Carbon nanotubes (CNTs) are taken up into the body dependent on the administration route and their composition (single-walled, multi-walled, modified) and can later be found in different organs and cell types. However, it is not possible to make a general statement on the behaviour of carbon nanotubes once within the body due to numerous differences of used CNTs, various applications and analytical methods.
To date, only little is known about the uptake of carbon nanotubes (CNTs) from the blood into the brain across the so-called blood-brain barrier (cross-cutting - nanoparticles at the blood-brain barrier).
Although they consist only of a carbon skeleton, carbon nanotubes (CNTs) have a plurality of different structures: single-walled and multi-walled tubes, different lengths, and surface coatings. These variations make it difficult to directly compare the environmental behaviour of carbon nanotubes. They also are often not present as single tube, but are aggregated to bundles. Therefore it is difficult to generalise about the environmental fate of this great diversity of CNTs.