Droplet assembly method

A process for moving a droplet from a first location in a hydrophobic medium to a second location in the hydrophobic medium, to assemble, disassemble or rearrange a droplet assembly, which process comprises:

• (i) exposing a droplet which is disposed in a hydrophobic medium and is situated at a first location on a solid surface in the hydrophobic medium, which droplet comprises (a) an aqueous medium, (b) an outer layer of amphipathic molecules around the surface of the aqueous medium, and (c) a magnetic material disposed in the aqueous medium, to a magnetic field of a magnet, and thereby causing the droplet to be attracted to said magnet by magnetic attraction;
• (ii) moving the magnet relative to the first location in the hydrophobic medium whilst maintaining said magnetic attraction, and thereby causing the droplet to move away from said first location in the hydrophobic medium and towards a second location in the hydrophobic medium, wherein moving the magnet relative to the first location in the hydrophobic medium moves the magnet in a direction away from the first location in the hydrophobic medium;
• and
• (iii) disposing the droplet at said second location in the hydrophobic medium;
• wherein:
• disposing the droplet at said second location in the hydrophobic medium comprises bringing the droplet into contact with another droplet in the hydrophobic medium, which said another droplet comprises (a) an aqueous medium and (b) an outer layer of amphipathic molecules around the surface of the aqueous medium, so that a bilayer of amphipathic molecules is formed at an interface between the contacting droplets.