珊瑚在临床上已经被广泛用于骨缺损的修复，效果良好，其主要成分是碳酸钙。然而，关于人工合成多孔碳酸钙陶瓷作为骨修复材料的研究报道很少，主要的原因是碳酸钙在高温下容易分解，难以烧结。此外，碳酸钙的成骨机制尚不清楚。本项目拟结合等静压处理技术，创新性地采用两种方式制备多孔碳酸钙基骨修复材料：（1）研制具有良好生物相容性的可降解低熔点磷酸盐玻璃作为烧结助剂对碳酸钙进行低温快烧；（2）利用常温下亚稳态和不稳定的碳酸钙在水相环境中发生溶解-再结晶反应生成热力学相对稳定的碳酸钙。评价多孔碳酸钙基骨修复材料的基本理化性能、稳定性、体外降解和细胞行为、体内降解和成骨等，进而筛选实验条件，获得综合性能优化的多孔碳酸钙基骨修复材料。通过系统研究不同晶型、结晶度碳酸钙材料的体外和体内生物活性，结合体内成骨情况，阐明碳酸钙的成骨机制。本项目研究的多孔碳酸钙基骨修复材料有望成为骨缺损填充修复的另一个合适选择。

The coral, whose main composition is calcium carbonate, has been widely used to repair bone defect with good result in clinic. However, the studies on synthetic porous calcium carbonate bioceramics as bone repair materials are barely reported mainly because of difficulty in sintering the calcium carbonate that is liable to decompose at high temperature. Furthermore, the osteogenetic mechanism of calcium carbonate is yet to be clarified. In the present project, we originally proposed two methods of fabricating porous calcium carbonate-based bone repair materials in combination with the isostatic pressing technique: (1) sintering the calcium carbonate fast at lower temperature by introducing the biocompatible, degradable, low-melting-temperature phosphate glass as the sintering agent; (2) fabricating the calcium carbonate biomaterials according to the mechanism that metastable and unstable calcium carbonates transform to thermodynamically stable calcium carbonates by the dissolution-recrystallization reaction as the water is involved. The optimal experimental conditions for preparing porous calcium carbonate-based bone repair materials with excellent comprehensive performances will be determined by evaluating the basic physiochemical properties, stability, in vitro degradation and cell behaviors, in vivo degradation and osteogenesis of the porous materials. In an attempt to reveal the osteogenetic mechanism of calcium carbonate, aside from in vivo osteogenesis, the in vitro and in vivo bioactivity of the calcium carbonate with different crystal form and crystallinity will be studied. The porous calcium carbonate-based bone repair materials, which this project aim to prepare, is promising as another appropriate choice for filling and repairing the bone defects.