DNA counterion current and saturation examined by a MEMS-based solid state nanopore sensor
Date of this Version6-23-2006
We would like to thank the NASA Institute for Nanoelectronics and Computing (INAC) at Purdue under award no. NCC 2-1363 for funding the work. We also want to thank Edward Basgall at The Pennsylvania State University for electron beam lithography through the NSF-funded National Nanotechnology Infrastructure Network (NNIN). Partial wafer fabrication was performed at Nanotechnology Core Facility at University of Illinois at Chicago.
This document has been peer-reviewed.
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.
Nanopore . DNA counterions . Single molecule