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Journal of Drug Delivery
Volume 2011, Article ID 415621, 9 pages
Research Article

Unveiling Stability Criteria of DNA-Carbon Nanotubes Constructs by Scanning Tunneling Microscopy and Computational Modeling

1Department of Chemistry and Biochemistry, North Dakota State University, Fargo, ND 58108-6050, USA
2Los Alamos National Laboratory, Center for Integrated Nanotechnologies, Los Alamos, NM 87545, USA
3NIST Center for Nanoscale Science and Technology, Energy Research Group, Gaithersburg, MD 20899, USA
4Los Alamos National Laboratory, Theoretical Division, Los Alamos, NM 87545, USA

Received 1 November 2010; Accepted 22 January 2011

Academic Editor: Giorgia Pastorin

Copyright © 2011 Svetlana Kilina et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


We present a combined approach that relies on computational simulations and scanning tunneling microscopy (STM) measurements to reveal morphological properties and stability criteria of carbon nanotube-DNA (CNT-DNA) constructs. Application of STM allows direct observation of very stable CNT-DNA hybrid structures with the well-defined DNA wrapping angle of 63.4° and a coiling period of 3.3 nm. Using force field simulations, we determine how the DNA-CNT binding energy depends on the sequence and binding geometry of a single strand DNA. This dependence allows us to quantitatively characterize the stability of a hybrid structure with an optimal π-stacking between DNA nucleotides and the tube surface and better interpret STM data. Our simulations clearly demonstrate the existence of a very stable DNA binding geometry for (6,5) CNT as evidenced by the presence of a well-defined minimum in the binding energy as a function of an angle between DNA strand and the nanotube chiral vector. This novel approach demonstrates the feasibility of CNT-DNA geometry studies with subnanometer resolution and paves the way towards complete characterization of the structural and electronic properties of drug-delivering systems based on DNA-CNT hybrids as a function of DNA sequence and a nanotube chirality.