A colorimetric and ratiometric fluorescent probe for Cu2+ with a large red shift and its imaging in living cells

Abstract

The ester derived from picolinic acid and 4-hydroxynaphthalimide has been developed as a colorimetric and ratiometric fluorescent probe for the detection of Cu²⁺. Upon exposure to Cu²⁺ in a buffered solution, the probe displays a large red shift both in its absorption (110 nm) and emission (143 nm) spectra. This novel probe has a high sensitivity and an excellent selectivity for Cu²⁺ ions over competing metal ions (K⁺, Na⁺, Zn²⁺, Ni²⁺, Mn²⁺, Mg²⁺, Ca²⁺, Hg²⁺, Cd²⁺, Pb²⁺, Fe²⁺, Co²⁺, Ba²⁺, Ag⁺ and Fe³⁺). Most importantly, this new picolinate probe can successfully detect Cu²⁺ in living cells.