DESIGN OF NONTHROMBOGENIC POLYMER SURFACES FOR BLOOD-CONTACTING MEDICAL DEVICES

Although significant progress has been made in the design of blood-com patible polymers in the past decades, there is no ideal polymer surfac e which is comparable with a natural endothelial surface in preventing surface-induced thrombosis and maintaining hemostasis. This is due to the complex pattern of protein and cellular interactions with foreign surfaces, which still demands defining a proven hypothesis to develop non-thrombogenic surfaces, Synthesis of new polymers with optimal mec hanical properties and the in vitro and in vivo characterization of th ese surfaces will require many more years of work. In this article, th e surface modification of existing medical polymers for the improvemen t of blood compatibility is introduced, Surface immobilizing of hepari n onto polyurethane, coatings of a polyurethane-poly(ethylene oxide)-h eparin graft copolymer, and a coating of thermosensitive polymers on p olyurethane will be discussed, All modified surfaces demonstrated supe rior blood compatibility both in vitro and in vivo, The biological res ponse of these designed systems in vitro, ex vivo and in vivo should p rovide state-of-the-art materials for the specific application of cont rolling thrombosis and solving biocompatibility problems.