A nitrobenzoxadiazole-based near-infrared fluorescent probe for the specific imaging of H 2 S in inflammatory and tumor mice.

As a common gaseous signaling molecule, hydrogen sulfide (H 2 S) plays a vital role in physiology and pathology. The development of fluorescent probes for detecting H 2 S 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 H 2 S, instead of specifically detecting H 2 S. Herein, a novel NBD-based near-infrared (NIR) fluorescent probe named CX-N for the detection of H 2 S is synthesized. The selectivity of CX-N for H 2 S is significantly higher than that for biothiols and other potential interferences. After reacting with H 2 S, 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 H 2 S is given and confirmed by HPLC and HRMS. Based on the low cytotoxicity of CX-N, it has been used for H 2 S imaging in live cells and zebrafish. More importantly, CX-N has also been successfully applied for the real-time imaging of H 2 S in inflammatory and tumor mice based on its NIR emission, which provides a reliable platform for the specific recognition of H 2 S in complex biological systems.