Volume 117, Number 3, February 2017
|Number of page(s)||7|
|Section||Interdisciplinary Physics and Related Areas of Science and Technology|
|Published online||15 March 2017|
Localization and diffusion of tracer particles in viscoelastic media with active force dipoles
1 Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University Tokyo 192-0397, Japan
2 Department of Physical Chemistry, Fritz Haber Institute of the Max Planck Society - Faradayweg 4-6, 14195 Berlin, Germany
3 Department of Mathematical and Life Sciences, Hiroshima University - Hiroshima 739-8526, Japan
Received: 24 December 2016
Accepted: 21 February 2017
Optical tracking in vivo experiments reveal that diffusion of particles in biological cells is strongly enhanced in the presence of ATP and the experimental data for animal cells could previously be reproduced within a phenomenological model of a gel with myosin motors acting within it (Fodor É. et al., EPL, 110 (2015) 48005). Here, the two-fluid model of a gel is considered where active macromolecules, described as force dipoles, cyclically operate both in the elastic and the fluid components. Through coarse-graining, effective equations of motions for idealized tracer particles displaying local deformations and local fluid flows are derived. The equation for deformation tracers coincides with the earlier phenomenological model and thus confirms it. For flow tracers, diffusion enhancement caused by active force dipoles in the fluid component, and thus due to metabolic activity, is found. The latter effect may explain why ATP-dependent diffusion enhancement could also be observed in bacteria that lack molecular motors in their skeleton or when the activity of myosin motors was chemically inhibited in eukaryotic cells.
PACS: 87.16.dj – Dynamics and fluctuations / 87.16.Uv – Active transport processes / 83.60.Bc – Linear viscoelasticity
© EPLA, 2017
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.