【摘要】 用本体开环聚合方式合成不同摩尔比的PLGA(n(dl-LA)/n(GA)分别为85/15,75/25,65/35,55/45)共聚物。1H NMR和溶解试验结果表明,共聚物中各链段呈无规分布,GA序列长度在1.3~1.8之间。通过溶液浇铸-低热模压-粒子沥滤技术构建了高度多孔的PLGA组织工程支架,考察了它们在Na2HPO4-NaH2PO4缓冲溶液中的降解行为。结果表明:随着水解的进行,PLGA的特性粘度及构建的多孔支架的压缩强度迅速下降,共聚物中GA组分含量越大,下降的速率越快,与之对应的多孔支架的多孔结构形态保持时间也随共聚物中GA组分含量增加而下降,分别为8周(n(dl-LA)/n(GA)分别为85/15和75/25)、4周(n(dl-LA)/n(GA)为65/35)和2周(n(dl-LA)/n(GA)为55/45);但质量损失速率比[η]下降速率慢得多;多孔支架的降解速率慢于薄膜的降解速率。更多还原

【Abstract】 Poly (dl-lactide-co-glycolide) s (PLGA) with different compositions were prepared by bulk ring-opening copolymerization of dl-lactide and glycolide. 1H NMR results and solubility tests indicated that the comonomers were basically randomly distributed in the copolymer chains, and the average sequence length of glycolide was in the range of 1.3 to 1.8, depending on the feed ratio of the comonomers. Tissue engineering scaffolds with high porosity were fabricated using these PLGAs by means of a modified solvent-casting/compression-molding/particulate-leaching technique, and their degradation behaviors in Na2HPO4-NaH2PO4 buffer solution (pH = 7.2) at 37℃ were studied. Both the intrinsic viscosity of PLGA copolymers and the compression strength of the scaffolds decreased very fast and became more significant as the glycolide component in the copolymers increased. The maintainable time of the morphology and structure of the scaffolds also decreased with the increasing of the glycolide component in the copolymers, with 8 weeks for PLGA 85/15 and 75/25, 4 weeks for PLGA 63/35, and 2 weeks for PLGA 55/45 respectively. Compared with the viscosity decreasing rates of the copolymers, the mass decreasing rates were slower. The degradation rates of the scaffolds were lower than those of the corresponding copolymer films.更多还原