Electrochemical detection of DNA hybridization based on polypyrrole/ss-DNA/multi-wall carbon nanotubes paste electrode

Honglan Qi; Xiaoxia Li; Pei Chen; Chengxiao Zhang

doi:10.1016/j.talanta.2006.12.032

Electrochemical detection of DNA hybridization based on polypyrrole/ss-DNA/multi-wall carbon nanotubes paste electrode

Talanta. 2007 May 15;72(3):1030-5. doi: 10.1016/j.talanta.2006.12.032. Epub 2007 Jan 3.

Authors

Honglan Qi¹, Xiaoxia Li, Pei Chen, Chengxiao Zhang

Affiliation

¹ Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province, School of Chemistry and Materials Science, Shaanxi Normal University, Xi'an 710062, PR China.

PMID: 19071720
DOI: 10.1016/j.talanta.2006.12.032

Abstract

A sensitive electrochemical detection of DNA hybridization using a paste electrode assembled by multi-wall carbon nanotubes (MWNT) and immobilizing DNA probe within electropolymerized polypyrrole (ppy) was developed. The detection approach relied on entrapping of DNA probe within electropolymerized ppy film on the MWNT paste electrode and monitoring the current change generated from an electroactive intercalator of ethidium bromide (EB) after DNA hybridization. As a consequence of DNA hybridization, significant changes in the current of EB intercalated with double-stranded DNA (ds-DNA) on the MWNT paste electrode were observed. Based on the response of EB, only the complementary DNA sequence gave an obvious current signal compared with the five-point mismatched and non-complementary sequences. The oxidation peak current was linearly related to the logarithm of the concentration of the complementary DNA sequence from 1.0x10(-10) to 1.0x10(-8)M with a detection limit of 8.5x10(-11)M. This work demonstrates that the incorporation of MWNT paste electrode with electropolymerization is a promising strategy of functional interfaces for the immobilization of biological recognition elements.