Yield stress fluids in microfluidics: research, applications and opportunities

Area of Science:

• Microfluidics and Complex Fluids
• Rheology and Material Science

Background:

• Microfluidic technologies are crucial for precision medicine, diagnostics, and drug delivery.
• Many microfluidic applications involve complex fluids (e.g., blood, bioinks) with non-Newtonian properties like yield stress and viscoelasticity.
• The interaction between complex fluid rheology and microscale environments is not fully understood.

Purpose of the Study:

• To review microfluidic applications where yield stress and rheological properties are critical.
• To highlight how rheology influences transport, mixing, and interfacial dynamics in microscale systems.
• To identify opportunities for utilizing rheological properties in microfluidic design.

Main Methods:

• Literature review of microfluidic applications involving complex fluids.
• Analysis of rheological effects on device design and function.
• Exploration of physics-biology links in microfluidic systems.

Main Results:

• Yield stress and viscoelasticity significantly impact microfluidic device performance in areas like cell separation and bioprinting.
• Electrorheological fluids offer tunable properties for microfluidic components (valves, pumps).
• Rheology controls transport phenomena and enables fabrication of microstructures and hydrogels.

Conclusions:

• Yield-stress and viscoelastic effects are powerful design variables, not just complications, in microfluidics.
• Further research can leverage these properties to enhance microfluidic science and technology.
• Understanding rheology is essential for optimizing microfluidic applications in various fields.