| 1. |
- Gowtham, S., et al.
(författare)
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First-principles study of physisorption of nucleic acid bases on small-diameter carbon nanotubes
- 2008
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Ingår i: Nanotechnology. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 19:12, s. 125701-
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Tidskriftsartikel (refereegranskat)abstract
- We report the results of our first-principles study based on density functional theory on the interaction of the nucleic acid base molecules adenine (A), cytosine (C), guanine (G), thymine (T), and uracil (U), with a single-walled carbon nanotube (CNT). Specifically, the focus is on the physisorption of base molecules on the outer wall of a (5, 0) metallic CNT possessing one of the smallest diameters possible. Compared to the case for CNTs with large diameters, the physisorption energy is found to be reduced in the high-curvature case. The base molecules exhibit significantly different interaction strengths and the calculated binding energies follow the hierarchy G>A>T>C>U, which appears to be independent of the tube curvature. The stabilizing factor in the interaction between the base molecule and CNT is dominated by the molecular polarizability that allows a weakly attractive dispersion force to be induced between them. The present study provides an improved understanding of the role of the base sequence in deoxyribonucleic acid (DNA) or ribonucleic acid (RNA) in their interactions with carbon nanotubes of varying diameters.
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| 2. |
- Gowtham, S., et al.
(författare)
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Physisorption of nucleobases on graphene : Density-functional calculations
- 2007
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 76:3, s. 033401-
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Tidskriftsartikel (refereegranskat)abstract
- We report the results of our first-principles investigation on the interaction of the nucleobases adenine (A), cytosine (C), guanine (G), thymine (T), and uracil (U) with graphene, carried out within the density-functional theory framework, with additional calculations utilizing Hartree-Fock plus second-order Møller-Plesset perturbation theory. The calculated binding energy of the nucleobases shows the following hierarchy: G>A~T~C>U, with the equilibrium configuration being rather similar for all five of them. Our results clearly demonstrate that the nucleobases exhibit significantly different interaction strengths when physisorbed on graphene. The stabilizing factor in the interaction between the base molecule and graphene sheet is dominated by the molecular polarizability that allows a weakly attractive dispersion force to be induced between them. The present study represents a significant step toward a first-principles understanding of how the base sequence of DNA can affect its interaction with carbon nanotubes, as observed experimentally.
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| 3. |
- He, Haiying, et al.
(författare)
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Functionalized Nanopore-Embedded Electrodes for Rapid DNA Sequencing
- 2008
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Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 112:10, s. 3456-3459
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Tidskriftsartikel (refereegranskat)abstract
- With the aim of improving nanopore-based DNA sequencing, we explored the effects of functionalizing the embedded gold electrodes with purine and pyrimidine molecules. Hydrogen bonds formed between the molecular probe and target bases stabilize the scanned DNA unit against thermal fluctuations and thus greatly reduce noise in the current signal. The results of our first-principles study indicate that this proposed scheme could allow DNA sequencing with a robust and reliable yield, producing current signals that differ by at least 1 order of magnitude for the different bases.
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| 4. |
- Mukhopadhyay, Saikat, et al.
(författare)
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Sensitivity of Boron Nitride Nanotubes toward Biomolecules of Different Polarities
- 2011
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Ingår i: The Journal of Physical Chemistry Letters. - : American Chemical Society (ACS). - 1948-7185. ; 2:19, s. 2442-2447
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Tidskriftsartikel (refereegranskat)abstract
- The effect of molecular polarity on the interaction between a boron nitride nanotube (BNNT) and amino acids is investigated with density functional theory. Three representative amino acids, namely, tryptophane (Trp), a nonpolar aromatic amino acid, and asparatic acid (Asp) and argenine (Arg), both polar amino acids are considered for their interactions with BNNT. The polar molecules, Asp and Arg, exhibit relatively stronger binding with the tubular surface of BNNT. The binding between the polar amino acid molecules and BNNT is accompanied by a charge transfer, suggesting that stabilization of the bioconjugated complex is mainly governed by electrostatic interactions. The results show modulation of the BNNT band gap by Trp. Interestingly, no change in band gap of BNNT is seen for the polar molecules Asp and Arg. The predicted higher sensitivity of BNNTs compared to carbon nanotubes (CNTs) toward amino acid polarity suggests BNNTs to be a better substrate for protein immobilization than CNTs.
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| 5. |
- Mukhopadhyay, Saikat, et al.
(författare)
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Theoretical study of physisorption of nucleobases on boron nitride nanotubes : a new class of hybrid nano-biomaterials
- 2010
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Ingår i: Nanotechnology. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 21:16, s. 165703-
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Tidskriftsartikel (refereegranskat)abstract
- We investigate the adsorption of the nucleic acid bases-adenine (A), guanine (G), cytosine (C), thymine (T) and uracil (U)-on the outer wall of a high curvature semiconducting single-walled boron nitride nanotube (BNNT) by first-principles density functional theory calculations. The calculated binding energy shows the order: G > A approximate to C approximate to T approximate to U, implying that the interaction strength of the high curvature BNNT with the nucleobases, G being an exception, is nearly the same. A higher binding energy for the G-BNNT conjugate appears to result from hybridization of the molecular orbitals of G and the BNNT. A smaller energy gap predicted for the G-BNNT conjugate relative to that of the pristine BNNT may be useful in the application of this class of biofunctional materials to the design of next-generation sensing devices.
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| 6. |
- Zhong, Xiaoliang, et al.
(författare)
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Electronic structure and quantum transport properties of trilayers formed from graphene and boron nitride
- 2012
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Ingår i: Nanoscale. - : Royal Society of Chemistry (RSC). - 2040-3364 .- 2040-3372. ; 4:17, s. 5490-5498
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Tidskriftsartikel (refereegranskat)abstract
- We report the results of a theoretical study of graphene/BN/graphene and BN/graphene/BN trilayers using the van-der-Waals-corrected density functional theory in conjunction with the non-equilibrium Green's Function method. These trilayer systems formed from graphene and BN exhibit distinct stacking-dependent features in their ground state electronic structure and response to an applied electric field perpendicular to the trilayer planes. The graphene/BN/graphene system shows a negligible gap in the electronic band structure that increases for the AAA and ABA stackings under an external electric field, while the zero-field band gap of BN/graphene/BN remains unaffected by the electric field. When both types of trilayer systems are contacted with gold electrodes, a metal-like conduction is predicted in the low-field regime, which changes to a p-type conduction with an increase in the applied perpendicular bias field.
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