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A mitochondrial targeted two-photon iridium(III) phosphorescent probe for selective detection of hypochlorite in live cells and in vivo

Li, Guanying, Lin, Qian, Sun, Lingli, Feng, Changsheng, Zhang, Pingyu, Yu, Bole, Chen, Yu, Wen, Ya, Wang, Hui, Ji, Liangnian, Chao, Hui
Biomaterials 2015 v.53 pp. 285-295
Danio rerio, absorption, chlorides, endotoxins, hydrogen peroxide, image analysis, ions, iridium, lipopolysaccharides, liver, mitochondria, moieties, myeloperoxidase, oxidation, phosphorescence
Endogenous hypochlorite ion (ClO⁻) is a highly reactive oxygen species (ROS) that is produced from hydrogen peroxide and chloride ions catalyzed by myeloperoxidase (MPO). And mitochondrion is one of the major sources of ROS including ClO⁻. In the present work, a two-photon phosphorescent probe for ClO⁻ in mitochondria was developed. An iridium(III) complex bearing a diaminomaleonitrile group as ClO⁻ reactive moiety specifically responded to ClO⁻ over other ions and ROSs. When the probe was reacted with ClO⁻ to form an oxidized carboxylate product, a significant enhancement in phosphorescence intensity was observed under one-photon (402 nm) and two-photon (750 nm) excitation, with a two-photon absorption cross-section of 78.1 GM at 750 nm. More importantly, ICP-MS results and cellular images co-stained with Mito-tracker Green demonstrated that this probe possessed high specificity for mitochondria. This probe was applied in the one- and two-photon imaging of ClO⁻ in vitro and in vivo. The results suggested endotoxin lipopolysaccharide (LPS) induced ClO⁻ mostly generated in the liver of zebrafish.