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

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.