A highly sensitive and rapidly responding fluorescent probe with a large Stokes shift for imaging intracellular hypochlorite

A naphthalimide-based fluorescent probe NACl with a large Stokes shift has been successfully developed for highly sensitive, selective and ultrafast detection of hypochlorite (ClO^-). This probe utilizes an oxidative deoximation reaction to provide high selectivity and optical dynamic range for detection of ClO^- in aqueous solution. Compared to similar systems involving reactive oxygen species (ROS), including superoxide, tert-butyl hydroperoxide, hydroxyl radical, alkylperoxyl radical, and H₂O_2, NACl provides 138-fold fluorescence enhancement. Its outstanding response time of less than 3 s and detection limit of 2.88 nM establish the potential value of NACl for interrogating the pathology and physiology of intracellular endogenous ClO^-.