Concentration-controlled particle focusing in spiral elasto-inertial microfluidic devices

Area of Science:

• Fluid dynamics
• Microfluidics
• Biophysics

Background:

• Elasto-inertial flows are crucial in microfluidic particle manipulation.
• Controlling particle focusing is essential for applications like flow cytometry.
• Viscoelastic fluid properties significantly influence particle behavior.

Purpose of the Study:

• To propose and investigate a strategy for controlling particle focusing positions.
• To explore the underlying physics of particle manipulation in Dean-coupled elasto-inertial flows.
• To demonstrate particle concentration at high throughput using this method.

Main Methods:

• Utilizing Dean-coupled elasto-inertial flows in a spiral microchannel.
• Adjusting polymer concentration in viscoelastic fluids to alter particle focusing.
• Analyzing the interplay of elastic, inertial, and Dean drag forces.

Main Results:

• High polymer concentrations achieve single-line particle focusing at the channel centerline.
• Decreasing polymer concentrations shift particles to the outer channel.
• This position-shifting was leveraged for efficient particle concentration.

Conclusions:

• Polymer concentration is an effective parameter for controlling particle focusing in viscoelastic microfluidics.
• The developed method offers a high-throughput particle concentration technique.
• This approach shows promise for microflow cytometry pretreatment.