左旋聚乳酸-聚三亚甲基碳酸酯共混物的降解特点和生物相容性的实验研究

The experimental study of PLLA-PTMC on degradation characteristics and biocompatibility

目的制备出左旋聚乳酸-聚三亚甲基碳酸酯(PLLA-PTMC)共混物的成型栓棒,研究其降解性能和生物相容性,探讨该栓棒作为生物可降解骨折内固定材料的可能性。方法选用分子量为16×10^4的左旋聚乳酸(PLLA)与不同的相对分子质量的聚三亚甲基碳酸酯(PTMC),采用热熔加压成型的方式制备二者的共混物栓棒。将PLLAPTMC共混物栓棒分别置于磷酸盐缓冲液(PBS)、脂肪酶溶液、成年新西兰大白兔股骨髁内,定期观察栓棒的表面形貌并测量各个时期的失重率变化,探寻其体内外降解规律。结果①在同一种降解环境下,PTMC的相对分子质量越高,该共混物降解越快。②三种不同的降解环境中,脂肪酶中共混物降解最快,动物体内次之,降解速率都较为理想,但PBS中共混物降解缓慢,PBS中共混物在16周内质量损失率最大不超过3%。相对分子质量为330×10^3的PTMC与PLLA共混物栓棒在脂肪酶中降解16周后质量损失率达到了79.48%,在动物体内降解16周后质量损失率达到了61.35%。③试件在植入8周后,植入物周围组织已经基本恢复正常。结论①PLLA-PTMC共混物具有良好的降解性能,其降解速率受PTMC的相对分子质量及降解环境等多种因素的影响。②PLLA-PTMC共混物具有良好的生物相容性。

Objective PLLA-PTMC is made into a plug by hot forming process to study its degradation characteristics and biocompatibility,and explore the possibility of the plug as a biodegradable fracture fixation material.Methods The hot-forming plug is made by PLLA with a molecular weight of 16×10^4 and PTMC with different relative molecular mass.The plug was soaked in rabbits,phosphate buffer and lipase solution.Exploring its degradation laws by observing the morphology and mass loss regularly.Results①Under the same environment,the higher the molecular weight of PTMC,the faster the degradation.②Among the three different environments,the plug degrades fastest in lipase,and the degradation rate is moderate in the animal body,but the degradation rate of the plug in PBS is slow,and the maximum mass loss rate of the plug in PBS within 16weeks is not more than 3%.When the PTMC with a relative molecular weight of 330×10^3,the mass loss rate of plugs after degradation in lipase for 16weeks reached 79.48%,and after degradation for 16weeks in rabbits,the mass loss rate reached 61.35%.③After 8weeks of implantation,the tissues around the implant have basically returned to normal.Conclusion①PLLA-PTMC has good degradation performance,and its degradation rate is affected by various factors such as the relative molecular mass of PTMC and the degradation environment.②PLLA-PTMC has good biocompatibility.