Squalene

Aqueous solutions were loaded into syringes (1 mL, BD Medical, Franklin Lakes, NJ). Oils (OIL1, OIL2, OIl3) were also loaded into syringes (1mL, 10 mL, 3 mL, BD Medical). Droplet generation oil (OIL1) was squalene (TCI America, Portland, OR) containing KF-6038 (4% w/w, ShinEtsu, Tokyo, Japan). The droplet generation oil was prepared by combining squalene and KF-6038 and mixing with rotation (16 h, 500 rpm). The spacing (OIL2) and flow focusing oil (OIL3) were neat squalene. All syringes were fitted with blunt-tip Luer-Lok needles and connected to fluidic inputs via microbore Tygon tubing (0.01” × 0.03” IC × OD, Saint Gobain, Valley Forge, PA). Displacement syringe pumps (Legato 100, KD Scientific, Holliston, MA) drove fluids from syringes though the circuit. Oil2 and OIL3 were flowed (8 and 3 μL/min, respectively), while hit and waste tubing were clamped to backfill the circuit. The hit and waste outlets were unclamped once the incubator was primed with oil. The aqueous inputs, library (LIB) and Target (TAR) and OIL1, OIL2, OIL3 flows were held constant (0.4, 12.7, 1.3 μL min, respectively). Flow was equilibrated (25 min), then data acquisition and screening began.

Unless otherwise noted, oil for droplet generation consisted of 3% w/w KF-6038 (ShinEtsu, Tokyo, Japan) in squalene (TCI America, Portland, OR). Oil was prepared by combining components and mixing with agitation (1 h, 500 rpm).