Dielectrophoretic sorting of particles and cells in a microsystem

Area of Science:

• Microfluidics
• Analytical Chemistry
• Biotechnology

Background:

• Sensitive analytical techniques are crucial for studying cellular and molecular events in small volumes.
• Developing microtools for sample handling and separation in microvolumes remains a significant challenge.
• Existing microseparation devices predominantly rely on electrophoresis and chromatography.

Purpose of the Study:

• To demonstrate the utility of negative dielectrophoresis (DEP) for microscale particle manipulation and separation.
• To present a novel microfluidic device utilizing AC fields for particle handling.
• To explore the potential of this method for miniaturized analytical systems.

Main Methods:

• Fabrication of a microfluidic device with integrated miniaturized electrode arrays.
• Application of high-frequency AC fields to induce negative dielectrophoresis (DEP).
• Utilizing a laminar liquid flow to transport particles past electrodes.
• Incorporating a planar funnel, aligner, field cage, and switch for particle manipulation.
• Employing platinum/titanium and indium tin oxide (ITO) electrodes on glass substrates.

Main Results:

• Demonstrated control over particle trajectories by modifying AC drive parameters.
• Successfully handled micrometer-sized latex particles and living mammalian cells.
• Achieved particle concentration and switching at linear flow velocities up to 10 mm s-1.
• The device integrates particle concentration, alignment, trapping, and sorting functionalities.

Conclusions:

• Negative dielectrophoresis (DEP) provides an effective alternative to electrophoretic and chromatographic methods for microscale separation.
• The developed microfluidic device demonstrates efficient particle handling and manipulation.
• This approach, combined with optical detection, holds promise for the development of miniaturized flow cytometry systems.