Facile Synthesis of Cu-Doped TiO 2 Particles for Accelerated Visible Light-Driven Antiviral and Antibacterial Inactivation.

In this work, we present a facile and scalable hydrolysis-based route for the synthesis of copper-doped TiO 2 particles for highly effective light-activated antiviral and antibacterial applications. The performance of the synthesized Cu-doped TiO 2 particles is then evaluated using solution-phase antimicrobial photodynamic inactivation assays. We demonstrate that the Cu-doped TiO 2 particles can successfully inactivate a wide range of pathogens with exposure to light for 90 min, including bacteria ranging from methicillin-resistant Staphylococcus aureus (99.9999%, ∼6 log units) to Klebsiella pneumoniae (99.93%, ∼3.3 log units), and viruses including feline calicivirus (99.94%, ∼3.4 log units) and HCoV-229E (99.996%, ∼4.6 log units), with the particles demonstrating excellent robustness toward photobleaching. Furthermore, a spray-coated polymer film, loaded with the synthesized Cu-doped TiO 2 particles achieves inactivation of methicillin-resistant S. aureus up to 99.998% (∼4.8 log units). The presented results provide a clear advance forward in the use of metal-doped TiO 2 for aPDI applications, including the scalable synthesis (kg/day) of well-characterized and robust particles, their facile incorporation into a nontoxic, photostable coating that may be easily and cheaply applied to a multitude of surfaces, and a broad efficacy against drug-resistant Gram-positive and Gram-negative bacteria, as well as against enveloped and nonenveloped viruses.