传统骨生物材料的设计仅注重对成骨细胞的正向调节作用，而忽视了免疫细胞在骨修复过程中对成骨的重要调节作用。生物材料植入机体后，巨噬细胞作为固有免疫系统最重要的免疫细胞被首先招摹到植入部位。研究表明，巨噬细胞在骨生物材料所激活的免疫反应中起重要作用。近年来，生物仿生材料成为骨组织工程的研究热点，然而，关于仿生材料如何影响体内局部免疫微环境从而诱导骨缺损区域再生的机制尚无报道。本课题组在前期的研究中，通过生物模拟组装了一种与天然骨具有一致等级结构的矿化胶原，其对骨缺损的再生效果明显优于传统无等级结构的矿化胶原。本项目拟在前期的研究基础上，探讨不同矿化胶原与体内局部免疫微环境相互作用，尤其是对M1/M2型巨噬细胞极化的影响；并通过调节免疫微环境来促进矿化胶原对骨缺损的修复效果。本项目有望发现一种新的材料诱导骨修复机制，为骨替代材料的设计提供新理念，为临床骨缺损修复提供新材料。

Traditional bone biomaterial design focuses on the positive regulatory effect of the osteoblasts, yet ignoring the important regulatory role of immune cells in the osteogenesis during bone repair process. After implantation of biological materials in vivo, macrophages as the most important immune cells in innate immune system are first recruited to the implant site. Previous studies have shown that macrophages play an important role in bone biomaterial-activated immune response. In recent years, biomimetic materials is becoming a hot topic of bone tissue engineering. However, the mechanism of how biomimetic materials influence local immune microenvironment to induce regeneration of bone defect regions is not reported. In our previous studies, hierarchical mineralized collagen fabricated through a biomimetic assembling approach, exhibits similar hierarchical nanostructure to natural bone and improves bone regeneration compared to non-hierarchical mineralized collagen. On the basis of previous research, we plan to explore interactions between different mineralized collagen and immunological microenvironment in vivo, especially on M1 / M2 macrophages polarization; and to promote bone regeneration by regulating the immune microenvironment in this project. This project is targeted to find a novel mechanism promoting materials to induce bone regeneration, to provide a new idea for the design of bone substitutes, and therefore to provide a new material for clinical bone defect repair.