a science devoted to engineering things that are unimaginably
small, may pose a health hazard and should be investigated
further, warns a University of Rochester scientist
and worldwide expert in the field, who received a
$5.5 million grant to conduct such research. Günter
Oberdörster, Ph.D., professor of Toxicology in
Environmental Medicine and director of the university's
EPA Particulate Matter Center, has already completed
one study showing that inhaled nano-sized particles
accumulate in the nasal cavities, lungs and brains
speculate this buildup could lead to harmful inflammation
and the risk of brain damage or central nervous system
disorders. Oberdörster's study is scheduled to
appear in the May 2004 journal Inhalation Toxicology,
and is receiving widespread attention in the scientific
community; it was cited at an international nanotechnology/health
conference earlier this year in England by the Institute
of Physics. "I'm not advocating that we stop
using nanotechnology, but I do believe we should continue
to look for adverse health effects," says Oberdörster,
who also leads the UR division of Respiratory Biology
and Toxicology. "
years ago scientists showed that in primates, nano-sized
particles traveled along nerves from the nose and
settled into the brain. But this has mostly been forgotten.
The difference today is that more nano-particles exist,
and the technology is moving forward to find additional
uses for them – and yet we do not have answers to
important questions of the possible health impact."
Backed by $600 million in recent federal funding and
the support of President Bush, nanotechnology is a
rising industry in the United States. Japan, Taiwan
and other countries are also racing to produce nanomaterials,
which can be applied to electronics, optics, medical
devices and other industries.
technology evolved when scientists found ways to manipulate
carbon, zinc and gold molecules into microscopic clusters
that could be useful in building almost anything ultra-small.
Medical applications under development include using
nanoparticles as drug-delivery systems, or as a super-advanced
type of radiation therapy that could zap tumors with
heat-seeking missile precision. But some scientists
are concerned the industry is moving too fast. The
U.S. Department of Defense awarded to grant to Oberdörster
and colleagues, to develop a model that would predict
the toxicity of certain nanoparticles.
is leading the five-year study, employing a multidisciplinary
team from 10 departments at three universities (UR,
University of Minnesota, University of Washington
at St. Louis.) They plan to test a hypothesis that
the chemical characteristics of nanoparticles determine
how they will ultimately interact with human or animal
cells. A negative cellular response may indicate impaired
function of the central nervous system, they propose.
In previous studies, Oberdörster showed that
nano-sized particles depositing in the nose of rats
traveled into the olfactory bulb. At this point the
team is not entirely opposed to nanotechnology, Oberdörster
fact, researchers hope to work with the industry,
as well as with the American and Canadian governments,
to seek solutions if problems arise. Another goal
is to develop an educational program so that future
engineers and scientists will understand the health
consequences of nanotechnology. For decades Oberdörster
has studied how the body interacts with ambient ultrafine
particles, including automotive and power plant emissions
and dust from the World Trade Center disaster. What's
different about nanotechnology is that these particles
are man-made into a well-defined size, down to a billionth
of a meter, and appear to seep all the way into the
mitochondria, or energy source, of living cells.
"We must consider many different issues before
we come to a judgment on risk," he says. "Foremost
is an assessment of potential human and environmental
exposure by different routes: inhalation, ingestion,
dermal. Then, what is their fate in the organism?
And what are the risks of cumulative effects, given
that these particles are being mass produced? At this
point we're trying to balance the tremendous opportunity
that nanotechnology presents with any potential harm."