Effects of amide and amine plasma-treated ePTFE vascular grafts on endothelial cell lining in an artificial circulatory system

We sought to examine whether surface modification of expanded polytetrafluoroethylene (ePTFE) vascular grafts might extend graft patency without modifying the graft structure. Amide and amine plasma (butylamine) were applied to graft surfaces using radio frequency glow discharge. Surface analyses by Fourier transform infrared spectroscopy-attenuated total reflectance, X-ray photoelectron spectroscopy, and dynamic contact angle measurements revealed the presence of nitrogen-containing functional groups on the plasma modified graft surfaces, along with an increased surface hydrophilicity. Bovine aortic endothelial cells were seeded on amide and amine plasma coated ePTFE vascular grafts and placed inside an artificial circulatory system under well-defined flow conditions. The seeded endothelial cells were exposed to either constant or pulsatile flow condition for 5 days. Their corresponding maximum wall shear stresses were 1 dyn/cm2 under constant flow and 65, 108, and 259 dyn/cm2 under various pulsatile flows. Plasma modified ePTFE vascular grafts enhanced the endothelial cell lining under constant and pulsatile flow conditions. Fluorescence nuclear staining, scanning electron microscopy, and histological staining indicated the formation of an endothelial cell monolayer on the plasma coated graft surfaces.