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

•A ratiometric sensor for Zn2+ detection was reported.•The fluorescent changes were attributed to ICT and FRET mechanisms.•The sensor is cell-permeable and can be used to detect Zn2+ within living cells.

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 I497nm/I420nm and the concentrations of Zn2+ ranging from 0 μM to 40 μM, 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+.

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