Recognition and detection of ssDNA using 2-mercaptobenzothiazole self-assembled monolayer modified gold electrode

Abstract

A novel method for sensitive detection of single-stranded DNA (ssDNA) using 2-mercaptobenzothiazole (MBT) self-assembled monolayer (SAM) modified gold electrode (Au-MBT) has been developed. Based on the intercalating effect of MBT into double stranded DNA (dsDNA), Au-MBT electrode possessed the ability to distinguish ssDNA and dsDNA. Cyclic voltammetry (CV) was used to preliminarily characterize the MBT self-assembled monolayer on gold electrode. In the mixture of excessive probe ssDNA and target ssDNA, current signal recorded by differential pulse voltammetry (DPV) after DNA hybridization reflected the extent of the hybridization. Definite relations were observed between the reductive peak currents and the concentration of target ssDNA. The quantitative detection of target ssDNA was achieved with a linear range from 1.59 × 10−8 to 2.4 × 10−6 mol/L. The detection limit was 2.38 × 10−9 mol/L (3σ, n = 11). The Au-MBT electrode possessed high reusability and reproducibility, no significant deterioration of peak currents occurring over 10 detection/regeneration cycles. Combined with the advantages of simplicity and low-cost, the developed electrochemical biosensor shows potential in continuous and quantitative detection of ssDNA in biological samples.