Fluorogenic Biosensors Constructed via Aggregation-induced Emission Based on Enzyme-catalyzed Coupling Reactions for Detection of Hydrogen Peroxide.

Hydrogen peroxide (HO) is a main reactive oxygen by-product produced in the metabolism of organisms and a common biomarker of oxidative stress. Aggregation-induced emission (AIE) probes for HO have been proposed. Such AIEgens mostly use benzeneboronic acid as a recognition group. Recently, a strategy involving enzyme-catalyzed polymerization of AIE compounds shows great potential in AIEgens design. We herein modify the AIE motif, tetraphenylethene (TPE) with o-phenylenediamine (TPE-TAF), which can be oxidated by HO in HRP to form an intramolecular phenazine structure. Compared with a similar approach, the proposed strategy is simple and the TPE-TAF showed a sensitive "turn-on" fluorescence with HO. The detection limit (LOD) is 3.39 μM and the probe is highly specific against HO. We further verified the reaction mechanism of the enzyme-catalyzed coupling reaction. The probe is a promising candidate as a stable and safe fluorescent substrate in HO sensing.