2020/05/04(Mon) 15:00 -16:00 Webex Meetings
Title
The rheology of active biological materials
Speaker
Dr. Hui-Shun Kuan (Friedrich-Alexander Universität Erlangen-Nürnberg)Abstract
Aggregates of living cells are an example of active materials with unconventional material properties. The rheological properties of cellular aggregates can be markedly different from those exhibited by passive soft systems due to the active interactions. Motivated by colonies of Neisseria gonorrhoea bacteria, which utilize type IV pili, long and thin retractable filaments, to generate active pulling force, we develop a continuum theory to study cellular aggregates formed by pili-mediated, intercellular forces. The activity-induced viscoelastic properties of such aggregates are determined by the pili-mediated 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 shear with large amplitude. In addition, the transition of solid-like to liquid-like properties of aggregates can be controlled solely by pili turnover without changing steady-state pili-mediated interactions. Our theory provides an essential insight on how intercellular forces in cellular aggregates govern their material properties which in the future could be tested experimentally.
Language
演講語言 (Language): in English
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