title: Toxicity of single-walled carbon nanohorns.
abstract: We extensively investigated in vitro and in vivo the toxicities of as-grown single-walled carbon nanohorns (SWNHs), a tubular nanocarbon containing no metal impurity. The SWNHs were found to be a nonirritant and a nondermal sensitizer through skin primary and conjunctival irritation tests and skin sensitization test. Negative mutagenic and clastogenic potentials suggest that SWNHs are not carcinogenic. The acute peroral toxicity of SWNHs was found to be quite low--the lethal dosage for rats was more than 2000 mg/kg of body weight. Intratracheal instillation tests revealed that SWNHs rarely damaged rat lung tissue for a 90-day test period, although black pigmentation due to accumulated nanohorns was observed. While further toxicological assessments, including chronic (repeated dose), reproductive, and developmental toxicity studies, are still needed, yet the present results strongly suggest that as-grown SWNHs have low acute toxicities.
authors.affiliation: JST/SORST, c/o NEC, 34 Miyukigaoka, Tsukuba, Ibaraki 305-8501, Japan. jin_m@frl.cl.nec.co.jp
authors.forename: Jin
authors.initials: J
authors.lastname: Miyawaki
authors.forename: Masako
authors.initials: M
authors.lastname: Yudasaka
authors.forename: Takeshi
authors.initials: T
authors.lastname: Azami
authors.forename: Yoshimi
authors.initials: Y
authors.lastname: Kubo
authors.forename: Sumio
authors.initials: S
authors.lastname: Iijima
mesh_terms: D000818:Animals; D002869:Chromosome Aberrations / Q000139:chemically induced*; D004305:Dose-Response Relationship, Drug; D003875:Drug Eruptions / Q000175:diagnosis / Q000209:etiology*; D009877:Endophthalmitis / Q000139:chemically induced* / Q000175:diagnosis; D006168:Guinea Pigs; D007928:Lethal Dose 50; D037742:Nanotubes, Carbon / Q000633:toxicity*; D011817:Rabbits; D051381:Rats; D018570:Risk Assessment / Q000379:methods*
chemical_list: D037742:Nanotubes, Carbon