Synthetic Chemotaxis and Collective Behavior in Active Matter

Area of Science:

• Physical Chemistry
• Soft Matter Physics
• Chemical Engineering

Background:

• Microorganisms utilize chemotaxis (navigation in chemical gradients) for survival, finding resources, and escaping toxins.
• Microbial chemotaxis enables signaling and coordinated behavior, exemplified by Dictyostelium cell aggregation during starvation.
• Synthetic microswimmers, self-propelling via chemical production, offer a model system analogous to microorganisms.

Purpose of the Study:

• To review recent theoretical advancements in synthetic chemotaxis, primarily from simulations and field theory.
• To explore self-interactions and cross-interactions in ensembles of synthetic microswimmers.
• To focus on the role of repulsive chemical interactions in generating patterns in active systems.

Main Methods:

• Theoretical descriptions based on simulations.
• Field theoretical descriptions of particle interactions.
• Analysis of both self-interactions and cross-interactions (attractive and repulsive).

Main Results:

• Single particles exhibit self-trapping or self-avoidance due to self-produced chemical trails.
• Attractive interactions in ensembles lead to clustering, resembling Dictyostelium aggregation or dynamic clustering.
• Repulsive interactions drive novel pattern formation, including chemical-shelled clusters and traveling waves.

Conclusions:

• Synthetic microswimmers serve as valuable analogues for studying microbial chemotaxis and communication.
• Synthetic signaling is a key determinant of collective behavior in microswimmer ensembles.
• Repulsive chemical interactions offer a design principle for creating diverse patterns in active matter.