Stochastic localization of microswimmers by photon nudging

Area of Science:

• Physics, Soft Matter
• Microfluidics
• Nanotechnology

Background:

• Photophoretically self-propelled Janus particles are microswimmers with potential applications in targeted delivery and sensing.
• Controlling the motion of individual microswimmers, especially in complex environments, remains a significant challenge.

Purpose of the Study:

• To experimentally demonstrate force-free trapping and steering of single photophoretically self-propelled Janus particles.
• To utilize a feedback mechanism for real-time optical control of particle self-propulsion.
• To investigate the role of orientational Brownian motion in microswimmer reorientation.

Main Methods:

• Real-time monitoring of particle position and orientation.
• Optical switching of the particle's self-propulsion mechanism based on feedback.
• Analysis of particle size dependence on photophoretic propulsion velocity.

Main Results:

• Successful demonstration of force-free trapping and steering of Janus particles.
• Utilized orientational Brownian motion for effective reorientation of the microswimmer.
• Observed increased position accuracy with decreasing particle radius due to photon nudging.

Conclusions:

• The developed optical steering mechanism offers precise control over microswimmers.
• This technique is suitable for navigation in complex biological environments.
• The method facilitates in-depth studies of collective swimming behaviors.