A highly sensitive endoplasmic reticulum-targeting fluorescent probe for the imaging of endogenous H2S in live cells

Hydrogen sulfide (H2S) as an important signaling biomolecule participates in a series of complex physiological and pathological processes. In situ and rapid detection of H2S levels in endoplasmic reticulum (ER) is of great importance for the in-depth study of its virtual functional roles. However, the ER-targeting fluorescent probe for the detection of H2S in live cells is still quite rare. Herein, a new ER-targeting fluorescent probe (FER-H2S) for detecting H2S in live cells was characterized in the present study. This probe FER-H2S was built from the hybridization of three parts, including fluorescein-based skeleton, p-toluenesulfonamide as ER-specific group, and 2,4-nitrobenzene sulfonate as a response site for H2S. The response mechanism of the probe FER-H2S to H2S is on the basis of the ring-opening and ring-closing processes in fluorescein moiety. Moreover, the probe FER-H2S was successfully used for the imaging of exogenous and endogenous H2S in ER of live cells.