A reaction-based long-wavelength fluorescent probe for Cu2+ detection and imaging in living cells

Abstract A turn-on fluorescent probe 1 has been developed for Cu 2+ by the incorporation of picolinate onto a tricyanofuran-based fluorophore. The probe was weakly fluorescent due to the masked phenolic group and the resulted inhibition of the push-pull character of the fluorophore. The chemoselective reaction of probe 1 with Cu 2+ leads to a dramatic fluorescence enhancement at 610 nm via the Cu 2+ -mediated hydrolysis of picolinate moiety and the subsequent release of the highly emissive fluorophore. This probe features high selectivity for Cu 2+ over other cations, as well as high sensitivity with a low detection limit of 54 nM. Moreover, cell cytotoxicity and imaging tests indicate that probe 1 is biocompatible and can be utilized for imaging Cu 2+ in live cells.