Microfluidic Free-Flow Electrophoresis Based Solvent Exchanger for Continuously Operating Lab-on-Chip Applications

Area of Science:

• Microfluidics
• Analytical Chemistry
• Biotechnology

Background:

• Lab-on-chip (LOC) systems require seamless integration of synthesis and analytical modules.
• Solvent incompatibilities hinder in-line processes in multi-step synthesis and integrated bio-assays.
• Efficient solvent exchange is crucial for serial module operation in LOC devices.

Purpose of the Study:

• To develop a continuously operating microfluidic solvent exchanger for miscible organic/aqueous fluids.
• To demonstrate the efficacy of free-flow electrophoresis for solvent replacement in LOC systems.
• To validate the compatibility of the solvent exchanger for cell-based downstream applications.

Main Methods:

• Utilized free-flow electrophoresis (FFE) principle for solvent exchange.
• Employed a microfluidic device for continuous operation.
• Optimized microfluidic layout and inlet flow ratio for performance enhancement.
• Assessed solvent removal efficiency and dilution factor.
• Evaluated cellular compatibility using impedimetric monitoring of HEK293A cells.

Main Results:

• Achieved 95% dimethyl sulfoxide (DMSO) removal efficiency through layout optimization.
• Minimized dilution factor to 5 by optimizing inlet flow ratio.
• Demonstrated reduced instrumentation requirements without significant performance loss.
• Confirmed no adverse effects on HEK293A cells after solvent exchange.
• Validated the device for cell-based downstream applications.

Conclusions:

• Microfluidic free-flow electrophoresis is effective for continuous solvent exchange in lab-on-chip systems.
• The developed solvent exchanger overcomes solvent incompatibility challenges in integrated microfluidic processes.
• The system supports seamless integration of chemical synthesis and cell-based biological testing on a chip.