Fig. 2.

Droplet networks printed in bulk aqueous solution. (A) Schematic of printing in aqueous solution. Aqueous droplets are ejected into a drop of oil suspended in bulk aqueous solution. Excess oil can be removed after printing by suction through a printing nozzle. (B) Micrograph of a network printed in aqueous solution, viewed from above. A core of orange droplets is surrounded by a shell of blue droplets, which contain the fluorescent dye pyranine. Scale bar, 400 μm. (C) Horizontal sections of the network in (B) obtained by confocal microscopy, showing the fluorescent shell of droplets around the non-fluorescent core. The sections span approximately the bottom 150 μm of the network. Scale bar, 400 μm. (D) Micrographs of three other networks printed in bulk aqueous solution. Scale bars, 400 μm.