Surface modification of stent material: experimental study of adhesion and migration of human aortic endothelial cells on stent material

To evaluate the relative adhesion and migration rate of cultured human aortic endothelial cells on to modified stent material in vitro. Flat 1 X 1 cm square, stainless steel 316L pieces(600 μm thick) were initially glow discharged to increase the polarity of the metal and were coated with 1% poly hydroxyethylmethacrylate to which two different amino acid peptide sequences (GRGDY, GREDVY) were covalently linked via an amide to an amino-terminus, thus providing a known orientation of these covalently bound peptides. To stimulate implantation of a stent onto the intact arterial wall, human aortic endothelial cells were seeded and grown to confluence on thick, firm collagen gel. The peptide coated steel pieces were then implanted on this endothelialized surface and migration of HAEC to the surface was monitored and measured for ten days. The contact angle of steel was measured before and after glow-discharge treatment. Our results indicate that the migration and adhesion rate of HAEC to surfaces bearing either GRGDY or GREDVY adhesive peptide sequences was significantly higher than that of uncoated stainless steel. The contact angles of glow-discharged steel (either positive or negative charge) were significantly lower, and this indicates the increased wettability of steel. Furthermore, migration to a GREDVY-coated surface was greater than to one coated with GRGDY. These results indicate that a specific peptide sequence (GREDVY), together with positive glow-discharge treatment of steel can selectively enhance endothelial cell migration to metallic stent material