We first developed a technique for the regular and automatic formation of invariable LMs. This was achieved by programming a syringe driver (CareFusion Alaris GH) to feed a 21 gauge needle (0.8 mm diameter) at a typical rate of 7.0 ml h -1 . The rate can be easily increased or decreased, and this rate gave sufficiently fast LM formation for our purpose. The produced droplets (11.60 ± 0.16 µl) were permitted to fall onto a sheet of acrylic, slanted to 20 • from horizontal, and surface-treated with a commercial hydrophobic spray (Rust-Oleum R NeverWet R ). This formed beads of water, which were allowed to roll over a bed of appropriate hydrophobic powder. The result was a continuous 'stream' of LMs with the same volume, coating and coating thickness. It should be noted that whilst the forming of LMs by running droplets down a powder slope has been separately developed by another group , our system prevents premature destruction of the powder bed by initially preforming the droplet on a treated hydrophobic surface.