含悬挂羧基手臂聚乳酸材料的合成与血小板粘附性研究

制备了乳酸-β-苹果酸共聚物,并在此基础上进一步修饰合成了含悬挂羟基(PLMAHE)以及悬挂羧基(PCA-PLA)的聚乳酸共聚物,利用原子力显微镜及环境扫描电镜,观察了聚合物膜的表面形貌以及粘附在聚合物膜上的血小板数量与形态.结果表明含悬挂羟基材料表面粘附血小板时发生聚集并有伪足生成,含悬挂羧基材料表面血小板粘附数量较少且形态正常,有望成为优良的抗凝血材料.

SYNTHESIS AND PLATELET ADHESION CAPACITIES STUDY OFFUNCTIONALIZED POLYLACTIDES WITH PENDANT CARBOXYL ARMS

The use of synthetic vascular for cardiovascular and cerebrovascular tissue engineering has made tremendous progress in the past thirty years,but the clinical use of vascular conduits with diameters less than 6 mm remains unsuccessful because of the thrombus formation.Poly(lactic acid) (PLA) was well-suited for applications as tissue engineering materials due to their good biocompatibility and biodegradability.To improve the blood compatibility of polylactide,three polymers based on PLA and poly(malic acid) were synthesized by ring-opening polymerization,namely poly(lactide-co-β-malic acid) (PLMA),poly(lactide-co-RS-hydroxyethyl-b-malolactonate) (PLMAHE) and PLA with pendant carboxyl arms (PCA-PLA).The structure,composition and molecular weight of the copolymers were confirmed by 1H-NMR and GPC.AFM was first used to observe the morphology of the adhered platelets on the polymer films.The platelet adhesion amount on the polymer films was calculated by Hematology Analyzer.The results showed that the copolymers with functional side chains especially with pendant carboxyl arms could obviously reduce the platelet adhesion capacity on the copolymer films compared with PLA.The platelet amount adhered on PLA,PLMA and PLMAHE was 3.2×10~3,2.5×10~3 and 1.8×10~3 after 30 min,respectively,and there was few platelets adhered on the film with pendant carboxyl arms after 1 hour.The thickness of polymer films was determined by AFM,all films of each polymer were about 50 nm thick.From the images of AFM and SEM,it could be seen that only the polymer with hydroxyl groups could activate the platelet.In conclusion,the copolymer with pendant carboxyl was a hopeful material for vessel substitution with good blood compatibility.