title: The effect of environmental factors on the electrical conductivity of a single oligo-DNA molecule measured using single-walled carbon nanotube nanoelectrodes.
abstract: We present an electrical conductivity study on a double-stranded DNA molecule bridging a single-walled carbon nanotube (SWNT) gap. The amine terminated DNA molecule was trapped between carboxyl functionalized SWNT electrodes by dielectrophoresis. The conductivity of DNA was measured while under the influence of various environmental factors, including salt concentration, counterion variation, pH and temperature. Typically, a current of tens of picoamperes at 1 V was observed at ambient conditions, with a decrease in conductance of about 33% in high vacuum conditions. The counterion variation was analyzed by changing the buffer from sodium acetate to tris(hydroxymethyl) aminomethane, which resulted in a two orders of magnitude increase in the conductivity of the DNA. A reversible shift in the current signal was observed for pH variation. An increase in conductivity of the DNA was also observed at high salt concentrations.
authors.affiliation: Nanomaterials and Device Laboratory, Department of Mechanical and Materials Engineering, Florida International University, Miami, FL 33174, USA.
authors.forename: Harindra
authors.initials: H
authors.lastname: Vedala
authors.forename: Somenath
authors.initials: S
authors.lastname: Roy
authors.forename: Melissa
authors.initials: M
authors.lastname: Doud
authors.forename: Kalai
authors.initials: K
authors.lastname: Mathee
authors.forename: Sookhyun
authors.initials: S
authors.lastname: Hwang
authors.forename: Minhyon
authors.initials: M
authors.lastname: Jeon
authors.forename: Wonbong
authors.initials: W
authors.lastname: Choi