Injection and transport of bacteria in nanotube-vesicle networks

The microinjection of bacteria (the MG1655 strain of E. coli) into unilamellar lipid vesicles contained in surface-immobilized nanotube-vesicle networks is demonstrated. The density of bacteria can be controlled from a single bacterium up to several thousands of bacteria per injected vesicle. The bacteria retain flagellar motion and propulsion. The bacteria (approximately 2 × 0.8 μm) cannot escape from one vesicle to another as the size of the nanotubes is too small (∼200 nm in diameter) to allow for entry. Bacteria can, however, be moved from one vesicle to another in a nanotube-vesicle network by using Marangoni flows. Thus, single or several species can be transferred to a neighboring vesicle at will. The technique offers new possibilities for live matter functionalization into synthetic host networks, and may provide means for studying the effect of compartmentalization and perfusion of chemical species on a single bacterium. Furthermore, it may serve as an experimental model to study how vesicle-encapsulated bacteria evade destruction in macrophages or how bacteria surf along thin membrane nanotubes toward connected macrophage cell bodies. © 2008 The Royal Society of Chemistry.