Berlin 2018 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 18: Focus Session: Physics of Microbial Systems - organized by Tobias Bollenbach and Benedikt Sabass
BP 18.8: Vortrag
Mittwoch, 14. März 2018, 11:45–12:00, H 2013
Modelling of front instabilities in surfactant-driven biofilm spreading — •Sarah Trinschek1,2, Karin John2, Sigolène Lecuyer2, and Uwe Thiele1,3 — 1Institut für Theoretische Physik, WWU, Münster, Germany — 2Université Grenoble-Alpes, CNRS, Laboratoire Interdisciplinaire de Physique, Grenoble, France — 3Center for Nonlinear Science (CeNoS), WWU, Münster, Germany
The spreading of bacterial colonies at solid air interfaces hinges on physical processes connected to the properties of the involved interfaces. The production of surfactant molecules by the bacteria is one strategy that allows the bacterial colony to efficiently expand over a substrate. These surfactant molecules affect the surface tension which results in an increased wettability as discussed in [1] as well as in outward-pointing Marangoni fluxes that promote spreading. These fluxes may cause an instability of the circular colony shape and the subsequent formation of fingers. In this work, we study the front instability of bacterial colonies at solid-air interfaces induced by surfactant production in the framework of a passive hydrodynamic thin-film model which is extended by bioactive terms. We show that the interplay between wettability and Marangoni fluxes determines the spreading dynamics and decides whether the colony can expand over the substrate. We observe four different types of spreading behaviour, namely, arrested and continuous spreading of circular colonies, slightly modulated front lines and the formation of pronounced fingers.
[1] S. Trinschek et al., PRL 119, 078003 (2017)