Chemotactic behavior for a self-phoretic Janus particle near a patch source of fuel

Area of Science:

• Colloid and Interface Science
• Chemical Physics
• Biophysics

Background:

• Microswimmers, including biological organisms and synthetic particles, utilize chemotaxis to navigate chemical gradients.
• Synthetic active colloids with chemotactic abilities are promising for applications in targeted drug delivery and advanced materials.

Purpose of the Study:

• To investigate the chemotactic behavior of a Janus particle near an axisymmetric chemical patch on a planar wall.
• To understand how fuel release/consumption rates and phoretic mobility influence particle movement and stability.

Main Methods:

• Simulating a Janus particle that converts fuel to product molecules at its catalytic cap, generating self-phoresis.
• Analyzing particle behavior as a function of fuel dynamics and phoretic response parameters.

Main Results:

• The Janus particle's movement is governed by the interplay of fuel release and consumption rates.
• Under specific conditions, the particle achieves a stable hovering state, aligning normal to the wall above the chemical patch.
• The hovering distance is dependent on the particle's activity.

Conclusions:

• The study elucidates the chemotactic mechanisms of synthetic Janus particles.
• A stable hovering state was identified, offering potential for controlled positioning in microfluidic or material assembly applications.