title: DNA counterion current and saturation examined by a MEMS-based solid state nanopore sensor.
abstract: 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.
authors.affiliation: Birck Nanotechnology Center, School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, USA.
authors.forename: Hung
authors.initials: H
authors.lastname: Chang
authors.forename: Bala Murali
authors.initials: BM
authors.lastname: Venkatesan
authors.forename: Samir M
authors.initials: SM
authors.lastname: Iqbal
authors.forename: G
authors.initials: G
authors.lastname: Andreadakis
authors.forename: F
authors.initials: F
authors.lastname: Kosari
authors.forename: G
authors.initials: G
authors.lastname: Vasmatzis
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Peroulis
authors.forename: Rashid
authors.initials: R
authors.lastname: Bashir
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D004247:DNA / Q000032:analysis*; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods; D008567:Membranes, Artificial; D049329:Nanostructures; D036103:Nanotechnology
chemical_list: D008567:Membranes, Artificial; D004247:DNA