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