A novel ratiometric fluorescent probe for the detection of HOCl based on FRET strategy

•A novel ratiometric HOCl fluorescent probe was developed based on the imidazo[1,5-a]pyridine −rhodamine FRET platform.•The probe showed superior sensitivity and selectivity toward HOCl.•The probe could selectively stain lysosomes.•The probe was suitable for imaging endogenous HOCl in RAW264.7 cells.

A novel ratiometric fluorescent probe (RIM) for HOCl was designed on imidazo[1,5-a]pyridine-rhodamine FRET platform. Upon addition of HOCl, the imidazo[1,5-a]pyridine fluorescence increased and the rhodamine fluorescence increased simultaneously. The ratios (I585/I465) displayed brilliant HOCl-dependent performance and responded linearly to HOCl. RIM could respond to HOCl rapidly (within 20 s) with a low detection limit of 24 nM RIM also exhibited high selectivity, and low cytotoxicity. Moreover, it has been successfully applied in fluorescence imaging in living cells and the results confirmed that the probe could selectively stain lysosomes with excellent photostability.

Graphical abstractA novel ratiometric fluorescent probe (RIM) for HOCl was designed on imidazo[1,5-a]pyridine-rhodamine FRET platform, which responded to HOCl with short response time, high selectivity, excellent photostability and lysosomal-targeting ability. RIM was applied to monitor endogenous HOCl in RAW264.7 cells with low cytotoxicity.Download high-res image (148KB)Download full-size image