Nanopores are molecular-scale holes in insulating membranes that can, when used to divide an electrochemical cell, permit the direct detection of single molecules. The size, shape and surface charge of the nanopore are critical parameters for determining their performance. The experimental challenges facing traditional three-dimensional characterizations of the nanopore geometry limit the routine determination of nanopore shapes and sizes. In consequence, there has been tremendous interest in alternative methods. A prominent approach seeks to extract the nanopore shape from the dramatic dependence of the nanopore conductance on the nanopore geometry, surface charge and electrolyte concentration. We explore the performance limits of such conductance-based methods and show that the ability to accurately reproduce the dependence of the conductance on electrolyte concentration does not necessarily guarantee the accuracy of nanopore dimensions. We present a nanopore model that addresses these performance limits and can serve as the foundation for extensions of this approach.

Characterizing single-molecule nanopore sensors:  Performance limits of conductance-based methods

244th National Meeting (2012)

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