A nitrobenzoxadiazole-based near-infrared fluorescent probe for the specific imaging of HS in inflammatory and tumor mice.

As a common gaseous signaling molecule, hydrogen sulfide (HS) plays a vital role in physiology and pathology. The development of fluorescent probes for detecting HS has attracted widespread attention. However, most of the reported fluorescent probes with nitrobenzoxadiazole (NBD) as the recognition group have been widely used to simultaneously detect biothiols and HS, instead of specifically detecting HS. Herein, a novel NBD-based near-infrared (NIR) fluorescent probe named CX-N for the detection of HS is synthesized. The selectivity of CX-N for HS is significantly higher than that for biothiols and other potential interferences. After reacting with HS, CX-N shows a significant increase in NIR fluorescence (75-fold), large Stokes shift (155 nm) and fast response (4 min). And the possible response mechanism of CX-N to HS is given and confirmed by HPLC and HRMS. Based on the low cytotoxicity of CX-N, it has been used for HS imaging in live cells and zebrafish. More importantly, CX-N has also been successfully applied for the real-time imaging of HS in inflammatory and tumor mice based on its NIR emission, which provides a reliable platform for the specific recognition of HS in complex biological systems.