Ultrafast Electrochemical DNA Biosensor Based on Electrical Potential-Assisted Hybridization Using Differential Pulse Voltammetry (DPV)

A simple electrochemical DNA (E-DNA) biosensor for rapid and specific determination of DNA was developed based on electrical potential-assisted hybridization. The E-DNA biosensor was constructed by a capture probe immobilized on the gold electrode. An external alternating voltage was applied to the electrode interface during DNA hybridization between the capture probe with its target chain and a ferrocene-labeled peptide nucleic acid (Fc-PNA). The PNA was used to minimize the electrostatic repulsion between nucleic acids due to its neutral backbone. The hybridized DNA was examined by differential pulse voltammetry (DPV) and electrochemical impedance spectroscopic (EIS). Compared with the passive hybridization strategy that generally takes several hours, this E-DNA biosensor took the advantage of controllable potential to accelerate nucleic acid hybridization and significantly shorten it to less than 90 s, thereby achieving rapid detection. The electrochemical signal showed a good linear relationship with the target DNA from 10 pM to 10 nM. In addition, this E-DNA biosensor had good specificity that was capable of distinguishing mismatched sequences. The developed biosensor is a promising diagnostic for the rapid and accurate determination of DNA.