Surface biocompatible construction of polyurethane by heparinization

A macromolecular biocompatible surface modifier for polyurethane (PU), namely, polyurethane-block-poly (chloromethyl styrene) (PU-b-PCMS) copolymer, was synthesized by coupling hydroxyl-terminated PCMS with diisocyanate-terminated PU and further quaternizing. The synthesized surface modifier was blended with PU and heparin was absorbed on PU surface by ion exchange. The modification effectively increased the hydrophilicity and water absorption of PU. To evaluate the hemocompatibility of the modified blend films, the extent of platelet adsorption, plasma recalcification time and hemolysis were measured. To determine if the blend films were toxic to mammalian cells, viability of the cells cultured on the blend films was assayed. All results indicated that the blood and cell compatibilities of the PU films were improved significantly after entrapment of a few quaternized PU-b-PCMS copolymers into PU and further heparinizing.