A novel mitochondria-targeted phosphorescence probe for hypochlorite ions detection in living cells

Monitoring hypochlorite anion (ClO^-) in living cells is particularly meaningful and valuable, because over-exposure of the ClO^- may cause a potential health hazard towards animals and humans. Considering the special structure and properties of the gemini surfactant, a novel amphiphilic gemini-iridium complex Ir[(ppy-iso)₂(bpy-tma₂Br₂)] (Ir-iso) with isoniazide as a recognition site for ClO^- was designed. The Ir-iso possessed an excellent water-solubility as well as a strong ClO^- binding capacity, as revealed from the rapid response of emission signal towards ClO^-. It was worth noting that such probe had a highly-specific selectivity with a low detection limit (20.5 nM) and was suitable in physiological environment. The cell viability assay, cell imaging, and co-location studies further proved that the Ir-iso had little cytotoxicity and was specifically localized in the mitochondria of breast cancer cells, being a promising candidate of chemo-sensor to detect the endogenous ClO^- in living cells.