Exact steady-state velocity of ratchets driven by random sequential adsorption

TL;DR

This paper provides an exact solution for the steady-state velocity of a polymer translocating through a pore driven by random sequential adsorption, revealing how particle size influences translocation speed and efficiency.

Contribution

It introduces the exact steady-state distribution for the gap in a polymer ratchet driven by irreversible particle deposition, a novel analytical result in this context.

Findings

Smaller adsorbing particles lead to faster translocation.

Smaller particles reduce dispersion in ratcheted motion.

The study compares efficiencies of different particle sizes in ratcheting.

Abstract

We solve the problem of discrete translocation of a polymer through a pore, driven by the irreversible, random sequential adsorption of particles on one side of the pore. Although the kinetics of the wall motion and the deposition are coupled, we find the exact steady-state distribution for the gap between the wall and the nearest deposited particle. This result enables us to construct the mean translocation velocity demonstrating that translocation is faster when the adsorbing particles are smaller. Monte-Carlo simulations also show that smaller particles gives less dispersion in the ratcheted motion. We also define and compare the relative efficiencies of ratcheting by deposition of particles with different sizes and we describe an associated "zone-refinement" process.