English
 
Help Privacy Policy Disclaimer
  Advanced SearchBrowse

Item

ITEM ACTIONSEXPORT

Released

Journal Article

Stokesian dynamics simulations of a magnetotactic bacterium

MPS-Authors
/persons/resource/persons245166

Mohammadinejad,  Sarah
Stefan Klumpp, Theorie & Bio-Systeme, Max Planck Institute of Colloids and Interfaces, Max Planck Society;

/persons/resource/persons121274

Faivre,  Damien
Damien Faivre, Biomaterialien, Max Planck Institute of Colloids and Interfaces, Max Planck Society;

/persons/resource/persons121488

Klumpp,  Stefan
Stefan Klumpp, Theorie & Bio-Systeme, Max Planck Institute of Colloids and Interfaces, Max Planck Society;

External Resource
No external resources are shared
Fulltext (public)

Article.pdf
(Publisher version), 2MB

Supplementary Material (public)
There is no public supplementary material available
Citation

Mohammadinejad, S., Faivre, D., & Klumpp, S. (2021). Stokesian dynamics simulations of a magnetotactic bacterium. The European Physical Journal E, 44(3): 40. doi:10.1140/epje/s10189-021-00038-5.


Cite as: http://hdl.handle.net/21.11116/0000-0008-3CDD-D
Abstract
The swimming of bacteria provides insight into propulsion and steering under the conditions of low-Reynolds number hydrodynamics. Here we address the magnetically steered swimming of magnetotactic bacteria. We use Stokesian dynamics simulations to study the swimming of single-flagellated magnetotactic bacteria (MTB) in an external magnetic field. Our model MTB consists of a spherical cell body equipped with a magnetic dipole moment and a helical flagellum rotated by a rotary motor. The elasticity of the flagellum as well as magnetic and hydrodynamic interactions is taken into account in this model. We characterized how the swimming velocity is dependent on parameters of the model. We then studied the U-turn motion after a field reversal and found two regimes for weak and strong fields and, correspondingly, two characteristic time scales. In the two regimes, the U-turn time is dominated by the turning of the cell body and its magnetic moment or the turning of the flagellum, respectively. In the regime for weak fields, where turning is dominated by the magnetic relaxation, the U-turn time is approximately in agreement with a theoretical model based on torque balance. In the strong-field regime, strong deformations of the flagellum are observed. We further simulated the swimming of a bacterium with a magnetic moment that is inclined relative to the flagellar axis. This scenario leads to intriguing double helical trajectories that we characterize as functions of the magnetic moment inclination and the magnetic field. For small inclination angles (≲20°) and typical field strengths, the inclination of the magnetic moment has only a minor effect on the swimming of MTB in an external magnetic field. Large inclination angles result in a strong reduction in the velocity in direction of the magnetic field, consistent with recent observations that bacteria with large inclination angles use a different propulsion mechanism.