壳聚糖/肝素共价包被先天性心脏病介入封堵材料血液相容性的体外试验研究

Hemocompatibility of biomaterial designed for the closure of congenital heart defects covalently coated by chitosan/heparin:an evaluation in vitro

目的:体外评价壳聚糖/肝素(Chi/Hep)共价包被先天性心脏病介入封堵材料的血液相容性。方法:实验分成血液对照组、未包被组、基础包被组(壳聚糖)、Chi/Hep包被组,其中按肝素浓度又分为低又分为低、中、高(0.1、1.0、10.0g/L)3个剂量组。Chi/Hep共价交联于试验用镍钛金属表面,通过血液溶血试验,观察红细胞细胞毒性;动态全人血接触试验检测各样本部分凝血活酶活化时间(APTT)、凝血酶原时间(PT)、纤维蛋白原、凝血酶时间(TT)、D-二聚体观察其抗血栓性能;扫描电子显微镜观察镍钛金属表面血小板黏附、聚集。结果:实验各组红细胞、白细胞、血小板计数均在正常范围内且组间未见明显差异,实验组溶血率均小于5%。Chi/Hep包被组APTT、PT、TT、均明显延长,其余各组两两比较未见明显差异,肝素浓度包被之间差异亦无显著性。扫描电镜显示,Chi/Hep包被组金属表面少量血小板黏附。结论:Chi/Hep包被先天性心脏病介入封堵材料有利于预防血栓形成,减少血栓形成风险。

Objective：To assess the hemocompatibility of biomaterial covalently coated by chitosan/heparin designed for the closure of congenital heart defects in vitro. Methods：Chitosan （Chi）/heparin （Hep） was covalently immobilized onto the surface of Nitinol slices. The hemocompatibility of biomaterials was evaluated by using the hemolysis test. Anticoagulant activity was studied in vitro in a dynamic model with whole blood, and partial thrombin time（APTY）, prothrombin time（PT）, fibrinogen time, thrombin time（TT） and D-Dimer respectively. Surface characterizations such as protein adsorption and platelet adhesion were performed by using scanning electron microscopy. Results：White blood count, red blood count and platelet count （PC） were all in normal range and there were no evident difference in each group. The hemolysis rates of biomaterials was all less than 5%. Chi/Hep did significantly prolong the APTT, PT, and TT. In addition, the APTT, PT, and TT in groups coated with different concentration of Hep showed no significant difference. The immobilization of Chi/Hep caused the protein adsorption, platelet adhesion, and thrombus formation were all reduced by the immobilization of Hep. Conclusion：In vitro hemocompatibility of biomaterials designed for the closure of congenital heart defects can be improved by conjugating Chi/Hep onto the surface.