Acoustophoresis in polymer-based microfluidic devices: Modeling and experimental validation

Area of Science:

• Acoustofluidics
• Microfluidics
• Biotechnology

Background:

• Acoustophoresis enables precise manipulation of microparticles in microfluidic devices.
• Traditional devices often use silicon-glass or glass, limiting material choices.
• Ultrasound resonances in microfluidic systems are crucial for efficient particle manipulation.

Purpose of the Study:

• To develop and validate a 3D finite-element model for acoustophoresis in polymer microchannels.
• To investigate the role of whole-system ultrasound resonances for optimizing acoustophoretic performance.
• To compare the performance of polymer-based devices with conventional silicon-glass or glass devices.

Main Methods:

• A 3D finite-element model was developed for simulating acoustophoresis.
• Numerical simulations were performed for microparticles in a polymer microchannel driven by a piezoelectric transducer.
• Acoustic focusing experiments were conducted using polystyrene particles in a polymethylmethacrylate (PMMA) chip.

Main Results:

• An optimal resonance mode, based on whole-system ultrasound resonances, was identified for enhanced acoustophoresis.
• The acoustophoretic performance in the polymer microchannel was comparable to conventional silicon-glass or glass devices.
• Experimental validation showed efficient particle focusing (6.6 s) at specific acoustic energy densities (13 J/m³).

Conclusions:

• Polymer-based microfluidic devices can achieve high-quality acoustophoretic particle manipulation.
• The principle of whole-system ultrasound resonances offers a new approach for optimizing microfluidic acoustics.
• This work demonstrates the potential of MHz frequency acoustophoresis in polymer chips for microparticle manipulation.