A turn-on endoplasmic reticulum-targeted two-photon fluorescent probe for hydrogen sulfide and bio-imaging applications in living cells, tissues, and zebrafish.

As one of the important gas signal molecules, hydrogen sulfide (H2S) is associated with many important physiological processes in living organisms. Organelles, especially endoplasmic reticulum (ER), play a crucial role in the cell metabolism. Accordingly, the detection of H2S in the ER is of high interest. Toward this goal, we have described the development of the first ER-targeted fluorescent H2S probe (Na-H 2 S-ER). The new probe exhibited favorable features, such as a large turn-on fluorescence signal (45-fold fluorescence enhancement), high sensitivity and selectivity. The probe was successfully employed for imaging exogenous and endogenous H2S in the living HeLa cells. Significantly, the new probe Na-H 2 S-ER was employed to visualize H2S in the ER of living cells for the first time. In addition, the probe was also successfully used for imaging H2S in the living tissues up to a depth of 100 μm and in the living zebrafish.