Dielectrophoretic isolation of cells using 3D microelectrodes featuring castellated blocks

Area of Science:

• Biomedical Engineering
• Microfluidics
• Cell Separation Technology

Background:

• Traditional microelectrodes often struggle with achieving both high cell viability and efficient separation.
• Existing volumetric electrodes typically have linear profiles, limiting their integration with fluidic systems.

Purpose of the Study:

• To develop novel 3D microelectrodes with castellated blocks for improved dielectrophoretic cell isolation.
• To enhance cell viability and separation efficiency compared to conventional thin-film surface electrodes.
• To create versatile monolithic structures with integrated fluidic paths for cell manipulation.

Main Methods:

• Fabrication of 3D microelectrodes with castellated surfaces using a self-aligned etching process in single-crystal silicon.
• Design of an interdigitated comb array incorporating these electrodes with integrated fluidic pores.
• Application of low-voltage AC oscillations (±5 Vp, 400 kHz) for dielectrophoretic cell manipulation.

Main Results:

• Demonstrated a more effective dielectrophoretic force field compared to thin-film surface electrodes.
• Achieved immobilization of cells near stagnation points within a parabolic flow profile.
• Reported high retention of viable cells (90.2% ± 3.5%) while effectively removing nonviable cells (88.5% ± 5%).
• Attained a high throughput of 5 × 10(5) cells per hour.

Conclusions:

• The 3D castellated microelectrodes offer a versatile and effective platform for dielectrophoretic cell isolation.
• The unique electrode geometry enhances cell viability and separation efficiency in microfluidic devices.
• This technology enables label-free cell separation with high throughput and minimal cell damage.