Diffusion and binding of finite-size particles in confined geometries

TL;DR

This paper investigates how finite-size particles diffuse and bind within confined channels, revealing how channel-to-particle size ratios influence transport behavior through analytical and simulation methods.

Contribution

It introduces a lattice model to analyze particle diffusion and binding in confined geometries, highlighting the effects of particle size and channel width on transport properties.

Findings

Transport behavior varies with channel-to-particle size ratio.

Analytical results agree well with simulations.

System exhibits different regimes depending on confinement.

Abstract

Describing the diffusion of particles through crowded, confined environments with which they can interact is of considerable biological and technological interest. Under conditions where the confinement dimensions become comparable to the particle dimensions, steric interactions between particles, as well as particle-wall interactions, will play a crucial role in determining transport properties. To elucidate the effects of these interactions on particle transport, we consider the diffusion and binding of finite-size particles within a channel whose diameter is comparable to the size of the particles. Using a simple lattice model of this process, we calculate the steady-state current and density profiles of both bound and free particles in the channel. We show that the system can exhibit qualitatively different behavior depending on the ratio of the channel width to the particle size. We also perform simulations of this system, and find excellent agreement with our analytic results.