Naphthalimide-based a highly selective two-photon fluorescent probe for imaging of hydrogen sulfide in living cells and inflamed tissue of mouse model.

Hydrogen sulfide (HS) is a very important third endogenously generated gaseous signaling molecule and plays a key role in physiological and pathological regulation processes of living biosystems. Although a lot of HS fluorescent probes have been reported, the relationship between the physiology and pathology of HS in inflamed tissues remains unclear. Herein, by adopting a donor-π-acceptor (D-π-A)-structured naphthalimide derivative as the two-photon (TP) fluorophore and a 4-dinitrobenzene-ether (DNB) with a strong intramolecular charge transfer (ICT) effect as the recognition moiety, we reported a novel TP bioimaging probe NP-HS for HS with improved sensitivity. The NP-HS exhibits very low background fluorescence in the absence of HS, and a significant 258-fold fluorescence intensity enhancement was observed in the presence of HS, resulting in a high sensitivity and selectivity to HS in aqueous solutions with a detection limit of 18.8 nM observed. The probe also shows a wide linear response concentration range (0-10.0 μM) to HS with high selectivity. All these features are favorable for direct monitoring of HS in complex biological samples. It was then applied for direct TP imaging of HS in tissues of inflammation model with satisfactory sensitivity, indicating it has the latent capability in further biological applications for investigation of the interaction HS with inflammation.