Investigation into the mechanism of bacterial adhesion to hydrogel-coated surfaces

As a model for hydrogel-coated biomaterials, self-assembled monolayers of p olyoxyethylene (POE) derivatives on sheets of polymeric biomaterials were p repared. The POE derivatives consisted of hydrophilic chains with different lengths and a long-chain alkyl group that served as an anchor function. Th e coatings obtained were analyzed with XPS and contact angle measurements s howing hydrophilic chains of different lengths extending away from the surf ace. Bacterial adhesion was measured with a clinically relevant Klebsiella pneumoniae type strain and measurements reproduced 12 times. Bacterial adhe sion decreased markedly with increasing hydrophilic chain length. Based upo n these findings a new model for bacterial adhesion to hydrogel-coated surf aces is suggested: steric repulsion effects that increase with increasing c hain length of grafted hydrophilic chains play an important role in bacteri al adhesion to hydrogel-coated surfaces. (C) 1999 Kluwer Academic Publisher s.