Deterministic Cell Pairing with Simultaneous Microfluidic Merging and Sorting of Droplets

Area of Science:

• Biotechnology
• Microfluidics
• Cell Biology

Background:

• Cell-cell interactions are crucial for biological processes like immune response and tissue repair.
• Studying cell crosstalk requires methods to create defined cell pairs, which are currently limited.
• High-throughput droplet microfluidics often suffers from random cell loading, yielding low percentages of desired combinations.

Purpose of the Study:

• To develop a microfluidic device for deterministic isolation of specific cell pairs.
• To enable high-throughput studies of cell crosstalk using precise cell co-culture.
• To overcome the limitations of random loading in droplet microfluidics.

Main Methods:

• A microfluidic device utilizing droplet merging and sorting ('merge-sorting') was developed.
• The system employs fluorescence detection to identify target cell combinations.
• Simultaneous electrocoalescence and dielectrophoretic sorting are triggered for isolation.

Main Results:

• Achieved 98.6% purity of merged and sorted fluorescent dye-loaded droplets.
• >90% recovery of desired cell pairs, a significant improvement over <1% with random loading.
• Produced monodisperse alginate hydrogels with 92% target cell pairs, maintaining viability for 18 hours.

Conclusions:

• The merge-sort platform enables flexible enrichment of specific droplet and cell combinations for high-throughput cell crosstalk studies.
• This method offers superior purity and recovery compared to existing techniques, facilitating cleaner downstream workflows.
• The device supports pre-incubation, multi-step assays, and isolation of desired pairs, offering versatile capabilities for biological research.