Fabrication and characterization of gold nano particles for DNA biosensor applications

This research involves the preparation of a biosensor using silicon oxide for biomedical applications, and its effective use for the detection of target DNA hybridization. An electrochemical DNA biosensor was successfully fabricated by using (3-aminopropyl) tri-ethoxysilane (APTES) as a linker molecule combined with gold nanoparticles (GNPs) on a thermally oxidized SiO2 thin film. The size of the GNPs was calculated by utilizing UV-vis data with an average calculated particle size within the range of 30 +/- 5 nm, and characterization by transmission electron microscopy (TEM) and atomic force microscopy (AFM). The GNP-modified SiO2 thin films were electrically characterized through the measurement of capacitance, permittivity and conductivity using a low-cost dielectric analyzer. The capacitance, permittivity and conductivity profiles of the fabricated sensor clearly differentiated DNA immobilization and hybridization. (C) 2016 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences. Published by Elsevier B.V. All rights reserved.