Flow-Field-Assisted Dielectrophoretic Microchips for High-Efficiency Sheathless Particle/Cell Separation with Dual...

Area of Science:

• Microfluidics
• Biotechnology
• Cell Separation Technology

Background:

• Traditional dielectrophoretic (DEP) cell separation relies on sheath flow for prefocusing, which limits flow velocity and complicates integration with other microfluidic systems.
• Complex fluid control systems in existing DEP methods hinder their application in comprehensive biomedical workflows.

Purpose of the Study:

• To develop a high-efficiency, sheathless particle and cell separation method that eliminates the need for prefocusing.
• To combine electric field (E-field) and flow field (F-field) effects for advanced cell manipulation.
• To create a versatile microfluidic device with switchable separation modes.

Main Methods:

• Designed a microfluidic chip with hollow lemon-shaped electrodes to generate an E-field gradient for lateral particle displacement.
• Incorporated arc-shaped protrusion structures to create an F-field for guiding particles without prefocusing.
• Utilized AC electric fields and microchannel flow dynamics for particle manipulation.

Main Results:

• Achieved sheathless separation (ShLS) of breast cancer cells from erythrocytes with 95.5% recovery and polystyrene particles from yeast cells with 97.1% purity at flow velocities over 2.59 mm/s.
• Demonstrated an adjustable particle mixing ratio (AMR) mode for controlled cell mixture preparation.
• Validated the device's high efficiency, ease of use, and versatility for biological and medical applications.

Conclusions:

• The developed flow-field-assisted DEP method offers a significant advancement over traditional sheath-flow techniques.
• The sheathless, prefocusing-free approach enhances separation efficiency and broadens microfluidic integration possibilities.
• The dual-mode functionality (ShLS and AMR) provides a versatile platform for diverse biomedical research and applications.