THE EFFECTS OF POLYHEMA COATING ON THE ADHESION OF BACTERIA TO POLYMER MONOFILAMENTS

Bacterial adhesion to implants is the initial stage in the pathogenesi s of device-related infections, the extent of attachment being depende nt on the surface properties of both the bacteria and the substrate. O ne approach to preventing infection involves incorporating antiadhesiv e agents onto the surface of indwelling devices. Hydrogels of poly(2-h ydroxyethylmethacrylate) (polyHEMA) homopolymer have been shown previo usly not to support the attachment and growth of mammalian cells but t heir interaction with bacterial cells has not been extensively investi gated. The purpose of this study was to modify the surfaces of polymer ic monofilaments by coating them with polyHEMA, and then test their ab ility to support bacterial attachment before and after coating. Monofi laments composed of polyester, polyvinylidene chloride (PVDC) and nylo n were dip-coated in a 5% (w/v) polyHEMA solution in 95% (v/v) ethanol . Work of adhesion (WA) was determined from determination of the conta ct angle between the monofilaments and water. Adhesion of E. coli was assessed using a bioluminescent method based on adenosine triphosphate determination and scanning electron microscopy was used to investigat e the surface morphologies of the monofilaments. Coating the monofilam ent fibres with polyHEMA increased the value of WA from 100.6, 94.6 an d 91.2 mJ m-2 for PVDC, polyester and nylon, respectively, to a common value of 113.7 mJ m-2, indicating that the monofilaments were more hy drophilic after coating. Adhesion of E. coli cells to all monofilament s occurred rapidly and was almost complete after 2 h incubation. The c oating of the monofilaments with polyHEMA reduced the surface rugosity of the monofilaments and significantly reduced the numbers of adheren t bacteria. The modification of the surface in this manner is likely t o have implications for situations where bacterial adhesion is a facto r in predisposing infection.