title: Gastrointestinal biodurability of engineered nanoparticles: Development of anin vitroassay.
abstract: The toxicity of engineered nanoparticles is expected to depend in part on their stability in biological systems. To assess the biodurability of engineered nanomaterials in the human digestive system, we adapted anin vitroassay previously used to evaluate the bioaccessibility of metals in contaminated soils. The compositions of the simulated gastric and intestinal fluids, temperature and residence times were designed to closely mimic conditions in the stomach and duodenum of the small intestine. We demonstrated the utility of the assay using CdSecore/ZnSshellquantum dots functionalized with polyethylene glycol (PEG) thiol of two different molecular masses (PEG350and PEG5000). Under gastric conditions, removal of the PEG ligand diminished the stability of PEG350-quantum dot suspensions, while PEG5000-quantum dots were severely degraded. Inclusion of the glycoprotein mucin, but not the digestive protein pepsin, in simulated gastric fluids provided both PEG350- and PEG5000-coated quantum dots partial protection from transformations induced by gastric conditions.
authors.affiliation: Molecular and Environmental Toxicology Center, University of Wisconsin, Madison, WI, USA.
authors.forename: Paige N
authors.initials: PN
authors.lastname: Wiecinski
authors.affiliation: Environmental Chemistry and Technology Program, University of Wisconsin, Madison, WI, USA.
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Metz
authors.affiliation: Department of Chemistry, University of Wisconsin, Madison, WI, USA.
authors.forename: Andrew N
authors.initials: AN
authors.lastname: Mangham
authors.affiliation: Department of Civil and Environmental Engineering, University of Wisconsin, Madison, WI, USA.
authors.forename: Kurt H
authors.initials: KH
authors.lastname: Jacobson
authors.affiliation: Department of Chemistry, University of Wisconsin, Madison, WI, USA.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Hamers
authors.affiliation: Molecular and Environmental Toxicology Center, University of Wisconsin, Madison, WI, USA ; Environmental Chemistry and Technology Program, University of Wisconsin, Madison, WI, USA ; Department of Civil and Environmental Engineering, University of Wisconsin, Madison, WI, USA ; Department of Soil Science, University of Wisconsin, Madison, WI, USA.
authors.forename: Joel A
authors.initials: JA
authors.lastname: Pedersen
keywords: degradation; exposure assessment; gastrointestinal biodurability; ingestion; mucin; quantum dot