Hydrodynamic Instabilities Provide A Generic Route To Spontaneous Biomimetic Oscillations In Chemomechanically Active Filaments

TL;DR

This paper demonstrates that hydrodynamic interactions and nonlinear elasticity in chemomechanically active filaments can spontaneously generate oscillations similar to biological flagella, without complex structures or regulation.

Contribution

It reveals a universal physical mechanism for biomimetic oscillations in simple active filament models, bypassing the need for structural complexity.

Findings

Hydrodynamic interactions destabilize active filaments leading to oscillations.

Nonlinear elasticity stabilizes the filament, enabling sustained oscillations.

Spontaneous oscillations can be achieved in simple bead chains, mimicking biological motion.

Abstract

Non-equilibrium processes which convert chemical energy into mechanical motion enable the motility of organisms. Bundles of inextensible filaments driven by energy transduction of molecular motors form essential components of micron-scale motility engines like cilia and flagella. The mimicry of cilia-like motion in recent experiments on synthetic active filaments supports the idea that generic physical mechanisms may be sufficient to generate such motion. Here we show, theoretically, that the competition between the destabilising effect of hydrodynamic interactions induced by force-free and torque-free chemomechanically active flows, and the stabilising effect of nonlinear elasticity, provides a generic route to spontaneous oscillations in active filaments. These oscillations, reminiscent of prokaryotic and eukaryotic flagellar motion, are obtained without having to invoke structural complexity or biochemical regulation. This minimality implies that biomimetic oscillations, previously observed only in complex bundles of active filaments, can be replicated in simple chains of generic chemomechanically active beads.