Carbon coatings for cardiovascular applications: physico-chemical properties and blood compatibility

Two different types of carbon coatings for cardiovascular applications were characterized both as regards to their physico-chemical properties and blood compatibility upon contact with human plasma and platelets. The samples were analyzed by means of a wide range of techniques, including scanning electron microscopy (SEM) and atomic force microscopy (AFM), contact angle goniometry, Raman spectroscopy and X-ray Diffraction (XRD). Multiple tests have been performed to evaluate plasma protein adsorption and platelets adhesion and activation, and to investigate possible correlations between the surface properties of the materials and their blood compatibility. We proposed a similar mechanism of blood/material interaction for the carbon-based materials tested. It has been suggested that the characteristic wettability and surface heterogeneity of the coatings guide protein adsorption and retention onto the carbon surfaces, promoting a preferential, extensive and tight adsorption of albumin molecules, that in turn leads to surface passivation and inhibits subsequent platelets adhesion and activation.