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

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(APTT),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.