Ratiometric fluorescent probe for the detection of HOCl in lysosomes based on FRET strategy

Abstract A ratiometric fluorescent probe ( RIL ) for imaging lysosomal HOCl was prepared, which was designed based on the imidazo[1,5- a ]pyridine-rhodamine platform. The probe’s selectivity was excellent, and the detection was not affected by other analytes. Probe RIL responded to HOCl rapidly with a low detection limit of 27 nM. For the biological application, RIL performed well in detecting endogenous HOCl in RAW264.7 cells. Furthermore, the probe could target lysosomes and monitor lysosomal HOCl changes due to the introduction of morpholine moiety, which was identified as a lysosome-targeting group. We believe that RIL had significant potential as a practical molecular tool for HOCl-related research in lysosomes.