Prof. Dr. Holger Stark, Division of Theoretical Physics, Institute of Physics and Astronomy, Technische Universität Berlin, Germany

Seminar Room 0.125, MPZPM, Kussmaulallee 2, 91054 Erlangen
Location Details

Abstract
Understanding the living microscopic world needs modeling approaches that include hydrodynamics and elasticity. It also provides inspiration for mimicking the real world and for guiding robotic applications.
The talk consists of two parts. First, we address a collection of active Brownian particles that consume energy to move forward. We use non-reciprocal interaction torques between the particles, either avoiding or cohesive, and demonstrate a variety of emergent collective behavior, including travelling bands, dynamic flocking, and tumbling particle clusters. Adding aligning torques, a persistent worm emerges, which shows a remarkable flexibility and integrity when performing shape changes, as we demonstrate in different situations. Its responsiveness to external cues, such as chemotactic fields, and to confinement makes the worm interesting for robotic applications.
In the second part, we address the African trypanosome that causes the life-threatening sleeping sickness. It has a spindle-shaped cell body to which an eukaryotic flagellum is firmly attached. When a bending wave runs along the flagellum, the whole cell body is distorted and thereby propels the trypanosome forward. When injected into the skin through a bite of the tsetse fly, the trypanosome needs to move through different types of tissue before entering the blood flow and ultimately invading the brain. Thereby, it has to move in tight spaces and squeeze through narrow openings. I present our modeling approach of a trypanosome and demonstrate how it moves in confining geometries such as microchannels, narrow contrictions, and spherical cavities using its thin anterior end.