A Label-free Electrochemical Biosensor for Acrylamide Based on DNA Immobilized on Graphene Oxide-Modified Glassy Carbon Electrode

Abstract

Acrylamide (AA) is a widely used chemical compound, which has strong neurotoxicity, and potential carcinogenicity and genotoxicity. In the present work, the interaction between AA and DNA was confirmed by UV-visible spectroscopy. According to such an interaction, a label-free DNA biosensor for electrochemical determination of AA was proposed. To fabricate the sensor, graphene oxide (GO) was firstly coated on glassy carbon electrode (GCE) surface. Then DNA was immobilized on GO/GCE by electroadsorption. Due to large surface area of GO, DNA was effectively immobilized on the electrode surface. Moreover, the unique nanostructure and excellent electron transfer ability of GO significantly promoted the direct electron transfer of DNA. Thus, DNA showed two strong oxidation peaks on GO/GCE, which could be used as the electrochemical signal for AA sensing. The Influences of adsorption potential and adsorption time on the immobilized DNA and pH for AA sensing were systematically investigated. Under optimum conditions, the response of DNA/GO/GCE was linear to the concentration of AA from 5.0×10-8 to 1.0×10-3 mol/L. Moreover, the sensor showed good reproducibility and high stability.