Constrained motion of self-propelling eccentric disks linked by a spring

Area of Science:

• Physics
• Biophysics
• Soft Matter Physics

Background:

• Non-equilibrium behaviors in biological systems are crucial but lack experimental models.
• The interplay of elasticity and activity is hypothesized to be a key driver of these behaviors.

Purpose of the Study:

• To design and investigate a model system for studying the dynamics of active chains.
• To explore the interplay of activity, elasticity, and friction in generating non-equilibrium phenomena.

Main Methods:

• Development of an active chain model comprising eccentric disks linked by springs.
• Simulations of individual and long chains, including analysis of motion under different constraints (pinning, clamping).
• Analysis of scaling relationships for rotational and beating frequencies.

Main Results:

• The model system qualitatively reproduces self-rotation and self-beating behaviors.
• A hairpin conformation emerges in free-moving chains.
• Rotational and beating frequencies scale with the flexure number (χ) as ∼(χ)4/3 in constrained motions.

Conclusions:

• Topological constraints are vital for non-equilibrium synergy behaviors in active matter systems.
• The observed scaling suggests a balance between self-propelling forces and energy dissipation.
• The eccentric-disk model provides insights into complex dynamics in active biological systems.