Methylene Blue as a Novel Electrochemical Hybridization Indicator

Abstract

The interaction of double stranded DNA (dsDNA) and single stranded DNA (ssDNA) with Ru(II) complex with 2,2′-bipyridine ligand (Ru(bpy)3]2+) and methylene blue (MB) were explored by using voltammetric and spectrophotometric methods. The electrochemistry of [Ru(bpy)3]2+ and MB was also investigated at a dsDNA-modified carbon paste electrode (CPE), a ssDNA-modified CPE and a bare CPE by means of differential pulse voltammetry (DPV), and cyclic voltammetry (CV) and the increased peak currents were observed, in respect to the order of electrodes. The structure of DNA was determined by the magnitudes of the voltammetric peaks of [Ru(bpy)3]2+ and MB. The hypochromicity of the visible absorption bands of [Ru(bpy)3]2+ and MB upon the interaction with dsDNA and ssDNA was observed. Numerous factors affecting the DNA immobilization, indicator binding reactions and ionic strength were optimized to maximize the sensitivity and reduce the assay time.