Investigation of Metal Ion Effect on Specific DNA Sequences and DNA Hybridization

Abstract

In this article, we investigated the sequence specific interaction of single (ssDNA) and double stranded (dsDNA) with silver ions (Ag+) with electrochemical methods. We, for the first time, examined the effect of base sequences, base content and physiochemical properties of different DNA sequences on interaction with Ag+ in detail. We used different base contents to show how the composition of nucleic acid influences the electrochemical signals. We first immobilized ssDNA probes on bare graphite electrodes. Then, we showed the sequence effect on oxidation signals of AgDNA complex by sensing Ag+ to the probe coated surfaces to interact with different ssDNA sequences. Furthermore, we investigated the effect of Ag+ on dsDNA. We measured the oxidation signals obtained from Ag+-ssDNA and Ag+-dsDNA complex at approximately 0.2 V and 1.0 V (vs Ag/AgCl), respectively with Differential Pulse Voltammetry (DPV). We showed that the oxidation signals of the AgDNA complex obtained from dsDNA-modified electrodes is higher than the electrodes modified with ssDNA. More importantly, we showed that Ag+-ssDNA and Ag+ ion-dsDNA exhibit different electrochemical behaviors.