Endothelialization of synthetic surfaces has been challenging with limited success thus far. We investigated the hypothesis that covalent attachment of cholesterol to polyurethane via the urethane nitrogen groups would create a high-affinity surface for attachment and adhesion of endothelial cells. Cholesterol was covalently bound to the polyether polyurethane, Tecothane®, by first derivatizing the polyurethane nitrogen groups with bromoalkyl side chains, followed by reacting mercapto-cholesterol to the bromoalkyl sites. Cholesterol-modified polyurethane demonstrated a qualitatively smoother surface per atomic force microscopy than nonmodified and increased surface energy (contact angle measurements) compared with unmodified polyurethane. Cell attachment assays showed a significantly greater number of attached bovine arterial endothelial cells (p = 0.0003) after 45 min of seeding on cholesterol-modified polyurethane versus unmodified polyurethane. Bovine arterial endothelial cells cultivated on cholesterol-modified Tecothane® showed significantly greater levels of cell retention compared with unmodified Tecothane® when exposed to arterial level shear stress for 2 h (25 dynes/cm2) with 90.0 ± 6.23% cells remaining adherent compared with unmodified polyurethane, 41.4 ± 11.7%, p = 0.0070. Furthermore, ovine endothelial precursors, obtained as blood outgrowth endothelial cells, were seeded on cholesterol-modified polyurethane and exposed to 25 dynes/cm 2 shear conditions for 2 h, with the retention of 90.30 ± 3.25% of seeded cells versus unmodified polyurethane, which retained only 4.56 ± 0.85% (p < 0.001). It is concluded that covalently linking cholesterol to polyurethane results in improved material properties that permit increased endothelial cell retention compared with unmodified polyurethane.
- Blood outgrowth endothelial cells
- Bovine arterial endothelial cells
- Polyether polyurethane