Micro contactor based on isotachophoretic sample transport.

Area of Science:

• Microfluidics
• Analytical Chemistry
• Biotechnology

Background:

• Micromixers are crucial for rapid reactions in microfluidic channels.
• Existing micromixers often require complex designs.
• Digital microfluidics offers precise control over sample volumes.

Purpose of the Study:

• To demonstrate isotachophoresis (ITP) as a novel method for controlled sample contact in microfluidic devices.
• To present ITP as an alternative to traditional micromixers, enabling digital microfluidic approaches.
• To explore the application of ITP in synchronizing sample zones and facilitating molecular interactions like DNA hybridization.

Main Methods:

• Utilizing isotachophoresis (ITP) within a microfluidic device to manipulate and bring sample volumes into contact.
• Employing Ohm's law principles to predict and control sample trajectories and zone transport.
• Investigating the relationship between ITP zone extension and contacting time.

Main Results:

• ITP enables reproducible and predictable zone transport in microchannels.
• The ITP contactor synchronizes sample zones arriving at different times.
• Contacting time is directly proportional to ITP zone extension, allowing tunable mixing times (<1 second).
• Successful demonstration of DNA hybridization between complementary strands within ITP zones.

Conclusions:

• ITP serves as an effective microfluidic contactor, analogous to micromixers but with simpler architecture.
• The ITP method supports digital microfluidic principles by maintaining compact sample volumes.
• This technique offers precise control over mixing duration and is applicable to biochemical reactions such as DNA hybridization.