A ratiometric fluorescent probe for lysosomal hypochlorous acid based on through-bond energy transfer strategy

In this paper, we synthesized a ratiometric fluorescence probe (IRh-Ly) for lysosomal hypochlorous acid (HOCl) by adopting a through-bond energy transfer (TBET) strategy on rhodamine-imidazo[1,5-a]pyridine platform. IRh-Ly showed brilliant selectivity, rapid response for HOCl. The probe also exhibited high sensitivity with the detection limit calculated to be 10.2 nM. Moreover, we demonstrated its successful application of detecting lysosomal HOCl in living RAW264.7 cells. Notably, the morpholine was integrated into the fluorescent probe IRh-Ly and the results revealed that IRh-Ly could target lysosome and detect the lysosomal HOCl. All the unique features made IRh-Ly particularly suitable for ratiometric HOCl detection and bio-imaging applications. [Display omitted] •A novel ratiometric HOCl fluorescent probe was developed based on the imidazo[1,5-a]pyridine -rhodamine TBET platform.•The probe showed superior selectivity and sensitivity toward HOCl.•The probe could selectively stain lysosome.•The probe was suitable for imaging endogenous HOCl in RAW264.7 cells.