Direct preparation and loading of lipid and polymer vesicles using inkjets

The direct preparation of nanometer-sized, unilamellar lipid and polymer vesicles, was investigated using inkjet printers. The one-step method allows the efficient encapsulation of predefined drug mixtures and is compatible with combinatorial and high throughput screening technology. The size can be controlled via the amphiphilic concentration and the cartridge. The inkjet printers were modified to hold the cartridge at a fixed position above a small water-filled container and then the cartridge was filled with a solution of the vesicle forming amphiphile in ethanol. About 1-1.5 mL of the amphiphile solution was then printed into 10 mL of water under stirring, yielding a turbid vesicular solution depending on the amphiphile and vesicle size. The solutions were then diluted with water to determine their size distribution and structure using dynamic light scattering (DLS) and cryo-transmission electron microscopy.