Publication Date:
2019
Description:
〈h3〉Abstract〈/h3〉
〈p〉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 μM Hg(II) concentration range.〈/p〉
〈p〉
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〈caption〉
〈strong〉Graphical abstract〈/strong〉
〈em〉
〈div〉Schematic representation of a colorimetric assay for Hg(II) based on the use of a mercury(II)-specific aptamer, gold nanoparticles modified with complementary DNA strands, and exonuclease I.〈/div〉
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〈/caption〉
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〈img alt="" src="https://static-content.springer.com/image/MediaObjects/604_2019_3876_Figa_HTML.png"〉
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〈/p〉
Print ISSN:
0369-2795
Electronic ISSN:
1436-5073
Topics:
Chemistry and Pharmacology