1,8-Naphthalimide modified [12]aneN3 compounds as selective and sensitive probes for Cu2+ ions and ATP in aqueous solution and living cells

Abstract

A new fluorescent probe 1 featuring one 1,8-naphthalimide and two [12]aneN3 units was synthesized. In the presence of Cu2+ ions, the fluorescence emission of 1 was quenched by a factor of 127-fold and no interference by other metal ions was observed under physiological conditions. By means of titration and a Job's plot it was established that 1 forms a complex with Cu2+ ions in a 1:2 ratio. The fluorescence of the 1-Cu2+ complex was recovered by the addition of Adenosine-5′-triphosphate (ATP) in aqueous solution. Due to its low cytotoxicity, good water solubility, and high sensitivity, probe 1 was successfully applied in the sequential recognition of Cu2+ and ATP in aqueous solution and HeLa cells. The highly selective and sensitive ability of 1-Cu2+ complex to detect ATP even enables its bio-analytical applications in real-time imaging in living cells.