Dresden 2020 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 14: Focus: Phase Separation in Biological Systems II (joint session BP/CPP)
BP 14.8: Vortrag
Dienstag, 17. März 2020, 12:00–12:15, ZEU 250
Formation of pilus induced cellular aggregates and their rheological properties — •Hui-Shun Kuan1,3, Frank Jülicher2, and Vasily Zaburdaev1,3 — 1Department of Biology, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany — 2Max Planck Institute for the Physics of Complex Systems, Dresden, Germany — 3Max-Planck-Zentrum für Physik und Medizin, Erlangen, Germany
Aggregates of living cells are an example of active materials with unconventional material properties. The rheological properties of cellular aggregates can, therefore, be markedly different from those exhibited by passive soft systems. Motivated by colonies of Neisseria gonorrhoeae bacteria, we develop a continuum theory to study cellular aggregates formed by attractive pili--pili intercellular interactions which introduce active stresses in the system. The formation of cellular aggregates can be explained by an active phase separation process, and the activity-induced viscoelastic properties of such aggregates are coupled with pili--pili interactions. By studying the behaviour of aggregates under oscillatory shear, the loss and storage moduli of the aggregates can be linked to the dynamics of the active intercellular forces. Due to the turnover of pili, the aggregates show a liquid-like behaviour at large times and strong shear-thinning effect under the large amplitude oscillatory shear. Our theory provides an essential insight on how pilus mediated intercellular forces in cellular aggregates govern their material properties which in the future could be tested experimentally.