Linearisation of λdNA molecules by instantaneous variation of the trapping electrode voltage inside a micro-channel

Itsuo Hanasaki, Naoya Yukimoto, Satoshi Uehara, Hirofumi Shintaku, Satoyuki Kawano

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


Because long DNA molecules usually exist in random coil states due to the entropic effect, linearisation is required for devices equipped with nanopores where electrical sequencing is necessary during single-file translocation. We present a novel technique for linearising DNA molecules in a micro-channel. In our device, electrodes are embedded in the bottom surface of the channel. The application of a voltage induces the trapping of λDNA molecules on the positive electrode. An instantaneous voltage drop is used to put the λDNA molecules in a partly released state and the hydrodynamic force of the solution induces linearisation. Phenomena were directly observed using an optical microscopy system equipped with a high-speed camera and the linearisation principle was explored in detail. Furthermore, we estimate the tensile characteristics produced by the flow of the solution through a numerical model of a tethered polymer subject to a Poiseuille flow. The mean tensile force is in the range of 0.1-1pN. This is sufficiently smaller than the structural transition point of λDNA but counterbalances the entropic elasticity that causes the random coil shape of λDNA molecules in solution. We show the important role of thermal fluctuation in the manipulation of molecules in solution and clarify the tensile conditions required for DNA linearisation using a combination of solution flow and voltage variation in a microchannel.

Original languageEnglish
Article number135402
JournalJournal of Physics D: Applied Physics
Issue number13
Publication statusPublished - 2015 Apr 10


  • Brownian dynamics
  • mechanical engineering
  • microfluidics

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Acoustics and Ultrasonics
  • Surfaces, Coatings and Films


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