A highly specific pyrene-based fluorescent probe for hypochlorite and its application in cell imaging

A fluorescent probe, 1-pyrenecarboxaldehyde, 2-phenylhydrazone (1), has been successfully developed for the detection of hypochlorite on the basis of a specific reaction with phenylhydrazone. The design strategy for the probe is based on the strong quenching effect of electron-donor phenylhydrazone on pyrene fluorescence via the photoinduced electron transfer process, and is accomplished through constructing the conjugated molecule by using a cleavable CN bond as a linker. This probe reacts selectively with hypochlorite over other ions and reactive oxygen species (ROS), accompanied by 42.6-fold fluorescence enhancement. Biological imaging studies using living cells (HeLa cells) to detect hypochlorite are successfully demonstrated.