Bacteria living on surfaces are often confined to droplets. When these droplets evaporate, the motion of the liquid-air interface and the associated internal capillary flow confine the bacteria. Within this project we will unravel how interfacial flows control the distribution of biological soft matter and, vice versa, how small organisms such as bacteria may exploit these flows to manipulate their dispersal or assembly.
Interfacial flows in evaporating liquid droplets can form remarkably rich and complex deposition patterns of suspended microparticles. The topography of the microscopic pattern that emerges is the result of a complex interplay between the flows that arise inside the liquid, for example due to droplet evaporation, the motion of the liquid-air interface, the suspension rheology, and the properties of the solutes.
E. coli bacteria are self-propelled organisms that actively navigate their environment and that, already in bulk fluids, show complex emergent behaviour via hydrodynamic interactions between the individual swimmers.
Figure 1: Active pattern formation by E. coli bacteria in an evaporating droplet. Through collective motion, the bacteria control their own dispersal and counteract the interfacial flow.In this Postdoc project you will study how motile
E. coli bacteria interact with the capillary confinement imposed by an evaporating droplet and investigate active bacterial pattern formation in droplets.
Preliminary experiments (see e.g. Figure 1) have shown that bacteria can exploit and even overcome interfacial flows to promote their own dispersal through, e.g., collective motion and surfactant secretion. Within the project we will identify, within the vast parameter space, the few key control parameters governing the self-assembly of
E. coli under the influence of interfacial flow and determine the physical mechanisms that govern the pattern formation. To this end, you will perform experiments with
E. coli as well as theoretical and/or numerical modelling. The identification of the physical mechanisms at play will present a big step forward in fundamental physics, with a strong application perspective in biology.
Embedding of the projectThe project will be carried out in the team of
Prof.dr. Hanneke Gelderblom, assistant professor in the Fluids and Flows group at the department of Applied Physics, and
Prof.dr. Alexander Morozov, full professor of Fluid Mechanics at the University of Edinburgh and parttime professor in the Fluids and Flows group in Eindhoven. The PhD project will be embedded within the Department of Applied Physics and the Institute of Complex Molecular Systems (ICMS) at Eindhoven University. Within the project you will closely collaborate with researchers Prof. Morozov's group in Edinburgh, and with the team of
Dr. Remy Colin, our collaborator at the Max Planck Institute for Terrestrial Microbiology in Marburg (Germany). You will also contribute to education in the Eindhoven Applied Physics department. Apart from supervising BSc and MSc students in their research projects, other assistance in education, e.g. in bachelor courses, is usually limited to about 5% of your contract time.