Gradient elution moving boundary electrophoresis for high-throughput multiplexed microfluidic devices

Area of Science:

• Analytical Chemistry
• Microfluidics
• Biotechnology

Background:

• Conventional capillary electrophoresis requires complex injection mechanisms and larger areas.
• Existing methods often lack the resolution needed for complex sample mixtures.

Purpose of the Study:

• To introduce a novel electrophoretic separation technique, gradient elution moving boundary electrophoresis (GEMBE).
• To demonstrate GEMBE's capability for high-resolution separations in miniaturized microfluidic devices.
• To showcase GEMBE's applicability to diverse analytes, including dyes, amino acids, DNA, and immunoassays.

Main Methods:

• GEMBE combines electrophoretic migration with variable hydrodynamic bulk counterflow.
• Continuous sample introduction eliminates the need for separate injection mechanisms.
• Variable counterflow velocity and bulk flow acceleration provide enhanced selectivity and temporal separation.

Main Results:

• GEMBE achieved high-resolution separations in very short channels, suitable for microfluidic chips.
• A multiplexed eight-channel device demonstrated reduced area requirements (<1 in.2) and efficient fluidic access (n+1 ports for n analyses).
• Demonstrated low relative standard deviation (<3% for interchannel migration, <5% for peak/height) in parallel separations and immunoassay calibration.

Conclusions:

• GEMBE offers a miniaturized, high-resolution alternative to conventional capillary electrophoresis.
• The technique's efficiency and reduced footprint are ideal for microfluidic applications.
• GEMBE's versatility is shown across various analytical targets, including immunoassays.