Electrochemical Behaviors of Methylene Blue on DNA Modified Gold Electrode

Abstract

DNA modified electrode was prepared by covalent immobilization of single-stranded calf thymus DNA (ssDNA) or double-stranded calf thymus DNA (dsDNA) on a mercaptoethanol monolayer self-assembled gold electrode with the help of N-(3-dimethylaminopropyl)-N-ethylcarbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS). The electrochemical behaviors of methylene blue (MB) on ssDNA/self-assembled monolayer (SAM)/Au or dsDNA/SAM/Au electrodes were studied. MB binds to ssDNA or dsDNA with different models. The adsorptive constants are larger for dsDNA/SAM/Au electrode than ssDNA/SAM/Au electrode. MB binds to dsDNA predominantly intercalative models. The results show that dsDNA had a stronger appetency for MB, which indicates that MB is a suitable hybridization indicator. Keywords: DNA modified gold electrode, Self-assembled monolayer, Electrochemistry, Methylene blue, Electrochemical Behaviors, covalent immobilization, single-stranded calf thymus DNA (ssDNA), double-stranded calf thymus DNA (dsDNA), mercaptoethanol monolayer, N-hydroxysuccinimid, methylene blue (MB)sDNA/self-assembled monolayer (SAM), dsDNA/SAM/Au, hybridization indicator, DNA biosensors, Gold Electrode, sonicating electrodes, SAM-modified gold electrode, Cyclic voltammetry (CV), electrochemical indicator, bare gold, MB-based DNA, MB-guanines interaction, double helix of dsDNA, SAM/Au electrode, Langmuir adsorption curve, electron transfer resistance, DNA electrochemistry