Extending the Biocompatibility of Polyurethane Surfaces in Blood Contact by Pulsed Laser deposited Thin Films

Polyurethane (PU) plastics are commonly used for artificial human implants in blood contact, like stents, artificial heart valves or hearts. Their major advantage is the easy and cheap manufacturing process. Although large efforts are taken to improve the topography, morphology and chemistry of their surfaces there is still lack in blood-contact biocompatibility for long-term implantation in the human body. Besides the coating of PU surfaces by organic films, the application of metal and ceramic films seems to allow improvements of these properties. Until now, the low temperature resistance of PU plastics as well as the high deformability cause problems in vacuum coating by PVD and CVD coating techniques. Using the pulsed laser deposition (PLD) technique for room temperature coating (RT-PLD), these restrictions can be overcome. The current work focuses on the development of thin inorganic PLD titanium films on PU substrates and the characterization of their surface topography, biocompatibility in contact to fibroblast cells. All results reveal a very high adhesion of the films due to the surface penetration of high-energetic vapor particles during deposition, extremely smooth film surfaces allowing the reproduction of the initial PU surface, and a strongly decreased tendency to cell adhesion.