Direct DNA hybridization on the single-walled carbon nanotubes modified sensors detected by voltammetry and electrochemical impedance spectroscopy

Carboxylic acid functionalized single-walled carbon nanotubes modified graphite sensors (SWCNT-PGEs) were developed for electrochemical monitoring of direct DNA hybridization related to specific sequence of Hepatitis B virus, which substantially enhance the electrochemical transduction resulting from guanine oxidation signal comparison to bare PGEs. The performance characteristics of DNA hybridization on disposable CNT-PGE were explored measuring the guanine signal in terms of optimum analytical conditions; probe and target concentration, hybridization time, and selectivity. The voltammetric results were also complemented with electrochemical impedance spectroscopy (EIS), that was used to characterize the successful construction of carbon nanotubes modification onto the surface of PGEs. © 2009 Wiley-VCH Verlag GmbH & Co.