Two-photon fluorescence probe for precisely detecting endogenous H2S in lysosome by employing a dual lock system

Hydrogen sulfide (H 2 S) is involved in various pathological and physiological processes as well as regulation of lysosomal functions. Thus, it is essential to develop precise method for the detection of H 2 S in lysosome. Although a large number of fluorescent probes for H 2 S have been developed, the probe for lysosomal H 2 S assay still remains rare. Herein, a two-photon fluorescent probe, named Lyso-Nap, is designed and synthesized for detecting H 2 S in lysosome by employing a dual lock system (dual PET process and dual reaction sites). The fluorescence of Lyso-Nap with dual lock system is opened by H 2 S only when the probe is localized within acidic lososomes, which can avoid the disturbance from neutral cytosol and other organelles. Moreover, two-photon fluorescent probes with weak auto-fluorescence, large penetration depth and reduced photodamage, are particularly favored for bioimaging. Accordingly, Lyso-Nap can be successfully used for precisely tracking and detecting endogenous H 2 S in lysosome of living cells and tissue.