Ultra-fast colorimetric detection of glutathione by magnetic Fe NPs with peroxidase-like activity

The nanozymes-based sensing platforms have been attracted in recent years due to their outstanding performances in the practical applications. In this work, the magnetic Fe nanoparticles (NPs) with peroxidase-like activity was developed for the fast detection of glutathione (GSH). The Fe NPs were facilely prepared through the reduction of iron trichlorrde hexahydrate (FeCl 3 ‧6H 2 O) by sodium borohydride (NaBH 4 ) at room temperature, exhibiting a merit of simplicity. Significantly, the achieved Fe NPs have high peroxidase-like catalytic activity. At the room temperature, the colorimetric substrates such as 3,3′,5,5′-tetramethylbenzidine (TMB) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) can be rapidly oxidized by Fe NPs with the help of H 2 O 2 . After incubated for just 30 s, the catalytic system could achieve a colored solution. Thus, the Fe NPs-based sensing systems can be employed in the development of the colorimetric biosensors with the naked-eye detection. • Fe NPs were synthesized by one-step reduction of Fe 3+ by NaBH 4 . • Fe NPs can exhibit high peroxidase-like activity at room temperature. • A fast glutathione assay was realized by the Fe NPs-based catalytic system. • The magnetic Fe nanozymes have a superior reusability.