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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.


DNA resistance versus molecular length.(a) A(CG)nT (n=3–7), (b) ACGC(AT)mGCGT (m=0–4) and ACGC(AT)m−1AGCGT (m=1–3) sequences, and (c) the AT blocks ((AT)m and (AT)m−1A) in ACGC(AT)mGCGT and ACGC(AT)m−1AGCGT sequences. The solid lines in a,b and c are linear fits to the data, and the dashed line in b is a guide to eye. The transition from tunnelling to hopping occurs the AT block is longer than 4 base pairs, which is markers with a shaded orange region.
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f2: DNA resistance versus molecular length.(a) A(CG)nT (n=3–7), (b) ACGC(AT)mGCGT (m=0–4) and ACGC(AT)m−1AGCGT (m=1–3) sequences, and (c) the AT blocks ((AT)m and (AT)m−1A) in ACGC(AT)mGCGT and ACGC(AT)m−1AGCGT sequences. The solid lines in a,b and c are linear fits to the data, and the dashed line in b is a guide to eye. The transition from tunnelling to hopping occurs the AT block is longer than 4 base pairs, which is markers with a shaded orange region.

Mentions: The conductance (or resistance) of DNA depends on both the molecular length and sequence. For A(CG)nT (n=3–7), the resistance increases linearly with the molecular length (Fig. 2a), which is expected for hopping transport202728. According to the hopping model2930, holes hop along a DNA molecule from one end to another, where the individual G bases act as hopping sites such as stepping stones. Consequently, the total resistance is proportional to the number of hopping sites (G bases), and thus the length of the molecule (see more discussions in Supplementary Fig. 7 and Supplementary Discussion 2). When DNA is connected to two electrodes (tip and substrate), an additional contribution to the resistance arises from the two contacts. The total resistance of the DNA is given by2930


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)

DNA resistance versus molecular length.(a) A(CG)nT (n=3–7), (b) ACGC(AT)mGCGT (m=0–4) and ACGC(AT)m−1AGCGT (m=1–3) sequences, and (c) the AT blocks ((AT)m and (AT)m−1A) in ACGC(AT)mGCGT and ACGC(AT)m−1AGCGT sequences. The solid lines in a,b and c are linear fits to the data, and the dashed line in b is a guide to eye. The transition from tunnelling to hopping occurs the AT block is longer than 4 base pairs, which is markers with a shaded orange region.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f2: DNA resistance versus molecular length.(a) A(CG)nT (n=3–7), (b) ACGC(AT)mGCGT (m=0–4) and ACGC(AT)m−1AGCGT (m=1–3) sequences, and (c) the AT blocks ((AT)m and (AT)m−1A) in ACGC(AT)mGCGT and ACGC(AT)m−1AGCGT sequences. The solid lines in a,b and c are linear fits to the data, and the dashed line in b is a guide to eye. The transition from tunnelling to hopping occurs the AT block is longer than 4 base pairs, which is markers with a shaded orange region.
Mentions: The conductance (or resistance) of DNA depends on both the molecular length and sequence. For A(CG)nT (n=3–7), the resistance increases linearly with the molecular length (Fig. 2a), which is expected for hopping transport202728. According to the hopping model2930, holes hop along a DNA molecule from one end to another, where the individual G bases act as hopping sites such as stepping stones. Consequently, the total resistance is proportional to the number of hopping sites (G bases), and thus the length of the molecule (see more discussions in Supplementary Fig. 7 and Supplementary Discussion 2). When DNA is connected to two electrodes (tip and substrate), an additional contribution to the resistance arises from the two contacts. The total resistance of the DNA is given by2930

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.