Cholesterol‐derivatized polyurethane: Characterization and endothelial cell adhesion

Abstract

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/cm2 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.

Regulation of polyurethane hemocompatibility and endothelialization by tethered hyaluronic acid oligosaccharides

“…Thus, numerous studies have addressed this deficiency via several types of PU surface modification. [40][41][42][43][44][45][46]. PU has been treated with gas plasma to improve EC adhesion and growth [42], although such a treatment also risks increasing the non-specific attachment of undesirable proteins and cells.…”

Endothelial delivery of antioxidant enzymes loaded into non-polymeric magnetic nanoparticles

“…Bovine aortic endothelial cells (BAEC) were obtained as previously described [20] and cultured in DMEM (Mediatech, Inc., Herndon, VA, USA) supplemented with 10% fetal calf serum. Primary human umbilical vein endothelial cells (HUVEC, Clonectics, San Diego, CA), 4th passage, grown to near confluence were cultured on 1% gelatin-coated 24 well plates.…”

CD47-dependent molecular mechanisms of blood outgrowth endothelial cell attachment on cholesterol-modified polyurethane

“…A number of novel alterations to PU has been attempted to alleviate these problems. Our group synthesized and characterized a bulk-modified PU configured with mercapto-cholesterol (PU-Chol) via bromoalkylation of hard segment urethane nitrogen [4, 13]. Analysis of the physical properties of PU-Chol films revealed that the addition of cholesterol moieties to PU increased the surface hydrophobicity and decreased the surface roughness [4].…”