Characterization of poly(ethylene oxide) brushes on glass surfaces and adhesion of Staphylococcus epidermidis

Poly(ethylene oxide) brushes have been covalently bound to glass surfaces and their presence was demonstrated by an increase in water contact angles from fully wettable on glass to advancing contact angles of 54 degrees, with a hysteresis of 32 degrees. In addition, electrophoretic mobilities of glass and brush-coated glass were determined using streaming potential measurements. The dependence of the electrophoretic mobilities on the ionic strength was analyzed in terms of a softlayer model, yielding an electrophoretic softness and fixed charge density of the layer. Brush-coated glass could be distinguished from glass by a 2-3-fold decrease in fixed charge density, while both surfaces were about equally soft. Adhesion of Staphylococcus epidermidis HBH276 to glass in a parallel plate flow chamber was extremely high and after 4 h, 19.0 x 10(6) bacteria were adhering per cm2. In contrast, the organisms did not adhere to brush-coated glass, with numbers below the detection limit, i.e. 0.1 x 10(6) per cm2. These results attest to the great potential of polymer brushes in preventing bacterial adhesion to surfaces.