磷酸钙基仿生压电生物陶瓷制备及骨诱导性能研究

Calcium phosphates ceramics, as a composition close to natural bone mineral or hard tissue, are capable of supporting bone growth and osteointegration for bone tissue regeneration. However the osteoinductivity of calcium phosphate biomaterials still remain as a challenge. Up to now, extensive fundamental studies and clinical application have demonstrated that calcium phosphate ceramics with special structure and piezoelectric function may induce bone formation in soft tissue. .In this proposal, the macroporous titanate nanowire matrix on Ti metal will be fabricated by a hydrothermal method, and followed by growing piezoelectric-ceramics on titanate nanowire via a hydrothermal method, and then coating ordered hydroxyapatite naostructures on the piezoelectric-ceramics via an electrochemical deposition method. Then the piezoelectric bioceramics can be developed. The interest in combining traditional bioceramics with piezoelectric ceramics can be driven by the potential to improve materials for clinical applications and generate new biomimetic. The studies will investigate composites of calcium phosphates (CaP bioceramic used for synthetic bone materials) with barium titanate (piezoelectric material). The incorporation of titanate nanowire matrix with high oriented hydroxyapatite nanoparticles generates hierarchical scaffolds with highly osteogenic, structural integrity and excellent mechanical performance. The piezoelectric bioceramic displays osteoinductivity, which facilitates the cell attachment and proliferation, and induces the in vitro tissue-engineered bone..The project will make a unique contribution to understanding the the optimal design for improved osteoinductivity of HA-based piezoelectric bioceramics. Future studies will seek to generate these materials, by exploiting novel synthesizing methods. To develop more advanced piezoelectric bioceramics (Ba2TiO3, ZnO or Bi0.5Na0.5TiO3), a design study will undertaken to better understand the complex interactions that occur. It will be supported by experimental characterization of the manufactured ceramics (SEM, XRD and EDX) and the resulting piezoelectric properties measured. As-prepared scaffolds, mimicking the nature's extracellular matrix, can provide a suitable microenvironment for tissue cell ingrowth and differentiation. Human osteoblast-like MG63 cells will be cultured on the piezoelectric bioceramic-modified titanate nanowire scaffold to confirm the promoted bioactivity and osteoconductivity. Further, the in vivo test will also be applied to confirm the osteoinductivity of the piezoelectric bioceramics. .From the practical investigation, a generic design will be produced that can be used to optimize the properties of the ceramic composition and microstructure, which can be helpful to explore potential new combinations of bio-/electro-ceramic combinations.

羟基磷灰石（HA）具有良好的生物活性和生物相容性，是人工关节表面重要的涂层材料，但 HA 涂层与自然骨相比在成分、微结构和骨诱导性等方面的差异严重影响其临床应用效果。.本项目拟制备模拟天然骨骼复杂微结构、成分和压电功能的多级仿生HA生物陶瓷涂层材料，并研究其压电性能定向吸引钙离子沉积所产生的骨诱导机制。宏观仿生结构研究压电陶瓷@ HA壳核复合结构在三维TiO2纤维织构骨架上的构筑，获得可容纳细胞生长且孔间相互贯通的Ca-P陶瓷复合结构；微观仿生结构研究包覆在压电陶瓷和TiO2纳米纤维表面HA微晶成分和微观结构界面对骨骼再生的促进机制；功能仿生研究压电效应吸引钙盐在植入HA基生物陶瓷表面定向沉积及诱导骨质钙化生长规律，研究压电效应与矿化生长的HA纳米微晶大小、形貌、取向、晶区和晶界等微观结构的关系，揭示其矿化机理和骨诱导机制，为结构和功能仿生生物材料设计与制备提供理论基础。

本研究在分析天然骨骼微结构、成分、生物功能和已有工作的基础上，根据结构仿生和功能仿生的基本原则，针对目前生物医用材料的研究进展以及存在的问题，进行了如下研究：构筑结构仿生型支架，即在钛合金表面原位生长织构钛酸盐纳米纤维微腔；并以此为基础，重点围绕力学功能仿生和电学功能仿生进行深入研究，开发了基于“氧化石墨烯纳米片层结构”机械增强的钛基钛酸盐纳米线生物支架材料以及基于“压电功能陶瓷”电学相容的的钛基钛酸盐纳米线生物支架材料。所制备的一系列材料延续了钛基钛酸盐纳米线矩阵发达的微孔结构，不仅有利于细胞的粘附与移动，也有利于血管的形成，达到结构仿生的目的；同时具有良好的压电性能，可诱导细胞在支架材料上的增殖和分化，达到电学仿生的目的。对功能仿生生物材料进行了表面微环境调控，提高其生物相容性，并通过不同的生物学方法对功能化额支架材料进行评估，为今后临床应用和工作提供了一定的实验参考价值和理论基础。. 此外，我们还研究了复杂多级仿生结构，如yolk-shell结构及贵金属纳米材料的多级构筑，实现了其生物性能以及催化性能的优化，在细胞标记、蛋白质分离及污水处理等环境领域有着重要的应用价值。