Nonlinear Science & Mathematical Physics Seminar
November 20, 2019 - 12:00pm to 1:00pm
Howey- School of Physics
Max Planck Institute
A cell’s interactions with the environment are mediated by its cellular membrane and its ultrastructures. Since cells contain and are surrounded by fluids, the hydrodynamics involved during these interactions are critical. They determine the transport of ions and molecules, locomotion, and sensing. Overall, they mediate a cells’ homeostasis. In this talk, I will present investigations into the fluid-structure interactions of membrane-bound unicellular organisms, specifically fluid slip close to and transmission of shear forces across cellular membranes, and flow enhancement due to fibrous flagellar hairs during swimming. Optical tweezers are used to both apply and measure local forces on free-standing membranes and tethered algal cells. Through these measurements, we find that fluid slip and shear force transmission are highly dependent on the membrane’s lipid composition, and that, contrary to previous claims, the fibrous flagellar hairs of algae do not increase the flagella's effective area while swimming. Our studies therefore contribute towards building a fundamental understanding of the physical principles governing the transfer of hydrodynamic forces by and through the membrane and its ultrastructures.