Asymmetric bistability of chiral particle orientation in viscous shear flows

Autor(en)

Andreas Zöttl, Francesca Tesser, Daiki Matsunaga, Justine Laurent, Olivia du Roure, Anke Lindner

Abstrakt

The migration of helical particles in viscous shear flows plays a crucial role in chiral particle sorting. Attaching a nonchiral head to a helical particle leads to a rheotactic torque inducing particle reorientation. This phenomenon is responsible for bacterial rheotaxis observed for flagellated bacteria as Escherichia coli in shear flows. Here, we use a high-resolution microprinting technique to fabricate microparticles with controlled and tunable chiral shape consisting of a spherical head and helical tails of various pitch and handedness. By observing the fully time-resolved dynamics of these microparticles in microfluidic channel flow, we gain valuable insights into chirality-induced orientation dynamics. Our experimental model system allows us to examine the effects of particle elongation, chirality, and head heaviness for different flow rates on the orientation dynamics, while minimizing the influence of Brownian noise. Through our model experiments, we demonstrate the existence of asymmetric bistability of the particle orientation perpendicular to the flow direction. We quantitatively explain the particle equilibrium orientations as a function of particle properties, initial conditions and flow rates, as well as the time-dependence of the reorientation dynamics through a theoretical model. The model parameters are determined using boundary element simulations, and excellent agreement with experiments is obtained without any adjustable parameters. Our findings lead to a better understanding of chiral particle transport and bacterial rheotaxis and might allow the development of targeted delivery applications.

Organisation(en)

Computergestützte Physik und Physik der Weichen Materie

Externe Organisation(en)

Université de recherche Paris Sciences et Lettres, Université Paris VI - Pierre-et-Marie-Curie, Technische Universität Wien, Osaka University

Journal

Proceedings of the National Academy of Sciences of the United States of America

Band

120

Anzahl der Seiten

8

ISSN

0027-8424

DOI

https://doi.org/10.1073/pnas.2310939120

Publikationsdatum

10-2023

Peer-reviewed

Ja

ÖFOS 2012

103043 Computational Physics

Schlagwörter

ASJC Scopus Sachgebiete

General

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/59a73835-02f1-4cc7-bf0d-77d69cba909c