Fast-Response Mitochondria-Targeted Fluorescent Probe for H 2 S Imaging in Tumors and Inflammation

In order to explore the complex interaction between H2S and the development of related diseases, it is urgently necessary to develop effective visualization methods to monitor the dynamic changes of H2S in real time. Herein, we constructed the NIR fluorescent probe HCy-SSPy based on disulfide cleavage for the rapid imaging of H2S. The hemicyanine (HCy-NH2) unit was used as a NIR fluorophore, and asymmetric pyridyl disulfides (SSPy) acted as the specific recognition receptor for H2S. The synthesized HCy-SSPy showed a remarkable NIR turn-on signal at 765 nm activated by H2S. This probe also possessed excellent selectivity and high sensitivity, as well as rapid detection ability for H2S (∼5 s). Moreover, the low cytotoxicity, mitochondrial localization, and excellent cell imaging performance of HCy-SSPy were discussed. Further biological experiments revealed that the probe not only imaged H2S in tumor-bearing mice but also showed great potential for H2S detection in inflammatory processes.