Lysosome-Targeted Single Fluorescence Probe for Two-Channel Imaging Intracellular SO₂ and Biothiols

As the members of reactive sulfur species, SO2 and biothiols play a significant role in physiological and pathological processes and directly influence numerous diseases. Furthermore, SO2 and biothiols can provide a reductive environment for lysosomes to carry out their optimal functionality. To this end, the development of single fluorescent probes for imaging SO2 and biothiols from different emission channels is highly desirable for understanding their physiological nature. Here, a lysosome-targeted fluorescent probe (BPO-DNSP) with a dual reaction site for SO2 and biothiols was presented. BPO-DNSP can sensitively and selectively respond to SO2 in the green channel with a large Stokes shift over 105 nm, and to biothiols in the near-infrared emission channel with a large Stokes shift over 109 nm. The emission shift for the two channels was as high as 170 nm. Colocalization experiments verified that BPO-DNSP can selectively enrich lysosomes. Notably, BPO-DNSP can not only be used to image intracellular SO2 and biothiols from two different channels, but also to monitor the conversion of biothiols to SO2 without adding exogenous enzymes in living HeLa cells