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 (H2S) 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 H2S fluorescent probes have been reported, the relationship between the physiology and pathology of H2S 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-H2S for H2S with improved sensitivity. The NP-H2S exhibits very low background fluorescence in the absence of H2S, and a significant 258-fold fluorescence intensity enhancement was observed in the presence of H2S, resulting in a high sensitivity and selectivity to H2S 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 H2S with high selectivity. All these features are favorable for direct monitoring of H2S in complex biological samples. It was then applied for direct TP imaging of H2S in tissues of inflammation model with satisfactory sensitivity, indicating it has the latent capability in further biological applications for investigation of the interaction H2S with inflammation.