What Are Carbon Nanotubes?

Carbon nanotubes (CNTs) are allotropes of carbon, made of graphite and constructed in cylindrical tubes with nanometer in diameter and several millimeters in length. Their impressive structural, mechanical, and electronic properties are due to their small size and mass, their strong mechanical potency, and their high electrical and thermal conductivity.

What are the structure and properties of carbon nanotubes?

It is well known that CNTs are intrinsically composed of pure carbon atoms that arrange and interact with each other by the strong sp2 carbon-carbon chemical bonds and form the unique geometric structure of a carbon network; this gives CNTs fascinating and attractive properties.

How strong is a carbon nanotube?

Like graphene, nanotubes are strong, and they conduct electricity because they have delocalized electrons. The tensile strength of carbon nanotubes is about 100 times that of steel with the same diameter.

How does a carbon nanotube work?

Because of their small size, nanotubes can selectively capture and retain small gas molecules inside. The adsorption of one molecule within another molecule provides a unique opportunity to control substances on the nanoscale.

Are carbon nanotubes toxic?

CNTs are considered to have carcinogenicity and can cause lung tumors. However, the carcinogenicity of CNTs may attenuate if the fiber length is shorter. The available data provide initial information on the potential reproductive and developmental toxicity of CNTs.

Is graphene toxic?

Rationales provided for this are that graphene is not toxic, that exposure is low, that small amounts are expected to be produced and used, that graphene can be made safe, that graphene is similar to harmless materials (e.g., being "just carbon"), and that graphene is different from hazardous materials such as carbon nanotubes.

What is the use of carbon nanotubes?

Carbon nanotubes have been first used as additives to various structural materials for electronics, optics, plastics, and other materials of nanotechnology fields. Since the beginning of the 21st century, they have been introduced in pharmacy and medicine for drug delivery system in therapeutics.

Applications in pharmacy and medicine?

CNTs have been successfully applied in pharmacy and medicine due to their high surface area that is capable of adsorbing or conjugating with a wide variety of therapeutic and diagnostic agents (drugs, genes, vaccines, antibodies, biosensors, etc.). They have been first proven to be an excellent vehicle for drug delivery directly into cells without metabolism by the body. Then other applications of CNTs have been extensively performed not only for drug and gene therapies but also for tissue regeneration, biosensor diagnosis, enantiomer separation of chiral drugs, extraction and analysis of drugs and pollutants. Moreover, CNTs have been recently revealed as a promising antioxidant.