Health Concerns in Nanotechnology
March 29, 2004
By BARNABY J. FEDER
Buckyballs, a spherical form of carbon discovered in 1985
and an important material in the new field of
nanotechnology, can cause extensive brain damage in fish,
according to research presented yesterday at a national
meeting of the American Chemical Society in Anaheim, Calif.
Eva Oberdˆrster, an environmental toxicologist at Southern
Methodist University in Dallas, said the buckyballs also
altered the behavior of genes in liver cells of the
juvenile largemouth bass she studied.
Buckyballs are part of a group of materials called
fullerenes for their structural resemblance to the geodesic
domes designed by Buckminster Fuller. Synthetically
produced buckyballs, along with more recently created
fullerenes like carbon nanotubes, have played a major role
in igniting interest in nanotechnology, the field in which
researchers manipulate materials with dimensions measured
in nanometers. A nanometer is a billionth of a meter - tens
of thousands of times thinner than a human hair.
The new carbon molecules have been studied for numerous
potential uses in advanced computer processors, lubricants,
fuel cells and drug delivery systems.
But yesterday's report is the latest of several that raise
questions about the potential health and environmental
effects of synthetic nanoscale materials. Other
researchers, including Dr. Oberdˆrster's father, G¸nter
Oberdˆrster, a professor of environmental medicine at the
University of Rochester, have shown that such particles can
enter the brain. The fish studies, however, were the first
to indicate destruction of lipid cells, the most common
form of brain tissue.
Dr. Oberdˆrster of S.M.U. said that the results underscored
the need to learn more about how buckyballs and other
nanoscale materials are absorbed, how they might damage
organisms and what levels of exposure represent hazards.
But she rejected arguments made by some nanotechnology
critics that the limited toxicological research to date
justified a moratorium on the development and sale of the
"This is a yellow light, not a red one," Dr. Oberdˆrster
said in a telephone interview last week.
Vicki L. Colvin, whose laboratory at Rice University's
Center for Biological and Environmental Nanotechnology
supplied the buckyballs used by Dr. Oberdˆrster, was even
more cautious about the results, which have not yet been
reviewed by other scientists.
Dr. Colvin said that the surface characteristics of the
lab's buckyballs, which are not a form that is commercially
available, needed further study. She said that they had not
been coated, a process that is commonly used to limit the
toxicity of such materials in applications like drug
David B. Warheit, a DuPont researcher who led a session on
nanoparticles last week at the Society of Toxicology's
national meeting in Baltimore and also presented a paper in
Anaheim yesterday, said that numerous fundamental questions
about their toxicity are beginning to be addressed. Dr.
Warheit said that how nanoparticles are coated and how
quickly they clump together may be more important factors
in toxicity than their size.
Some companies making nanoparticles have conducted
toxicology studies that might offer additional
illumination. The extent of those studies is not known, and
some results have not been disclosed, either for
competitive reasons or because of the costs of preparing
the data for publication in scientific journals.
For example, C Sixty Inc., a start-up company in Houston
working on drugs and drug delivery systems based on
buckyballs, said that unreported data on its coated
buckyballs in zebra fish embryos and adult rodents showed
toxicity levels comparable to or lower than many existing
The rodent tests indicated that C Sixty's buckyballs
collect in the kidneys and liver and are excreted like
other wastes after completing their function of delivering
medicines, said Russell M. Lebovitz, the company's vice
president for research and business development.
The zebra fish studies were conducted by a contractor; the
rodent studies were done by Dr. Laura L. Dugan, an
associate professor of neurology and medicine at Washington
University in St. Louis, Mr. Lebovitz said. Dr. Dugan is
preparing her work for submission to a scientific journal.