A fast-responsed lysosomal-targeted fluorescent probe based on BODIPY with low limit detection for hypochlorous acid and its application of intracellular hypochlorous acid bioimaging

For highly sensitive and selective detection of ClO − over other reactive oxygen species (ROS) and anions, a fluorescent probe MN-BODIPY by introducing a morpholine group into the 8-position of BODIPY which could be used for targeting lysosome and improving water solubility was designed and synthesized. As a result of the C=N isomerization mechanism at 2-position of BODIPY, the probe alone generated extremely weak fluorescence. However, in the presence of ClO − , the probe exhibited a dramatic enhancement of fluorescence intensity by a 29-fold increase at 530 nm accompanying with quantum yield changing from 0.03 to 0.25. Accordingly, the probe displayed fast response for ClO − within 60 s. The limit of detection (LOD) for ClO − was calculated as 16.5 nM from the titration experiments, which is lower than most previously reported ClO − -selective probes. Moreover, MN-BODIPY had been successfully employed for monitoring exogenous and endogenous hypochlorous in MCF-7 cells with satisfying results, perhaps it was feasible for detecting abnormal contents of hypochlorous in a biological system and accomplished the goal of maintaining normal human activities. At last, the fluorescence imaging showed that MN-BODIPY was capable of localizing lysosomes in living cells.