Mitochondrial Specific H2Sn Fluorogenic Probe for Live Cell Imaging by Rational Utilization of a Dual-Functional-Photocage Group

Reactive sulfur species play a very important role in modulating neural signal transmission. Hydrogen polysulfides (H2Sn, n > 1) are recently suggested to be the actual signaling molecules. There are still few spatiotemporal controllable-based probes to detect H2Sn. In this work, for the first time, we proposed the photocleavage product of the common photoremovable protecting group (2-nitrophenyl moiety) capable of trapping H2Sn. Taking advantage of this, we constructed the probe H1 containing a photocontrollable group, a mitochondrial directing unit and a signal reporter fluorescein dye. H1 exhibited excellent fluorescence enhancement (50-fold) in response to H2Sn under the aqueous buffer only after UV irradiation. H1 also showed high selectivity and sensitivity for H2Sn over other reactive sulfur species, reactive oxygen species, and other analytes, especially biothoils including hydrogen sulfide, cysteine, homocysteine, and glutathione. We showed the utility of H1 to image H2Sn in living cells with high spatiotemporal resolution.