BPCPPDYSOE21 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 24: Poster B: Active Biological Matter, Cell Mechanics, Systems Biology, Computational Biophysics, etc.
BP 24.3: Poster
Dienstag, 23. März 2021, 16:00–18:30, BPp
Magnetic stirbars as a tunable stirrer for cell-like systems — •Mithun Thampi, Pierre-Yves Gires, and Matthias Weiss — University of Bayreuth, Bayreuth, Germany
Transport inside living systems or biofluid droplets is governed by diffusion and energy-dependent active transport. Speeding up these processes remains challenging: here we report on an easy way to gently stir biofluid droplets. We produce micrometer long magnetic stirbars (MSBs) by aligning Fe3O4 nanoparticles and stabilizing them by a biocompatible silica coating. The successful production of these MSBs is confirmed by scanning electron microscopy1. The rotating magnetic field is achieved by using two pairs of Helmholtz-like coils with a custom build controller, which can tune both the frequency and the strength of the magnetic field. Using single-particle tracking of tracer beads, we demonstrate via a broad palette of measures that local stirring of the fluid at different frequencies leads to an enhanced but apparently normal and homogeneous diffusion process. The signature of stirring is visible in the power-spectral density and in the autocorrelation function of the trajectories2. We finally look at their stirring effects on the out of equilibrium self-organization of Xenopus laevis egg extract1.
References:
1. P.-Y. Gires, M. Thampi, M. Weiss. "Miniaturized magnetic stirbars for controlled agitation of aqueous microdroplet". Sci. Rep., 10, 10911, (2020).
2. P.-Y. Gires, M. Thampi, M. Weiss. "Quantifying active diffusion in an agitated fluid". Phys. Chem. Chem. Phys., 22, 21678, (2020).