Electrochemical DNA Biosensor Based on Magnetite/Multiwalled Carbon Nanotubes/Chitosan Nanocomposite for Bacillus Cereus Detection of Potential Marker for Gold Prospecting

Limei Zuo; Qing Qu; Lei Li; Xin Ran; Jingwei Gui; Qiang Wang; Xinhua Cui; Changliang Jiang

Index: 10.1002/elan.201700801

Full Text: HTML

Abstract

A label‐free DNA biosensor based on magnetite/multiwalled carbon nanotubes/chitosan (Fe3O4/MWCNTs‐COOH/CS) nanomaterial for detection of Bacillus cereus DNA sequences was fabricated. Negatively charged DNA was electrostatically adsorbed onto materials by protonation of positively charged chitosan under acidic conditions. The electrode surface and hybridization process were carried out by cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS). Under optimal conditions, the biosensor showed a good linear relationship between peak currents difference (ΔI) and logarithm of the target DNA concentration (Log C) ranging from 2.0×10−13 to 2.0×10−6 M with a detection limit of 2.0×10−15 M (signal/noise ratio of 3). The biosensor also revealed an excellent selectivity to three‐base, completely mismatched and completely matched DNA. This is a simple, fast and friendly method with a low detection limit for the detection of Bacillus cereus specific DNA compared with previously reported electrochemical DNA biosensor. Furthermore, the DNA biosensor may lead to the development of a technology for gold prospecting in the wild.