Chiral self-sorting of active semiflexible filaments with intrinsic curvature

TL;DR

This paper uses Brownian dynamics simulations to explore how intrinsic curvature and flexibility in active semiflexible filaments influence their collective self-organization, revealing a curvature-driven phase transition and changes in transport behavior.

Contribution

It introduces the first simulation study of how filament curvature and rigidity affect collective behavior in active semiflexible filament systems.

Findings

Curvature induces a phase transition from polar flocks to chiral clusters.

Filament flexibility modifies the nature of the phase transition.

Transport shifts from ballistic to diffusive due to curvature effects.

Abstract

Many-body interactions in systems of active matter can cause particles to move collectively and self-organize into dynamic structures with long-range order. In cells, the self-assembly of cytoskeletal filaments is critical for cellular motility, structure, intracellular transport, and division. Semiflexible cytoskeletal filaments driven by polymerization or motor-protein interactions on a two-dimensional substrate, such as the cell cortex, can induce filament bending and curvature leading to interesting collective behavior. For example, the bacterial cell-division filament FtsZ is known to have intrinsic curvature that causes it to self-organize into rings and vortices, and recent experiments reconstituting the collective motion of microtubules driven by motor proteins on a surface have observed chiral symmetry breaking of the collective behavior due to motor-induced curvature of the filaments. Previous work on the self-organization of driven filament systems have not studied the effects of curvature and filament structure on collective behavior. In this work, we present Brownian dynamics simulation results of driven semiflexible filaments with intrinsic curvature and investigate how the interplay between filament rigidity and radius of curvature can tune the self-organization behavior in homochiral systems and heterochiral mixtures. We find a curvature-induced phase transition from polar flocks to self-sorted chiral clusters, which is modified by filament flexibility. This phase transition changes filament transport from ballistic to diffusive at long timescales.