Selectable encapsulated cell quantity in droplets via label-free electrical screening and impedance-activated sorting

Area of Science:

• Biotechnology
• Single-cell analysis
• Droplet microfluidics

Background:

• Single-cell encapsulation in droplets is crucial for immunotherapy, drug discovery, and single-cell analysis.
• Current methods suffer from low purity and throughput due to random cell encapsulation, leading to many empty or multi-cell droplets.

Purpose of the Study:

• To develop and demonstrate the first label-free, selectable cell quantity encapsulation in droplets sorting system.
• To overcome the limitations of random encapsulation by efficiently isolating single-cell droplets.

Main Methods:

• Integration of electrical impedance-based screening (98.9% accuracy) with biocompatible acoustic sorting.
• Development of a system to select single-cell droplets, rejecting empty and multi-cell droplets.

Main Results:

• Achieved 90.3% efficiency in single-cell droplet selection.
• Demonstrated high rejection rates for multi-cell (∼60%) and empty (∼90%) droplets.
• Increased the throughput of single-cell encapsulation by approximately 9-fold compared to random methods, with a throughput of up to 200 Hz.

Conclusions:

• The developed droplet sorting system significantly enhances the purity and throughput of single-cell encapsulation.
• This technology offers a powerful tool for advancing immunotherapy, drug discovery, and single-cell analysis.