DNA counterion current and saturation examined by a MEMS-based solid state nanopore sensor

Hung Chang, Bala Murali Venkatesan, Samir M. Iqbal, G. Andreadakis, F. Kosari, G. Vasmatzis, Dimitrios Peroulis, Rashid Bashir

Research output: Contribution to journalArticlepeer-review

43 Scopus citations


Reports of DNA translocation measurements have been increasing rapidly in recent years due to advancements in pore fabrication and these measurements continue to provide insight into the physics of DNA translocations through MEMS based solid state nanopores. Specifically, it has recently been demonstrated that in addition to typically observed current blockages, enhancements in current can also be measured under certain conditions. Here, we further demonstrate the power of these nanopores for examining single DNA molecules by measuring these ionic currents as a function of the applied electric field and show that the direction of the resulting current pulse can provide fundamental insight into the physics of condensed counterions and the dipole saturation in single DNA molecules. Expanding on earlier work by Manning and others, we propose a model of DNA counterion ionic current and saturation of this current based on our experimental results. The work can have broad impact in understanding DNA sensing, DNA delivery into cells, DNA conductivity, and molecular electronics.

Original languageEnglish (US)
Pages (from-to)263-269
Number of pages7
JournalBiomedical Microdevices
Issue number3
StatePublished - Sep 2006


  • DNA counterions
  • Nanopore
  • Single molecule

ASJC Scopus subject areas

  • Biomedical Engineering
  • Molecular Biology


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