Plasma-synthesised carbon-based coatings for cardiovascular applications

Current cardiovascular stent platforms interact poorly with the human vasculature and still rely on drug therapy to avoid early failure due to blood clotting. A drug-free coating technology that could fully integrate an implanted stent through a combination of hemocompatibility and differential regulation of endothelial cells and smooth muscle cells would present a clear advantage over existing clinical approaches. Plasma discharges have been used as a coating technology in a wide range of applications over the last decades. Carbon-based thin films prepared by different plasma deposition methods are usually regarded as biocompatible materials as they are able to prevent the adhesion and activation of platelets and preferentially promote the adsorption of albumin over fibrinogen. However, the available literature seldom addresses entirely the aspects of biocompatibility and the challenging mechanical demands of such materials for stent coating. Recent advances suggest that plasma enhanced chemical vapour deposition can be used to prepare carbon-based thin films that allow for the linker-free immobilization of bioactive molecules. If successfully applied to a stent these coatings could represent a step towards stent specific biofunctionalization. This review examines the feasibility of using plasma discharges for the synthesis of carbon-based biocompatible materials for cardiovascular implantable devices, particularly stents