A FRET-based fluorescent probe for mercury ions in water and living cells

Abstract

On the basis of fluorescence resonance energy transfer (FRET), a new rhodamine derivative (DRh) was synthesized as a ratiometric fluorescent probe for detecting Hg2+ in water and living cells samples. The recognition properties of the probe DRh with metal ions had been investigated in H2O/CH3CN (9:1, v/v; Tris-HCl 50mmolL−1; pH=7.0) solution by the UV–Vis spectrophotometry and the fluorescence spectrophotometry. The results showed that the probe DRh exhibited the selective recognition of Hg2+. Upon the addition of Hg2+, the spirolactam ring of probe DRh was opened. The 1:1 stoichiometric structure between DRh and Hg2+ were supported by Job's plot, MS and DFT theoretical calculations. The linearly fluorescence intensity ratio (I582/I538) is proportional to the concentration of Hg2+ in the range 0–30μmolL−1. The limit of detection (LOD) of Hg2+ is 0.008μmolL−1 (base on S/N=3). The present probe was applied to the determination of Hg2+ in neutral water samples and gave recoveries ranging from 104.5 to 107.9%. Furthermore, the fluorescent probe also can be applied as a bioimaging reagent for Hg2+ detection in HeLa cells.