Haemocompatibility of tetrahedral amorphous carbon films

Tetrahedral amorphous carbon (ta-C) films have been prepared by filtered arc deposition (FAD). The structure of the ta-C films was characterised by Raman Spectroscopy. The haemocompatibility of the formed films was studied by measurement of haemolysis ratio and observation of platelet adhesion. Compared with low-temperature isotropic pyrolytic carbon (LTI-carbon), which is being used as the material for artificial heart valves in clinical use at present, the ta-C films showed improved anticoagulation property. In order to understand the observed haemocompatibility results, the surface energy of the films was evaluated to analyse surface adsorption of human serum albumin (HSA) and human fibrinogen (HFG). However, it was found that the ta-C films are identical to LTI-carbon with respect to protein adsorption. It is believed that effective work function could be a reason for the observed variation in haemocompatibility between the ta-C films and LTI-carbon.