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Portrait of Jonas Tegenfeldt. Photo: Kennet Ruona

Jonas Tegenfeldt

Professor, Coordinator Nanobiology & Neuronanoscience

Portrait of Jonas Tegenfeldt. Photo: Kennet Ruona

Nanoconfinement-enhanced conformational response of single DNA molecules to changes in ionic environment

Author

  • Walter Reisner
  • Jason Beech
  • Niels B. Larsen
  • Henrik Flyvbjerg
  • Anders Kristensen
  • Jonas Tegenfeldt

Summary, in English

We show that the ionic environment plays a critical role in determining the configurational properties of DNA confined in silica nanochannels. The extension of DNA in the nanochannels increases as the ionic strength is reduced, almost tripling over two decades in ionic strength for channels around 100x100 nm in dimension. Surprisingly, we find that the variation of the persistence length alone with ionic strength is not enough to explain our results. The effect is due mainly to increasing self-avoidance created by the reduced screening of electrostatic interactions at low ionic strength. To quantify the increase in self-avoidance, we introduce a new parameter into the de Gennes theory: an effective DNA width that gives the increase in the excluded volume due to electrostatic repulsion.

Department/s

  • Solid State Physics

Publishing year

2007

Language

English

Publication/Series

Physical Review Letters

Volume

99

Issue

5

Document type

Journal article

Publisher

American Physical Society

Topic

  • Condensed Matter Physics

Status

Published

ISBN/ISSN/Other

  • ISSN: 1079-7114