Dynamics of a polymer in an active and crowded environment

TL;DR

This paper investigates how active forces and a crowded, viscoelastic environment influence the dynamics and swelling of a polymer chain, with implications for understanding chromosomal motion in bacteria.

Contribution

It provides a theoretical analysis of polymer dynamics under active and viscoelastic conditions, highlighting superdiffusive and subdiffusive regimes and quantifying polymer swelling effects.

Findings

Monomers exhibit superdiffusive motion at short times.

Polymer swelling depends on environmental viscoelasticity.

Active forces induce measurable changes in polymer dynamics.

Abstract

We study the dynamics of an ideal polymer chain in a crowded, viscoelastic medium and in the presence of active forces. The motion of the centre of mass and of individual monomers is calculated. On time scales that are comparable to the persistence time of the active forces, monomers can move superdiffusively while on larger time scales subdiffusive behaviour occurs. The difference between this subdiffusion and that in absence of active forces is quantified. We show that the polymer swells in response to active processes and determine how this swelling depends on the viscoelastic properties of the environment. Our results are compared to recent experiments on the motion of chromosomal loci in bacteria.