When applied to surfaces or incorporated directly within the biomaterial, poly(ethylene oxide) (PEO) can inhibit protein adsorption and bacterial adhesion. This polymer and its derivatives can be very effective in reducing adhesion from 60–90% for a variety of bacterial species.
For example, we have developed PEO-like oligoglyme coatings [CH3-O-(CH2-CH2-O) n-CH3, in which n = 1–4], using radio frequency gas plasma discharge techniques that can apply these coating to a variety of base materials . The degree to which this family of coatings protects surfaces depends in part on which oligomer is used and what bacterial species is being used. In our studies with Pseudomonas aeruginosa, a tetraglyme (n = 4) coating can reduce colonization by 99% relative to uncoated controls. In other experiments, tetraglyme was deposited on glass in a pattern using photolithographic methods before exposure to a suspension of Methylobacterium extorquens. After 72 hours, almost all of the bacteria were adhering to the bare glass, with very few bacteria on the glyme-coated regions.
The elegance of the RF plasma technique is that such PEG-like coatings can be deposited onto a variety of existing materials and geometric shapes (e.g., inside and outside of catheters, porous scaffold structures, metals, polymers, ceramics, orthodontic materials, and enamel). Although such glyme-plasma coatings resist protein adsorption for at least one week, longer-term bacterial challenges are needed to more fully evaluate these coatings.