On the landscape of the nanoscience and nanothecnology carbon nanotubes (1) have played an important role on the development of 1D materials. They consist of single (SWCNT) or multi (MWCNT) layers of graphene cylinders arranged around a central hollow. In the case of the SWCNT the size distribution is narrow (1-2 nm) while it is broader for MWCNT (2-25 nm) exhibiting a constant separation between layers, nearly equal to that of graphite-layer spacing (0.34 nm). In both cases, the length extends up to several microns. These characteristics provide large external and internal surfaces making both functionalization and filling processes very attractive for potential performances in several areas like electronic, spintronic, or drug release