The effect of substrate hydrophobicity on endothelial cell adhesion

The purpose of this study was to investigate the effect of substrate surface hydrophobicity on endothelial cell adhesion strength. Bovine aortic endothelial cells (BAEC) were plated for 2 h with and without preadsorbed fihronectin (Fn) on homopolymer and copolymer coated slides of hydrophilic polyhyd roxyet hylmethacrylate (polyHEMA) and hydrophobic polyethylmethecrylate (polyEMA). The polarity of the substrata was determined from Withelmy piate contact angle measurement Two concentrations of Fn (10 p.g/mL and 1 p.g,'mL) were adsorbed onto the substrates for 1 h. The amount of adsorbed Fn was determined using 125]-Iabeled Fn. The cells were subjected to a brief exposure of laminar flow in a variable height flow chamber that provided a range of shear stresses varying from 15 to 146 dynes/cm 2. With and without preadsorbed Fn, the critical shear stress (defined as the shear stress at which 50% of the cells remained attached) increased with increasing EMA content. With the 10 p.g/mL Fn incubation concentration, the amount of adsorbed Fn increased with increasing EMA content. With the 1 p.g/mL Fn incubation concentration, the amount of Fn adsorbed was similar on all substrates. Therefore, BAEC adhesion strength is dependent on more than just the amount of Fn adsorbed (i.e. Fn conformation), and any difference in cell adhesion can ultimately be attributed to the substrate's hydrophobicity.