ABSTRACT
Colorimetric or fluorescent biosensors based on mimic enzymes have come into the spotlight in virtue of their visual detection. In traditional visual sensors, fluorescent-changing or color-changing substances should be introduced for the catalytic reaction with mimic enzymes. Herein, a mimic enzyme (Au@Fe-MIL-88B) with self-triggered fluorescent property was prepared. By incorporating Au nanoparticles (Au NPs) in Fe-MIL-88B, a higher peroxidase activity of Au@Fe-MIL-88B was monitored due to the synergistic effect between Au NPs and Fe-MIL-88B. Besides, Au NPs can change the valence of Fe ion in metal organic framework (MOF), thus lower background fluorescence was discovered, but the addition of H2O2 can trigger the self-fluorescence of Au@Fe-MIL-88B. By using Au@Fe-MIL-88B as a label to anchor secondary antibody, a competitive immunosensor based on fluorescence and photoelectrochemistry was constructed for the immunoassay of rosiglitazone (RSG), a kind of hypoglycemic drug. Finally, a portable instrument was homemade for the on-site and convenient detection of RSG in functional tea. This self-triggered fluorescent MOF may provide a possible route to design biosensors for the detection of hazardous materials.