Fe–N–C Single-Atom Nanozymes for the Intracellular Hydrogen Peroxide Detection

Recently, in situ detection of hydrogen peroxide (H2O2) generated from live cells have caused tremendous attention, because it is of great significance in the control of multiple biological processes. Herein, Fe–N–C single-atom nanozymes (Fe–N–C SAzymes) with intrinsic peroxidase-like activity were successfully prepared via high-temperature calcination using FeCl2, glucose, and dicyandiamide as precursors. The Fe–N–C SAzymes with FeNx as active sites were similar to natural metalloproteases, which can specifically enhance the peroxidase-like activity rather than oxidase-like activity. Accordingly, owing to the excellent catalytic efficiency of the Fe–N–C SAzymes, colorimetric biosensing of H2O2 in vitro was performed via a typical 3,3′,5,5′-tetramethylbenzidine induced an allochroic reaction, demonstrating the satisfactory specificity and sensitivity. With regard to the practical application, in situ detection of H2O2 generated from the Hela cells by the Fe–N–C SAzymes was also performed, which can expand the applications of the newborn SAzymes.