Resonantly-driven nanopores can serve as nanopumps

TL;DR

This paper demonstrates that unbiased AC fields can induce controllable directional flows in nanopores through resonance effects, enabling potential applications in particle translocation and nanopumping.

Contribution

It introduces a novel mechanism for nanopumping driven by resonant AC fields in gated conical nanopores, supported by analytical and numerical modeling.

Findings

Resonant AC fields induce directional flow in nanopores.

Flow occurs only at specific intermediate frequencies.

The analytical model accurately reproduces simulation results.

Abstract

Inducing transport in electrolyte-filled nanopores with dc fields has led to influential applications ranging from nanosensors to DNA sequencing. Here we use the Poisson-Nernst-Planck and Navier-Stokes equations to show that unbiased ac fields can induce comparable directional flows in gated conical nanopores. This flow exclusively occurs at intermediate driving frequencies and hinges on the resonance of two competing timescales, representing space charge development at the ends and in the interior of the pore. We summarize the physics of resonant nanopumping in an analytical model that reproduces the results of numerical simulations. Our findings provide a generic route towards real-time controllable flow patterns, which might find applications in controlling the translocation of particles such as small molecules or nanocolloids.