Grantee Research Project Results
Functionalized Metal Oxide Nanoparticles: Environmental Transformations and Ecotoxicity
EPA Grant Number: R833860Title: Functionalized Metal Oxide Nanoparticles: Environmental Transformations and Ecotoxicity
Investigators: Pedersen, Joel A. , Peterson, Richard E. , Hamers, Robert J. , Heideman, Warren
Institution: University of Wisconsin - Madison
EPA Project Officer: Aja, Hayley
Project Period: July 1, 2008 through June 30, 2011
Project Amount: $382,345
RFA: Exploratory Research: Nanotechnology Research Grants Investigating Fate, Transport, Transformation, and Exposure of Engineered Nanomaterials: A Joint Research Solicitation - EPA, NSF, & DOE (2007) RFA Text | Recipients Lists
Research Category: Nanotechnology , Safer Chemicals
Objective:
Nanoscale forms of magnetic Fe3O4 and the photocatalysts TiO2 and ZnO have a wide range of current and proposed applications, and rank among the highest production volume nanoparticles (NPs). Many applications of these NPs require surface functionalization. Nanoparticle surface chemistry influences uptake and toxicity, as well as interactions with environmental media. Microbially mediated redox processes have the potential to alter the surface chemistry of functionalized TiO2, ZnO, and Fe3O4, thereby impacting their toxicity and fate. Fundamental information on changes in the surface chemistry of these commercially important metal oxide NPs under environmentally relevant oxidative and reductive conditions is currently lacking. Furthermore, the influence of surface coatings on metal oxide NP toxicity has not been thoroughly studied, and little information exists on the effects of environmentally induced changes in surface chemistry on toxicity. The objectives of this study are to determine (1) the extent to which the surface chemistry of functionalized metal oxide NPs is altered under oxidative and reductive environmental conditions, and (2) the degree to which such transformations modify their inherent and photo-enhanced toxicity.
Approach:
The surfaces of TiO2, ZnO and Fe3O4 NPs will be coated using a variety of strategies (e.g., ligand exchange through different anchoring groups, silica shells, polymer wrapping) and extensively characterized. Alterations in the surface chemistry of the coated metal oxide NPs will be investigated using in vitro biomimetic assays modeled after important microbially mediated redox processes. Oxidative transformations will be examined using methoxyhydroquinone-driven Fenton’s reaction as chemical model for reactive oxygen species produced by lignolytic fungi. Reductive transformations will be studied using reduced cobalamin as a model for microbial reduction processes. The inherent and photo-enhanced toxicity of the as-synthesized functionalized NPs and their transformation products will be investigated using the embryonic zebrafish model. Mortality, sublethal morphological and functional endpoints of toxicity, oxidative stress and metallothionein induction will be examined.
Expected Results:
This study will provide fundamental information on alterations in the surface chemistry of commercially important functionalized metal oxide NPs under environmentally relevant oxidative and reductive conditions, as well as needed data on the inherent and photo-enhanced toxicity of these same materials as synthesized and after transformation. This research will enable the development of environmentally benign nanomaterials and facilitate environmental risk assessment of these materials.
Publications and Presentations:
Publications have been submitted on this project: View all 41 publications for this projectJournal Articles:
Journal Articles have been submitted on this project: View all 6 journal articles for this projectSupplemental Keywords:
nanotechnology, environmental chemistry, ecological effects, bioavailability, biology, nanoparticle toxicity, nanomaterials, titanium, zinc, iron,, Health, Scientific Discipline, Risk Assessments, Biochemistry, bioavailability, nanomaterials, carcinogenic, human exposure, biological pathways, CNT, nanoparticle toxicity, nanotechnology, toxicologic assessmentProgress and Final Reports:
The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.