Immobilized Phospholipid Analogs for Hemocompatibility

The materials used currently in blood-contacting medical devices must be improved to reducethrombosis, embolization, complement activation, and device-centered infection. The long-term objectiveis to prepare surfaces which reduce thrombogenesis by mimicking the nonthrombogenic externalmembrane of the red blood cell, which contains a high concentration of phosphorycholine (PC)-contain-ing lipids. Technologies have been developed by other investigators to prepare PC-containing surfaces(which do indeed show improved interactions with blood components), but they are not applicable tomany polymers nor are they simple to apply in a manufacturing setting. The proprietary photochemicalcoupling techniques presented herein overcome these limitations. PC derivatives, compsed of aphotoactivatible moiety couple to phosphatidylcholine analogs, will be synthesized and immobilized ontopolyethylene, polyurethane, and silicone rubber. ESCA, SSIMS, and contact angles will be used todetermine the presence and uniformity of the PC on the substrates; in vitro protein adsorption andplatelet adhesion and activation assays, and acute, jugular vein implants will be conducted to screen thesurfaces for improvements in blood compatibility. If the results of these assays are favorable, theobjective of the Phase II project will be to examine the performance of PC surfaces in medium and longterm animal implants.