title: Biodegradation of carbon nanohorns in macrophage cells.
abstract: With the rapid developments in the medical applications of carbon nanomaterials such as carbon nanohorns (CNHs), carbon nanotubes, and graphene based nanomaterials, understanding the long-term fate, health impact, excretion, and degradation of these materials has become crucial. Herein, the in vitro biodegradation of CNHs was determined using a non-cellular enzymatic oxidation method and two types of macrophage cell lines. Approximately 60% of the CNHs was degraded within 24 h in a phosphate buffer solution containing myeloperoxidase. Furthermore, approximately 30% of the CNHs was degraded by both RAW 264.7 and THP-1 macrophage cells within 9 days. Inflammation markers such as pro-inflammatory cytokines interleukin 6 and tumor necrosis factor α were not induced by exposure to CNHs. However, reactive oxygen species were generated by the macrophage cells after uptake of CNHs, suggesting that these species were actively involved in the degradation of the nanomaterials rather than in an inflammatory pathway induction.
authors.affiliation: Nanotube Research Center, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan. m-zhang@aist.go.jp m-yudasaka@aist.go.jp.
authors.forename: Minfang
authors.initials: M
authors.lastname: Zhang
authors.forename: Mei
authors.initials: M
authors.lastname: Yang
authors.forename: Cyrill
authors.initials: C
authors.lastname: Bussy
authors.forename: Sumio
authors.initials: S
authors.lastname: Iijima
authors.forename: Kostas
authors.initials: K
authors.lastname: Kostarelos
authors.forename: Masako
authors.initials: M
authors.lastname: Yudasaka
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D006801:Humans; D006861:Hydrogen Peroxide / Q000737:chemistry; D007249:Inflammation / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism; D008264:Macrophages / Q000166:cytology / Q000378:metabolism*; D051379:Mice; D046529:Microscopy, Electron, Transmission; D009000:Monocytes / Q000378:metabolism; D036103:Nanotechnology / Q000379:methods*; D037742:Nanotubes, Carbon / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry; D009195:Peroxidase / Q000378:metabolism; D000067996:RAW 264.7 Cells; D017382:Reactive Oxygen Species / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D015850:Interleukin-6; D037742:Nanotubes, Carbon; D017382:Reactive Oxygen Species; D014409:Tumor Necrosis Factor-alpha; D006861:Hydrogen Peroxide; D009195:Peroxidase; D010100:Oxygen