title: Influence of the Gastrointestinal Environment on the Bioavailability of Ethinyl Estradiol Sorbed to Single-Walled Carbon Nanotubes.
abstract: Recent evidence suggests that, because of their sorptive nature, if single-walled carbon nanotubes (SWCNTs) make their way into aquatic environments, they may reduce the toxicity of other waterborne contaminants. However, few studies have examined whether contaminants remain adsorbed following ingestion by aquatic organisms. The objective of this study was to examine the bioavailability and bioactivity of ethinyl estradiol (EE2) sorbed onto SWCNTs in a fish gastrointestinal (GI) tract. Sorption experiments indicated that SWCNTs effectively adsorbed EE2, but the chemical was still able to bind and activate soluble estrogen receptors (ERs) in vitro. However, centrifugation to remove SWCNTs and adsorbed EE2 significantly reduced ER activity compared to that of EE2 alone. Additionally, the presence of SWCNTs did not reduce the extent of EE2-driven induction of vitellogenin 1 in vivo compared to the levels in organisms exposed to EE2 alone. These results suggest that while SWCNTs adsorb EE2 from aqueous solutions, under biological conditions EE2 can desorb and retain bioactivity. Additional results indicate that interactions with gastrointestinal proteins may decrease the level of adsorption of estrogen to SWCNTs by 5%. This study presents valuable data for elucidating how SWCNTs interact with chemicals that are already present in our aquatic environments, which is essential for determining their potential health risk.
authors.affiliation: Department of Environmental and Global Health, University of Florida , 101 South Newell Drive, Box 100188, Gainesville, Florida 32610, United States.|Center for Environmental and Human Toxicology, University of Florida , 2187 Mowry Road, Box 110885, Gainesville, Florida 32611, United States.
authors.forename: Joseph H
authors.initials: JH
authors.lastname: Bisesi
authors.affiliation: Department of Environmental and Global Health, University of Florida , 101 South Newell Drive, Box 100188, Gainesville, Florida 32610, United States.|Center for Environmental and Human Toxicology, University of Florida , 2187 Mowry Road, Box 110885, Gainesville, Florida 32611, United States.
authors.forename: Sarah E
authors.initials: SE
authors.lastname: Robinson
authors.affiliation: Department of Environmental and Global Health, University of Florida , 101 South Newell Drive, Box 100188, Gainesville, Florida 32610, United States.|Center for Environmental and Human Toxicology, University of Florida , 2187 Mowry Road, Box 110885, Gainesville, Florida 32611, United States.
authors.forename: Candice M
authors.initials: CM
authors.lastname: Lavelle
authors.affiliation: Department of Environmental and Global Health, University of Florida , 101 South Newell Drive, Box 100188, Gainesville, Florida 32610, United States.|Center for Environmental and Human Toxicology, University of Florida , 2187 Mowry Road, Box 110885, Gainesville, Florida 32611, United States.
authors.forename: Thuy
authors.initials: T
authors.lastname: Ngo
authors.affiliation: Department of Environmental and Global Health, University of Florida , 101 South Newell Drive, Box 100188, Gainesville, Florida 32610, United States.|Center for Environmental and Human Toxicology, University of Florida , 2187 Mowry Road, Box 110885, Gainesville, Florida 32611, United States.
authors.forename: Blake
authors.initials: B
authors.lastname: Castillo
authors.affiliation: Department of Environmental and Global Health, University of Florida , 101 South Newell Drive, Box 100188, Gainesville, Florida 32610, United States.|Center for Environmental and Human Toxicology, University of Florida , 2187 Mowry Road, Box 110885, Gainesville, Florida 32611, United States.
authors.forename: Hayleigh
authors.initials: H
authors.lastname: Crosby
authors.affiliation: Nicholas School of the Environment, Duke University , Box 90328, Durham, North Carolina 27708, United States.|Department of Civil and Environmental Engineering, Duke University , 121 Hudson Hall, Box 90287, Durham, North Carolina 27708, United States.|Center for the Environmental Implications of Nanotechnologies (CEINT), Duke University , 121 Hudson Hall, Box 90287, Durham, North Carolina 27708, United States.
authors.forename: Keira
authors.initials: K
authors.lastname: Liu
authors.affiliation: Department of Civil, Architectural and Environmental Engineering, University of Texas at Austin , 301 East Dean Keeton Street, Austin, Texas 78712, United States.
authors.forename: Dipesh
authors.initials: D
authors.lastname: Das
authors.affiliation: Department of Civil, Architectural and Environmental Engineering, University of Texas at Austin , 301 East Dean Keeton Street, Austin, Texas 78712, United States.
authors.forename: Jamie
authors.initials: J
authors.lastname: Plazas-Tuttle
authors.affiliation: Department of Civil, Architectural and Environmental Engineering, University of Texas at Austin , 301 East Dean Keeton Street, Austin, Texas 78712, United States.
authors.forename: Navid B
authors.initials: NB
authors.lastname: Saleh
authors.affiliation: Nicholas School of the Environment, Duke University , Box 90328, Durham, North Carolina 27708, United States.|Department of Civil and Environmental Engineering, Duke University , 121 Hudson Hall, Box 90287, Durham, North Carolina 27708, United States.|Center for the Environmental Implications of Nanotechnologies (CEINT), Duke University , 121 Hudson Hall, Box 90287, Durham, North Carolina 27708, United States.
authors.forename: P Lee
authors.initials: PL
authors.lastname: Ferguson
authors.affiliation: Center for Environmental and Human Toxicology, University of Florida , 2187 Mowry Road, Box 110885, Gainesville, Florida 32611, United States.|Department of Physiological Sciences, University of Florida , 2187 Mowry Road, Box 110885, Gainesville, Florida 32611, United States.
authors.forename: Nancy D
authors.initials: ND
authors.lastname: Denslow
authors.affiliation: Department of Environmental and Global Health, University of Florida , 101 South Newell Drive, Box 100188, Gainesville, Florida 32610, United States.|Center for Environmental and Human Toxicology, University of Florida , 2187 Mowry Road, Box 110885, Gainesville, Florida 32611, United States.
authors.forename: Tara
authors.identifier: 0000-0002-1968-6802
authors.initials: T
authors.lastname: Sabo-Attwood
mesh_terms: D000818:Animals; D001682:Biological Availability; D004958:Estradiol; D004967:Estrogens; D004997:Ethinyl Estradiol / Q000378:metabolism* / Q000633:toxicity; D005399:Fishes / Q000378:metabolism*; D065569:Gastrointestinal Absorption; D041981:Gastrointestinal Tract / Q000378:metabolism*; D037742:Nanotubes, Carbon
chemical_list: D004967:Estrogens; D037742:Nanotubes, Carbon; D004997:Ethinyl Estradiol; D004958:Estradiol