Nanotube-vesicle network

Karlsson M, Sott K, Davidson M, Cans AS, Linderholm P, Chiu D, Orwar O (2002) Formation of geometrically complex lipid nanotube-vesicle networks of higher-order topologies. Proc. Natl. Acad. Sci. USA 99 11573-11578. 

Chemical reactions occurring in geometries resembling those found in a cell can be investigated with the help of nanotube-vesicle networks (NVNs, Fig. 23.3 [fO]). NVNs are highly flexible lipid bilayer structures in which the main building blocks are surface-immobilized vesicles connected by nanotubes. 

Liposomes Tethered Liposomes Nanotube-Vesicle Networks... 

A projection of nanotube vesicle networks onto surfaces is a viable strategy to overcome challenging difficulties with respect to stability portability and ease of fabrication. 

Fig. 23.7. Dynamics of an enzymatic reaction in lipid nanotube networks with variable topology numeric calculations (bottom)/fluorescence intensity of the reaction product (top) vs. time for three differently chosen network geometries, (a) Reference experiment a static four-vesicle network. The product concentration displays a cascade-like behavior in time and space, (b) Linear-to-circular topology change in the four-vesicle network (c) A model study of the effect of product inhibition as the linear four-vesicle network (top panel) undergoes the same change in structure (bottom panel) as the network in the reference experiment ([28], reprinted with permission)...

Artificial cell models have been developed to help understand the membrane fusion process. A common model that involves vesicles containing channel proteins that are driven by osmotic pressure to fuse with a planar lipid bilayer was reported. A protein-free model has also been used to demonstrate transient opening of fusion pores. " Liposomes have been described as artificial cells and have also been used to examine membrane fusion. - Recently, an electroinjection technique has been developed, which makes it possible to form lipid nanotubes and networks between liposome reservoirs. - Here, we briefly present two models, recent advances in the development of a liposome-lipid nanotube network as an artificial cell model that mimics the latter stages of exocytosis for cell study and fusion of vesicles inside liposomes with a DNA zipper. 

Fujima, T., Frusawa, H., Minamikawa, H., Ito, K. and Shimizu, T. (2006) Elastic precursor of the transformation from glycolipid nanotube to vesicle, Journal of Physics Condensed Matter, 18, 3089—3096. Kameta, N., Minamikawa, H., Masuda, M., Mizuno, G. and Shimizu, T. (2008) Controllable biomolecule release from self-assembled organic nanotubes with asymmetric surfaces pH and temperature dependence. Soft Matter, 4 (8), 1681-1688. Weiss R.G. and Terech P. (eds.) (2006) Molecular Gels Materials with Self-Assembled Fibrillar Networks, Springer, Dordrecht. 

In view of the extensive literature, this chapter does not aim to be comprehensive, but uses selected notable examples from the field to demonstrate the concepts and applications of these fascinating species. For example, there are numerous examples of linear supramolecular polymers in solution [32], solvated nanotubes [33], vesicles [34] and gel networks [35-38] that rely on donor-acceptor interactions however, this review focuses on unsolvated, cross-linked supramolecular polymers and their bulk properties. 

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