Gastrointestinal actions of orally-administered single-walled carbon nanohorns

Carbon nanomaterials, such as single-walled carbon nanohorns (SWCNHs) and carbon nanotubes, demonstrate great potential as drug delivery systems. However, no reports to date have detailed the use of SWCNHs as oral drug carriers. This study shows for the first time the actions of orally-administered SWCNHs in normal mice and mice with dextran sulfate sodium (DSS)-induced colitis. SWCNHs labeled with gadolinium oxide for quantification purposes were detected in the gastrointestinal tract and the feces of mice, but not in the blood or other bodily organs. These results indicate that the nanohorns were not absorbed into the body from the gastrointestinal tract. SWCNH absorption was not influenced by the functionalization or size control of SWCNH. Neither death nor behavioral aberrations were observed in normal mice following SWCNH administration. However, histological observation of mice with DSS-induced colitis at 24 h after oral administration of SWCNHs revealed the presence of black particles, presumed to be SWCNHs, in the inflamed areas of the colon and the cecum. Thus, SWCNHs might serve as efficacious drug delivery carriers for the treatment of ulcerative colitis.