A new mitochondria-targeting fluorescent probe for ratiometric detection of HO in live cells.

With this research we presented a ratiometric and mitochondria-target fluorescent probe (Mito-HT) for detection of HO both in vitro and in live cells. Mito-HT was constructed by direct conjugation of aryl boronate to fluorophore with three synthetic steps. The borate group is cleaved from Mito-HT in the presence of HO, resulting in the exposure of the hydroxyl group of the electron donating group. Then the ICT mechanism was turned on, and the fluorescence emission of Mito-HT at 493 nm was red-shifted to 562 nm, thereby achieving radiometric detection of HO. Mito-HT exhibited a highly selectivity towards HO, and this interaction can be completed within 40 min. Mito-HT could be used for quantitative detection of HO (0-200 μM) through ratiometric fluorescence signal readout. And limit of detection (LOD) is approximately 0.33 μM. The relatively high stability and medium fluorescence quantum yield of Mito-HT (0.39) and Mito-HT-OH (0.43) enable clear mitochondria localization and dual-channel fluorescence imaging of HO in live cells with confocal microscopy.