Figure 2. Optimat coated ePTFE tubings show better hydrophilicity.

Water contact angle measurements of untreated ePTFE tubings and after each stage of treatment are shown in (A). Acid-treatment and OptiMat-coating (74 ng/cm²) reduced the contact angle to as low as 70° indicating conversion of hydrophobic surface (water contact angle 125°) to a hydrophilic surface (water contact angle 70°). For easy visualization of cells, we used transparent polystyrene capillaries with similar hydrophobic properties to that of ePTFE tubings. We observed that endothelial cells show minimal attachment to untreated surfaces (B) but better adhesion and growth over acid-treated and OptiMat-coated surfaces (C). White dotted boxes in capillary images on left side in (B,C) are enlarged to visualize cell growth (shown on right side) in each capillary.