MnO2 nanosheets as an artificial enzyme to mimic oxidase for rapid and sensitive detection of glutathione

Nanozymes are increasingly used as components in assays and diagnostics. Here, we describe a rapid and highly sensitive colorimetric assay for the detection and quantification of glutathione (GSH) employing MnO2 nanosheets as an artificial oxidase. In the assay pale yellow 3,3´,5,5´-tetramethylbenzidine (TMB) is oxidized to a blue product (oxTMB) under catalyzing of MnO2 nanosheets with a significant change in absorption at 650nm. GSH selectively inhibits this reaction with a detection limit of 300nM. The high specificity of inhibition by GSH allows this system to be used to determine the GSH concentrations in human serum samples. The MnO2 nanosheet-based assay is simple, rapid, sensitive and selective for the quantification of GSH and surpasses detection methods based on other MnO2 nanomaterials. •The MnO2 nanosheets were used as nanozymes to mimic the structure, complexity and function of nature enzymes.•A rapid and robust colorimetric assay for the quantification of GSH based on MnO2 nanosheets as an artificial oxidase.•The colorimetric assay with high sensitivity and selectivity could be applied for detection of GSH in biological samples.