Rounded multi-level microchannels with orifices made in one exposure enable aqueous two-phase system droplet...

Area of Science:

• Microfluidics
• Materials Science
• Biotechnology

Background:

• Aqueous two-phase systems (ATPS) are crucial for bioseparations but face challenges due to low interfacial tension, hindering droplet formation.
• Existing microfluidic methods struggle to balance channel geometry for both valve closure and efficient droplet generation in ATPS.

Purpose of the Study:

• To develop a microfluidic system capable of generating stable aqueous two-phase system droplets.
• To overcome the limitations of low interfacial tension in ATPS droplet formation.
• To design microchannels that facilitate both efficient valve function and enhanced droplet generation.

Main Methods:

• Fabrication of multi-level rounded channels with narrow orifices using backside lithography and a negative photoresist.
• Construction of microfluidic systems utilizing the fabricated channels.
• Generation of aqueous two-phase system droplets within the microfluidic devices.

Main Results:

• Successfully created multi-level channels with integrated narrow orifices in a single exposure step.
• Demonstrated the capability of the microfluidic system to produce aqueous two-phase system droplets.
• Showcased how the dual-channel geometry (narrow for valves, wide for flow) enhances droplet formation by reducing capillary number.

Conclusions:

• Backside lithography offers a facile method for fabricating advanced microfluidic channel geometries.
• The developed microfluidic system effectively addresses the challenges of ATPS droplet generation.
• This technology holds promise for applications in bioseparation and other fields requiring precise control over multiphase fluid systems.