Facile in situ microwave synthesis of Fe3O4@MIL-100(Fe) exhibiting enhanced dual enzyme mimetic activities for colorimetric glutathione sensing

In recent decades, artificial nanozymes with excellent stability, low cost and availability have been gradually explored to avoid the limits of natural enzymes such as poor stability, high cost and difficult preparation. Herein, for the first time, we investigated the capability of nanoscale Fe 3 O 4 @MIL-100(Fe) as a nanozyme, which was quickly synthesized in situ by a microwave-assisted method within 20 min using Fe 3 O 4 as the metal precursor. The obtained Fe 3 O 4 @MIL-100(Fe) showed satisfactory intrinsic dual enzyme mimetic activities, including peroxidase (POD)- and catalase (CAT)-like activities. Moreover, a simple and effective colorimetric biosensor was fabricated to detect glutathione (GSH) based on its POD-like activity. The proposed measurement had a linear range of 1–45 μM and a limit of detection (LOD) of 0.26 μM (3.3 δ/S). It was proved that the established colorimetric sensing system could be successfully applied to detect GSH in actual biological samples. Importantly, the outstanding reusability and stability made it extremely valuable as a catalyst. The present work implied that Fe 3 O 4 @MIL-100(Fe) synthesized in situ by the microwave-assisted method was a very promising candidate for biocatalyst and biosensing.