A near-infrared fluorescent probe for Cu2+ in living cells based on coordination effect

A near-infrared (NIR) fluorescence probe for copper(Ⅱ) ions (Cu2+) has been synthesized and demonstrated that it could selectively and sensitively react with Cu2+ through specific coordination reaction. ESI-Mass and Job’s plot confirmed a stoichiometric ratio of 2–1 between the probe molecules and Cu2+. This NIR fluorescence probe shows a fast response, high sensitivity and anti-interference performance for Cu2+ and has been successfully applied for the detection of Cu2+ in aqueous solution. The detection limit was calculated as low as 14 nM. It has been further demonstrated that the probe exhibited good cell permeability and could be applied for monitoring the fluctuation of Cu2+ in living cells by NIR fluorescence imaging.