Photoregulated Oxidase-Mimicking and Antibacterial Activity with Cascade Catalysis Probed by Copper Nanoclusters

Abstract The development of light-responsive metal nanoclusters (MNCs) for showcasing photoregulated biomimicking catalysis and developing light-mediated potent antibacterial agents remains a central attraction of the present research. However, strategic modulation of the electronic structure in MNCs to impart light-triggered biocatalysis and antibacterial activity is associated with formidable challenges. In this study, the multidimensionally served enzymatic features in tyramine-protected CuNCs (Cu@Tyra NCs) have been comprehensively investigated, which display efficient peroxidase-like activity and a biocatalytic cascade upon coupling with a suitable natural enzyme. Upon visible light activation, photoexcited charge carriers in the Cu@Tyra NCs promote the generation of a hydroxyl radical (•OH) as a reactive oxygen species (ROS), which significantly enhances the catalytic efficiency. The photoinduced ROS also imparts strong antibacterial effects against Gram-negative bacteria (Escherichia coli) by inducing oxidative damage to cell membranes and intracellular components, exclusively in the presence of light.