1. Detection of copper ions through recovery of the fluorescence of DNA-templated copper/silver nanoclusters in the presence of mercaptopropionic acid
- Author
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Su, Yu-Ting, Lan, Guo-Yu, Chen, Wei-Yu, and Chang, Huan-Tsung
- Subjects
Fluorescence -- Research ,Metal ions -- Chemical properties ,Metal ions -- Identification and classification ,Metal ions -- Composition ,DNA -- Chemical properties ,Nanoparticles -- Chemical properties ,Nanoparticles -- Composition ,Copper -- Chemical properties ,Copper -- Atomic properties ,Silver -- Chemical properties ,Silver -- Atomic properties ,Propionic acid -- Chemical properties ,Chemistry - 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.sup.2+] ions. The fluorescence of the DNA-Cu/Ag NCs was quenched by MPA, which was recovered in the presence of [Cu.sup.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.sup.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.sup.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.sup.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.sup.2+] ions in environmental samples through analyses of Montana soil and pond water samples. 10.1021/ac101659d more...
- Published
- 2010