HA/PDLLA复合材料的制备及其降解性能研究

首先采用开环聚合合成了PDLLA, 液相-沉淀法合成了HA超微粉, 然后采用液相吸附法制备了HA/PDLLA复合材料. 以纯PDLLA进行对照, 对HA/PDLLA复合材料进行体外降解实验和体内植入实验, 并进行扫描电镜观察. 结果表明HA/PDLLA复合材料较单纯PDLLA材料的降解速度减慢, 机械强度升高, 避免了过早的丧失力学强度. HA颗粒从材料表面脱落后, 成纤维细胞向组织内长入, 并伴有少量新生骨痂的形成, 显示HA/PDLLA复合材料具有良好的降解性能, 一定的成骨性和骨连接性. 24周时, HA/PDLLA材料被组织分隔包裹, 新生骨组织长入材料, 骨愈合情况良好, 具有足够的强度保证实验性松质骨骨折正常愈合.

Preparation and Biodegradability of HA/PDLLA Composites

PDLLA and HA ultra-fine powders were synthesized by the ring opening polymerization and the liquid phase deposition, respectively. HA/PDLLA composites were prepared by using the liquid phase absorption method. The degradation processes of HA/PDLLA and PDLLA were investigated in vitro and in vivo. The results show that HA/PDLLA composites have higher mechanical strength and slower degradation rate than pure PDLLA, and avoid losing mechanical strength at the initial implantation stage. The HA granules break off from the surface; fibroblast starts growing and fresh callus come into being. This indicates that HA/PDLIA composites have good biodegradability, certain bioactivity and osteoconductibility. A favorable biocompatibility can be seen on the material/bone interface. At 24^th week, the materials are separated and enwrapped by tissue, and the fracture healed up successfully. Consequently, HA/PDLLA composites have sufficient mechanical strength for the fixation of fractures and osteotomies in cancellous bone.