Antimicrobial FeO-CuO-PO glasses.

Glasses with high antimicrobial efficacy were developed in the FeO-CuO-PO ternary system to mitigate fomite-mediated transmission of infectious diseases in high-risk settings such as hospitals, daycares, and nursing homes. Binary CuO-PO glasses were not durable enough for use as high touch point articles, so FeO was added to the compositions to increase the chemical durability. The amount of Cu leachate decreased by at least 3 orders of magnitude when FeO was increased from 0 to 13.1 mol%. At the highest FeO contents and corresponding highest durability, the glass was no longer able to pass a test of antimicrobial efficacy with < 3 log kill compared to > 5 log kill for all other compositions. Ab-initio molecular dynamics simulations showed increasing bridging oxygen species at the expense of non-bridging oxygen species with the increase in FeO content, showing that the glasses exhibited increased chemical durability because they were more interconnected and structurally bound. Experimental results with glasses at fixed CuO and decreasing FeO confirmed that FeO content (not CuO) controlled the Cu release rate and, thus, the antimicrobial efficacy of the glasses. The significance of the oxidation state of the leached Cu was overwhelmed by the importance of the amount of Cu leachate.