介导干细胞成骨分化形成新骨是实现骨再生修复的关键。micorRNA（miRNA）对骨形成及干细胞成骨分化具有重要的调控作用，然而裸miRNA存在稳定性差、难以穿透细胞膜等问题，限制了其深入研究和应用。本项目拟基于新型二维纳米材料黑磷，发展一种生物可降解的miRNA 输送体系，并开展其调控脂肪干细胞成骨分化行为及机制研究。项目拟研究黑磷纳米片及量子点的制备及修饰方法，并探讨尺寸和表面修饰对其理化性能及生物学效应的影响；构建黑磷输送miRNA体系，并研究其与miRNA的结合机理、跨膜转运和细胞内运输及降解代谢的机制；在细胞和动物层面系统研究黑磷介导miRNA对人脂肪干细胞成骨能力的影响并探讨其作用机制。本项目的成功实施，可构建一种高效低毒miRNA输送体系，实现黑磷介导miRNA对脂肪干细胞成骨分化以及骨缺损再生修复的有效调控，为新一代适用于组织修复的核酸载体的构建提供新思路和理论依据。

The key to bone defect regeneration is to actively mediate osteogenic differentiation of stem cells and finally achieve new bone formation. microRNA plays an important role in regulating bone formation and osteogenic differentiation of stem cells. However, naked microRNA is easily degraded by RNA enzyme in the physiological environment, and it is difficult to penetrate the cell membrane into the cells. Therefore, it is necessary to build nano-carriers with high efficiency and low toxicity to protect and deliver microRNAs. This project attempted to use black phosphorus (BP) to construct a biodegradable microRNA delivery system. We will systematic study the synthetic methods of BP nanosheets and quantum dots and study the effect of particle size and surface modification of BP on its physical and chemical properties and biological effects. Then we will study the effect of particle size of black phosphorus on the efficiency of cellular uptake ability and the target gene silencing efficiency of microRNA. We will also investigate the effect of microRNA delivered by black phosphorus on the osteogenesis of stem cells and new bone formation in vitro and in vivo. The successful implementation of this project is to build a BP based microRNA delivery system with high efficiency and good biocompatibility, and to realize the effective meditation of osteogenesis of adipose stem cells and new bone formation in vivo and in vitro. This paper provides new ideas and theoretical basis for the construction of a new generation of nucleic acid carrier which is suitable for tissue repair.