A Comparative Study of Carbon Nanotube paste Electrode for Development of Indicator-free DNA Sensors Using DPV and EIS: Human Interleukin-2 Oligonucleotide as a Model

Abstract

Differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) were employed for development of electrochemical DNA hybridization biosensors based on carbon paste electrode (CPE) and multi-wall carbon nanotubes incorporated into carbon paste electrode (CNTPE). The sensors rely on immobilization of a 20-mer single stranded oligonucleotide (chIL-2) probe for detection of target DNA, as a model. The hybridization event was compared by DPV and EIS. Result showed that employment of EIS for detection of hybridization on CNTPE surface was impossible and on CPE surface was not beneficial. However, DPV method demonstrated a proper potential for detection of hybridization event on the surface of the electrodes. Moreover, CNTPE showed some advantages over CPE. Accordingly, further studies including CNTPE electrochemical pretreatment effect on probe adsorption, probe immobilization conditions including potential and time as well as selectivity of the biosensor were carried out using DPV method and optimum conditions were suggested.