PROTEIN ADSORPTION OF POLY(ETHER URETHANE) SURFACES MODIFIED BY AMPHIPHILIC AND HYDROPHILIC POLYMERS

A commercial biomedical poly(ether urethane), Pellethane 2363-80AE, wa s surface modified through the use of amphiphilic polymeric additives, and through surface grafting with poly(ethylene glycol), PEG. Two dif ferent amphiphilic polymers, Polymer C and Pluronic PE9400, were used as additives. Polymer C, a segmented polyurethane, was prepared from P EG1500, 4,4'-diphenylmethane diisocyanate and a C-16-C18 monoglyceride chain extender. Pluronic PE9400 is a propylene oxide-ethylene oxide t ri-block co-polymer obtained from BASF. Adsorption of human albumin an d fibrinogen to the modified surfaces was studied by means of radiolab elled proteins. By contact angle measurements and X-ray photoelectron spectra the amphiphilic polymers were shown to accumulate at the polyu rethane surfaces. Adsorption of fibrinogen, in particular, was signifi cantly reduced by the amphiphilic additives to levels similar to those obtained for Pellethane surfaces grafted with PEG 20000. In vitro clo tting times for citrate-buffered blood in contact with the amphiphilic surfaces increased as compared with the unmodified ones.