A mitochondria targetable two-photon excited near-infrared fluorescent probe for imaging of H2O2 in live cells and tissues.

Hydrogen peroxide (H2O2), a member of small-molecule reactive oxygen species (ROS), plays an important role in physiological and/or pathological process within live systems. Herein, to quantitatively investigate the biological role of H2O2 in subcellular level, we constructed of a novel two-photon (TP) in near-infrared (NIR) out fluorescent probe (TP-NIR-H2O2) for visualization of mitochondria H2O2 in living cells and tissues. Specifically, TP-NIR-H2O2 utilized the oxonium ion as the mitochondrial targeting unit and phenylboric acid as the H2O2 reaction moiety. After the phenylboric acid moiety reaction with H2O2, TP-NIR-H2O2 displayed a ~105-fold fluorescence intensity enhancement in 665 nm. Selectivity experiment demonstrated that the probe can detect H2O2 with high selectivity over other ROS. Moreover, TP-NIR-H2O2 could be employed for imaging H2O2 in mice liver tissues with large tissue-image depth (50-170 µm) under two-photon excitation (800 nm).