Capillary force assembly of giant vesicles on a microstructured substrate

Convective capillary force assembly has shown to efficiently assemble nm to μm solid colloids onto a surface. We show here that this technique can also efficiently trap liposomes with 10 μm mean size or films of lipid into microstructures. We hypothesize that whether liposomes or lipids are trapped in the template depends on the interfacial interaction of the objects with the surface. After solvent evaporation, ruptured and deflated liposomes are observed onto oxidized (hydrophilic) PDMS while uniform films of lipids are found in untreated (hydrophobic) PDMS microstructures. This assumption is supported by the analysis of the evaporation of a droplet containing a dispersion of liposomes in free environment.