A Multilevel Antimicrobial Coating Based on Polymer-Encapsulated ClO2

A multilevel antimicrobial coating with "release-killing", "contact-killing" and "anti-adhesion" properties was prepared from polymer-encapsulated chlorine dioxide (ClO2), water-in-oil-in-water (w/o/w) double emulsion. A slow sustained release of gaseous ClO2 at a rate sufficient to inhibit bacterial growth (similar to 1300 mu g of ClO2 . g(-1) . day(-1)) was demonstrated for a prolonged period of time (i.e., 28 days). Touch and infectious droplets triggered an increased release of the biocides at the sites of contamination, resulting in rapid disinfection. Zinc chloride (i.e., 30 ppm) was added to provide "contact-killing" properties, while bacterial adhesion was prevented by the Pluronic polymer used to encapsulate ClO2. The new antimicrobial coating is effective against Gram positive and Gram negative bacteria, including Bacillus subtilis, Staphylococcus aureus, and Escherichia coli. A greater than 5 log (i.e., >= 99.999%) reduction of viable bacteria was obtained at a short contact time of 10 min.