Genomics-based Determination of Nanoparticle Toxicity: Structure-function Analysis
|Principal Investigator||Alan Bakalinsky|
|Relevance to Implications||High|
|Class of Nanomaterial||Engineered Nanomaterials|
|Impact Sector||Human Health|
|Broad Research Categories||
|Anticipated Total Funding||$199,993.00|
|Anticipated End Year||2009|
The nanotechnology industry is growing rapidly due to the multitude of applications for engineered nanomaterials. Although environmental and human exposure is expected to increase proportionally, relatively few studies have evaluated the toxicological and environmental consequences. While fullerenes and derived materials have been demonstrated to possess antioxidant activity in vivo and in vitro, they have also been reported to induce oxidative stress, growth inhibition, inflammation, and other undesirable health effects. At a mechanistic level, it is not obvious how to reconcile these contradictory observations. The current lack of toxicological data represents a major potential impediment to continuing growth of this technology.
The long-term goal of this project is to determine the mechanisms by which manufactured nanomaterials cause cytotoxicity in realistic environments of exposure. The objectives of this proposal are: 1) to use a genomics approach to identify genes and functions that are protective against toxicity caused by fullerene and fullerol in a well-developed and experimentally-tractable model organism, the yeast Saccharomyces cerevisiae; 2) to discover how the physical-chemical properties of engineered nanomaterials correlate with toxicity; and 3) to determine if particle uptake is necessary for toxicity. Our central hypothesis is that the toxicity of nanoparticles is a function of their specific physical-chemical state, which in turn, is determined by the solution chemistry of the medium in which cells are exposed.
A commercially-available library of approximately 4,800 yeast deletant mutants will be systematically screened for sensitivity to fullerene and to fullerol under controlled conditions in which the physical-chemical properties of these particles will be manipulated through formulation of the solution chemistry to mimic a range of potential environmental conditions. Particle size, shape, surface charge, specific surface area, and the surface functionality of these materials will be measured and correlated with particle toxicity. Genes missing in mutants found to exhibit sensitivity will likely encode functions that normally provide protection. Uptake of nanomaterial will be assessed by indirect immunofluorescence.
We expect to identify yeast genes and processes needed to protect cells from the toxicity of these nanomaterials. Based on the recognized conservation of cellular functions among distantly-related species, we anticipate that many of the genes and functions implicated in these mutants will have related counterparts in humans and other species. Thus, gene discovery in yeast will provide a reasonable biological basis for evaluating candidate genes and processes in humans. We expect to establish a correlation between the physical-chemical properties of the nanoparticles and cytotoxicity, which will help to identify structural features of these materials that are most responsible for cell damage and environmental conditions that enhance or decrease toxicity. This is expected to aid in establishing future safety guidelines for industrial and environmental exposure. We expect to determine if particle uptake is required for cytotoxicity.