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Life in Complex Geometries : Curvature-guided Motility and Adhesion of Microalgae at Interfaces - Oliver Bäumchen

Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany

The natural habitats of many living microorganisms are complex geometric environments and include a plethora of typically curved interfaces. For organisms like bacteria and microalgae, which propel themselves through a liquid medium within their microhabitat, the prevailing picture is that the precise nature of contact and hydrodynamic forces governs their interactions with interfaces. Here, we demonstrate that, in confined spaces, the geometry of the habitat controls the motility of microalgae that propel themselves by the beating of two anterior flagella. Brownian dynamics simulations and analytical theory both quantitatively match the experimental data and capture a characteristic curvature scaling observed in microfluidic experiments.

For such microorganisms, flagella play a crucial role since they are the source of locomotion and may come into direct contact with a wall. The interactions of individual microalgae and their flagella with interfaces are characterized by means of in vivo adhesion experiments on the single cell level. In micropipette force spectroscopy experiments, we observe that only the flagella and not the cell body may adhere to surfaces and provide precise adhesion force measurements of eukaryotic flagella to different model substrates for various environmental conditions.

The way microorganisms interact with and explore their surroundings does not only entail important implications for the colonization of porous media and the formation of biofilms, but is also of great relevance for applications involving water filtration, bioremediation, biofuel production, targeted cargo delivery and cell sorting in lab-on-a-chip devices.


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