Durotaxis in viscoelastic fluids

TL;DR

This paper presents a theoretical study on how active particles, such as microorganisms, reorient and move in response to spatial variations in viscoelastic fluid properties, revealing a new form of durotaxis in fluids.

Contribution

It introduces a novel mechanism for active particle reorientation driven by spatial variations in fluid relaxation time in viscoelastic fluids.

Findings

Spatial variations in fluid relaxation time induce reorientation of active particles.

The mechanism acts as a form of durotaxis in viscoelastic fluids.

Theoretical model predicts particle behavior in inhomogeneous fluids.

Abstract

Organisms often swim through fluids that are spatially inhomogeneous. If the fluids are polymeric, gradients in polymer concentration may lead to gradients in both fluid viscosity and elasticity. In this letter, we present theoretical results for the dynamics of active particles, biological or otherwise, swimming through spatially inhomogeneous viscoelastic fluids. We model the active particles using the squirmer model, and show that spatial variations in fluid relaxation time lead to a novel mechanism for reorientation and taxis in viscoelastic fluids, which we refer to as a form of durotaxis in fluids.