title: Flow loading induces oscillatory trajectories in a bloodstream parasite.
abstract: The dynamics of isolated microswimmers are studied in bounded flow using the African trypanosome, a unicellular parasite, as the model organism. With the help of a microfluidics platform, cells are subjected to flow and found to follow an oscillatory path that is well fit by a sine wave. The frequency and amplitudes of the oscillatory trajectories are dependent on the flow velocity and cell orientation. When traveling in such a manner, trypanosomes orient upstream while downstream-facing cells tumble within the same streamline. A comparison with immotile trypanosomes demonstrates that self-propulsion is essential to the trajectories of trypanosomes even at flow velocities up to ∼40 times higher than their own swimming speed. These studies reveal important swimming dynamics that may be generally pertinent to the transport of microswimmers in flow and may be relevant to microbial pathogenesis.
authors.affiliation: Department of Complex Fluids, Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany. uppaluri@princeton.edu
authors.forename: Sravanti
authors.initials: S
authors.lastname: Uppaluri
authors.forename: Niko
authors.initials: N
authors.lastname: Heddergott
authors.forename: Eric
authors.initials: E
authors.lastname: Stellamanns
authors.forename: Stephan
authors.initials: S
authors.lastname: Herminghaus
authors.forename: Andreas
authors.initials: A
authors.lastname: Zöttl
authors.forename: Holger
authors.initials: H
authors.lastname: Stark
authors.forename: Markus
authors.initials: M
authors.lastname: Engstler
authors.forename: Thomas
authors.initials: T
authors.lastname: Pfohl
mesh_terms: D000818:Animals; D001769:Blood / Q000469:parasitology*; D048430:Cell Shape; D048429:Cell Size; D057446:Hydrodynamics; D046210:Microfluidic Analytical Techniques; D014346:Trypanosoma brucei brucei / Q000166:cytology*