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Thermoelectric effect and its dependence on molecular length and sequence in single DNA molecules.

Li Y, Xiang L, Palma JL, Asai Y, Tao N - Nat Commun (2016)

Bottom Line: The thermoelectric effect is small and insensitive to the molecular length in the hopping regime.In contrast, the thermoelectric effect is large and sensitive to the length in the tunnelling regime.We describe the experimental results in terms of hopping and tunnelling charge transport models.

View Article: PubMed Central - PubMed

Affiliation: Center for Bioelectronics and Biosensors, Biodesign Institute, Arizona State University, Tempe, Arizona 85287-5801, USA.

ABSTRACT
Studying the thermoelectric effect in DNA is important for unravelling charge transport mechanisms and for developing relevant applications of DNA molecules. Here we report a study of the thermoelectric effect in single DNA molecules. By varying the molecular length and sequence, we tune the charge transport in DNA to either a hopping- or tunnelling-dominated regimes. The thermoelectric effect is small and insensitive to the molecular length in the hopping regime. In contrast, the thermoelectric effect is large and sensitive to the length in the tunnelling regime. These findings indicate that one may control the thermoelectric effect in DNA by varying its sequence and length. We describe the experimental results in terms of hopping and tunnelling charge transport models.

No MeSH data available.


Related in: MedlinePlus

Thermoelectric and conductance measurements of DNA.(a) Conductance and thermoelectric effect of a DNA molecule bridged between STM tip (kept at 295 K) and substrate (cold). (b) Two families of DNA sequences are studied in this work, denoted as (1) A(CG)nT, (2) ACGC(AT)mGCGT and ACGC(AT)m−1AGCGT (see Table 1 for a full list). (c) Conductance traces without (black) and with (red) dsDNA A(CG)3T, where plateaus are marked with red arrows. (d) Conductance histogram of A(CG)3T, where the solid red curve is Gaussian fit to the conductance peak. Note: G0=2e2/h=77.48 μS.
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f1: Thermoelectric and conductance measurements of DNA.(a) Conductance and thermoelectric effect of a DNA molecule bridged between STM tip (kept at 295 K) and substrate (cold). (b) Two families of DNA sequences are studied in this work, denoted as (1) A(CG)nT, (2) ACGC(AT)mGCGT and ACGC(AT)m−1AGCGT (see Table 1 for a full list). (c) Conductance traces without (black) and with (red) dsDNA A(CG)3T, where plateaus are marked with red arrows. (d) Conductance histogram of A(CG)3T, where the solid red curve is Gaussian fit to the conductance peak. Note: G0=2e2/h=77.48 μS.

Mentions: To study the thermoelectric effect in the hopping regime, we selected DNA molecules with sequences of 5′-A(CG)nT-3′ (n=3, 4, 5, 6 and 7; Fig. 1b), where A, C, G and T denote the four DNA bases, adenine, cytosine, guanine and thymine, respectively. Note that this sequence notation shows only one strand of the dsDNA, and the second strand has the complementary sequence. The complete sequences of all the dsDNA studied in this work are listed in Table 1. Previous studies have shown that charge transport in GC sequences is dominated by hopping of holes along the molecules with G as hopping sites8910111213. To investigate the thermoelectric effect in the tunnelling regime, we studied DNA sequences, 5′-ACGC(AT)mGCGT-3′, where m=1, 2, 3 and 4, and 5′-ACGC(AT)m−1AGCGT-3′, where m=1, 2 and 3 (Fig. 1b; Table 1). The insertion of a block of AT bases in the middle of the GC sequences introduces a tunnelling barrier into the DNA molecules, as shown in literature141516171819, allowing us to investigate the thermoelectric effect in the tunnelling regime. To measure the DNA conductance and thermal electric effect, we modified T base at the 3′ end with an amino group, which binds to gold electrodes to establish electrical contact between the electrodes and the molecule20.


