Fast-Response Mitochondria-Targeted Fluorescent Probe for H₂S 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.