【摘要】 采用磷酸盐缓冲溶液(PBS)(pH=7.4)为降解介质,37℃下对可分解食道支架聚(L-丙交酯)(PLLA)和聚(乙交酯-丙交酯)(PGLA)缝合线进行8周的体外降解实验。通过测试降解过程中其质量损失、pH值、特性粘度、抗张强度、取向度、结晶度、熔点及表面形貌等变化情况,对其体外降解行为进行研究。结果表明PLLA缝合线各项性能无明显变化,而PGLA缝合线各项性能发生了显著变化。随着降解进行PGLA缝合线的pH值、特性粘度、抗张强度、取向度和结晶度逐渐下降,质量损失率增加,6周时抗张强度几乎为零,8周时质量损失率近70%。DSC结果表明,随着体外降解PGLA缝合线晶区熔点保持不变,晶区的熔融热焓逐渐增加,而无定形区产生新的有序区.并且含量不断增加。SEM结果表明PGLA缝合线在降解过程中,涂层首先脱落,然后线体以横向断裂方式断裂。因此,PGLA缝合线适用于良性食道狭窄的可分解食道支架,而PLLA缝合线制备的支架分解时间大于2个月,不适于良性狭窄的治疗。更多还原

【Abstract】 Poly(L-lactide)(PLLA) and poly(glycolide-co-lactide)(PGLA) sutures for decomposable esophageal stent were investigated in phosphate buffer solution(PBS)(pH=7.4) at 37℃ for period of 8 weeks.The in vitro degradation was studied by determining the change of weight loss,pH value,intrinsic viscosity,tensile strength,orientation degree,degree of crystallinity,melting point and surface morphology of the suture samples.The results showed that all properties of PLLA sutures had no obvious changes in 8 weeks,however,the properties of PGLA sutures all changed significantly.The pH value,intrinsic viscosity,tensile strength,orientation degree and degree of crystallinity decreased gradually,but the weight loss of PGLA sutures increased with the increase of degradation time.At 6th week,tensile strength of PGLA sutures nearly reached zero,and weight loss approached to 70% at 8th week.The results of DSC showed that melting point of crystalline region of PGLA sutures substantially remained unchanged and melting heat enthalpy increased gradually during in vitro degradation,and the new ordered regions appeared in the amorphous area.The results of SEM showed that surface coating of PGLA sutures spalled initially,and then the sutures occured transverse rupture.Therefore PGLA suture is suitable to prepare decomposable esophageal stent to expand benign esophageal stenosis or stricture,but stent prepared by PLAA suture is not appropriate for treatment of benign esophageal stenosis because it is decomposed for more than 2 months.更多还原