期刊
MICROCHIMICA ACTA
卷 186, 期 11, 页码 -出版社
SPRINGER WIEN
DOI: 10.1007/s00604-019-3876-9
关键词
Mercury assay; Gold nanoparticle aggregation; Dark-field microscope; Exonuclease I; Red nanodots; Green nanodots; Aptamer; High sensitivity
资金
- Scientific Research Project of Beijing Educational Committee [KM201710028009]
- Youth Innovative Research Team of Capital Normal University
- Capacity Building for Sci-Tech Innovation-Fundamental Scientific Research Funds [19530050179]
An optical method for determination of Hg(II) is described that exploits the aggregation of gold nanoparticles (AuNPs) under dark-field microscope (DFM) observation. This assay is based on the use of a Hg(II)-specific aptamer, AuNPs modified with complementary DNA strands, and exonuclease I (Exo I). In the absence of Hg(II), the added dsDNA prevents salt-induced aggregation of the green-colored AuNPs. If Hg(II) is added, the aptamer will capture it to form T-Hg(II)-T pairs, and the complementary strand is digested by Exo I. On addition of a solution of NaCl, the AuNPs will aggregate. This is accompanied by a color change from green to orange/red) in the dark-field image. By calculating the intensity of the orange/red dots in the dark-field image, concentration of Hg(II) can be accurately determined. The limit of detection is as low as 36 fM, and response is a linear in the 83 fM to 8.3 mu M Hg(II) concentration range.
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