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Journal of Analytical Methods in Chemistry
Volume 2012, Article ID 327603, 7 pages
Research Article

Detection of Quadruplex DNA by Gold Nanoparticles

Department of Chemistry, Susquehanna University, 514 University Avenue, Selinsgrove, PA 17870, USA

Received 23 November 2011; Revised 24 January 2012; Accepted 25 January 2012

Academic Editor: Christos Kontoyannis

Copyright © 2012 Heather F. Crouse et al. 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.


Gold nanoparticles have been used as a probe to detect low (<10 ppb) concentrations of quadruplex DNA. These nanoparticles display a tendency to form aggregates in the presence of certain quadruplex forms, as observed via enhanced plasmon resonance light scattering (PRLS) signals. These nanoparticles showed differing degrees of interactions with different types of quadruplex and mixed sequences but no interaction with duplex DNA. Enhancement of PRLS signals greater than 50% was observed at nanomolar DNA concentration, and a lower limit of detection of 2.1 nM was established for three different quadruplex DNA sequences, including the thrombin-inhibiting single-stranded 15 mer aptamer DNA, d(GGTTGGTGTGGTTGG), and the double-stranded 12 mer DNA, d(G4T4G4). Two different sample preparation protocols were used for the PRLS experiments, and they yielded similar results.