Cis-Trans Dynamical Asymmetry in Driven Polymer Translocation

TL;DR

This paper investigates the asymmetric dynamics of polymer segments during driven translocation through nanopores, revealing how force distribution and chain length effects influence the process.

Contribution

It introduces a continuum model linking cis and trans dynamics via nonlinear diffusion, explaining asymmetry and force allocation in polymer translocation.

Findings

Cis-trans asymmetry explained by nonlinear diffusion models

Finite-chain length effects influence translocation scaling

Trans-side pushing impacts force distribution and dynamics

Abstract

During polymer translocation driven by e.g. voltage drop across a nanopore, the segments in the cis-side is incessantly pulled into the pore, which are then pushed out of it into the trans-side. This pulling and pushing polymer segments are described in the continuum level by nonlinear transport processes known, respectively, as fast and slow diffusions. By matching solutions of both sides through the mass conservation across the pore, we provide a physical basis for the cis and trans dynamical asymmetry, a feature repeatedly reported in recent numerical simulations. We then predict how the total driving force is dynamically allocated between cis (pulling) and trans (pushing) sides, demonstrating that the trans-side event adds a finite-chain length effect to the dynamical scaling, which may become substantial for weak force and/or high pore friction cases.