Segregation dynamics in active-passive mixtures of semiflexible filaments

TL;DR

This study investigates how filament flexibility and activity influence segregation and remixing in active-passive filament mixtures, revealing mechanisms like collision-induced softening and providing insights relevant to biological and material systems.

Contribution

The paper introduces a comprehensive simulation analysis of active-passive semiflexible filaments, highlighting the role of activity and flexibility in segregation dynamics and filament softening.

Findings

Segregation occurs at low activity levels.

High activity leads to remixing due to filament softening.

Scaling laws match simulation results for filament stiffness reduction.

Abstract

We study the segregation of motile semiflexible filaments from a background of similar but non-motile filaments. Our Langevin dynamics simulations reveal a wide range of emergent structures governed by filament flexibility and activity, i.e., self-propulsion strength. The system segregates at low activities, while at high activities it undergoes remixing which is a characteristic feature of semi-flexible active filaments. We show that collision-induced softening of single filaments is the dominant mode for this remixing. We provide a scaling argument for the lowering of the active polymer stiffness and show that it agrees well with the lowering of the segregation order parameter. We expect that our studies will shed light on the spatial organization of biofilaments within the cell, on the plasma-membrane, and beyond, and help in the design of novel biomaterials whose structure can be tuned via the properties of the active or the passive filaments.