Elasto-inertial microfluidic separation of microspheres with submicron resolution at high-throughput

Area of Science:

• Microfluidics
• Bioseparation
• Fluid Dynamics

Background:

• Elasto-inertial microfluidics offers high throughput and resolution for particle separation.
• Precise control of flow conditions is crucial but lacks established guidelines.

Purpose of the Study:

• To develop a dimensionless analysis for predicting microsphere behavior at the interface of Newtonian and viscoelastic fluids.
• To establish guidelines for elasto-inertial microfluidic separation.

Main Methods:

• Utilized Reynolds number, modified Weissenberg number, and modified elastic number to analyze inertial and elastic forces.
• Introduced a new dimensionless number: Newtonian fluid stream width divided by microsphere diameter.
• Validated theoretical predictions with experimental separation of polystyrene microspheres and biological samples.

Main Results:

• The proposed dimensionless analysis accurately predicts microsphere migration across fluid interfaces.
• Achieved high-throughput, high-purity (>95%), and high-recovery (>97%) submicron separation of microspheres (2.1 and 2.5 μm).
• Successfully demonstrated applicability by separating platelets from *Escherichia coli* (E.coli).

Conclusions:

• The developed dimensionless analysis provides precise estimation of microsphere behavior in elasto-inertial microfluidics.
• This method enables effective and reliable microparticle and cell separation.
• The findings pave the way for standardized protocols in microfluidic separations.