Crawling in a Fluid

Abstract

There is increasing evidence that mammalian cells not only crawl on substrates but can also swim in fluids. To elucidate the mechanisms of the onset of motility of cells in suspension, a model which couples actin and myosin kinetics to fluid flow is proposed and solved for a spherical shape. The swimming speed is extracted in terms of key parameters. We analytically find super-and subcritical bifurcations from a non-motile to a motile state and also spontaneous polarity oscillations that arise from a Hopf bifurcation. Relaxing the spherical assumption, the obtained shapes show appealing trends.

Amoeboid swimming in a compliant channel

“…The enclosing and suspending fluid and cell cortex act as a dashpots in parallel and are responsible for dissipation within the system. In other words, swimming features depend on the effective viscosity of the system which is linear combination of these three viscosities (see [91]).…”

Self-Assembly of Polymeric Particles in Poiseuille Flow: A Hybrid Lattice Boltzmann/External Potential Dynamics Simulation Study

“…In particular, we can expect a much richer spectrum of irreversible shape transitions under shear. According to recent studies of vesicles in Poiseuille flow one might expect parachutes or, in case the vesicles are not in the flow maximum, slipper shapes 56,57 . In strong shear flows it seems likely, that, according to [61][62][63][64] , fingers will develop and lead to long rods as in two dimensions.…”

“…The lateral drift and the equilibrium position of parti-cles or droplets in Poiseuille flow has already been subject to many studies. In most of these studies, the droplets were introduced as a separate fluid, which did not mix with the solvent 54,56,57,60 and had a conserved volume and in some cases even a conserved surface area. Therefore, hydrodynamic boundaries played an important role.…”

“…A number of studies have considered the behavior of vesicles in external flows such as Poiseuille flow or shear flow. They have typically focussed on the deformations of droplets and vesicles in shear flow [48][49][50][51][52][53][54][55] and on lifting forces that determine their lateral position in the channel [56][57][58][59][60] . Most of them were based on a particle description, where the droplets/vesicles are treated as individual (possibly deformable) objects, and they did not address self-assembly.…”

The Shape and Function of Solid Fascias Depend on the Presence of Liquid Fascias

“…This means that the biological behavior of the cell and its extracellular relationships will vary greatly. The displacement of the cell depends on the fluids present and on the rheological nature of the same, as well as the transport capacity of the various biochemical substances [41][42]. In the theoretical conception of biotensegrity, the branch of physics that studies fluid dynamics has not been taken into consideration.…”