PDMS free-flow electrophoresis chips with integrated partitioning bars for bubble segregation.

Area of Science:

• Microfluidics
• Electrophoresis
• Analytical Chemistry

Background:

• Gas bubbles are a common issue in microfluidic electrophoresis devices, hindering separation efficiency.
• Existing methods for bubble prevention can be complex or compromise device performance.

Purpose of the Study:

• To present a novel microfluidic free-flow electrophoresis device with an integrated bubble prevention mechanism.
• To demonstrate a straightforward and rapid chip prototyping process for microfluidic devices.

Main Methods:

• A three-layer sandwich chip design incorporating partitioning bars between electrode channels and the separation chamber.
• Softlithography for casting the polydimethylsiloxane (PDMS) microfluidic layer.
• Fabrication using a reusable carrier plate and a sealing glass slide.

Main Results:

• The partitioning bars effectively prevent gas bubbles from entering the separation area while maintaining electrical contact.
• Successful free-flow zone electrophoretic separations of fluorescent dye mixtures were achieved.
• Separation of labeled amines and amino acids was demonstrated at voltages up to 297 V.

Conclusions:

• The developed microfluidic device offers an effective solution for gas bubble management in electrophoresis.
• The novel design facilitates rapid and easy chip prototyping.
• The device demonstrates high performance for various separation applications in analytical chemistry.