An on-chip, multichannel droplet sorter using standing surface acoustic waves

Area of Science:

• Fluid dynamics
• Acoustic manipulation
• Microfluidics

Background:

• Droplet microfluidics is a rapidly advancing field.
• Effective on-chip droplet handling and sorting are crucial for microfluidic systems.
• Current methods may lack efficiency or require complex integration.

Purpose of the Study:

• To develop and demonstrate a microfluidic device for sorting picoliter water-in-oil droplets.
• To utilize standing surface acoustic waves (SSAW) for precise droplet manipulation.
• To enable multi-output sorting capabilities within a single microfluidic chip.

Main Methods:

• Integration of a single-layer microfluidic channel with interdigital transducers (IDTs).
• Generation and manipulation of picoliter water-in-oil droplets within an SSAW field.
• Control of droplet sorting by tuning SSAW frequency to alter acoustic pressure nodes.

Main Results:

• Demonstrated successful sorting of water-in-oil droplets into multiple outputs.
• Achieved droplet sorting rates of up to 222 droplets per second.
• The device exhibited simplicity, controllability, and non-invasiveness.

Conclusions:

• The developed SSAW-based microfluidic device offers an effective solution for droplet sorting.
• This technique is valuable for developing droplet-based micro total analysis systems (microTAS).
• The system's versatility and integration potential support future microfluidic innovations.