A nanometer is one-billionth of a meter, or relatively one ten-thousandth of the thickness of a human hair. A nanometer-scale tube-like structure is called nanotube. It may represent carbon nanotube (CNT), silicon nanotube, boron nitride nanotube, inorganic nanotube, DNA nanotube and membrane nanotube comprising of tubular membrane connected in the middle of cells. Nanotubes are similar to a powder or black soot. The CNTs, representing others, are in reality rolled-up sheets of graphene that establish hollow threads having walls with one atom thickness 1. © 2016, Springer International Publishing Switzerland.