Electrostatically charged rutile TiO2 surfaces with enhanced photocatalytic activity for bacteria inactivation

In this work, the fabrication of a series of rutile-TiO2 films with different submicron thicknesses supported on thermally grown SiO2 is proposed. The aim is to determine the correlation between the generation of a positively charged TiO2 surface, caused by the presence of dipoles formed at the TiO2/SiO2 interface, with E. coli attraction. This electrostatic interaction leads to an improvement in the photocatalytic antibacterial activity. The positively charged TiO2 surface formation was confirmed by Kelvin Probe Force Microscopy, E. coli adhesion tests, molecular docking, methylene blue, and methyl orange adsorption experiments. This effect on the photocatalytic surface of R-TiO2 could favor the adsorption and degradation of negatively charged substances, as well as most of the pathogenic bacteria and viruses.