Wall-induced lateral migration in particle electrophoresis through a rectangular microchannel.

Area of Science:

• Physics, Applied
• Microfluidics
• Electrophoresis

Background:

• Particle electrophoresis in microchannels is crucial for various applications.
• Traditionally, particles were assumed to move parallel to electric fields in uniform microchannels.

Purpose of the Study:

• To experimentally demonstrate lateral particle migration in electrophoresis within a rectangular microchannel.
• To investigate the phenomenon of wall-induced dielectrophoresis-resembled motion in microfluidic electrophoresis.

Main Methods:

• Experimental setup for observing particle movement in a rectangular microchannel under an applied electric field.
• Measurement of particle stream widths at varying electric field strengths.

Main Results:

• First experimental evidence of lateral particle migration during electrophoresis in a microchannel.
• Observed particle focusing into a stream along the channel centerline.
• Demonstration that wall-induced forces drive this migration, decaying away from the wall.

Conclusions:

• Lateral particle migration in microchannel electrophoresis is a real phenomenon.
• The observed focused particle stream aligns with theoretical predictions from an analytical model.
• This finding offers new possibilities for particle manipulation and separation in microfluidic devices.