Article abstract
Nature Materials 2, 338 - 342 (2003)
Published online: 6 April 2003 | doi:10.1038/nmat877
Subject Categories: Biological materials | Nanoscale materials
DNA-assisted dispersion and separation of carbon nanotubes
Ming Zheng1, Anand Jagota1, Ellen D. Semke1, Bruce A. Diner1, Robert S. Mclean1, Steve R. Lustig1, Raymond E. Richardson1 & Nancy G. Tassi1
Abstract
Carbon nanotubes are man-made one-dimensional carbon crystals with different diameters and chiralities. Owing to their superb mechanical and electrical properties, many potential applications have been proposed for them. However, polydispersity and poor solubility in both aqueous and non-aqueous solution impose a considerable challenge for their separation and assembly, which is required for many applications. Here we report our finding of DNA-assisted dispersion and separation of carbon nanotubes. Bundled single-walled carbon nanotubes are effectively dispersed in water by their sonication in the presence of single-stranded DNA (ssDNA). Optical absorption and fluorescence spectroscopy and atomic force microscopy measurements provide evidence for individually dispersed carbon nanotubes. Molecular modelling suggests that ssDNA can bind to carbon nanotubes through 
-stacking, resulting in helical wrapping to the surface. The binding free energy of ssDNA to carbon nanotubes rivals that of two nanotubes for each other. We also demonstrate that DNA-coated carbon nanotubes can be separated into fractions with different electronic structures by ion-exchange chromatography. This finding links one of the central molecules in biology to a technologically very important nanomaterial, and opens the door to carbon-nanotube-based applications in biotechnology.
- DuPont Central Research and Development, Experimental Station, Wilmington, Delaware 19880, USA
Correspondence to: Ming Zheng1 e-mail: Ming.Zheng@usa.dupont.com
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