Electrical transport, direct

In Sects. 2.1 and 2.2 we will review the direct electrical transport experiments reported on DNA single molecules, bundles, and networks. 

A few measmements of direct electrical transport were also performed on single bundles. Other measurements were done on networks formed of either double-stranded DNA [67] or alternative polynucleotides [68]. All the reported measurements showed current flowing through the bundles. We will show a few examples here. 

D. Porath, A. Bezryadin, S. de Vries, and C. Dekker, Direct measurements of electrical transport through DNA molecules. Nature 403, 635-637 (2000). 

The concept of electric transport in polymers due to the availability of polymeric materials with characteristics similar to those of metals is certainly fascinating and, indeed, many studies have been directed towards the preparation and the characterisation of these new electroactive conductors. The final goal is their use as new components for the realisation of electronic and electrochemical devices with exotic designs and diverse applications. 

Electrokinetic transport is a patented, in situ, commercially available technology for the bioremediation of organic contaminants in aquifer soils and groundwater. The technology involves the application of a direct electrical current across the area to be treated to facilitate the movement of biodegrading bacteria to the site of contamination. 

The letter I represents the concentration of a property Q (e.g., mass, heat, electrical energy) per unit volume, i.e., I = QIV, t is time, x is the distance measured in the direction of transport, 8 is the generalized diffusion coefficient, and E is the gradient or driving force for transport. 

Ea of 0.01 V/ftm is then applied. This is required for two reasons to induce directional charge transport along the wavevector axis, and due to the collective orientational response that produces the index of refraction change. In other words, the applied field, which is greater in magnitude than the internal space-charge field, is required to keep the modulation of the internal electric field... 

The number of electrical charges carried by all the ions of an electrolyte under the driving force of an electrical potential gradient through a certain area A in the direction of transport is given by ... 

Porath D, Bezryadin A, de Vries S, Dekker C. Direct measurement of electrical transport through DNA molecules. Nature 2000 403 635-8. 

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