A study on surface endothelialization of plasma coated intravascular stents

In this study, plasma nanocoatings with thickness of less than 50nm were deposited onto two types of intravascular stents made of nitinol (NiTi alloy) and stainless steel from gas mixtures of trimethylsilane (TMS) and oxygen (O2) in a direct current (DC) plasma reactor system. The surface properties, surface morphology, and surface chemistry of the plasma coated stents were characterized using surface contact angle measurements, scanning electron microscopy (SEM), and energy dispersive spectrometer (EDS). In order to investigate their surface endothelialization effects, plasma coated stents were seeded with human umbilical vein endothelial cells (HUVECs) for cell culture study. The cell culture data showed that plasma nanocoatings deposited from a gas mixture of TMS:O2=1:3 gave rise to a statistically significant increase in adhered cell numbers, which were 79.75±6.18 on nitinol stents vs. 41.25±9.38 cells on uncoated bare controls and 119.50±12.40 on stainless stents vs. 56.85±12.53 cells on uncoated bare controls. These results evidently demonstrated that plasma nanocoatings prepared from appropriate plasma chemistry or gas composition could significantly enhance the surface endothelialization on both nitinol stents and stainless steel intravascular stents.