Active matter in a viscoelastic environment

Abstract

Active matter systems such as eukaryotic cells and bacteria continuously transform chemical energy to motion. Hence living systems exert active stresses on the complex environments in which they reside. One recurring aspect of this complexity is the viscoelasticity of the medium surrounding living systems: bacteria secrete their own viscoelastic extracellular matrix, and cells constantly deform, proliferate, and self-propel within viscoelastic networks of collagen. It is therefore imperative to understand how active matter modifies, and gets modified by, viscoelastic fluids. Here, we present a two-phase model of active nematic matter that dynamically interacts with a passive viscoelastic polymeric phase and perform numerical simulations in two dimensions to illustrate its applicability. Motivated by recent experiments we first study the suppression of cell division by a viscoelastic medium surrounding the cell. We further show that the self-propulsion of a model keratocyte cell is modified by the polymer relaxation of the surrounding viscoelastic fluid in a non-uniform manner and find that increasing polymer viscosity effectively suppresses the cell motility. Lastly, we explore the hampering impact of the viscoelastic medium on the generic hydrodynamic instabilities of active nematics by simulating the dynamics of an active stripe within a polymeric fluid. The model presented here can provide a framework for investigating more complex dynamics such as the interaction of multicellular growing systems with viscoelastic environments.

13 pages, 11 figures. Accepted in Physical Review Fluids

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Cited by in corpus (10)

• Filopodia rotate and coil by actively generating twist in their actin shaft
• Fluid viscoelasticity triggers fast transitions of a Brownian particle in a double well optical potential
• Orbital Magnetism of Active Viscoelastic Suspension
• Activity pulses induce spontaneous flow reversals in viscoelastic environments
• Self-sustained patchy turbulence in shear-thinning active fluids
• Vortex pattern stabilization in thin films resulting from shear thickening of active suspensions
• Rheologically tuned modes of collective transport in active viscoelastic films
• Self-sustained oscillations of active viscoelastic matter
• Unified description of viscous, viscoelastic, or elastic thin active films on substrates
• Active viscoelastic nematics with partial degree of order