Electrochemical DNA biosensor based on chitosan/nano-V2O5/MWCNTs composite film modified carbon ionic liquid electrode and its application to the LAMP product of Yersinia enterocolitica gene sequence

A new electrochemical DNA biosensor was fabricated by using a V2O5 nanobelts (nano-V2O5), Multiwalled carbon nanotubes (MWCNTs) and chitosan (CTS) nanocomposite materials modified carbon ionic liquid electrode (CILE) as the working electrode. The CILE was prepared by using N-hexylpyridinium hexafluorophosphate (HPPF6) as the binder with the graphite powder. The CTS-V2O5-MWCNTs/CILE was used as the basal electrode for the immobilization of the single-stranded DNA (ssDNA) probe. After the hybridization with the target ssDNA sequence, the electrochemical indicator of methylene blue (MB) was used to monitor the hybridization reaction. Experimental data indicated that the synergistic effect of nano-V2O5 and MWCNTs increased the amounts of ssDNA adsorbed on the electrode surface and resulted in the corresponding increase of the electrochemical responses. This DNA biosensor combined the advantages such as the biocompatibility of V2O5 nanobelt, the excellent electron transfer ability of MWCNTs, the good film-forming ability of CTS and the high conductivity of CILE. Under the optimal conditions differential pulse voltammetry (DPV) was used to record the electrochemical response of MB and the specific ssDNA sequence could be detected in the concentration range from 1.0 x 10(-11) to 1.0 x 10(-6) mol L-1 with the detection limit as 1.76 x 10-11 mol L-1 (3 sigma). The DNA biosensor showed good stability and discrimination ability to the one-base and three-base mismatched ssDNA sequence. The loop-mediated isothermal amplification (LAMP) product of Yersinia enterocolitica gene sequence in pork meat was detected by the proposed method with satisfactory result, suggesting that the CTS-V2O5-MWCNTs/ClLE had the potential for the sensitive detection of specific gene sequence. (C) 2009 Elsevier B.V. All rights reserved.