A highly sensitive and selective ratiometric fluorescent sensor for Zn2+ ion based on ICT and FRET

A ratiometric sensor (QA) for detecting Zn2+ with high sensitivity and selectivity was reported. The fluorescence changes of sensor upon the addition of Zn2+ were attributed to the conjugation of internal charge transfer and fluorescence resonance energy transfer mechanisms. There is a good linear relationship between the fluorescence ratio I-497 nm/I-420 nm and the concentrations of Zn2+ ranging from 0 mu M to 40 mu M, which makes an effective ratiometric detection of Zn2+ ion. The limit of detection (LOD) was evaluated to be 33.6 nM. The imaging experiments indicated that QA is cell-permeable and can be used to detect Zn2+ within living cells with good selectivity over Cd2+. Crown Copyright (C) 2013 Published by Elsevier Ltd. All rights reserved.