Active Fluid Patterning in Inhomogeneous Environments

TL;DR

This paper presents a minimal model demonstrating how inhomogeneous external friction influences pattern formation in active fluids, revealing mechanisms like frictiotaxis and oscillations driven by mechanochemical interactions.

Contribution

It introduces a novel minimal model showing how environmental inhomogeneity controls active fluid patterning through hydrodynamic screening and mechanochemical frustration.

Findings

Active stress patterns exhibit frictiotaxis influenced by external friction.

Hydrodynamic screening mediates the interaction between friction patterns and fluid self-organization.

Inhomogeneous friction can induce oscillatory pattern dynamics via mechanochemical frustration.

Abstract

Active stresses in biological cells and tissues drive many developmental processes. However, increasing experimental evidence suggests that additional mechanical interactions with surrounding material can play a crucial role in guiding these processes. We introduce a minimal model of this scenario and investigate how pattern formation in an active material can be controlled by an inhomogeneous environment. Specifically, we consider an active fluid in which a chemical species regulates local active stresses and is redistributed by the resulting flows. We show that active stress patterns within such a fluid exhibit frictiotaxis and systematically characterize how inhomogeneous external friction affects mechanochemical pattern formation instabilities. We find that hydrodynamic screening plays a crucial role in mediating the cross-talk between friction patterns and active fluid self-organization and identify a mechanochemical frustration mechanism that gives rise to pattern oscillations caused by inhomogeneous friction.