Semiconductor oxide based electrodes for the label-free electrical detection of DNA hybridization: Comparison between Sb doped SnO2 and CdIn2O4
First results are reported regarding the design, fabrication and operation of a DNA biochip based on a semiconductor oxide electrode that employs label-free electrical detection of the DNA hybridization. The same process of DNA functionalisation, including hydroxylation and silanization steps, was performed on two types of semiconductor oxide: Sb doped SnO2 and CdIn2O4 thin films. These oxide electrodes were laboratory-made films deposited on glass substrates using a chemical vapour deposition method, i.e. the aerosol pyrolysis technique. After having characterized some physico-chemical properties of the bare films, the label-free electrical DNA hybridization detection, without redox couple labelling, was performed using electrochemical impedance spectrometry (EIS) before and after hybridization. On both oxides, over a large frequency range, a significant increase in the impedance modulus was obtained. The increase in the case of CdIn2O4 was by a factor of 2.1 +/- 0.5 and in the case of Sb doped SnO2 was by a factor of 1.6 +/- 0.1. This phenomenon was especially marked on CdIn2O4 thin films, which exhibit a higher sensitivity to the surface event. The DNA hybridization to complementary DNA targets labelled with fluorescent markers was confirmed using fluorescence microscopy. (c) 2006 Elsevier Ltd. All rights reserved.
18th International Symposium on Bioelectrochemistry and Bioenergetics/3rd Spring Meeting of the International-Society-of-Electrochemistry JUN 19-24, 2005 Coimbra, PORTUGAL
Record created on 2009-05-12, modified on 2016-08-08