聚磷酸钙/左旋聚乳酸软骨组织工程支架复合材料的分析

背景用左旋聚乳酸(PLLA),聚羟基乙酸(PGA)等可降解吸收性高分子材料加工而成的纤维状支架材料和海绵状支架材料在软骨组织工程中已获得广泛应用.但这类支架材料存在着弹性模量低,受力时易变形,容易导致种子细胞损伤和降解吸收时间过长等缺陷.目的研制出可任意调控降解速率且具有良好力学性能、生物相溶性能和毒理学性能的聚磷酸钙(Calcium Polyphosphate,CPP)纤维,并用该纤维为增强材料研制软骨组织工程复合材料.设计以不同质量比例分组对照的实验研究.地点和对象实验在兰州交通大学材料工程研究所完成,基体材料选用PLLA(中科院化学所高分子合成室提供),增强材料选用自制CPP纤维.干预以高强度、高模量可设计降解速率的CPP纤维为增强材料,PLLA为基体材料,应用溶媒投放、颗粒滤取技术制备出CPP/PLLA软骨组织工程支架复合材料,测试了该支架复合材料的物理力学性能和体外37℃下Hank's人工降解液中的生物降解特性.主要观察指标物理力学性能,降解性能.结果CPP/PLLA支架复合材料具有三维连通、微孔、网状微观结构,微孔分布均匀,微孔尺寸为130～350μm,孔隙率90%;压缩模量随CPP纤维体积分数的增加而增加;降解速率随CPP纤维体积分数的增大而增大.结论CPP/PLLA支架复合材料的物理力学性能和体外降解性能在体外构建的组织化软骨的早期生物学性能基本满足软骨组织工程的要求,故可用作软骨组织工程支架材料.

Analysis of calcium polyphosphate/poly (L-lactic acid) cartilage-tissue engineering scaffold composite

BACKGROUND: Although fibriform and spongy scaffold made of degradable macromolecular materials like poly(L-lactic acid) (PLLA) and polyglycolic acid(PGA) has been greatly used , its shortcomings are obvious, such as low elastic modulus, deformable by force, inducing implanted cell injury,and delayed degradation speed.OBJECTIVE: To find a calcium polyphosphate (CPP) fiber with controllable degradation speed, good mechanical characteristic, biocompatibility and toxicological characteristic and to make cartilage tissue engineering composite with this fiber as enhancing agent.DESIGN: Different mass proportion grouped and controlled experiment was conducted.SETTING and PARTICIPANTS: The experiment was conducted in the Institute of Materials Engineering, Lanzhou Jiaotong University. The basic materials were PLLA(from Department of Polymer Synthesis, Institute of Chemistry, Chinese Academy of Sciences) and the enhancing material of CPP made by the authors.INTERVENTIONS: To make CPP/PLLA cartilage tissue engineering scaffold from PLLA as basic material and CPP as enhancing agent which has high strength and modulus, and predisposed degradation speed as well. The method adopted was solvent adding and granule extraction. The scaffold mechanics characteristic and in vitro biodegradation in Hank' s solution at 37 ℃ were tested.MAIN OUTCOME MEASURES: Mechanical characteristic and degradation characteristic.RESULTS: Microstructure of PLLA composite was full of 3 dimensionally interconnected microsopical net feature with evenly distributed micropores,whose size was 130-350 μm and aperture ratio of 90%. Its compression modulus and degradation speed increased as the CPP fiber fraction increased.