title: Dual fluorescence resonance energy transfer assay between tunable upconversion nanoparticles and controlled gold nanoparticles for the simultaneous detection of Pb²⁺ and Hg²⁺.
abstract: In this work, we presented a novel dual fluorescence resonance energy transfer (FRET) system for the simultaneous detection of Pb(2+) and Hg(2+). This system employed two color upconversion nanoparticles (UCNPs) as the donors, and controlled gold nanoparticles (AuNPs) as the acceptors. The two donor-acceptor pairs were fabricated by hybridizing the aptamers and their corresponding complementary DNA. Thus, the green and red upconversion fluorescence could be quenched because of a good overlap between the UCNPs fluorescence emission and the AuNPs absorption spectrum. In the presence of Pb(2+) and Hg(2+), the aptamers preferred to bind to their corresponding analytes and formed a G-quadruplexes structure for Pb(2+) and the hairpin-like structure for Hg(2+). As a result, the dual FRET was disrupted, and the green and red upconversion fluorescence was restored. Under optimized experimental conditions, the relative fluorescence intensity increased as the metal ion concentrations were increased, allowing for the quantification of Pb(2+) and Hg(2+). The relationships between the fluorescence intensity and plotting logarithms of ion concentrations were linear in the range from 0.1 to 100 nM for Pb(2+) and 0.5 to 500 nM for Hg(2+), and the detection limits of Pb(2+) and Hg(2+) were 50 pM and 150 pM, respectively. As a practical application, the aptasensor was used to monitor Pb(2+) and Hg(2+) levels in naturally contaminated samples and human serum samples. Ultimately, this type of dual FRET could be used to detect other metal ions or contaminants in food safety analysis and environment monitoring.
authors: State Key Laboratory of Food Science and Technology, Synergetic Innovation Center of Food Safety and Nutrition, School of Food Science and Technology, Jiangnan University, Wuxi 214122, PR China.
authors: Shijia
authors: S
authors: Wu
authors: State Key Laboratory of Food Science and Technology, Synergetic Innovation Center of Food Safety and Nutrition, School of Food Science and Technology, Jiangnan University, Wuxi 214122, PR China.
authors: Nuo
authors: N
authors: Duan
authors: State Key Laboratory of Food Science and Technology, Synergetic Innovation Center of Food Safety and Nutrition, School of Food Science and Technology, Jiangnan University, Wuxi 214122, PR China.
authors: Zhao
authors: Z
authors: Shi
authors: State Key Laboratory of Food Science and Technology, Synergetic Innovation Center of Food Safety and Nutrition, School of Food Science and Technology, Jiangnan University, Wuxi 214122, PR China.
authors: Congcong
authors: C
authors: Fang
authors: State Key Laboratory of Food Science and Technology, Synergetic Innovation Center of Food Safety and Nutrition, School of Food Science and Technology, Jiangnan University, Wuxi 214122, PR China. Electronic address: wangzp@jiangnan.edu.cn.
authors: Zhouping
authors: Z
authors: Wang
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry; D003116:Color; D005453:Fluorescence; D031541:Fluorescence Resonance Energy Transfer / Q000379:methods*; D005506:Food Contamination / Q000032:analysis; D054856:G-Quadruplexes; D006046:Gold / Q000737:chemistry*; D006801:Humans; D007854:Lead / Q000032:analysis* / Q000097:blood / Q000737:chemistry; D008628:Mercury / Q000032:analysis* / Q000097:blood / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D015203:Reproducibility of Results; D017747:Seafood / Q000032:analysis
chemical_list: D052157:Aptamers, Nucleotide; D007854:Lead; D006046:Gold; D008628:Mercury
keywords: Aptamer; Gold nanoparticles; Pb(2+) and Hg(2+); Upconversion nanoparticles