Cascade reaction biosensor based on gold nanocluster decorated iron-cobalt oxide nanosheets as a superior peroxidase mimic for dual-mode detection of α-glucosidase and its inhibitor

Herein, we have synthesized a novel kind of gold nanoclusters decorated iron-cobalt oxide nanosheets ([email protected]) assembled by electrostatic interaction, which possessed both outstanding peroxidase-like activity and fluorescence property. Taking advantage of our bifunctional hybrid nanozyme and enzyme cascade reactions, a sensitive dual-mode (colorimetric/fluorescent) detection method for α-glucosidase was constructed. The detection limits for α-glucosidase were 2.2 U/L and 3.3 U/L in fluorometric and colorimetric mode, respectively. This method not only provides high sensitivity, but also can correct itself to improve the accuracy of analysis due to the dual-response signals. Furthermore, it was employed for α-glucosidase determination in real samples and screening of α-glucosidase inhibitors.