Fig. 1.

Microfluidic setup. (A) A mixed population of hybridoma cells either expressing the ACE-1 inhibitory antibody 4E3 or the noninhibitory antibody Elec-403 is encapsulated into droplets together with recombinant ACE-1. (B) Fluorogenic ACE-1 substrate. The ACE-1 cleavage site is indicated by an arrow. (C) Microfluidic chip for cell encapsulation. (D) Integrated microfluidic chip for the reinjection of droplets after a 6 h off-chip incubation period. Droplets hosting cells are fused with droplets containing the fluorogenic ACE-1 substrate and subsequently incubated for 30 min in a delay line. The final sorting module allows specific collection of droplets with low fluorescence intensity (indicating inhibition of ACE-1).