title: Detection of copper ions through recovery of the fluorescence of DNA-templated copper/silver nanoclusters in the presence of mercaptopropionic acid.
abstract: We have developed a simple and homogeneous fluorescence assay, comprised of 3-mercaptopropionic acid (MPA) and DNA-Cu/Ag nanoclusters (NCs) in aqueous solution, for the detection of Cu(2+) ions. The fluorescence of the DNA-Cu/Ag NCs was quenched by MPA, which was recovered in the presence of Cu(2+) ions. This MPA-induced fluorescence quenching arises through changes in the DNA conformation that occur after interactions between MPA and the Cu/Ag clusters. The MPA-induced fluorescence quenching displayed typical characteristics in Stern-Volmer plots; it followed a static quenching mechanism. The presence of Cu(2+) ions resulted in the oxidation of MPA to form a disulfide compound, leading to recovery of the fluorescence of the DNA-Cu/Ag NCs. The fluorescence of the DNA-Cu/Ag NCs in the presence of MPA increased upon increasing the concentration of Cu(2+) ions over the range from 5 to 200 nM. The DNA-Cu/Ag NC probe provided the limit of detection (at a signal-to-noise ratio of 3) for Cu(2+) ions of 2.7 nM, with high selectivity (by at least 2300-fold over other tested metal ions). We validated the practicality of using this probe for the detection of Cu(2+) ions in environmental samples through analyses of Montana soil and pond water samples.
authors.affiliation: Department of Chemistry, National Taiwan University, 1, Section 4, Roosevelt Road, Taipei 106, Taiwan.
authors.forename: Yu-Ting
authors.initials: YT
authors.lastname: Su
authors.forename: Guo-Yu
authors.initials: GY
authors.lastname: Lan
authors.forename: Wei-Yu
authors.initials: WY
authors.lastname: Chen
authors.forename: Huan-Tsung
authors.initials: HT
authors.lastname: Chang
mesh_terms: D015097:3-Mercaptopropionic Acid; D002413:Cations, Divalent / Q000737:chemistry; D003300:Copper / Q000032:analysis* / Q000737:chemistry; D004247:DNA / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry*; D012834:Silver / Q000737:chemistry*; D012989:Soil Pollutants / Q000032:analysis; D013050:Spectrometry, Fluorescence / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000032:analysis
chemical_list: D002413:Cations, Divalent; D012989:Soil Pollutants; D014874:Water Pollutants, Chemical; D012834:Silver; D003300:Copper; D004247:DNA; D015097:3-Mercaptopropionic Acid