Visible-light-activated antibacterial and antipollutant properties of biocompatible Cu-doped and Ag-decorated TiO nanoparticles.

Optical and photocatalytic restrictions of anatase TiO nanoparticles (Nps) limit their potential applications, as antipollutant and antibacterial agents for sanitary applications, to the UV spectral region. While modification with transition metals extends the absorption capacity to the visible light spectrum, often undermines the photocatalysts' biocompatibility due to toxic ion leaching. In this study, we synthesized Cu-doped and Ag-decorated TiO photocatalysts by employing solvothermal (TiO:Cu) and sol-gel synthetic procedures (TiO:Ag), respectively. We acquired TiO Nps modified with three percentages of either Cu or Ag content, to examine the potential differentiation of their structural, photocatalytic, and biological impact. Comprehensive structural characterization supports the prevailing anatase crystalline structure of bare and modified titania nanostructures, while morphological differences are demonstrated among the different samples. Optical response in the visible region of TiO:Cu Nps stems from band gap narrowing and lattice-defect generation, while plasmonic effects are at play for TiO:Ag Nps. Their photocatalytic potential under visible light irradiation, originated from low-energy LED lamps commonly found in indoor spaces, was verified after monitoring the successful enhancement of methylene blue (MB) degradation rate. Safety assessment on immortalized healthy human keratinocyte cell line (HaCaT) revealed their biocompatibility up to a certain concentration, while reactive oxygen species (ROS) production was intensified after light irradiation. The visible-light-induced photocatalytic-driven antibacterial activity was confirmed against both gram-positive and gram-negative .