Polyurethane surfaces modified by amphiphilic polymers: effects on protein adsorption

Surface modification of polyurethane (PUR) surfaces was carried out by using three different amphiphilic polymers. Two of the polymers were graft copolymers, having backbones consisting of poly(methyl methacrylate-co-ethylhexyl acrylate) and poly(styrene-co-acrylamide), respectively, and poly(ethylene oxide) PEO 2000 grafts. The third polymer was a commercially available poly(ethylene oxide-b-propylene oxide-b-ethylene oxide) block copolymer, Pluronic 9400. The polymers were designated ACRY, STY2, and PE94, respectively. Surface modification was achieved by adsorption of the amphiphilic polymers at PUR surfaces from an aqueous solution, or by blending the amphiphiles into a PUR solution, followed by solution casting of films. The accumulation of the amphiphilic polymers at the PUR surfaces was observed by XPS and contact angle measurements. The ACRY and PE94 polymers were shown to adsorb poorly at the PUR surface, but gave strong surface effects when present in the PUR matrix. Protein adsorption was measured under static as well as under flow conditions. The modified surfaces had generally lower adsorption of blood proteins (HSA, Fg and IgG) than the unmodified PUR surfaces. ACRY blend modified surfaces had the lowest adsorption.