A novel H₂O₂ activated NIR fluorescent probe for accurately visualizing H₂S fluctuation during oxidative stress

Hydrogen sulfide (H₂S) is a typical gas signal molecule that plays a vital role in various pathological courses. Despite having the accumulated knowledge on the physiological functions of H₂S in many diseases, the process in the measurement of its level in mitochondria during oxidative stress is still far away from the expectation. In this regard, it is great significant to design a fluorescent probe for accurately monitoring the dynamics of H₂S during oxidative stress. In this work, we firstly synthesized an oxidative stress activated fluorescence probe QM-RSH for tracking H₂S level in mitochondria. It exhibited high selectivity and sensitivity for detecting H₂S with lower limit of detection (LOD = 44.6 nM) in the presence of H₂O₂. QM-RSH can be successfully applied to accurately monitor the fluctuation of H₂S level during oxidative stress without interference from other physiological processes in living cells and zebrafish. Therefore, this multifunctional probe QM-RSH has great potential as an image tool in biological research. It also provides a novel strategy for designing fluorescent probe to investigate biomolecular information and signaling pathways under specific physiological conditions.