Next Article in Journal
Embedded Ceria Nanoparticles in Crosslinked PVA Electrospun Nanofibers as Optical Sensors for Radicals
Next Article in Special Issue
Colorimetric Integrated PCR Protocol for Rapid Detection of Vibrio parahaemolyticus
Previous Article in Journal
Tracking Control of a Magnetic Shape Memory Actuator Using an Inverse Preisach Model with Modified Fuzzy Sliding Mode Control
Previous Article in Special Issue
Sensitive Bioanalysis Based on in-Situ Droplet Anodic Stripping Voltammetric Detection of CdS Quantum Dots Label after Enhanced Cathodic Preconcentration
Open AccessArticle

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
Author to whom correspondence should be addressed.
Academic Editor: Huangxian Ju
Sensors 2016, 16(9), 1370;
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)
PDF [1417 KB, uploaded 26 August 2016]


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

Graphical abstract

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

Share & Cite This Article

MDPI and ACS Style

Kleinke, K.; Saran, R.; Liu, J. Label-Free Ag+ Detection by Enhancing DNA Sensitized Tb3+ Luminescence. Sensors 2016, 16, 1370.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics



[Return to top]
Sensors EISSN 1424-8220 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top