Hydrodynamics of contraction-based motility in a compressible active fluid

¹ Dipartimento di Fisica, Universitá degli studi di Bari and INFN, Sezione di Bari - Via Amendola 173, 70126 Bari, Italy
² Istituto Applicazioni Calcolo, CNR - Via Amendola 122/D, 70126 Bari, Italy
³ SUPA, School of Physics and Astronomy, University of Edinburgh - Peter Guthrie Tait Road, Edinburgh EH9 3FD, UK

Received: 6 May 2019
Accepted: 28 August 2019

Abstract

Cell motility is crucial to biological functions ranging from wound healing to immune response. The physics of cell crawling on a substrate is by now well understood, whilst cell motion in bulk (cell swimming) is far from being completely characterized. We present here a minimal model for pattern formation within a compressible actomyosin gel, in both 2D and 3D, which shows that contractility leads to the emergence of an actomyosin droplet within a low density background. This droplet then becomes self-motile for sufficiently large motor contractility. These results may be relevant to understand the essential physics at play in 3D cell swimming within compressible fluids. We report results of both 2D and 3D numerical simulations, and show that the compressibility of actomyosin plays an important role in the transition to motility.