Responses of Lung Cells to Metals in Manufactured NanoparticlesEPA Grant Number: R831723
Title: Responses of Lung Cells to Metals in Manufactured Nanoparticles
Investigators: Veranth, John , Reilly, Christopher A. , Yost, Garold S.
Institution: University of Utah
EPA Project Officer: Hahn, Intaek
Project Period: October 1, 2004 through September 30, 2007
Project Amount: $332,958
RFA: Exploratory Research to Anticipate Future Environmental Issues: Impacts of Manufactured Nanomaterials on Human Health and the Environment (2003) RFA Text | Recipients Lists
Research Category: Nanotechnology , Health , Safer Chemicals , Health Effects
This proposal is based on the hypothesis that transition metals in particles induce pro-inflammatory signaling and cell damage through the production of reactive oxygen species. Established cell culture models and toxicology assays will be applied to the analysis of manufactured nanomaterials. Based on the literature and our own data, we expect that the small physical size and high surface area of nanoparticles ( d < 30 nm) will increase cellular uptake and increase induction of pro-inflammatory signaling compared to larger particles with the same elemental composition. In vitro studies with human and rat lung cells will evaluate the effects of manufactured nanoparticles in the as-sold condition, and the same materials after the particles have been subjected to surface modification simulating fire and wastewater treatment conditions. The emphasis will be on lower-cost nanomaterials that are sold in powder or liquid suspension form because these materials are expected to be produced and ultimately released in the largest amount.
A phased approach will be used to maximize useful results within the budget. In the first phase, low cost assays will be used to screen a wide range of samples with sufficient replicates for statistical power. This phase will emphasize measurement of cytotoxicity, induction of the proinflammatory cytokine IL-6, and dissolution rate in simulated lung fluid. Industrial collaborators will assist in prioritizing materials for testing and providing chemically similar materials in various sizes and grades. Materials selected in the screening phase will be used for more detailed, mechanistic studies. The second phase will test selected materials for particle uptake by the cells, for the induction of additional cytokines, and for the effect of antioxidants. Phase two physical characterization will include electron microscopy, BET surface area, zeta potential, and trace element analysis. In the third phase, the most inflammatory and most benign nanomaterials will be used in hypothesis-based toxicology experiments to evaluate plausible mechanisms by which the particles induce specific responses in cells. Cell culture toxicology studies with BEAS-2B cells, an immortalized human lung epithelial cell line, are emphasized and are consistent with the goal of refining, reducing, and replacing animal use. However, it is necessary to establish the relevance of cell culture data to whole animals and to human health. Experiments using normal macrophages and normal epithelial cells that are freshly harvested from rats will be conducted to test the ability of the cell culture assays to predict the induction of inflammation by specific nanomaterials.
The screening phase will provide new data on a range of commercially available nanoparticles using a consistent set of physical and cell culture assays to facilitate comparisons between materials. The surface modification studies will contribute to understanding the environmental fate of nanoparticles by evaluating whether the treatments enhance or decrease the biological effects of specific nanomaterials. The evaluation of plausable mechanisms and the experiments with freshly isolated rat airway cells will provide a transition between cell culture studies, inhalation studies, and extrapolation to sensitive human populations.