Electrochemical sensor for transgenic maize MON810 sequence with electrostatic adsorption DNA on electrochemical reduced graphene modified electrode

An electrochemical DNA biosensor for the detection of ssDNA sequence related to transgenic maize MON810 was fabricated with an electrochemical reduced graphene (ERG) modified carbon ionic liquid electrode (CILE) as the working electrode and methylene blue (MB) as the hybridization indicator. The probe ssDNA sequence was immobilized on the surface of ERG/CILE through electrostatic adsorption and the presence of ERG increased the adsorption amounts of probe ssDNA sequence on the electrode, which resulted in the corresponding increase of the reduction peak current of MB. Under the optimal conditions differential pulse voltammetric responses of MB were proportional to the concentration of target ssDNA sequences in the range from 1.0 × 10−11 to 1.0 × 10−6 mol/L with the detection limit as 4.52 × 10−12 mol/L (3σ). The sensor was further used for the detection of PCR products of transgenic maize samples with satisfactory results, which exhibited the advantages including simple and rapid procedure with the practical application.