Microfluidic electrical sorting of particles based on shape in a spiral microchannel

Area of Science:

• Biophysics
• Microfluidics
• Biotechnology

Background:

• Particle shape is crucial for cell cycle, bioparticle identification, and disease diagnostics.
• Label-free particle and cell separation methods are vital for various chemical and biological applications.
• Current separation techniques often lack specificity or require external forces.

Purpose of the Study:

• To demonstrate a novel method for continuous-flow electrical sorting of particles based on shape.
• To achieve label-free separation of spherical and peanut-shaped particles with similar volumes.
• To investigate the underlying physics of shape-based sorting in microfluidic devices.

Main Methods:

• Utilizing an asymmetric double-spiral microchannel for particle manipulation.
• Employing curvature-induced dielectrophoresis for particle focusing and displacement.
• Developing a numerical model to simulate particle trajectories within the microchannel.

Main Results:

• Successful continuous-flow electrical sorting of spherical and peanut-shaped particles.
• Demonstration of shape-dependent particle displacement without sheath flow or external forces.
• Numerical model predictions qualitatively matched experimental observations of particle trajectories.

Conclusions:

• Shape can serve as a specific marker for label-free particle and cell separation.
• Asymmetric double-spiral microchannels with dielectrophoresis offer an effective platform for shape-based sorting.
• This technique holds potential for diverse chemical and biological applications requiring precise particle manipulation.