3D-printed acoustic metasurface with encapsulated micro-air-bubbles for frequency-selective manipulation

Area of Science:

• Acoustic manipulation
• Microfluidics
• Materials science

Background:

• High-frequency ultrasound is costly for microfluidic object manipulation.
• Conventional micro-air-bubbles lack stability and precision due to surface tension and flow dynamics.

Purpose of the Study:

• To develop a stable, low-cost microfluidic manipulation system using low-frequency acoustic waves.
• To create artificial micro-air-bubbles that overcome the limitations of conventional bubbles.

Main Methods:

• Fabrication of artificial micro-air-bubbles using 3D-printed air holes encapsulated in PDMS film.
• Utilizing coupled vibration structures for stabilized bubble resonance and controlled acoustic forces.
• Employing laser Doppler vibrometry to characterize vibration modes and frequency dependence.

Main Results:

• Demonstrated stable, frequency-tunable vibration modes of artificial micro-air-bubbles.
• Achieved precise manipulation (aggregation, rotation, separation) of micro-objects.
• Developed a metasurface with a microbubble array for frequency-selective manipulation.

Conclusions:

• Artificial micro-air-bubbles offer a mechanically stable and cost-effective alternative for microfluidic manipulation.
• The proposed acoustic metasurface enables versatile, frequency-controlled sample handling for applications like drug screening.