A highly selective and sensitive ICT-based Cu2+ fluorescent probe and its application in bioimaging

Cu2+ is an essential trace element for the organism, but its excess can also cause irreversible damage to the organism. As such, a “Turn-Off” fluorescent probe DPAP for the specific detection of Cu2+ was successfully constructed. DPAP exhibits large Stokes shift (120 nm), fast reaction speed (1 min), low detection limit (15.2 nM), low toxicity, and good cell permeability. Cu2+ quenches the fluorescence of DPAP by blocking its intramolecular charge transfer process to achieve the detection of Cu2+ and has been confirmed by HRMS, 1H NMR and DFT calculations. Excitingly, the five-cycle detection of Cu2+ and the successful recovery of trace Cu2+ in environmental water samples fully demonstrate the potential of DPAP for practical applications. In particular, DPAP can observe the distribution and translocation patterns of exogenous Cu2+ in HeLa cells and zebrafish in real-time. This research concept has offered important theoretical support for the study of the environmental behavior of heavy metal ions.