Lipid Droplet-Specific Dual-Response Fluorescent Probe for the Detection of Polarity and H2O2 and Its Application in Living Cells

H2O2 and polarity are quite important in many physiological and pathological processes, and their relationship is complicated and obscure for researchers. Thus, it is vital and challenging to achieve simultaneous detection of H2O2 and polarity in vivo. Herein, the first naphthalimide–triphenylamine-based dual-site fluorescent probe NATPA is developed for simultaneously imaging intracellular H2O2 and polarity fluctuations. It exhibits excellent sensitivity (LOD = 44 nM), selectivity, and fast response (15 min) to H2O2 and a superior capacity for detecting polarity upon the intramolecular charge transfer (ICT) effect. Besides, the probe displays low cytotoxicity and lipid droplet targeting and is further applied in imaging H2O2 and polarity fluctuations in HepG2 and L-02 cells, so that NATPA is qualified to distinguish cancer cells from normal cells. This research contributes a new design principle for the construction of dual-site fluorescent probes for simultaneously detecting active molecules and polarity.