Differential Sorting of Microparticles Using Spiral Microchannels with Elliptic Configurations

Area of Science:

• Microfluidics
• Biotechnology
• Biomedical Engineering

Background:

• Label-free cell sorting relies on precise microparticle focusing.
• Inertial focusing phenomena are key to size-dependent cell separation.
• Existing spiral microchannels face limitations in separation precision.

Purpose of the Study:

• To introduce novel five-loop spiral microchannels with elliptic configurations.
• To investigate the effects of alternating curvature and channel Reynolds number on microparticle focusing.
• To evaluate the separation efficiency of these microchannels for different particle sizes.

Main Methods:

• Designed and fabricated five-loop spiral microchannels (90 µm height, 500 µm width) with varying elliptic aspect ratios.
• Investigated focusing of 10 µm and 20 µm fluorescent microparticles.
• Analyzed particle separation yields at flow rates from 0.5 to 3.5 mL/min.

Main Results:

• Achieved high separation yields: up to ~95% for 20 µm particles and ~90% for 10 µm particles.
• Demonstrated effective size-dependent separation using inertial focusing.
• Observed promising focusing behavior and enrichment levels compared to conventional designs.

Conclusions:

• Elliptic spiral microchannels offer enhanced precision for inertial focusing.
• These novel configurations show significant potential for label-free, size-dependent cell-sorting.
• The study highlights the importance of channel geometry in microfluidic particle manipulation.