Thermoelectric effect and its dependence on molecular length and sequence in single DNA molecules.

Li Y, Xiang L, Palma JL, Asai Y, Tao N - Nat Commun (2016)

Thermoelectric and conductance measurements of DNA.(a) Conductance and thermoelectric effect of a DNA molecule bridged between STM tip (kept at 295 K) and substrate (cold). (b) Two families of DNA sequences are studied in this work, denoted as (1) A(CG)nT, (2) ACGC(AT)mGCGT and ACGC(AT)m−1AGCGT (see Table 1 for a full list). (c) Conductance traces without (black) and with (red) dsDNA A(CG)3T, where plateaus are marked with red arrows. (d) Conductance histogram of A(CG)3T, where the solid red curve is Gaussian fit to the conductance peak. Note: G0=2e2/h=77.48 μS.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4835548&req=5

f1: Thermoelectric and conductance measurements of DNA.(a) Conductance and thermoelectric effect of a DNA molecule bridged between STM tip (kept at 295 K) and substrate (cold). (b) Two families of DNA sequences are studied in this work, denoted as (1) A(CG)nT, (2) ACGC(AT)mGCGT and ACGC(AT)m−1AGCGT (see Table 1 for a full list). (c) Conductance traces without (black) and with (red) dsDNA A(CG)3T, where plateaus are marked with red arrows. (d) Conductance histogram of A(CG)3T, where the solid red curve is Gaussian fit to the conductance peak. Note: G0=2e2/h=77.48 μS.
Mentions: To study the thermoelectric effect in the hopping regime, we selected DNA molecules with sequences of 5′-A(CG)nT-3′ (n=3, 4, 5, 6 and 7; Fig. 1b), where A, C, G and T denote the four DNA bases, adenine, cytosine, guanine and thymine, respectively. Note that this sequence notation shows only one strand of the dsDNA, and the second strand has the complementary sequence. The complete sequences of all the dsDNA studied in this work are listed in Table 1. Previous studies have shown that charge transport in GC sequences is dominated by hopping of holes along the molecules with G as hopping sites8910111213. To investigate the thermoelectric effect in the tunnelling regime, we studied DNA sequences, 5′-ACGC(AT)mGCGT-3′, where m=1, 2, 3 and 4, and 5′-ACGC(AT)m−1AGCGT-3′, where m=1, 2 and 3 (Fig. 1b; Table 1). The insertion of a block of AT bases in the middle of the GC sequences introduces a tunnelling barrier into the DNA molecules, as shown in literature141516171819, allowing us to investigate the thermoelectric effect in the tunnelling regime. To measure the DNA conductance and thermal electric effect, we modified T base at the 3′ end with an amino group, which binds to gold electrodes to establish electrical contact between the electrodes and the molecule20.

Bottom Line: The thermoelectric effect is small and insensitive to the molecular length in the hopping regime.In contrast, the thermoelectric effect is large and sensitive to the length in the tunnelling regime.We describe the experimental results in terms of hopping and tunnelling charge transport models.

View Article: PubMed Central - PubMed

Affiliation: Center for Bioelectronics and Biosensors, Biodesign Institute, Arizona State University, Tempe, Arizona 85287-5801, USA.

ABSTRACT
Studying the thermoelectric effect in DNA is important for unravelling charge transport mechanisms and for developing relevant applications of DNA molecules. Here we report a study of the thermoelectric effect in single DNA molecules. By varying the molecular length and sequence, we tune the charge transport in DNA to either a hopping- or tunnelling-dominated regimes. The thermoelectric effect is small and insensitive to the molecular length in the hopping regime. In contrast, the thermoelectric effect is large and sensitive to the length in the tunnelling regime. These findings indicate that one may control the thermoelectric effect in DNA by varying its sequence and length. We describe the experimental results in terms of hopping and tunnelling charge transport models.

No MeSH data available.


Related in: MedlinePlus