Regensburg 2007 – scientific programme
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SYPE: Symposium Polyelectrolytes
SYPE 3: Polyelectrolytes II
SYPE 3.5: Talk
Friday, March 30, 2007, 12:00–12:15, H1
The force on DNA in a nanopore — •U. F. Keyser1,2, S. van Dorp1, R. M. M. Smeets1, D. Krapf1, N. H. Dekker1, and C. Dekker1 — 1Kavli Institute of Nanoscience, Delft University of Technology, The Netherlands — 2Institut für Experimentelle Physik I, Universität Leipzig, Germany
Among the variety of roles for nanopores in biology, an important one is enabling transport of polyelectrolytes like DNA or RNA, for example in gene transfer between bacteria and transport of RNA through the nuclear membrane. Recently, this has inspired the use of protein and solid-state nanopores as single-molecule sensors for the detection and structural analysis of DNA and RNA by voltage-driven translocation [1]. The magnitude of the force involved is of fundamental importance in understanding and exploiting this translocation mechanism, yet so far it has remained unknown. Here, we demonstrate the *rst measurements of the force on a single DNA molecule in a solid-state nanopore by combining optical tweezers with ionic-current detection [2]. The opposing force exerted by the optical tweezers can be used to slow down and even arrest the translocation of the DNA molecules [3]. We obtain a value of 0.24*0.02 pN mV*1 for the force on a single DNA molecule, independent of salt concentration from 0.02 to 1M KCl. [1] R. M. M. Smeets, U. F. Keyser, et al. Nano Letters 6 (2006) [2] U. F. Keyser et al., Rev. Sci. Instr. 77, 105105 (2006) [3] U. F. Keyser et al., Nature Physics 2, 473 (2006)