低模量骨植入体的促血管再生三维细胞微环境构建及其成骨机理研究

How to promote angiogenesis and osseointegration have been the difficult and hot issues of bone reparative study.An ideal bone repair material should be with good ability on mechanics, possess osteoinductive activity and provide sufficient blood vessel supply, so as to stimulate osteogenic differentiation and promote angiogenesis to promote bone repair.Though porous titanium has excellent mechanical properties, it's poor angiogenesis and osseointegration was not ideal. Hydrogel is an ideal bone tissue engineering scaffold that can be highly conducive for cells proliferation and differentiation due to the high water content and extracellular matrix microenvironment. However, it's poor mechanical property can not satisfy the requirement of bone defect and reconstruction in load-bearing parts of human body. Therefore, This innovative project intends to combine laser district melt forming 3D printing with the "molecular brigade", to build a kind of low modulus, high strength of porous titanium massive bone defect scaffold. In micro scale, the three-dimension microenvironment will be constructed within the macro pores according to the extracellular matrix structure characteristics of containing cell hydrogel to build similar 3D microenvironment in the body for cells, to assist cell osteogenic differentiation and angiogenesis.Revealing the influence of signal pathways and mechanical adaptation law of the implanted materials and surrounding tissues. Discuss to further the mechanism of regulating cells by ERE/MAPK. To provide theoretical principl and experimental support for the research and development of new massive bone defect implants.

植入材料大段骨缺损的促血管再生和骨整合是临床骨科的难点和热点。理想的骨修复材料应具备良好的力学适配性、成骨诱导活性和功能性供血效果，以诱导成骨分化和血管再生，促进骨缺损修复。钛合金支架具有优异力学性能，但促血管生成和骨整合效果不理想。水凝胶能够为干细胞的增殖与分化提供接近于天然细胞外基质的微环境，但其力学性能差，无法满足承重部位大段骨缺损修复的要求。因此，本项目创新性采用激光选区熔化3D打印技术和偶联“分子桥”技术相结合，构建出低模量、高强度多孔钛大段骨缺损支架，在支架孔隙内复合载细胞仿细胞外基质的结构特征的水凝胶，为细胞构建类似体内的三维微环境，调控细胞在三维微环境中协同成骨分化与血管生成。揭示材料植入体内后对周围组织、细胞信号通络的影响及其力学适配规律，阐明低模量骨植入体三维微环境通过ERK/MAPK信号通路调控干细胞的作用机制，为新型大段骨缺损植入物的研发提供理论基础和实验支撑。

本项目采用激光选区熔化3D打印技术和偶联“分子桥”技术相结合，构建出低模量、高强度多孔钛合金大段骨缺损支架。体外细胞实验结果表明改性明胶水凝胶表面修饰3D打印多孔钛合金支架具有良好的生物安全性、成骨分化和成血管分化能力。在GelMA改性的PT支架中，浓度为10%(14.46±1.55 kPa)的GMPT在体内和体外都表现出最佳的促进细胞附着和分化的能力，RNA-seq和FCM揭示了10%GMPT的血管生成和成骨作用受Pi3K/Akt/mTOR信号调节的基本机制。体内动物植入实验进一步证实改性明胶水凝胶表面修饰的3D打印多孔钛合金支架能够显著提升提高血管化、成骨分化和骨整合，为新型大段骨缺损植入物的研发提供新思路。