Electrochemical behavior of DNA at a silver electrode studied by cyclic and elimination voltammetry.

Electrochemical characteristics of native and denatured calf thymus DNA have been studied by voltammetry on a silver electrode (AgE). Experimental results obtained from linear sweep or cyclic voltammetry (LSV or CV) have been employed in elimination voltammetry. The elimination voltammetry with linear scan (EVLS), using the linear combination of the total currents measured at different scan rates, enables one or two selected particular currents to be eliminated. The best results have been obtained by using a function eliminating the kinetic and charging currents (I(k),I(c)), and conserving the diffusion current (I(d)). This function makes it possible to increase significantly voltammetric signals of native and denatured DNAs, and to reveal processes not detectable by conventional electrochemical methods. The influence of electrochemical pretreatment of silver electrode surfaces and of starting and switching potentials on DNA voltammetric signals have been discussed. Silver electrodes coupled with elimination voltammetry represent promising tools for developing new nucleic acids biosensors.