Single-atom Pt catalysts as oxidase mimic for p-benzoquinone and α-glucosidase activity detection

Highly-efficient nanozymes and suitable substrates are the two most important breakthroughs for the construction of novel nanozyme-based enzyme activity assays with good analytical performance. In this work, we demonstrated that the single-atom Pt catalysts could exhibit superior oxidase-mimetic activity due to the fully exposure and utilization of every Pt-involved active sites. This oxidase mimic efficaciously boosts the generation of H2O2 and 1O2 species, and ultimately the chromogenic reaction of 3,3′,5,5′-tetramethylbenzidine (TMB). Fascinatingly, hydroquinone (HQ) inhibits the above reaction more sensitively than other phenolics, based on which, colorimetric HQ detection can be rationally achieved. Further, a colorimetric assay for α-glucosidase (α-Glu) detection is innovatively designed by using a robust HQ-generating phenolic, α-Arbutin, as the substrate. The wide linear range (0.01–8 U/mL) and low detection limit (0.0038 U/mL) indicate an admirable analytical performance that surpasses the vast majority of α-Glu assays previously reported. Encouragingly, the proposed colorimetric sensor has been successfully used for the detection of α-Glu in serum samples and the construction of “NAND” logic gate. This study not only provides ideas for the preparation of novel single-atom catalysts with enhanced oxidase-like activity, but also broadens the prospect for the design of new optical α-Glu assays by exploring suitable substrates.