Surface-attached polymer monolayers for the control of endothelial cell adhesion

The goal of this work is to alter the properties of glutaraldehyde modified porcine heart valves in such a way that vital endothelial cells can grow on the implant surfaces. Our approach to achieve this goal is to mask glutaraldehyde residues on the valve surfaces with a layer of hydrophilic polymers. In order to find suitable polymers for endothelial cell attachment to such surfaces, firstly model studies were carried out in which polymer monolayers were covalently attached to glass surfaces. A photochemical approach proved to be well-suited for this study. The layer thickness of the films is mostly determined by the molecular weight of the polymer and varied from about 3 to 26 nm. These layers were tested for the adhesion and the growth of endothelial cells from humans (HUVECs) and fibrocytes from animals (sheep, rat) for comparison. Some polymers were identified, e.g. poly(2-ethyl-2-oxazoline) (PEtOx), poly(ethyleneimine) (PEI), Poly(2-(methacryloyloxy)ethyl trimethylammonium chloride) (PMTA), poly(methacrylic acid) (PMAA), that promote the formation of a dense layer of healthy endothelial cells.