Coupling Agents in Acoustofluidics: Mechanisms, Materials, and Applications

Area of Science:

• Biomedical Engineering
• Acoustics
• Microfluidics

Background:

• Acoustic coupling agents are essential for connecting piezoelectric transducers to microfluidic chips.
• Their performance influences wave transmission, device reusability, and reliability in biomedical applications.

Purpose of the Study:

• To provide a comprehensive reference on acoustic coupling agents in acoustofluidic devices.
• To summarize mechanisms, classifications, and applications of couplants in microfluidics.

Main Methods:

• Review of physical mechanisms, material classifications, and applications of acoustic coupling agents.
• Examination of gel-based agents' properties and performance.

Main Results:

• Gel-based agents are favored for stability, efficiency, and ease of preparation.
• Couplants enable microparticle trapping, droplet manipulation, and biosample sorting via impedance matching and wave mode conversion.
• Agent thickness and acoustic properties modulate sound fields for optimized forces and thermal effects.

Conclusions:

• Challenges include agent stability (evaporation, degradation) and chip compatibility.
• Future research should focus on multilayer designs, dynamic thickness control, and biocompatibility for advanced diagnostics and analysis.