The effect of fluid sheer stress on endothelial cell adhesiveness to polymer surfaces with wettability gradient

In this study, the adhesive strength of endothelial cells (ECs) attached on polymer surfaces with different hydrophilicity was investigated using wett ability gradient polyethylene (PE) surfaces prepared by corona discharge tr eatment from a knife-type electrode whose power increases gradually along t he sample length, The EC-attached wettability gradient surfaces were mounte d on parallel-plate flow chambers in a how system prepared for cell adhesiv eness test, Three different shear stresses (150, 200, and 250 dyne/cm(2)) w ere applied to the flow chambers and each shear stress was maintained for 1 20 min to investigate the effect of shear stress and surface hydrophilicity on the EC adhesion strength, It,vas observed that the ECs were adhered mor e onto the positions with moderate hydrophilicity of the wettability gradie nt surface than onto the more hydrophobic or hydrophilic positions, The max imum adhesion of the cells appeared at around water contact angles of 55 de grees. The EC adhesion strength was higher on the hydrophilic positions tha n on the hydrophobic ones. However the maximum adhesion strength of the cel ls also appeared at around water contact angles of 55 degrees, More than 90 % of the adhered cells remained on that position after applying the shear s tress, 250 dyne/cm(2) for 2 h, whereas the cells were completely detached o n the hydrophobic position (water contact angle, about 86 degrees) within 1 0 min after applying the same shear stress. It seems that surface hydrophil icity plays a very important role for cell adhesion strength. (C) 2000 Acad emic Press.