Development of a highly specific NIR fluorescent probe for imaging of mitochondrial HOBr fluctuations

As an essential reactive oxygen species (ROS), hypobromous acid (HOBr) plays a vital role in the immune process. Nevertheless, excessive HOBr can cause a series of diseases including cancers. Therefore, the development of the in situ detection methods for intracellular HOBr in biosystems is urgent and important to further uncover the detailed physiological and pathological effects of HOBr. In this work, a simple water-soluble nearinfrared (NIR) fluorescence dye was synthesized, which was satisfactory chosen as a highly selective and sensitive fluorescent probe for the rapid detection of HOBr based on the electrophilic bromination reaction mechanism. This probe can perform the specific detection of HOBr, which facilitates the accurate imaging of HOBr in biosystems. Finally, this probe was successfully applied to trace mitochondrial HOBr fluctuations with high resolution in living cells and zebrafish.