Chinese Journal of Applied Chemistry ›› 2010, Vol. 27 ›› Issue (08): 970-977.DOI: 10.3724/SP.J.1095.2010.90772

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Electrochemical Impedance Spectroscopy Study on SH-ssDNA Self-Assembling, Hybridization and Orientation on Thin-film Nana-gold Electrode

WEI Xu, HAO Qing-Li*, LU Lu-De, WANG Xin, YANG Xu-Jie   

  1. (Materials Chemistry Laboratory,Nanjing University of Science & Technology,Nanjing 210094)
  • Received:2009-11-23 Revised:2009-12-29 Published:2010-08-10 Online:2010-08-10

Abstract:

The self-assembling, hybridization and orientation of SH-ssDNA on the surface of thin-film nano-gold electrodes were characterized systematically by means of the electrochemical impedance technique. The effects of assembling time, concentration and the length of SH-ssDNA on its self-assembling were investigated. The Rct and surface coverage reached the highest values when assembling time was 15 h. The influences of the concentration and length of SH-ssDNA and its hybridization method with complementary DNA on the hybridization reaction were also studied. The result shows the change of Rct decreases with the increase of the SH-ssDNA concentration. The Rct was increased by 16% when the concentration of SH-ssDNA was 5 μmol/L. The data simulation and analysis of impedance spectroscopy indicated that a unique self-assembled monolayer of SH-ssDNA was formed with an upright orientation on the nano-Au electrode surface. The result shows the hybridization efficiency is closely associated with the coverage of SH-ssDNA.

Key words: Electrochemical Impedance Spectroscopy, SH-ssDNA, Self-Assembling, Hybridization, Orientation

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