Fig. 1. Microfluidic immuno-oncology chip and protocol.

a Microfluidic chip on a standard glass slide. b Expanded view of the trapping region of the chip (dashed box) showing an array of 234 trapped droplets. Each droplet contains a single B16 spheroid in Matrigel, as shown in the inset. c Distribution of spheroid radii within a single chip (N = 215). d Viability measurements using live-dead staining after 24 and 48 h (N = 54). e Schematic showing a primary droplet with a tumor spheroid, followed by the addition and fusion of a secondary droplet containing GFP-labeled CTLs, eventually leading to tumor cell killing and spheroid fragmentation. Scale bar is 200 μm. f Schematic representation of the complete experimental protocol.