Recently, Professor Weili Zhao’s group has successfully constructed a fluorescent probe with lysosomal targeting and specific detection of Cys by modifying BODIPY dye. This paper was selected as Hot Paper and Frontispiece Paper.

1,7-dimethyl, 3,5-diaryl substituted BODIPY is designed and developed and its conformationally restricted species with a meso-arylmercapto moiety as selective fluorescent probes for Cys. Moreover, the lysosome-target probes based on DMBDP-SAr carrying one or two morpholinoethoxy moieties were developed. Both probes localized nicely in lysosomes in living HeLa cells. Moreover, a novel fluorescence quenching mechanism was proposed from the calculations by density functional theory (DFT). The probes may go through intersystem crossing (from singlet excited state to triplet excited state) to result in fluorescence quenching.