A simple salicylaldehyde-based fluorescent “turn-on” probe for selective detection of Zn2+ in water solution and its application in live cell imaging

Abstract

A simple salicylaldehyde-based fluorescent probe 1 for Zn²⁺ was prepared. The probe 1 has been proven to be highly selective and very sensitive to Zn²⁺, and also shows remarkable fluorescence emission improvement upon combining with Zn²⁺ in a Tris–HCl buffer system at pH 7.2. The great fluorescence changes of probe 1 after incorporation with Zn²⁺ are mainly ascribed to the photo-induced electron transfer (PET) mechanism. The experimental results reveal that probe 1 could effectively complex Zn²⁺ at a molar ratio of about 1 : 1 and the binding constant (K) between probe 1 and Zn²⁺ was determined to be 3.78 × 10⁶ M⁻¹. The detection limit (DL) of probe 1 was also calculated to be 5.9 × 10⁻⁹ M. In addition, the probe has been successfully applied to fluorescence imaging in living MCF-7 cells.