Electrophoretic partitioning of proteins in two-phase microflows

Area of Science:

• Biophysics
• Chemical Engineering
• Analytical Chemistry

Background:

• Protein partitioning in two-phase systems is crucial for separation.
• Microfluidic systems offer precise control over liquid-liquid interfaces for enhanced separation.
• Continuous-flow electrophoresis can be utilized for protein separation based on phase affinity.

Purpose of the Study:

• To investigate protein transport phenomena in a novel continuous-flow two-phase electrophoresis system.
• To explore the effect of electric fields on protein partitioning at a microscale phase boundary.
• To characterize the asymmetric transport of proteins between immiscible aqueous phases.

Main Methods:

• Development of a microchannel setup for continuous-flow two-phase electrophoresis with a flow-direction phase boundary.
• Utilizing polyethylene glycol (PEG)-dextran systems for immiscible aqueous phases.
• Applying perpendicular electric fields to manipulate protein transport across the phase boundary.
• Employing gel material for ion conduction and electrode decoupling to prevent bubble generation.

Main Results:

• Demonstrated asymmetric electrophoretic transport of proteins between PEG-rich and dextran-rich phases.
• Bovine serum albumin (BSA) readily transferred from PEG-rich to dextran-rich phase with low electric fields or diffusion.
• BSA transfer from dextran-rich to PEG-rich phase was significantly inhibited until a higher electric field strength was applied.

Conclusions:

• The developed microfluidic electrophoresis system enables controlled protein partitioning.
• Protein transport across phase boundaries exhibits strong field-dependent asymmetry.
• This asymmetry can be leveraged for selective protein separation and purification in microfluidic devices.