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TECHNOLOGY REVIEW /
of their small size, nanoparticles can reach sites in the body
that large particles cannot, cross barriers, and react," says
In 2004, Oberdörster s daughter, Eva Oberdörster, a toxi-
cology researcher at Duke University, put largemouth bass
into water containing buckyballs at the concentration of one
part per million. After two days, the lipids in the brains
of the sh showed 17 times as much oxidative damage as
those of unexposed sh.
Carbon nanotubes, which are basically cylindrical ver-
sions of the spherical buckyballs, are one of the stars of nano-
tech, with potential uses in everything from solar cells to
computer chips. But in 2003, researchers at NASA s John-
son Space Center in Houston, headed by Chiu-Wing Lam,
showed that in the lungs of mice, carbon nanotubes caused
lesions that got progressively worse over time. Under the
conditions of the experiment, the researchers concluded,
carbon nanotubes were "much more toxic than carbon black
[that is, soot] and can be more toxic than quartz, which is
considered a serious occupational health hazard."
Another extremely promising nanoparticle is the uo-
rescent "quantum dot," now being explored for use in bio-
imaging. Researchers envision applications in which they
tag the glowing nanodots with antibodies, inject them into
subjects, and watch as they selectively highlight certain tis-
sues or, say, tumors. Quantum dots are typically made of
Instilling nanotubes in the
Not a realistic model of exposure: "Comparative Pulmonary Toxicity
lungs of rats can cause
the study had no findings on
Assessment of Single-Wall Carbon
Laboratory (2004) adverse reactions.
the effects of rats inhaling
Nanotubes in Rats," Toxicological
Sciences 77: 117--125
Günter Oberdörster, Inhaled nanoscale particles Results might not apply to hu-
"Translocation of Inhaled Ultrafine
can get into rats brains via
mans. The study did not demon- Particles to the Brain," Inhalation
Rochester (2004) the olfactory nerve.
strate toxicity or study common Toxicology 16(6--7): 437--445
Fullerenes can damage cells Cells in the gills and liver showed "Manufactured Nanomaterials
in the brains of fish by
decreased peroxidation after (Fullerenes, C60) Induce Oxidative
exposure to fullerenes, for
Stress in the Brain of Juvenile
Largemouth Bass," Environmental
Health Perspectives 112: 1058--1062
Nanoscale alumina can stunt Chemically altering the surfaces "Particle Surface Characteristics May
New Jersey Institute root growth in corn, soybeans, of the particles dramatically
Play an Important Role in Phyto-
of Technology (2005) and other plants, suggesting reduced their toxicity.
toxicity of Alumina Nanoparticles,"
nanoparticles can be toxic to
Toxicology Letters 158: 122--132
plants as well as animals.
Fullerenes can damage
The study models just one
"C60 in Water: Nanocrystal Forma-
microbes. (This study and the aspect of how nanoparticles
tion and Microbial Response," Envi-
of Technology (2005) next elucidate the mechan-
will interact with the environment. ronmental Science and Technology
isms of toxicity and may help
scientists predict the effects
of a range of nanoparticles.)
Jennifer West and In human cells, fullerenes can Particles may behave differently "Nano-C60 Cytotoxicity Is Due to
Vicki Colvin, Rice
cause damage like that seen in the body than they do in
Lipid Peroxidation," Biomaterials
University (2005) in the brain cells of fish.
Kevin Ausman and Modifying the surfaces of
"Functionalization Density Depen-
Vicki Colvin, Rice
carbon nanotubes with
can negate the very properties dence of Single-Walled Carbon
University (2006) functional molecules can
that make them useful for some Nanotubes Cytotoxicity in Vitro,"
increase their toxicity.
Toxicology Letters 161: 135--142
Mixed Findings on Toxicity
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