Fig. 1

Various carbon-based nanomaterials were reported to induce cytotoxicity. Carbon nanotubes (CNTs) are thin carbon filaments with cylindrical structure that comprise single or multiple graphene sheets, termed as single-wall carbon nanotubes (SWCNTs) and multiwall carbon nanotubes (MWCNTs), respectively. C-fullerene is a carbon allotrope organized solely by 60 carbon atoms with a polygonal structure. Carbon black nanoparticle is a traditional nanosized carbon-based nanomaterial of diameter between 10 to 100 nm with three nanometric dimensions. Nanographite, also called graphite nanoplatelet, is a one-atom-thick and two-dimensional sheet of sp2-bonded carbon atoms. Single-walled carbon nanohorns (SWCNHs) are horn-shaped single-walled tubules with cone angles of approximately 20°