Electrooxidation of DNA at glassy carbon electrodes modified with mutiwall carbon nanotubes dispersed in polyethylenimine.

GUILLERMINA L. LUQUE; NANCY F. FERREYRA; ADRIÁN GRANERO; SOLEDAD BOLLO; GUSTAVO A. RIVAS

ELECTROCHIMICA ACTA

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2011 vol. 56 p. 9121 - 9126

0013-4686

This work reports the electrochemical response of dsDNA and oligo(dG)21 at glassy carbon electrodes (GCE) modified with a dispersion of multi-walled carbon nanotubes in  olyethylenimine (CNT-PEI). Scanning Electron Microscopy and Scanning Electrochemical Microscopy demonstrate that the dispersion covers the whole surface of the electrode although there are areas with higher density of CNTs and, consequently, with higher electrochemical reactivity. The adsorption of DNA at GCE/CNT-PEI is fast and it is mainly driven by electrostatic forces. A clear oxidation signal is obtained either for dsDNA or oligo(dG)21 at potentials smaller than those for the oxidation at bare GCE. Comparison of the behavior of native, thermally denatured and renatured DNAs demonstrated that the electrochemical response highly depends on the 3D structure of the nucleic acid.