Modeling of an acoustically actuated artificial micro-swimmer

Area of Science:

• * Microfabrication
• * Biomedical Engineering
• * Acoustics

Background:

• * Ultrasound-actuated artificial micro-swimmers show promise for medical applications.
• * A theoretical framework for their actuation and swimming is currently lacking.
• * Sperm-like micro-swimmers offer a biomimetic model for propulsion.

Purpose of the Study:

• * To develop a theoretical model for acoustically actuated sperm-like artificial micro-swimmers.
• * To establish quantitative relationships between acoustic parameters and micro-swimmer performance.
• * To account for flagellar dynamics and realistic design considerations.

Main Methods:

• * Employed resistive force theory to model flagellar dynamics and swimmer motility.
• * Incorporated inertia and material damping into the governing equations.
• * Considered a variable cross-section for the flagellum in the theoretical model.

Main Results:

• * Demonstrated that ultrasound actuation can achieve significant micro-swimmer velocities, particularly at resonance.
• * Quantified the relationship between head oscillation amplitude and acoustic pressure/frequency.
• * Identified key non-dimensional parameters influencing micro-swimmer performance, including resonance index and sperm number.

Conclusions:

• * The proposed theoretical model accurately predicts the performance of ultrasound-actuated sperm-like micro-swimmers.
• * The model's validity is confirmed through comparison with experimental results.
• * This work provides a foundation for the realistic design and application of micro-swimmers.