Visible-Light-Driven Photoactivity of Copper/PVA Composite Films against Murine Coronavirus

In light of the Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2) pandemic in 2019, the global scientific community has focused their research on developing virucidal materials to mitigate the spread of viruses including self-disinfecting surfaces capable of inactivating viruses that are in contact with the material. Copper stands out in this context due to its intrinsic ability to disrupt viral structures and inhibit replication mechanisms, making cooper-based materials a powerful tool. Furthermore, copper absorbs light in the visible region, a property that has not been fully studied or reported in the literature considering its photoactivity on viruses. To fill this gap, in the present study, composite films containing 2% w/v of copper micro- and nanoparticles and copper oxide (I) microparticles in poly-(vinyl alcohol) (PVA) were synthesized by drop-casting. The films were evaluated against enveloped murine hepatitis virus type 3 (MHV-3) under dark and white light illumination. Using the L929 mouse fibroblast cell line, only the film with copper microparticles showed no cytopathic effect under illumination, indicating virucidal photoactivity. By performing the integrated cell culture and reverse transcription quantitative PCR (ICC-RT-qPCR) assay, it was found that the film promoted a 43.1% reduction of viral load when illuminated, while in the dark, the reduction was lower than 7%. Thus, it was possible to obtain photoactive composite films with relatively low-cost copper microparticles by a conventional deposition technique. These promising results contribute to advancing research on visible-light-driven materials and photofunctional surfaces that use solar energy as a power source, offering innovative solutions to combat the spread of pathogens.