Label-Free Detection of DNA Hybridization by Cyclic Voltammetry. An Advanced Undergraduate Analytical Chemistry Laboratory Experiment

Abstract

A electrochemical detection method for DNA hybridization has been developed and tested in an advanced analytical chemistry course. A set of experiments was designed to explore several concepts relevant to electropolymerization of intrinsically conducting polymers, their use as an electrically controlled ion-exchanger of chloride ions, and their ability to bind oligonucleotides through a noncovalent interaction with magnesium ions used as a linker between the polymer and the DNA strand. The electrostatic barrier on the modified electrode created by the phosphate groups of the probe DNA attached to the magnesium ion is modified by DNA hybridization. Changes in the transfer rate of chloride ions of the label-free DNA detector are detected as variations in cyclic voltammograms. The basic approach for the detection of the DNA hybridization event relies on the subtraction of cyclic voltammograms recorded before and after DNA hybridization. Different aspects of the experiments can be emphasized, dep...