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Article

Label-Free Ag+ Detection by Enhancing DNA Sensitized Tb3+ Luminescence

Department of Chemistry and Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
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Author to whom correspondence should be addressed.
Academic Editor: Huangxian Ju
Sensors 2016, 16(9), 1370; https://doi.org/10.3390/s16091370
Received: 10 July 2016 / Revised: 17 August 2016 / Accepted: 23 August 2016 / Published: 26 August 2016
(This article belongs to the Special Issue Nanobiosensing for Sensors)
In this work, the effect of Ag+ on DNA sensitized Tb3+ luminescence was studied initially using the Ag+-specific RNA-cleaving DNAzyme, Ag10c. While we expected to observe luminescence quenching by Ag+, a significant enhancement was produced. Based on this observation, simple DNA oligonucleotide homopolymers were used with systematically varied sequence and length. We discovered that both poly-G and poly-T DNA have a significant emission enhancement by Ag+, while the absolute intensity is stronger with the poly-G DNA, indicating that a G-quadruplex DNA is not required for this enhancement. Using the optimized length of the G7 DNA (an oligo constituted with seven guanines), Ag+ was measured with a detection limit of 57.6 nM. The signaling kinetics, G7 DNA conformation, and the binding affinity of Tb3+ to the DNA in the presence or absence of Ag+ are also studied to reveal the mechanism of emission enhancement. This observation is useful not only for label-free detection of Ag+, but also interesting for the rational design of new biosensors using Tb3+ luminescence. View Full-Text
Keywords: aptamers; biosensors; fluorescence; luminescence; terbium; silver aptamers; biosensors; fluorescence; luminescence; terbium; silver
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MDPI and ACS Style

Kleinke, K.; Saran, R.; Liu, J. Label-Free Ag+ Detection by Enhancing DNA Sensitized Tb3+ Luminescence. Sensors 2016, 16, 1370. https://doi.org/10.3390/s16091370

AMA Style

Kleinke K, Saran R, Liu J. Label-Free Ag+ Detection by Enhancing DNA Sensitized Tb3+ Luminescence. Sensors. 2016; 16(9):1370. https://doi.org/10.3390/s16091370

Chicago/Turabian Style

Kleinke, Kimberly, Runjhun Saran, and Juewen Liu. 2016. "Label-Free Ag+ Detection by Enhancing DNA Sensitized Tb3+ Luminescence" Sensors 16, no. 9: 1370. https://doi.org/10.3390/s16091370

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