12-crown-4-ether and tri(ethylene glycol) dimethyl-ether plasma-coated stainless steel surfaces and their ability to reduce bacterial biofilm deposition

It has been demonstrated that surfaces coated with poly(ethylene glycol) (PEG) are capable of reducing protein adsorption, bacterial attachment, and biofilm formation. In this communication cold-plasma-enhanced processes were employed for the deposition of PEG-like structures onto stainless steel surfaces. Stainless steel samples were coated under 1,4,7,10-tetraoxacyclododecane (12-crown-4)-ether and tri(ethylene glycol) dimethyl ether (triglyme)-radio frequency (RF)-plasma conditions. The chemistry and characteristics of plasma-coated samples and biofilms were investigated using electron spectroscopy for chemical analysis (ESCA), atomic force microscopy (AFM), and water contact angle analysis. ESCA analysis indicated that the plasma modification resulted in the deposition of PEG-like structures, built up mainly of -CH2-CH2-O- linkages. Plasma-coated stainless steel surfaces were more hydrophilic and had lower surface roughness values compared to those of unmodified substrates. Compared to the unmodified surfaces, they not only significantly reduced bacterial attachment and biofilm formation in the presence of a mixed culture of Salmonella typhimurium, Staphylococcus epidermidis, and Pseudomonas fluorescens but also influenced the chemical characteristics of the biofilm. Thus, plasma deposition of PEG-like structures will be of use to the food-processing and medical industries searching for new technologies to reduce bacterial contamination. (C) 2001 John Wiley & Sons, Inc.