Passive and active colloidal chemotaxis in a microfluidic channel: mesoscopic and stochastic models

Area of Science:

• Physics
• Chemistry
• Materials Science

Background:

• Chemotaxis, particle movement along chemical gradients, is observed in nature and is of interest for synthetic active particles like nanomotors.
• Previous studies demonstrated nanomotor chemotaxis in fluids and microfluidic channels using specific geometries.

Purpose of the Study:

• To demonstrate chemotaxis in a microfluidic channel using mesoscopic particle-based simulations.
• To analyze chemical concentration profiles and chemotactic forces for active and passive colloids.
• To develop a stochastic model explaining colloidal chemotaxis.

Main Methods:

• Mesoscopic particle-based simulations of colloids and solvent in a microfluidic channel.
• Evaluation of chemical concentration profiles.
• Computation of chemotactic forces.
• Development of a rationalizing stochastic model.

Main Results:

• Successful simulation of chemotaxis in a microfluidic channel.
• Detailed analysis of chemical gradients and forces acting on colloids.
• A novel stochastic model that explains simulated colloidal chemotaxis.
• The model also explains and extends interpretations of previous simulation results.

Conclusions:

• Mesoscopic simulations effectively model colloidal chemotaxis in microfluidic systems.
• The developed stochastic model provides a framework for understanding and predicting nanomotor behavior.
• This work contributes to the design and control of synthetic active particles.