Surface Au–H Species as Self-Generated Prosthetic Groups of a Formate Dehydrogenase-like Au Nanozyme to Engineer Multienzymatic Activities

Although the past decade has witnessed a rapid development of oxidoreductase-mimicking nanozymes, the mimicry of cofactors that play key roles in mediating electron and proton transfer remains limited. This study explores how surface Au–H species conjugated to Au nanoparticles (NPs) that imitate formate dehydrogenase (FDH) can serve as cofactors, analogous to NADH in natural enzymes, offering diverse possibilities for FDH-mimicking Au nanozymes to mimic various enzymes. Once O2 is present, Au–H species assist Au NPs to complete the on-demand H2O2 generation for cascade reactions. Alternatively, when oxidizing organic molecules are introduced as substrates, Au–H species confer nitro reductase- and aldehyde reductase-like activities on Au NPs under anaerobic conditions. Furthermore, similar to the dehydrogenase–NADH complex, Au NPs possessing Au–H species are gifted with esterase-like activity for ester hydrolysis. By revealing that Au–H species are prosthetic groups for FDH-mimicking Au nanozymes, this work may inspire explorations into future self-generated cofactor mimics for nanozymes, thereby circumventing the need for exogenous cofactors.