Pore wall charge patterning and spatial profiles of electrical conductivity in short nanopores

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Artificial nanopores are now used as filters, nanofluidic switches or biosensors. Given that their functioning often critically depends on pore conductivity it is important to determine what influences the pore conductivity and how far these influences extend. This informs us how much the longitudinal and radial shrinkage of the nanopore is realistic. We simulated the transport of K+, glutamate-¬¬, Na+ and Cl- in three idealized cases – a uniformly charged, a unipolar and a bipolar nanopore using Poisson–Nernst–Planck equation, and couple it to the transport of water using Navier–Stokes equations. Linear electrical properties of the nanopore were calculated from the potential and current profiles perturbed by changing the voltage difference between two compartments flanking the nanopore. In uni-polar and bi-polar nanopores the conductivity depends on radius in a complex manner. If the conductivity of the narrow pore is high, it will decrease as radius increases, but if it is low it will increase markedly. This is determined by the voltage bias. Finally, the bias also critically influences how the change of the pore wall charge in one half alters its resistance and that of the other half.

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Journal: TechConnect Briefs
Volume: 2, Nanotechnology 2014: MEMS, Fluidics, Bio Systems, Medical, Computational & Photonics
Published: June 15, 2014
Pages: 141 - 144
Industry sectors: Advanced Materials & Manufacturing | Sensors, MEMS, Electronics
Topic: Inkjet Design, Materials & Fabrication
ISBN: 978-1-4822-5827-1