Abstract
The interaction of a glycol-containing polyurethane, Hydrothane®, was assessed with respect to protein adsorption and cell and bacterial adhesion. The results obtained were compared with those from a second polyurethane, Chronoflex®. Dynamic contact angle (DCA) and protein adsorption studies indicated that the overall hydrophilic nature of Hydrothane in a physiological environment was affected by the possible presence of hydrophobic domains still exposed at the surface after wetting. Indeed, despite the high degree of hydrophilicity in an aqueous environment, a stronger protein binding was evidenced on Hydrothane when the two serum- and urine-conditioned polyurethane surfaces were selectively washed by isopropanol/water mixtures of increasing concentrations. Furthermore, immunoblotting of the serum proteins adsorbed on Hydrothane demonstrated the presence on its surface of proteins able to establish hydrophobic interactions such as human serum albumin (HSA) and a1-microglobulin (a1-m). The C3 fragment of complement showed an immunoblotting profile different from the control serum suggesting an activation of this fragment. The adhesion of fibroblasts and Pseudomonas aeruginosa on the surface of the two materials was evaluated and the data were related to protein adsorption. In both cases Hydrothane showed levels of adhesion of eukaryotic and prokaryotic cells significantly lower than Chronoflex. These data were related to the absence of a significant binding of proteins such as fibronectin bringing amino acid receptor sequences in their structure.