High-Quantum-Yield Mitochondria-Targeting Near-Infrared Fluorescent Probe for Imaging Native Hypobromous Acid in Living Cells and in Vivo.

The discovery that hypobromous acid (HOBr) can regulate the activity of collagen IV has attracted great attention. However, HOBr as an important reactive small molecule has hardly ever been studied using a detection method suitable for organisms. Herein, a high-quantum-yield mitochondria-targeting near-infrared (NIR) fluorescent probe for HOBr, RhSN-mito, was designed. RhSN-mito was easily obtained by the Suzuki cross-coupling reaction. The test results show that RhSN-mito can rapidly respond to HOBr with ultrasensitivity and high selectivity. The achievement of ultrasensitivity lies in the high signal-to-noise ratio and the highest fluorescence quantum yield of the reaction product (ΦF = 0.68) in the near-infrared region, as far as we know. RhSN-mito is successfully applied to image native HOBr in mitochondria of HepG2 cells and zebrafish. Thus, RhSN-mito is a powerful tool for detecting native HOBr in vivo and is expected to provide a method to further study the physiological and pathological functions related to HOBr.