title: Toxicological Profiling of Highly Purified Metallic and Semiconducting Single-Walled Carbon Nanotubes in the Rodent Lung and E. coli.
abstract: The electronic properties of single-walled carbon nanotubes (SWCNTs) are potentially useful for electronics, optics, and sensing applications. Depending on the chirality and diameter, individual SWCNTs can be classified as semiconducting (S-SWCNT) or metallic (M-SWCNT). From a biological perspective, the hazard profiling of purified metallic versus semiconducting SWCNTs has been pursued only in bacteria, with the conclusion that aggregated M-SWCNTs are more damaging to bacterial membranes than S-SWCNTs. However, no comparative studies have been performed in a mammalian system, where most toxicity studies have been undertaken using relatively crude SWCNTs that include a M:S mix at 1:2 ratio. In order to compare the toxicological impact of SWCNTs sorted to enrich them for each of the chirality on pulmonary cells and the intact lung, we used density gradient ultracentrifugation and extensive rinsing to prepare S- and M-SWCNTs that are >98% purified. In vitro screening showed that both tube variants trigger similar amounts of interleukin 1β (IL-1β) and transforming growth factor (TGF-β1) production in THP-1 and BEAS-2B cells, without cytotoxicity. Oropharyngeal aspiration confirmed that both SWCNT variants induce comparable fibrotic effects in the lung and abundance of IL-1β and TGF-β1 release in the bronchoalveolar lavage fluid. There was also no change in the morphology, membrane integrity, and viability of E. coli, in contradistinction to the previously published effects of aggregated tubes on the bacterial membrane. Collectively, these data indicate that the electronic properties and chirality do not independently impact SWCNT toxicological impact in the lung, which is of significance to the safety assessment and incremental use of purified tubes by industry.
authors.forename: Xiang
authors.initials: X
authors.lastname: Wang
authors.affiliation: Departments of Materials Science and Engineering, Chemistry, and Medicine, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Nikhita D
authors.initials: ND
authors.lastname: Mansukhani
authors.affiliation: Departments of Materials Science and Engineering, Chemistry, and Medicine, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Linda M
authors.initials: LM
authors.lastname: Guiney
authors.affiliation: Departments of Materials Science and Engineering, Chemistry, and Medicine, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Jae-Hyeok
authors.initials: JH
authors.lastname: Lee
authors.forename: Ruibin
authors.initials: R
authors.lastname: Li
authors.forename: Bingbing
authors.initials: B
authors.lastname: Sun
authors.forename: Yu-Pei
authors.initials: YP
authors.lastname: Liao
authors.forename: Chong Hyun
authors.initials: CH
authors.lastname: Chang
authors.forename: Zhaoxia
authors.initials: Z
authors.lastname: Ji
authors.forename: Tian
authors.initials: T
authors.lastname: Xia
authors.affiliation: Departments of Materials Science and Engineering, Chemistry, and Medicine, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Mark C
authors.initials: MC
authors.lastname: Hersam
authors.forename: André E
authors.initials: AE
authors.lastname: Nel
mesh_terms: D000818:Animals; D016207:Cytokines / Q000378:metabolism; D004926:Escherichia coli; D008168:Lung / Q000187:drug effects / Q000378:metabolism; D037742:Nanotubes, Carbon / Q000633:toxicity*; D051381:Rats
chemical_list: D016207:Cytokines; D037742:Nanotubes, Carbon
keywords: SWCNT; bacteria; electronic property; lung toxicity; metallic; semiconductor