Controlling Confined Collective Organization with Taxis

Area of Science:

• Microbiology
• Soft Matter Physics
• Complex Systems

Background:

• Biased locomotion is prevalent in microorganisms but its role in self-organization is poorly understood.
• Recent experiments show microorganisms transitioning to large-scale collective flows.

Purpose of the Study:

• To theoretically investigate the self-organization dynamics of magnetotactic bacteria within a confined drop.
• To identify mechanisms driving collective behavior and its impact on the surrounding environment.

Main Methods:

• Theoretical modeling of magnetotactic bacteria dynamics.
• Analysis of symmetry-breaking mechanisms (local chiral and global achiral).
• Investigation of collective behavior, vortex formation, and torque generation.

Main Results:

• Two symmetry-breaking mechanisms were identified, leading to self-organization.
• Global vortices and a net torque on the drop were observed.
• Microscopic chirality was found to control collective behavior, including oscillations and memory-like features.

Conclusions:

• Biased locomotion in microorganisms can lead to complex self-organized structures.
• The interplay of chirality and confinement dictates emergent collective phenomena.
• Magnetotactic bacteria exhibit tunable collective dynamics with potential for memory effects.