Temperature Dependence of Electrochemical DNA Charge Transport: Influence of a Mismatch

Abstract

Charge transfer through DNA is of interest as DNA is both the quintessential biomolecule of all living organisms and a self-organizing element in bioelectronic circuits and sensing applications. Here, we report the temperature-dependent properties of DNA charge transport in an electronically relevant arrangement of DNA monolayers on gold under biologically relevant conditions, and we track the effects of incorporating a CA single base pair mismatch. Charge transfer (CT) through double stranded, 17mer monolayers was monitored by following the yield of electrochemical reduction of a Nile blue redox probe conjugated to a modified thymine. Analysis with cyclic voltammetry and square wave voltammetry shows that DNA CT increases significantly with temperature, indicative of more DNA bridges becoming active for transport. The mismatch was found to attenuate DNA CT at lower temperatures, but the effect of the mismatch diminished as temperature was increased. Voltammograms were analyzed to extract the electron transfer rate k(0), the electron transfer coefficient α, and the redox-active surface coverage Γ*. Arrhenius behavior was observed, with activation energies of 100 meV for electron transfer through well-matched DNA. Single CA mismatches increased the activation energy by 60 meV. These results have clear implications for sensing applications and are evaluated with respect to the prominent models of DNA CT.

Charge transport in DNA nanowires connected to carbon nanotubes

“…However, for room temperature conformations, each case yields approximately the same average current, which is also comparable to those of the homogeneous sequences. This behavior is consistent with several experimental works, 23,66,67 which showed that that a sequence variation in a homogeneous DNA chain reduces the CT signal at low temperatures, but this effect diminishes as temperature increases. 75 have estimated that the coherent CT is relevant only over distances of about 3 bp, but the low value of the decay parameter taken together with extended delocalized regions indicates that coherent transport is relevant over much longer distances.…”

The Electronic Influence of Abasic Sites in DNA

“…This sharp drop correlates with the onset of the melting transition of this monolayer, consistent with prior reports (see Supporting Information Figure 2). 26,28 Detailed comparison of the T17 and T17-A monolayers reveals that the T17-A sequence SWV peak height grows at a slower rate. To ensure the consistency of this trend of CT yield with temperature, we measured the SWV peak heights with temperature from additional T17 and T17-A monolayers prepared on the same chips (three trials).…”

Accurate Zygote‐Specific Discrimination of Single‐Nucleotide Polymorphisms Using Microfluidic Electrochemical DNA Melting Curves

“…We observed a dramatic increase in redox current between 45 and 65 °C (Figure 2 A), consistent with the sudden transition expected during melting of the T2–PM duplex. In the absence of target, instead of the sudden current increase expected from a duplex melting transition, we saw a current increase resulting from increased thermal motion of probe molecules at higher temperatures,23 which in turn results in more frequent interaction between redox reporter molecules and the electrode (Figure S4).…”

“…Fluorescence‐based, solution‐phase methods such as dynamic allele‐specific hybridization (DASH) can, in contrast, distinguish homozygous and heterozygous SNPs by means of melting‐curve analysis in solution phase 20. This has spurred interest in integrating melting‐curve analysis with electrochemical detection, but these efforts have been confounded by difficulties in obtaining accurate electrochemical and temperature measurements with sufficient speed and resolution 21–23…”