Modeling of single-particle translocation through a low-aspect-ratio nanopore

Abstract

A theoretical model for the motion of tiny spherical particles in a nanopore device is developed. The nanopore has a low aspect ratio, and the particles have a radius slightly smaller than that of the nanopore. The translocation of the particle through the nanopore is driven by the difference in external electric potential between the entrance and the exit of the nanopore. The model includes the effects of electrophoresis, electroosmotic flow in the nanopore, and the repulsive potential of the nanopore wall. Using this model, the time-dependent velocity of the particles during translocation through the nanopore is calculated for various parameters, such as the particle radius, the nanopore height, and the surface charge density of the particle. The motion of the particles predicted by the present model qualitatively explains the important characteristics of temporal ionic current responses across the nanopore observed in previous experimental results.

Keywords

• nanofluidics
• nanopore
• coulter counter
• ionic current
• particle identification
• electrophoresis