由骨质疏松引起的椎体压缩性骨折是一种常见的骨科疾病。目前在临床治疗中广泛使用聚甲基丙烯酸甲酯骨水泥，该骨水泥存在机械强度与骨不匹配、单体释放引起并发症、聚合温度过高伤害周围组织、不能降解等诸多缺点，因此研制新型可注射骨水泥材料具有重要意义。作为一种生物相容性的可降解高分子材料，聚己内酯具有与人体松质骨类似的压缩模量，具备成为新型骨水泥的潜质。但该种材料无生物活性，不能促进骨组织再生，并且疏水、熔点偏高。基于此，本项目拟从分子结构角度出发，合成高相对分子质量聚己内酯-聚乙二醇嵌段聚合物，并首次在该类共聚物中复合具有成骨活性的镁粒子，合成出具有生物活性的可注射骨水泥材料。深入研究并揭示分子结构、结晶性能、成分组成、纳米结构等与材料生物力学强度、流变注射性能及体内外成骨生物学性能的内在联系，探讨其作为目前骨水泥替代材料的可行性，并为研究和发展其在临床上的应用奠定重要的材料理论基础。

Vertebral body fractures are very common fractures associated with osteoporosis. However, the most commonly used bone cement Polymethylmethacrylate (PMMA) has been found unsatisfactory on its clinic application due to bioinertness, increased risk of adjacent vertebral body fractures due to the mismatch of mechanical properties, and the strong exothermic reactions during polymerization that potentially lead to adjacent soft tissue necrosis and pulmonary embolism. Development of novel bone substitute is therefore needed. Polycaprolactone (PCL) is a suitable polymer to use as cement because of the biodegradability and similar biomechanical properties with bone. However, to use as bone cement, PCL still have some shortcomings. The melting point and melt viscosity of PCL is higher than expected, and it doesn’t have bioactivity, therefore, this biodegradable material has to be modified. In respect of molecular structure design, the project intends to synthesize polycaprolactone-polyethylene glycol (PCL-PEG) copolymers with high molecular weight, then osteogenic-active Mg will be add to prepare a series of composites for the first time. Internal relationship between molecular structure, molecular weight, composition, crystalline property, nano-structure and bio-mechanical properties, rheological properties, in vitro and in vivo biological properties of the material will be investigated. It is going to explore the feasibility of the composite as current cement replacement materials and lay an important foundation for its study and the development in clinical practice.