Polymers for biomedical applications:: Improvement of the interface compatibility

The true aim of biomaterials research is to create implant surfaces which interact actively with the biological system and provoke exactly the same reactions as the corporal tissues do. The improvement in the interface compatibility of polymers selected for implantation by directed surface modification is an important contribution to biomaterial development. Different polymer properties are adjusted and characterized independently of the carrier polymer by means of introduction of modern surface analytical methods and surface techniques. In addition, the interactions between the modified polymer surface and the biological system are measured. In this way, the hydrophilization of a polyurethane (Tecolex(TM)) and a poly(ether sulfone) by plasma induced graftcopolymerization of hydrogels like poly(hydroxyethyl methacrylate) leads to improved blood compatibility. Functionalization by means of SO2 plasma treatment of medical grade poly(vinyl chloride) increases the adsorption of the basal membrane protein fibronectin, which correlates with an improvement in cell growth. A suitable interface for an improved cell growth of hum an vascular endothelial cells as well as for cornea endothelial cells has been created by immobilization of the cell adhesion mediator fibronectin using bifunctional spacer molecules at several carrier polymer surfaces like smooth poly(vinyl chloride), modified polyurethane, Tecoflex(TM) and poly(dimethyl siloxane).