A highly sensitive turn-on fluorescent chemosensor for recognition of Zn(II) ions and its application in live cells imaging

Abstract

A novel and simple fluorescent chemosensor, DH, was synthesized. As designed, DH displayed excellent selectivity exhibiting a “turn-on” response for Zn2+ over other relevant metal ions based on PET mechanism in 100% aqueous media, and the binding constant of Zn2+ binding to DH was calculated to be 7.27 × 108 M−2. Importantly, DH exhibited high sensitivity as a Zn2+ fluorescent chemosensor with a limit of detection (LOD) of 19.25 nM, which is lower than WHO guidelines (76.0 μM). Moreover, the 2:1 stoichiometry between the chemosensor DH and Zn2+ was verified by Job's plot, fluorescent titration and high resolution mass spectroscopy. In addition, the recognition process of DH toward Zn2+ was chemically reversible and recyclable by adding Na2EDTA. Moreover, due to its good biocompatibility and low cytotoxicity, DH was successfully applied to the fluorescence imaging of Zn2+ and Na2EDTA in living HK2 cells.