Self-aligned sequential lateral field non-uniformities over channel depth for high throughput dielectrophoretic cell...

Area of Science:

• Biophysics
• Microfluidics
• Cellular Engineering

Background:

• Dielectrophoresis (DEP) separates cells using frequency-controlled electric fields, but current methods have limited throughput due to shallow electrode geometries.
• Existing DEP systems struggle with low flow rates (sub-μL min⁻¹) and cell concentrations (<10⁵ cells/mL), hindering applications in large-scale cell analysis.

Purpose of the Study:

• To develop a flow-through DEP device with enhanced throughput for cell separation.
• To enable precise isolation and characterization of cells based on phenotypic differences.
• To advance the concept of an 'all-electric' system for cellular analysis and cytometry.

Main Methods:

• Fabrication of a microfluidic device with self-aligned, sequential field non-uniformities patterned on sidewalls.
• Utilizing metal patterning across the entire channel depth (50 μm) for lateral field extension.
• Employing single-cell impedance cytometry to analyze collected cell fractions.

Main Results:

• Achieved high-throughput cell separation (>μL min⁻¹ flow rates and >10⁶ cells/mL) using the novel DEP geometry.
• Demonstrated phenotype-specific separation of healthy and fixed red blood cells with minimal dependence on cell position or orientation.
• Confirmed collected cell integrity and distinct electrical opacity differences correlating with capacitance-based DEP crossover frequencies.

Conclusions:

• The developed DEP device significantly overcomes throughput limitations of previous technologies.
• The innovative geometry enables robust, position-independent cell deflection for accurate phenotypic sorting.
• This technology paves the way for integrated, high-efficiency electric systems for cell isolation and phenotypic quantification.