Dual-site lysosome-targeted fluorescent probe for separate detection of endogenous biothiols and SO2 in living cells

Biothiols and SO2 play crucial roles in many physiological and pathological processes. To unravel their complicated interrelationship and cellular cross-talk, it would be highly desirable to develop single-molecule fluorescent probes that can selectively detect biothiols and SO2via different emission channels. Here, a novel chromenylium derivative, BPO-Py-diNO2, based on the rational design of dual recognition sites for biothiols and SO2 selectively and sensitively responded to biothiols with near-infrared fluorescence, and to SO2 with green fluorescence. The emission shift for the two channels was 170 nm. BPO-Py-diNO2 was selectively enriched in lysosomes. It could also be used to evaluate dual-channel imaging of endogenous biothiols and SO2 in living HeLa cells, and it could be used for monitoring the mutual interconversion of biothiols and SO2.