UC Davis is one of only three sites in California to become part of the National Institutes of Environmental Health Sciences (NIEHS) nanomaterials consortium. Researchers received a 2-year, $1 million grant through the American Recovery and Reinvestment Act to examine the health effects associated with engineered nanomaterials, with a focus on workplace exposures. Kent Pinkerton, director of the Center for Health and the Environment and COEH member, will lead the study.
Nanomaterials are particles of metals, ceramics, polymers or composite material engineered for commercial use in food, clothing, electronics and cosmetics. They are less than 100 nanometers in diameter, or about a 1,000th of the width of a sheet of paper. Nanomaterials have properties that are unique from the same compound at a larger scale making them useful in manufacturing, but potentially a risk to health.1
California leads the country in nanotechnology—a field that is rapidly expanding. "Today, approximately 900 products contain nanomaterials, up from 300 only one year ago," said Pinkerton. "By the year 2015, it's estimated to be a trillion dollar a year business."
Nanotechnologies hold a tremendous amount of promise, but scientists are concerned about their impacts on human health. "We know that eventually these materials may enter into the environment," said Pinkerton. "Those who are most at risk of potential health effects are the workers who are synthesizing these materials or handling them during packaging and shipping."
Though workers and consumers alike may be exposed to nanoparticles through hand-to-mouth ingestion and dermal or eye contact, from an occupational standpoint, inhalation is likely to be one of the most significant paths of exposure.2
"Titanium dioxide, for example, in large particle form has no health effects, but when you reduce it in size to less than 100 nanometers in diameter, the same material is known to be quite toxic," said Pinkerton. "Epidemiologic and toxicology studies show materials of this size can produce the greatest effects both in the lungs and the cardiovascular system."
Pinkerton's grant will support two doctoral students from pharmacology and toxicology, both involved in inhalation studies. Laurie Hopkins will be using quantum dots—nanomaterials that become florescent when hit with ultraviolet light—to visualize how they travel, literally within hours, from the nose to the olfactory bulb in the central nervous system.
Quantum dots may gain widespread use in the next generation of mobile phone cameras. InVisage, a start-up company from Menlo Park, California, announced plans to launch the first commercial quantum dot-based image sensors later this year, a technology they claim will improve photo quality by capturing more light than silicon.
Amy Madl will examine the potential health effects associated with single and repeated exposure to carbon nanotubes. "They are like little fibers," explained Pinkerton. "The question is whether nanotubes have some of the potentially adverse health effects of more commonly known fibers, such as fiberglass and asbestos."
Madl is also comparing carbon nanotubes to carbon black, its pure parent compound, and to a form of asbestos-- crocidolite--that has similar fiber-like properties. Both carbon nanotubes and crocidolite contain iron, which may be associated with their potential toxicity.
Pinkerton's participation in the consortium has led to new collaborations with Chris Vulpe, associate professor of Nutritional Science and Toxicology at UC Berkeley. Vulpe also won a federal stimulus grant from NIEHS. Their next proposal, if funded, will provide $3.7 million for five years to identify key genes and processes that determine cellular responses to nanomaterials. In addition, they will develop innovative risk exposure methodology for estimating their impacts on population health.
2 Madl AK, Pinkerton KE. Health effects of inhaled engineered and incidental nanoparticles. Crit Rev Toxicol. 2009;39(8):629-58.
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