Tuning nonequilibrium colloidal structure in external fields by density-dependent state switching

Area of Science:

• Statistical Physics
• Soft Matter Physics
• Biophysics

Background:

• Biological cells exhibit quorum sensing, altering internal states based on local cell density.
• Quorum sensing is crucial for collective behaviors like biofilm formation.
• Understanding density-dependent interactions is key to controlling cellular self-organization.

Purpose of the Study:

• To investigate a model of ideal colloids with switchable internal states and density-dependent switching rates.
• To explore how quorum sensing principles can induce collective structuring in noninteracting particles.
• To analyze the influence of environmental sensing range and rate functions on emergent structures.

Main Methods:

• Reactive Brownian dynamics simulations of ideal colloids.
• Application of reaction-diffusion theory to model the system.
• Analysis of different functional forms for density-dependent switching rates.

Main Results:

• Density-mediated interactions between ideal colloids lead to remarkable system structuring.
• The spatiotemporal sensing range significantly influences the resulting structures.
• Sigmoidal rate functions reveal tuneable correlation effects sensitive to noise and fluctuations.

Conclusions:

• Quorum sensing protocols can effectively mediate nonequilibrium structuring in simple models.
• The model provides insights into self-organization driven by density-dependent interactions.
• Environmental sensing range is a critical parameter for controlling emergent collective behavior.