Awareness: potential toxicities of carbon nanotubes

Carbon nanotubes belong to a class of tiny tubular structures composed of carbon atoms. These carbon atoms are arranged in a honeycomb-type (nano)tube and their structure and the strength of the bonds between the atoms provide exceptional physicochemical properties. Carbon nanotubes consist of either single graphene cylinders [single-walled carbon nanotube (SWCNT)] with an outer diameter of 1–3 nm, or multiple graphene cylinders arranged in concentric layers [multi-walled carbon nanotube (MWCNT)] with diameters ranging from 10 to 200 nm and a length from a few hundreds of nano-meters to several tens of micro-meters. The unique physicochemical, mechanical (strength/stiffness), electrical, and thermal properties of carbon nanotubes have contributed to an increased use of these materials in the electronics, aerospace, computer, and pharmaceutical industries.