Collective motion of model microorganisms in Poiseuille flow

• Applicant: Professor Dr. Holger Stark
• Subject Area: Statistical Physics, Nonlinear Dynamics, Complex Systems, Soft and Fluid Matter, Biological Physics
• Term: from 2012 to 2016
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 214525933

• Final Report Year: 2017

Final Report Abstract

In this project we studied the dynamics of microswimmers such as bacteria, algae or sperm in the presence of fluid flow and confinement, as well as their collective behavior. We first analysed numerically and analytically the motion of a swimmer in a microchannel Poiseuille flow and showed that it either shows upstream oriented swinging or tumbling motion. In 2D this motion can be mapped to the motion of a mathematical pendulum, where the upstreamoriented swinging motion corresponds to the back-and-forth oscillations of the pendulum, and tumbling to the turning-over motion of the pendulum. We further showed that experimental results for the pathogen African trypanosome can be well described by our theory, which has also been used by other experimentalists. We studied the collective behavior of spherical microswimmers in a quasi-2D geometry and showed that hydrodynamic flow fields determine the phase behavior of interacting swimmers in confinement. Our results have been highlighted as an Editor’s Suggestion and featured by the TU Berlin, pro-physik.de and welt-der-physik.de. Finally, we considered the collision of microswimmers with solid surfaces. We showed that the time a swimmer spends at the surface is governed by noise and hydrodynamic swimmer-wall interactions. Interestingly, the escape of very persistent swimmers can be mapped to the escape of a particle from a potential minimum over a potential barrier. http://www.pro-physik.de/details/news/6120431/Schwimmstil bestimmt kollektive Bewegung.html http://www.weltderphysik.de/gebiet/fluide/news/2014/schwimmtyp-bestimmt-kollektive-bewegung

Publications

• Flow loading induces oscillatory trajectories in a bloodstream parasite, Biophys. J. 103, 1162 (2012)
  S. Uppaluri, N. Heddergott, E. Stellamanns, S. Herminghaus, A. Zöttl, H. Stark, M. Engstler, and T. Pfohl
  (See online at https://doi.org/10.1016/j.bpj.2012.08.020)
• Nonlinear dynamics of a microswimmer in Poiseuille flow, Phys. Rev. Lett. 108, 218104 (2012)
  A. Zöttl and H. Stark
  (See online at https://doi.org/10.1103/PhysRevLett.108.218104)
• Periodic and quasiperiodic motion of an elongated microswimmer in Poiseuille flow, Eur. Phys. J. E 36, 1 (2013)
  A. Zöttl and H. Stark
  (See online at https://doi.org/10.1140/epje/i2013-13004-5)
• Hydrodynamics determines collective motion and phase behavior of active colloids in quasi-two-dimensional confinement, Phys. Rev. Lett. 112, 118101 (2014)
  A. Zöttl and H. Stark
  (See online at https://doi.org/10.1103/PhysRevLett.112.118101)
• Hydrodynamics of microswimmers in confinement and in Poiseuille flow, Dissertation, Technische Universität Berlin (2014)
  A. Zöttl
  
• Detention times of microswimmers close to surfaces: influence of hydrodynamic interactions and noise, Phys. Rev. Lett. 115, 038101 (2015)
  K. Schaar, A. Zöttl and H. Stark
  (See online at https://doi.org/10.1103/PhysRevLett.115.038101)
• Topical Review: Emergent behavior in active colloids, J. Phys.: Condens. Matter 28, 253001 (2016)
  A. Zöttl and H. Stark
  (See online at https://doi.org/10.1088/0953-8984/28/25/253001)