An Assessment of Covalent Grafting of RGD Peptides to the Surface of a Compliant Poly(Carbonate-Urea)Urethane Vascular Conduit versus Conventional Biological Coatings: Its Role in Enhancing Cellular Retention

Abstract

The aim of sodding prosthetic grafts with endothelial cells (EC) is to establish a functioning antithrombogenic monolayer of EC. Application of basement membrane proteins improves EC adherence on ePTFE grafts. Their addition to a biodurable compliant poly(carbonate-urea)urethane graft (CPU) was studied with respect to EC adherence. Preclot, fibronectin, gelatin, and collagen were coated onto CPU. RGD peptide, heparin, and both RGD and heparin were chemically bonded to CPU. Human umbilical vein EC (HUVEC) labeled with 111-Indium oxine were sodded (1.8 × 10⁶ EC/cm²) onto native and the modified CPU. The grafts were washed after 90 min and EC retention determined. The experiments were repeated six times. EC retention on native CPU was 1.0 ± 0.2 × 10⁵ EC/cm². The application of preclot, fibronectin, gelatin, and collagen did not improve EC retention, which was 0.8 ± 0.1, 0.4 ± 0.1, 0.3 ± 0.08, and 0.5 ± 0.2 × 10⁵ EC/cm², respectively. Bonding RGD, heparin, and both RGD and heparin significantly improved EC retention to 1.9 ± 0.6, 1.7 ± 0.5, and 2.6 ± 0.6 × 10⁵ EC/cm², respectively (p < 0.01). Bonding of RGD, heparin, and both RGD and heparin accelerates and enhances EC retention onto CPU. Simple coating of basement membrane proteins confers no advantage over native CPU.