Albumin and fibrinogen adsorption on boron nitride and carbon-based thin films

The haemocompatibility (in the sense of the least possibility of thrombus formation/thrombogenicity potential) of homogeneous and amorphous BN (a-BN) thin films through the adsorption of two basic blood plasma proteins, human serum albumin (HSA) and fibrinogen (Fib) is explored in this work. A comparative study of the thrombogenicity potential of BN, amorphous carbon (a-C) and amorphous hydrogenated carbon thin films (a-C:H) is also presented. a-BN and a-C thin films were produced by radio frequency (RF) magnetron sputtering onto c-Si (1 0 0) substrates under various values of substrate bias voltage. a-C:H thin films were developed by RF Reactive MS, with various values of substrate bias voltage and under different values of H2 partial pressure during deposition. For the consideration of the optical, compositional and structural properties of the films Spectroscopic Ellipsometry in the energy region of 1.5–6.5 eV was used, while for the study of surface topography and wetting properties Atomic Force Microscopy and Contact Angle measurements were additionally employed. The properties of the thin films were correlated with their thrombogenicity, through the estimation of the ratio of HSA/Fib surface concentration. a-BN films exhibit the smallest possibility of clot formation, with their wetting properties determining the thickness of the Fib layer formed on them as well as the ratio of HSA/Fib surface concentration. In the case of a-C thin films, the increase of % sp3 content is crucial, while the value of the fundamental gap seems to influence the possibility for clot formation on a-C:H thin films.