Dresden 2017 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 45: Microswimmers (joint session BP/DY)

DY 45.4: Talk

Thursday, March 23, 2017, 12:00–12:15, ZEU 250

Interface-Controlled Motility of Photoactive Microalgae in Confinement — •Tanya Ostapenko, Christian T. Kreis, and Oliver Bäumchen — Max Planck Institute for Dynamics and Self-Organization (MPIDS), Am Fassberg 17, 37077 Göttingen, Germany

The natural habitats of many biological microorganisms include complex interfaces and varying environmental conditions. For flagellated microalgae swimming in an aqueous medium, we showed that the curvature of the compartment wall governs their motility in geometric confinement [1]. This curvature-guided motility results in long detention times towards highly curved interfaces. We determined this from the analysis of individual cell trajectories, the results of which are supported by simulations and analytics. For puller-type microswimmers, the precise nature of their flagella-surface interactions are important and remain debated to this day. We discovered that the flagella adhesiveness for photoactive microalgae can be controlled by light [2]. Here, we report on the swimming dynamics of single Chlamydomonas cells isolated in two-dimensional microfluidic chambers under different light conditions. We find that the cell’s motility in confinement can be switched reversibly by light, which could be exploited for application in biological optical traps and wastewater decontamination. [1] T. Ostapenko, et al. (arXiv:1608.00363, 2016), [2] C. T. Kreis, et al. (in review, 2016).