Cubosomes and hexosomes were prepared on-chip as described in the methods section. Briefly, the lipid of choice was dissolved in anhydrous ethanol and injected to the central stream via a syringe connected to a syringe pump. Aqueous buffer, containing the stabilising polymer Pluronic F-127, was injected into the flanking channels in the same way, and a hydrodynamic flow regime generated. Lipids reached their respective solubility thresholds along the resulting diffusion gradient, aggregated into micellar structures, and eventually self-assembled into particles stabilised by F-127. The schematic in Fig. depicts the microfluidics-driven process. Images of the set-up, and details of the concentrations, flow rates and chip design can be found in the supplementary information section (SI Fig. ).