Nan -

Vesosomes are nested liposomal structures with high potential as advanced drug delivery vehicles, bioreactors and artificial cells. However, to date no method has been reported to prepare monodisperse vesosomes of controlled size. Here we report on a multi-step microfluidic strategy for hierarchically assembling uniform vesosomes from dewetting of double emulsion templates. The exquisite control afforded by our method is illustrated by the formation of concentric, pericentric and multicompartment liposomes. The microfluidic route to vesosomes offers an exceptional platform to build artificial cells as exemplified by the in vitro transcription in “nucleus” liposomes and the mimicry of architecture of eukaryotic cells. Finally, we showed the transport of small molecules across the nucleic envelope via insertion of nanopores into the bilayers. Vesosomes are multicompartmental liposomal structures of varied architectures. 1 These multivesicular vesicles can consist of multilayered concentric liposomes, or multiple liposomes arranged within or around large liposomes. These structures, as well as related multicompartment polymersomes 2 and proteinosomes, 3 have generated significant interest for their potential as drug delivery vehicles 1a,4 , compartmentalized nanoor microscale bioreactors, 5 or as artificial cell/protocell models. 6 Zasadzinski and coworkers have shown that vesosomes can protect encapsulated drug carrying compartments from blood components due to the presence of double bilayers, 4d and slow vesicle contents release. 4e Bolinger et al. 5b,c employed multicompartment vesosomes to perform consecutive enzymatic reactions by thermally remote release of different compounds encapsulated in smaller liposomes. Remarkably, vesosomes that contain a “nucleus” or “organelles” represent a promising new concept towards the design of artificial cells, especially the artificial eukaryotic cells. 6a However, conventional methods, 7 such as bulk hydration 8 or electroformation 9 of dried lipid membranes, do not readily yield complex hierarchical vesicular structures, and certainly do not provide any control over dimensions, offer low encapsulation efficiencies and low yields. Moreover, these strategies do not allow a systematic simultaneous loading of different components into diverse compartments. These limitations have severely hindered progress in the application of such multivesicular liposomes. Recently, droplet microfluidics has been shown to offer excellent emulsion templates for the preparation of monodisperse liposomes 10 as well as polymersomes 2a,c,11 , but no vesosomes have been reported.