TiO₂-based transparent coatings create self-cleaning surfaces

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.