Oxidative cleavage of alkene: A new strategy to construct a mitochondria-targeted fluorescent probe for hydrogen peroxide imaging in vitro and in vivo

Hydrogen peroxide (H2O2) is a significant reactive oxygen species (ROS) mainly produced in mitochondria, and it plays crucial roles in many physiological processes. Till now, a plenty of fluorescent probes relying on various organic reactions have been explored for H2O2. However, these probes still suffered from some problems, including the interference from ONOO– and ClO–, unsatisfying limit of detection (LOD > 100 nM), long response time (over 30 min) and lacking mitochondria-targeting ability. Herein, we employ the oxidative cleavage reaction of alkene as a novel sensing strategy, and successfully construct a turn-on fluorescent probe TBBP–Pro for detecting H2O2 in biological system. In this probe, the cyanovinyl-pyridinium moiety not only acts as a specific response site for H2O2, but also targets mitochondria efficiently. Comparing with previous H2O2 probes, TBBP–Pro possesses the advantages of high selectivity, excellent sensitivity (LOD = 47 nM) and fast response (within 5 min) toward H2O2. Additionally, TBBP–Pro successfully visualizes the endogenous H2O2 in mitochondria of HepG2 cells and zebrafish larvae. More importantly, TBBP–Pro is promising to monitor the dynamic change of H2O2 level for the diagnosis and treatment of inflammatory mice.