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

AUTHOR(S):
Hung Chang, Birck Nanotechnology Center and School of Elecrical and Computer Engineering, Purdue University
Bala Murali Venkatesan, Birck Nanotechnology Center and School of Electrical and Computer Engineering, Purdue University
Samir Muzaffar Iqbal, Birck Nanotechnology Center and School of Electrical and Computer Engineering, Purdue University
G. Andreadakis, Department of Laboratory Medicine and Pathology, Division of Experimental Pathology, Mayo Clinic
F. Kosari, Department of Laboratory Medicine and Pathology, Division of Experimental Pathology, Mayo Clinic
G. Vasmatzis, Department of Laboratory Medicine and Pathology, Division of Experimental Pathology, Mayo Clinic
Dimitrios Peroulis, Birck Nanotechnology Center and School of Electrical and Computer Engineering, Purdue University
Rashid Bashir, Birck Nanotechnology Center, School of Electrical and Computer Engineering, Weldon School of Biomedical Engineering, and School of Mechanical Engineering, Purdue University

Citation: Biomed Microdevices; Spring Science & Business Media; DOI 10.1007/s10544-006-9144-x

This document has been peer reviewed.

ABSTRACT:
Reports ofDNAtranslocation 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.