DNA sequence motifs for structure-specific recognition and separation of carbon nanotubes

Nature. 2009 Jul 9;460(7252):250-3. doi: 10.1038/nature08116.


Single-walled carbon nanotubes (SWNTs) are a family of molecules that have the same cylindrical shape but different chiralities. Many fundamental studies and technological applications of SWNTs require a population of tubes with identical chirality that current syntheses cannot provide. The SWNT sorting problem-that is, separation of a synthetic mixture of tubes into individual single-chirality components-has attracted considerable attention in recent years. Intense efforts so far have focused largely on, and resulted in solutions for, a weaker version of the sorting problem: metal/semiconductor separation. A systematic and general method to purify each and every single-chirality species of the same electronic type from the synthetic mixture of SWNTs is highly desirable, but the task has proven to be insurmountable to date. Here we report such a method, which allows purification of all 12 major single-chirality semiconducting species from a synthetic mixture, with sufficient yield for both fundamental studies and application development. We have designed an effective search of a DNA library of approximately 10(60) in size, and have identified more than 20 short DNA sequences, each of which recognizes and enables chromatographic purification of a particular nanotube species from the synthetic mixture. Recognition sequences exhibit a periodic purine-pyrimidines pattern, which can undergo hydrogen-bonding to form a two-dimensional sheet, and fold selectively on nanotubes into a well-ordered three-dimensional barrel. We propose that the ordered two-dimensional sheet and three-dimensional barrel provide the structural basis for the observed DNA recognition of SWNTs.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Base Sequence
  • Chemical Fractionation / methods*
  • DNA / chemistry*
  • DNA / genetics
  • Gene Library
  • Models, Molecular
  • Nanotubes, Carbon / chemistry*
  • Nucleic Acid Conformation
  • Sensitivity and Specificity
  • Spectrophotometry
  • Substrate Specificity


  • Nanotubes, Carbon
  • DNA