Novel Tumor-Specific and Mitochondria-Targeted near-Infrared-Emission Fluorescent Probe for SO2 Derivatives in Living Cells

Endogenous sulfur dioxide (SO2) is an important gaseous signal molecule, which was also regarded as one of the reactive sulfur spaces (RSS) and closely related to cardiovascular diseases and many neurological disorders. However, the design and synthesis of fluorescent probes with near-infrared-emission which can detect mitochondria] SO2 and its derivatives in living cells still remain unresolved. Herein, a biotin and coumarin-benzoindole conjugate BCS-1 was presented as a ratiometric and colorimetric fluorescent probe for tracing SO2 derivatives with excellent selectivity and rapid responsibility. Notably, it is the first mitochondria-targeted near-infrared-emission probe that could selectively detect SO2 in tumor cells. BCS-1 could selectively enter into mitochondria of tumor cells, and the detection limit for SO2 derivatives was determined as 72 nM.