Faculty of Engineering and Information Technologies, School of Aerospace, Mechanical and Mechatronic Engineering
Abstract
Modification of surfaces to improve the thrombo-resistance of a synthetic biomaterial is a vital aspect in the design of haemocompatible surfaces. Recent work suggests a non-haemocompatible surface may ubiquitously adsorb specific plasma proteins that form a proteinacious layer which mediates the adhesion and activation of platelets and rejection of the material and subsequently, the implanted medical device. Currently, apart from surface chemistry and wetability of the surface, preferential adsorption of specific proteins, their exact interaction and the effect of physical and spatial cues from the nano-environment prevents us from acknowledging a general interplay between biomaterials, proteins and platelets. Thus this study aims to investigate the effect of plasma protein adsorption and subsequent platelet interactions on the smooth and nano-patterned commercially used surface coatings such as hydrogenated amorphous carbon (a-C:H), tetrahedral amorphous carbon (ta-C) and titania (TiO2) surfaces. Results have shown a-C:H and ta-C surfaces exhibited increased affinity to fibrinogen than TiO2, while facilitating similar levels of platelet attachment. A-C:H resulted in decreased cellular spreading when compared with ta-C and TiO2, while same level of platelet activation was detected indicating that platelets could exist in their activated state without spreading. When platelet interactions on nano-patterned surfaces (RMS 5-8nm) were compared against flat surfaces, nano-rough surfaces presented with increased levels of platelet attachment as well as its spreading, while similar levels of platelet activation was detected amongst the smooth and rough substrates. Increased levels of platelet adhesion and spreading were positively correlated with increased fibrinogen adsorption, reinforcing the crucial role of fibrinogen in platelet binding but also its possible role in platelet spreading
