Gold Nanoclusters Perform Enzyme-like Photocatalysis for Prodrug Activation

Many synthetic nanomaterials known as nanozymes can catalyze biologically relevant molecular transformations just as natural enzyme does. "Photonanozyme" utilizes light as a spatial and temporal control for the regulation of nanozyme activities. Here we report a glutathione-modified gold nanocluster as a photonanozyme that catalyzes the reduction of nitrobenzene under light. Aniline was found as the sole photoreductive product. The photocatalytic reactions at variable light fluences were found to follow the classical Michaelis-Menten enzyme kinetics from which kinetic rate constants were quantified. Intracellular reduction of a nitro-group-containing fluorescent probe demonstrates the viability of gold nanoclusters as biocompatible photonanozymes performing catalysis in a mammalian cell environment. This study reinvents gold nanoclusters as photonanozymes that mimic naturally occurring nitroreductase for potential prodrug activation.