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, See ESI ? for detailed droplet production setup

, This 2.7-fold increase results from initial transient exchange as detailed in Fig, vol.3

E. Coli, cells encapsulation (at most, one cell per droplet, in presence of inducer) in 2 pL droplets and collection off chip. 2

, Electro-coalescence of the 2 pL droplets with 20 pL droplets containing the substrate in a periplasmic extraction buffer. 5. Incubation for the enzymatic activity to occur in delay lines. 6. Fluorescence measurement and droplet sorting

, Step Description 1. B. subtilis cells encapsulation (at most, one cell per droplet, in presence of inducer) in 20 pL droplets and collection off chip. 2. Induction off chip: rat trypsin secretion in the droplets

, Reinjection of 20 pL droplets containing the cells and electro-coalescence of the 20 pL droplets with 2 pL droplets containing the substrate 4. Incubation for the enzymatic activity to occur in delay lines. 6. Fluorescence measurement and droplet sorting

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