Effect of sulphonate incorporation on in vitro leucocyte adhesion to polyurethanes

A series of poly(tetramethylene oxide)-based polyurethane block copolymers was synthesized with varying levels of sulphonate ion incorporated in the hard segment block. Static in vitro adhesion of polymorphonuclear leucocytes (PMNs) on the underivatized and propyl sulphonate-grafted polyurethanes was investigated. The effect of plasma proteins on PMN adhesion to the polymers was also examined. The number of adherent cells on the sulphonated polyurethane surfaces was significantly higher than on the underivatized polyurethane under all conditions. The adherent PMNs on sulphonated polyurethanes showed increased cell spreading compared to the underivatized base polyurethane. Increasing the level of sulphonate incorporation from 5 to 17mol% had no effect on the extent of cell adhesion. The presence of preadsorbed proteins generally led to a decrease in the number of adherent PMNs on the surfaces. However, the presence of plasma proteins in the suspension medium had no effect on the degree of leucocyte adhesion to the sulphonated polyurethanes.