A highly selective and sensitive photoinduced electron transfer (PET) based HOCl fluorescent probe in water and its endogenous imaging in living cells.

A probe based on the phenothiazine-acridine orange conjugate (Ptz-AO) has been designed and synthesized for the sensitive and selective detection of HOCl. Ptz-AO has excellent properties, including pH-independence of fluorescence, high resistance to photobleaching, and response in real time. The value of Ptz-AO was confirmed by exogenous, endogenous and the real-time imaging of HOCl in vitro using a fluorescence microscope.