BSA-stabilized Pt nanozyme for peroxidase mimetics and its application on colorimetric detection of mercury(II) ions.

Bovine serum albumin (BSA) is chosen as the nucleation templates to synthesize Pt-based peroxidase nanomimetics with the average diameter of 2.0nm. The efficient Pt nanozymes consist of 57% Pt0 and 43% Pt2+, which possess highly peroxidase-like activity with the Km values of 0.119mM and 41.8mM toward 3,3′,5,5′-tetramethylbenzidine (TMB) and hydrogen peroxide (H2O2), respectively. Interestingly, Hg2+ is able to down-regulate the enzymatic activity of Pt nanoparticles, mainly through the interactions between Hg2+ and Pt0. It is the first report to explore a colorimetric Hg2+ sensing system on the basis of peroxidase mimicking activities of Pt nanoparticles. One of our most intriguing results is that BSA-stabilized Pt nanozymes demonstrate the ability to sense Hg2+ ions in aqueous solution without significant interference from other metal ions. The Hg2+ detection limit of 7.2nM is achieved with a linear response range of 0–120nM, and the developed sensing system is potentially applicable for quantitative determination of Hg2+ in drinking water.