Tunneling nanotube

Keywords Tunneling nanotube, TNT, cellular communication, intercellular transport... 

Abbreviations CNT, Carbonnanotube F-actin,Filamentous actin TNT, Tunneling nanotube... 

Tunneling nanotubes (TNTs) were first described in cultured rat pheochromocytoma PC 12 cells as thin continuous membranous channels that span the shortest distance between connected cells (Fig. 16.1) (Rustom et al., 2004). They have a diameter between 25 and 200 nm, a length up to several tens of micrometers, and they are extended above the substratum and not in contact with it (reviewed in Gerdes et al. 

Fig. 16.2 Schematic representation of cellular and artificial membrane nanotubes. (A) Two cells are connected by a tunneling nanotube (arrowhead) containing a bundle of filamentous actin (red line). N (grey), nucleus M (purple), mitochondrium ER (green), endoplasmic reticulum G (blue), Golgi apparatus. (B) Lipid nanotube connecting two lipid vesicles formed by pulling a membrane tether. (C) Membrane tether pulled from the plasma membrane of a cell (see Color Plates)...

Table 16.1 Comparison of major properties of tunneling nanotubes and carbon nanotubes... 

Transport mechanism Diffusion or active transport through tunneling nanotubes Diffusion or endocytotic uptake of carbon nano tubes... 

Gerdes H-H, Bukoreshtliev NV, Barroso JF (2007) Tunneling nanotubes A new route for the exchange of components between animal cells. FEBS Lett. 581 2194-2201. 

Gerdes H-H, Carvalho RN (2008) Intercellular transfer mediated by tunneling nanotubes. Curr. Opin. Cell Biol. doi. 10.1016/j.ceb.2008.03.005. 

Gurke S, Barroso JF, Gerdes H-H (2008) The art of cellular communication tunneling nanotubes bridge the divide. Histochem. Cell Biol. 129 539-550. 

Pontes B, Viana NB, Campanati L, Farina M, Neto VM, Nussenzveig HM (2007) Structure and elastic properties of tunneling nanotubes. Eur. Biophys. J. [Epub ahead of print]... 

SCANNING TUNNELING MICROSCOPY OF CARBON NANOTUBES AND NANOCONES... 

Key Words—Carbon nanotubes, scanning tunneling microscopy, spectroscopy, magnetoresistance, electrical resistivity, magnetic susceptibility. 

Scanning tunneling spectroscopy (STS) can, in principle, probe the electronic density of states of a singlewall nanotube, or the outermost cylinder of a multi-wall tubule, or of a bundle of tubules. With this technique, it is further possible to carry out both STS and scanning tunneling microscopy (STM) measurements at the same location on the same tubule and, therefore, to measure the tubule diameter concurrently with the STS spectrum. No reports have yet been made of a determination of the chiral angle of a tubule with the STM technique. Several groups have, thus far, attempted STS studies of individual tubules. 

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