Filter-less submicron hydrodynamic size sorting.

Area of Science:

• Microfluidics
• Biotechnology
• Particle Separation

Background:

• Traditional particle separation methods often rely on filters, which can clog and limit throughput.
• Achieving precise separation of submicron particles from complex samples remains a challenge in microfluidic applications.

Purpose of the Study:

• To develop a simple, filter-less microfluidic device for efficient submicron particle separation.
• To create a predictive model for microfluidic chip sorting properties based on geometry.
• To demonstrate the device's capability for both rapid small-size sorting and high-throughput micron-sized sorting.

Main Methods:

• Hydrodynamic filtration utilizing a microfluidic device with a minimum channel dimension of 5 μm.
• Development of a predictive model incorporating velocity profiles and hydrodynamic resistances.
• Fabrication and testing of two distinct chip designs: low-aspect ratio (two-level) and 3D architecture (lamination-based).

Main Results:

• The microfluidic device successfully separates submicron particles (critical size ~0.1 μm) without filters.
• The developed model accurately predicts chip sorting performance, showing quantitative agreement with experimental and numerical results.
• Two design families demonstrated efficient sorting: rapid separation of small sizes and micron-sized sorting at μL flow rates.

Conclusions:

• A passive, filter-less microfluidic device for submicron particle separation has been successfully demonstrated.
• The proposed hydrodynamic filtration method is simple, robust, and easy to fabricate.
• The study provides a validated model for predicting and optimizing microfluidic sorting performance.