Distinct dual enzyme-like activities of Fe–N–C single-atom nanozymes enable discriminative detection of cellular glutathione

Fe-N-C single-atom nanozymes readily achieved discriminative detection of glutathione (GSH) over other biothiols with similar structure due to the difference between POD-like and OXD-like activities regarding the kind of reactive oxygen species. This colorimetric sensor demonstrated the heterogeneity of GSH levels in different cells and accurately monitored cellular GSH fluctuation.