2-Aminopurine-modified DNA homopolymers for robust and sensitive detection of mercury and silver
Loading...
Date
2017-01-15
Authors
Zhou, Wenhu
Ding, Jinsong
Liu, Juewen
Journal Title
Journal ISSN
Volume Title
Publisher
Elsevier
Abstract
Heavy metal detection is a key topic in analytical chemistry. DNA-based metal recognition has advanced significantly producing many specific metal ligands, such as thymine for Hg2+ and cytosine for Ag+. For practical applications, however, robust sensors that can work in a diverse range of salt concentrations need to be developed, while most current sensing strategies cannot meet this requirement. In this work, 2-aminopurine (2AP) is used as a fluorescence label embedded in the middle of four 10-mer DNA homopolymers. 2AP can be quenched up to 98% in these DNA without an external quencher. The interaction between 2AP and all common metal ions is studied systematically for both free 2AP base and 2AP embedded DNA homopolymers. With such low background, Hg2+ induces up to 14-fold signal enhancement for the poly-T DNA, and Ag+ enhances up to 10-fold for the poly-C DNA. A detection limit of 3 nM is achieved for both metals. With these four probes, silver and mercury can be readily discriminated from the rest. A comparison with other signaling methods was made using fluorescence resonance energy transfer, graphene oxide, and SYBR Green I staining, respectively, confirming the robustness of the 2AP label. Detection of Hg2+ in Lake Huron water was also achieved with a similar sensitivity. This work has provided a comprehensive fundamental understanding of using 2AP as a label for metal detection, and has achieved the highest fluorescence enhancement for non-protein targets. (C) 2016 Elsevier B.V. All rights reserved.
Description
The final publication is available at Elsevier via http://dx.doi.org/10.1016/j.bios.2016.08.033 © 2017. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/
Keywords
Sybr-Green-I, Molecular Beacons, Base-Pairs, Selective Detection, Signaling Aptamers, Aqueous-Solution, Hg-II, Fluorescent, Ions, Duplexes