A FRET-based ratiometric fluorescent probe for hydrogen polysulfide detection in living cells and zebrafish.

Hydrogen polysulfide (HS, n > 1) is an important active sulfur molecule (RSS) in organisms, which have been considered to be involved in redox signaling and cytoprotective processes. In this work, in order to quickly and accurately detect HS in biosystems, 2-fluoro-5-nitrobenzoic ester was used as the response moiety for HS, and the FRET strategy was adopted to effectively connect the donor (6-hydroxy-2-naphthoic acid) and acceptor (4-substituted-1,8-naphthalimide) to construct a new ratiometric HS fluorescent probe NPNA-HS. NPNA-HS exhibited a more than ∼ 8.0-fold ratio enhancement towards HS at I/I and a very high sensitivity with a very low detection limit of 40.3 nM. Impressive, NPNA-HS was further used for fluorescence imaging of HS in living cells and zebrafish, which showed high-clear ratiometric images. Therefore, we have demonstrated that NPNA-HS could be applied for ratiometric images of endogenous HS in living biosystems and provide a powerful molecular tool for evaluating the physiological and pathological functions of HS.