Tunable in-situ electro-polymerization of hydrogel films for microchip-based bioanalysis

Area of Science:

• Microfluidics
• Polymer Science
• Materials Science

Background:

• Electro-polymerization is typically performed at the macroscale for large-area coatings.
• Electrical actuation offers precise control over polymerized film characteristics like position and thickness.
• Microfluidic systems benefit from localized control of material deposition.

Purpose of the Study:

• To introduce a microfabricated platform for on-chip electro-polymerization of hydrogel films.
• To demonstrate precise spatial control and customization of hydrogel films within microchannels.
• To explore the utility of electro-polymerized hydrogels in microfluidic applications.

Main Methods:

• Fabrication of a microfluidic platform with individually addressable on-chip electrodes.
• Utilizing sequential electrical actuation to initiate and control electro-polymerization of polyacrylamide hydrogel films.
• Characterizing the positioning, morphology, size, and growth rate of the electro-polymerized hydrogel films.

Main Results:

• Demonstrated the ability to generate discretely positioned electro-polymerized hydrogel films within microchannels in approximately 5 minutes.
• Achieved directed control over the size, shape, and growth rate of hydrogel films through sequential electrode actuation.
• Successfully encapsulated macromolecules within the hydrogel films during polymerization.

Conclusions:

• The developed platform enables precise, localized electro-polymerization of hydrogel films within microfluidic devices.
• This technique allows for the creation of custom hydrogel structures, obstacles, and barriers in microchannels.
• The ability to encapsulate macromolecules opens possibilities for applications in separations, sample purification, and immunoassays.