A novel mitochondria-targeted ratiometric fluorescent probe for endogenous sulfur dioxide derivatives as a cancer-detecting tool.

A new mitochondria-targeted fluorescent probe RBC, constructed using a coumarin moiety which was selected as the donor and a benzothiazole derivative as the acceptor, for SO2 derivatives (HSO3-/SO32-) was presented. The probe designed on a new FRET platform showed high selectivity and a low detection limit. Importantly, the probe could respond to HSO3-/SO32- within 35 s. Furthermore, the probe could target mitochondria and was successfully used for fluorescence imaging of endogenous bisulfite in HepG2 with low cytotoxicity, which significantly assisted in cancer diagnosis.