Mechanistic Exploration of Visible Light-Activated Carbon/TiO2 Hybrid Dots Damaging Bacterial Cells

Abstract

The carbon/TiO2 hybrid dots (C/TiO2-Dots) are structurally TiO2 nanoparticles (in the order of 25 nm in diameter from commercially available colloidal TiO2 samples) surface-attached by nanoscale carbon domains with organic moieties, thus equivalent to hybrids of individual TiO2 nanoparticles each decorated with many carbon dots. These hybrid dots with exposure to visible light exhibit potent antibacterial properties, similar to those found in neat carbon dots with the same light activation. The results from the use of established scavengers for reactive oxygen species (ROS) to “quench” the antibacterial activities, an indication for shared mechanistic origins, are also similar. The findings in experiments on probing biological consequences of the antibacterial action suggest that the visible light-activated C/TiO2-Dots cause significant damage to the bacterial cell membrane, resulting in higher permeability, with the associated oxidative stress leading to lipid peroxidation, inhibiting bacterial growth. The induced bacterial cell damage could be observed more directly in the transmission electron microscopy (TEM) imaging. Opportunities for the further development of the hybrid dots platform for a variety of antibacterial applications are discussed.

Visible Light-Induced Decolorization of Malachite Green over BP-TiO2 Photocatalyst

“…3(c) was also lower than that of pure TiO 2 . The reason for the decrease in photoluminescence intensity is that the BP may quench the photoluminescence of the TiO 2 (Adcock et al 2022). This can occur if the BP has defect states or defects that can trap the excited electrons and holes that are responsible for the photoluminescence, implying that BP could capture photoproduced electrons to promote electron-hole separation and inhibit recombination.…”