Dielectrophoresis of nanoscale double-stranded DNA and humidity effects on its electrical conductivity

Abstract

Differential conductance as a promising approach for rapid DNA sequencing with nanopore-embedded electrodes Appl. Phys. Lett. 97, 043701 (2010); 10.1063/1.3467194Electrical detection of single-base DNA mutation using functionalized nanoparticles Appl. Phys. Lett. 95, 073703 (2009); The dielectrophoresis method for trapping and attaching nanoscale double-stranded DNA between nanoelectrodes was developed. The method gives a high yield of trapping single or a few molecules only which enables transport measurements at the single molecule level. Electrical conductivity of individual 140-nm-long DNA molecules was measured, showing insulating behavior in dry conditions. In contrast, clear enhancement of conductivity was observed in moist conditions, relating to the interplay between the conformation of DNA molecules and their conductivity.

Ionic conductivity on a wetting surface

“…The result is a smaller self-energy and a larger resulting conductivity. Surprisingly, experiments on individual DNA molecules [9], DNA films [10,11,12,13], and DNA bundles [7,8] all show a similar exponential dependence of conductivity on humidity. The lack of a geometry-dependent difference remains a puzzle.…”

“…In recent years, studies examining the electrical properties of double-helical DNA and DNA bundles have found a similar dependence of conductivity on relative humidity [7,8,9]. Experimental data shows that the conductivity of DNA increases by a simple exponential over nearly the entire range of relative humidity (10% to 100%), and spans roughly six orders of magnitude.…”

Modeling the Kelvin polarization force actuation of micro- and nanomechanical systems

“…6,7 The dielectrophoretic force has been used to make contact less tweezers for single cell manipulation. 8 Furthermore, it has been used to control biomolecules, 9 DNA, 10,11 nanowires, 12 bundles of carbon nanotubes, 13 and single-walled carbon nanotubes. 14 Polarization forces are also used in electrohydrodynamic continuous flow micropumps 15,16 and to operate dropletbased lab-on-a-chip.…”

Rate-equation calculations of the current flow through two-site molecular device and DNA-based junction

“…The actual magnitude of DNA conductivity and its physical mechanism is still under debate, since experiments indicate that the discussed biomolecule can behave as: an Anderson insulator [7][8][9][10][11], a wide-band-gap semiconductor [12][13][14][15][16], an Ohmic conductor [17][18][19][20][21][22][23][24] or even a proximity-induced superconductor [25]. Among all of the conditions that can have a significant influence on the experimental results, we can enumerate: DNA base sequence, molecular length, orientation in space, stretching, nature of the molecule-electrode contact, ambient surrounding (humidity), temperature of the system, adsorption surface, structural form of the molecule (bundle or single chain), and preparation conditions.…”