[Blood compatibility of two novel polyurethane coating materials]

Amphiphilic coupling-polymer of stearyl poly (ethylene oxide)-co-4, 4'-methylendiphenyl diisocyanate-co-stearyl poly(ethylene oxide), MSPEO, was specially designed as surface-modifying additives. The blends of MSPEO in both polyether urethane (PEU) and chitosan(Chi), as the coating materials for intravascular device were investigated. Two kinds of static clotting time tests, plasma recalcification time (PRT) and prothrombin time(PT), as well as the static platelet adhesion experiment were carried out. And the dynamic anti-coagulation experiment was performed with a closed-loop tubular system under a blood shear rate of 1,500 s-1. The results demonstrate that both blend coatings can improve the anti-coagulation of polyurethane greatly and will not lead to hemolysis, and that more platelets adhere to the surface modified by Chi-MSPEO blend coating as compared with those adhere to the surface modified by PEU-MSPEO blend coating. The surface modified by Chi-MSPEO has longer PRT, whereas the surface modified by PEU-MSPEO has longer PT.