Non-equilibrium organosilane plasma polymerization for modulating the surface of PTFE towards potential blood contact applications
We report a novel and facile organosilane plasma polymerization method on widely used biomaterial poly(tetrafluoroethylene) (PTFE). More specifically, low temperature organosilane plasma polymerization method was designed to improve the surface characteristics of PTFE. We hypothesized that the polymerized silane coating imparts a highly adhesive surface for endothelial cells proliferation due to the very high amount of surface hydroxyl groups, while the large polymer networks formed over the surface of PTFE may offer very high steric hindrance for the platelets to attach. The plasma polymerized PTFE surfaces were then systematically characterized via different analytical techniques such as FTIR, XPS, XRD, Confocal Laser microscopy and SEM. The results of these characterizations have clearly suggested the successful plasma polymerization and subsequent deposition of an organiosilane layer on the surface of PTFE. This silane surface modification was found to endow favorable surface properties (specifically, enhanced cytocompatibility) to PTFE such as very high surface oxygen content, superhydrophilicity and improved surface mechanics. Endothelial cell proliferation assay (MTS), live dead staining, protein adsorption, and platelet adhesion studies performed on these silane plasma polymerized PTFE surfaces. They have exhibited high endothelial cell attachment with minimal platelet adhesion/thrombus formation. Thus, the reported new surface modification technique was found to address the current challenge associated with PTFE for blood contact applications, specifically lack of rapid endothelial cell growth and thrombosis.