TiO2-based transparent coatings create self-cleaning surfaces

Abstract

Implementation of self-cleaning surfaces is gaining attention as a tool to combat the healthcare associated infections (HAIs). In this study, we prepared TiO2-based transparent coatings as one such potential self-cleaning surface for touchscreen application and evaluated their antimicrobial efficacy under dark and illuminated conditions. To maintain high transparency and TiO2 coverage, clean borosilicate glass slides were dip-coated multiple times in a suspension of TiO2-based materials at a low concentration. The as-prepared samples were tested for their roughness and hydrophilicity via atomic force microscopy (AFM) and contact angle analysis, respectively. To screen the antimicrobial performance of the TiO2 coated samples, the number and viability of attached bacteria on the film surfaces were recorded after submerging them in a bacterial suspension for 45 min under dark or ultraviolet (UV) illuminated conditions. The antimicrobial performance of the commercially available regular and Ag-coated antimicrobial Corning® Gorilla® Glass were also evaluated under the same conditions and compared with those of the TiO2 coated samples. Among the test samples, n-Ag/TiO2 (<100 nm) coated samples achieved greater than 80% bactericidal efficacy with the lowest bacterial attachment after the UV exposure. TiO2-based transparent coatings show promise as an effective tool against bacterial attachment and displays greater bactericidal activity in comparison to commercial antibacterial glass.