title: Size-dependent toxicity of nano-C60 aggregates: more sensitive indication by apoptosis-related Bax translocation in cultured human cells.
abstract: The toxicity of NPs is not well characterized in terms of their size. In particular, the size-based toxicity of fullerene (C(60)) remains an issue because of a lack of C(60) NPs with a well-controlled size. In this work, six fractions of the nano-C(60) aggregates (nC(60)) with different size distribution were prepared by a simple differential centrifugation. By using these nC(60) fractions, we demonstrate the size-dependent inhibition of DNA polymerase and reduced-size enhanced cytotoxicity. Above all, we found that nC(60) NPs with smaller size may have higher toxicity potency. These size-dependent effects were observed at the high exposure doses (4-6 mg/L). Interestingly, at 20-times lower and noncytotoxic doses, the size-dependent effect can be indicated by apoptosis-related fluorescent protein fused Bax translocation. Considering the toxicity of NPs is often ignored in the traditional end-point analysis for cytotoxicity when the exposure dose is low, the findings presented here will assist in the evaluation of the size-dependent cytotoxicity and dose-response relationships of toxicity mediated by nC(60) NPs at low doses.
authors.affiliation: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
authors.forename: Maoyong
authors.initials: M
authors.lastname: Song
authors.forename: Shaopeng
authors.initials: S
authors.lastname: Yuan
authors.forename: Junfa
authors.initials: J
authors.lastname: Yin
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Wang
authors.forename: Zihui
authors.initials: Z
authors.lastname: Meng
authors.forename: Hailin
authors.initials: H
authors.lastname: Wang
authors.forename: Guibin
authors.initials: G
authors.lastname: Jiang
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D045744:Cell Line, Tumor; D037741:Fullerenes / Q000737:chemistry / Q000633:toxicity*; D006801:Humans; D046529:Microscopy, Electron, Transmission; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D010316:Particle Size; D013056:Spectrophotometry, Ultraviolet; D051028:bcl-2-Associated X Protein / Q000378:metabolism*
chemical_list: C494826:BAX protein, human; D037741:Fullerenes; D051028:bcl-2-Associated X Protein