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Journal of Nanomaterials
Volume 2014, Article ID 683460, 7 pages
http://dx.doi.org/10.1155/2014/683460
Research Article

Application of Gold Nanoparticles for Electrochemical DNA Biosensor

1Chemistry Department, College of Science, Al-Anbar University, Ramadi, Iraq
2Institute of Nano Electronic Engineering, Universiti Malaysia Perlis, 01000 Kangar, Perlis, Malaysia

Received 20 October 2013; Accepted 3 April 2014; Published 25 May 2014

Academic Editor: M. Ghoranneviss

Copyright © 2014 Ahmed Mishaal Mohammed 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.

Abstract

An electrochemical DNA biosensor was successfully fabricated by using (3-aminopropyl)triethoxysilane (APTES) as a linker molecule combined with the gold nanoparticles (GNPs) on thermally oxidized SiO2 thin films. The SiO2 thin films surface was chemically modified with a mixture of APTES and GNPs for DNA detection in different time periods of 30 min, 1 hour, 2 hours, and 4 hours, respectively. The DNA immobilization and hybridization were conducted by measuring the differences of the capacitance value within the frequency range of 1 Hz to 1 MHz. The capacitance values for DNA immobilization were 160 μF, 77.8 μF, 70 μF, and 64.6 μF, respectively, with the period of time from 30 min to 4 hours. Meanwhile the capacitance values for DNA hybridization were 44 μF, 54 μF, 55 μF, and 61.5 μF, respectively. The capacitance value of bare SiO2 thin film was 0.42 μF, which was set as a base line for a reference in DNA detection. The differences of the capacitance value between the DNA immobilization and hybridization revealed that the modified SiO2 thin films using APTES and GNPs were successfully developed for DNA detection.