title: Aging of fullerene C₆₀ nanoparticle suspensions in the presence of microbes.
abstract: Despite the growing use of carbon nanomaterials in commercial applications, very little is known about the fate of these nanomaterials once they are released into the environment. The carbon-carbon bonding of spherical sp(2) hybridized fullerene (C60) forms a strong and resilient material that resists biodegradation. Moreover, C60 is widely reported to be bactericidal. Here however, we observe the changing properties of fullerene nanoparticle aggregates aged in the presence of microbes. C60 aggregates were observed to decrease in size with aging, while hydroxylation and photosensitized reactivity measured by the production of reactive oxygen species (ROS) increased, suggesting that chemically and/or biologically-mediated activity is capable of partially transforming fullerene structure and reactivity in the environment. However, stable-isotope-labeling C60 aggregates incubated with microbial cultures from aged suspensions for 203 days did not produce significant labeled carbon dioxide, despite significant reduction in aggregate radius for biological samples. These results suggest that either the rate of biodegradation of these particles is too slow to quantify or that the biologically-enhanced transformation of these particles does not occur through microbial biodegradation to carbon dioxide.
authors.affiliation: School of Chemical and Biomolecular Engineering, The University of Sydney, NSW 2006, Australia.
authors.forename: So-Ryong
authors.initials: SR
authors.lastname: Chae
authors.affiliation: Center for the Environmental Implications of NanoTechnology (CEINT), USA; Division of Marine Science and Conservation, Nicholas School of the Environment and Earth Sciences, Duke University Marine Laboratory, Beaufort, NC 28516, USA.
authors.forename: Dana E
authors.initials: DE
authors.lastname: Hunt
authors.affiliation: Department of Geology, Baylor University, Waco, TX 76798, USA.
authors.forename: Kaoru
authors.initials: K
authors.lastname: Ikuma
authors.affiliation: Center for the Environmental Implications of NanoTechnology (CEINT), USA; Department of Chemistry, Duke University, Durham, NC 27708, USA.
authors.forename: Sungwoo
authors.initials: S
authors.lastname: Yang
authors.affiliation: Department of Electrical and Computer Engineering, Duke University, Durham, NC 27708, USA.
authors.forename: Jinhyun
authors.initials: J
authors.lastname: Cho
authors.affiliation: Center for the Environmental Implications of NanoTechnology (CEINT), USA; Department of Civil and Environmental Engineering, Pratt School of Engineering, Duke University, Durham, NC 27708, USA.
authors.forename: Claudia K
authors.initials: CK
authors.lastname: Gunsch
authors.affiliation: Center for the Environmental Implications of NanoTechnology (CEINT), USA; Department of Chemistry, Duke University, Durham, NC 27708, USA.
authors.forename: Jie
authors.initials: J
authors.lastname: Liu
authors.affiliation: Center for the Environmental Implications of NanoTechnology (CEINT), USA; Department of Civil and Environmental Engineering, Pratt School of Engineering, Duke University, Durham, NC 27708, USA. Electronic address: wiesner@duke.edu.
authors.forename: Mark R
authors.initials: MR
authors.lastname: Wiesner
mesh_terms: D001419:Bacteria / Q000235:genetics / Q000302:isolation & purification*; D001673:Biodegradation, Environmental; D037741:Fullerenes / Q000737:chemistry*; D020459:Genes, rRNA; D064307:Microbiota; D053758:Nanoparticles; D012335:RNA, Ribosomal / Q000235:genetics; D017382:Reactive Oxygen Species / Q000302:isolation & purification; D013535:Suspensions; D013997:Time Factors
chemical_list: D037741:Fullerenes; D012335:RNA, Ribosomal; D017382:Reactive Oxygen Species; D013535:Suspensions; C069837:fullerene C60
keywords: Aging; Carbon nanomaterials; Fullerene nanoparticles; Hydroxylation; Microbes; Photosensitized reactivity