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

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 x 106 M-1. The detection limit (DL) of probe 1 was also calculated to be 5.9 x 10(-9) M. In addition, the probe has been successfully applied to fluorescence imaging in living MCF-7 cells.