Study on interaction between the 2-(2-phenylethyl)-5-methylbenzimidazole and dsDNA using glassy carbon electrode modified with poly-3-amino-1,2,4-triazole-5-thiol

• Poly-3-amino-1,2,4-triazole-5-thiol (P(AT)) was coated on a glassy carbon electrode.
• Electrochemical DNA biosensor was prepared by adsorption of dsDNA onto P(AT) modified electrode.
• Guanine oxidation signals were linearly proportional to the concentration of BNN-17 in the range of 0.213–32.03 μmol L− 1.
• BNN-17 and dsDNA interaction was investigated using DPV, UV–vis, spectroscopy, and molecular docking methods.

In this study, we developed an electrochemical DNA biosensor based on a poly-3-amino-1,2,4-triazole-5-thiol (P(AT)) film modified glassy carbon electrode (GCE/P(AT)). For the first time, this electrode was used for the determination of a new benzimidazole molecule, 2-(2-phenyl ethyl)-5-methylbenzimidazole (BNN-17). The electrochemical behavior of the GCE/P(AT) electrode was investigated using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Differential pulse voltammetry (DPV) was carried out to obtain the change in the oxidation signals of the guanine and adenine before and after interaction with the BNN-17. Under the optimum conditions, a linear dependence of the guanine oxidation signals was observed when the BNN-17 concentration was in the range of 0.213–32.03 μmol L− 1 (R2 = 0.991). The limit of detection (LOD) and limit of quantification (LOQ) were found to be 0.063 μmol L− 1 and 0.21 μmol L− 1, respectively. The influence of potential interfering substances on BNN-17 determination was studied. Finally, the GCE/P(AT)/dsDNA electrode was utilized for the determination of BNN-17 in serum samples which gave sensitive, accurate, and precise results. The binding mode of BNN-17 with dsDNA was investigated using DPV, UV–vis absorption spectroscopy, and molecular docking methods. All of the experimental results indicated that BNN-17 preferred to bind on the minor groove of dsDNA. The results obtained from the experimental data were in good agreement with the molecular docking studies.