| Abstract
| - We describe fluidic control in lipid nanotubes 50−150 nm in radius, conjugated with surface-immobilizedunilamellar lipid bilayer vesicles (∼5−25 μm in diameter). Transport in nanotubes was induced bycontinuously increasing the surface tension of one of the conjugated vesicles, for example, by ellipsoidalshape deformation using a pair of carbon microfibers controlled by micromanipulators as tweezers. Theshape deformation resulted in a flow of membrane lipids toward the vesicle with the higher membranetension; this lipid flow in turn moved the liquid column inside the nanotube through viscous coupling.Thus, micrometer-sized vesicles are used as a handle for controlling fluid flow inside nanometer-sizedchannels. We show transport and trapping of a single 30-nm-diameter carboxylate-modified latex particleinside a ∼100-nm-radius nanotube. Fluidic control in nanometer-sized channels using a moving wallprovides pluglike liquid flows, offers a means for efficient routing and trapping of small molecules, polymers,and colloids, and offers new opportunities to study chemistry in confined spaces. Networks of nanotubesand vesicles might serve as a platform to build nanofluidic devices operating with single molecules andnanoparticles.
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