A dual-responsive fluorescent probe for simultaneous detection of H2S and SO2 and its application in an oxidative stress model of neuronal cells.

Despite their importance as gaseous signaling molecules, the simultaneous detection of both hydrogen sulfide (H2S) and sulfur dioxide (SO2) using a single fluorescent probe in living cells remains highly challenging due to their similar chemical reactivity and the complexity of the intracellular environment. To address this issue, we designated a probe RHO-DCO-NBD by combining a 7-nitro-1,2,3-benzodioxazole (NBD) unit and a dicyanoisophorone unit with a formylated rhodamine framework, which enables independent detection of H2S and SO2 via distinct emission channels. The probe was evaluated for its sensitivity, selectivity, and spectral performance in cellular environments. Confocal fluorescence imaging in PC12 cells demonstrated that RHO-DCO-NBD enables interference-free visualization of both endogenous and exogenous H2S and SO2. Additionally, the probe successfully monitored dynamic fluctuations of the two gasotransmitters in a lipopolysaccharide (LPS)-induced oxidative stress model of neuronal cells. These results highlight the probe's potential as a powerful tool for investigating the coordinated roles of H2S and SO2 in oxidative stress-related neuronal damage.