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Turn-On Fluoresence Sensor for Hg2+ in Food Based on FRET between Aptamers-Functionalized Upconversion Nanoparticles and Gold Nanoparticles

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journal contribution
posted on 2018-05-30, 00:00 authored by Yan Liu, Qin Ouyang, Huanhuan Li, Min Chen, Zhengzhu Zhang, Quansheng Chen
In this study, a turn-on nanosensor for detecting Hg2+ was developed based on the fluorescence resonance energy transfer (FRET) between long-strand aptamers-functionalized upconversion nanoparticles (UCNPs) and short-strand aptamers-functionalized gold nanoparticles (GNPs). In the absence of Hg2+, FRET between UCNPs and GNPs occurred because of the specific matching between two aptamers, resulting in the fluorescence quenching of UCNPs. In the presence of Hg2+, long-stranded aptamers fold back into a hairpin structure due to the stable binding interactions between Hg2+ and thymine, leading to the release of GNPs from UCNPs, resulting in the quenched fluorescence restoration. Under the optimized conditions, the nanosensor achieved a linear detection range of 0.2–20 μM and a low detection limit (LOD) of 60 nM. Meanwhile, it showed good selectivity and has been applied to detecting Hg2+ in tap water and milk samples with good precision.

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