ELLIPSOMETRIC STUDIES OF ANTISERA BINDING ONTO MEDICAL POLYURETHANES IMMERSED IN HUMAN PLASMA IN-VITRO

The plasma protein binding properties of four medical polyurethane mat erials were investigated. The polymers were Pellethane 2363-80AE, etha nol extracted Pellethane, a poly(ether urethaneurea) with a compositio n similar to Biomer and containing an acrylic polymer additive, and th e same polymer without the additive. The polymers were cast onto silic on wafers and then immersed in human plasma from solution followed by antisera. The deposition of organic material was measured with ellipso metry. All tested polymers displayed low anti-high molecular weight ki ninogen (alpha-HMWK), anti-Factor XII (alpha-F XII), and anti-fibronec tin (alpha-FN) depositions. Polymers containing additives also showed significantly lowered binding of anti-fibrinogen (alpha-FG). The resul ts show that protein binding to the tested polyurethane surfaces were largely modulated by surface active processing aids, and can be conven iently analysed using antisera techniques.