Simple Strategy to Develop Multifunctional NIR Fluorescent Probes for Simultaneous Identification of H2S and SO2.

H2S and SO2 have been considered as important gaseous signaling molecules in biological systems, functioning as regulatory roles in many physiological processes of organisms. To better understand the crosstalk and synergetic effects between H2S and SO2 in biological systems, developing a single fluorescent probe for dual-channel fast detection of H2S and SO2 is highly urgent. We herein report a simple strategy to develop multifunctional near-infrared (NIR) fluorescent probes for simultaneous identification of H2S and SO2. Based on the idea of modulating the reactivity of the benzopyrylium core with electron donors, two new NIR fluorescent probes (SW1 and SW2) were synthesized and evaluated. The probe SW2 could not only rapidly sense H2S and SO2 with different fluorescence signals but also be used as a reversible probe to investigate the flux of H2O2 and SO2. Moreover, SW2 was successfully applied in visualizing H2S and SO2 in living cells and mice. These results suggest that SW2 could serve as a useful tool in understanding the complex relationships between H2S and SO2 in biological systems.