Figure 1.

Experimental setup of high-throughput droplet-based cytotoxicity platform. (A) Experimental schematics showing cytotoxicity platform that combines (i) droplet generation and cell pairing using microfluidics, (ii) droplet immobilization for real-time microscopy, (iii) automated image analysis using custom-made MATLAB script to allow unbiased and high throughput detection of cytotoxic events. Stained NK cells and K562 cells were loaded into the chip using 200 µL pipette tips and encapsulated into droplets using a 3-inlet microfluidic chip. The viability dyes were included within the cell medium. The immobilized droplets were incubated in a stage top incubator set at 5% CO₂ and 37 °C. Image acquisition was performed at every hour interval for 10 h. (B) The three-inlet microfluidic device with flow-focusing junction to generate droplets. (C) A qualitative test of the observation chamber was performed by monitoring droplets movement in the chamber under the microscope for 10 h.