order to improve their healing interface, we researched the effect of surface modification on the biological properties of non-degradable composites in the previous study supported by the National Natural Science Foundation of China [Grant number81501876]. The results showed that the porous surface produced by laser processing improved the bone growth at the interface between nano-hydroxyapatite/polyamide composites and bone tissues. But it is the internal porous structure that allows the cells to migrate and blood vessels to grow inwards, and eventually achieve bone repair. Gradient porous structure can control the pore size, morphology and distribution in the same materials to balance the mechanical properties and the diffusion of both cells and nutrients, which meet the requirements of both biological and mechanical properties for the bone implants. Compared with traditional technologies, 3D printing can design and regulate the complex internal structure and precise scale of composites. Therefore, we proposed for the first time a strategy to 3D print gradient porous nano-hydroxyapatite/polyamide biomimetic composites reinforced by fibers which have enhanced mechanical properties and stable bioactivity. This project also would evaluate the capacity of 3D-printed biomimetic composites for bone repair and substitute.