Little is known about how engineered nanomaterials and
nanoparticles impact human health and
the environment. Particles at the scale of one-billionth of
a meter — so small they can slip across the
blood-brain barrier — pose many questions about the
safety of nanotechnology used in products
consumed and used by humans. The Institute for
NanoBioTechnology at Johns Hopkins recently
awarded $100,000 to fund research projects that seek to
answer these questions. Four $25,000 seed
grants were given to multidisciplinary research teams to
fund pilot projects across Johns Hopkins.
Jon Links, professor at the Bloomberg School of Public
Health and INBT's director of health
and environment research, says that risk assessment
performed in tandem with research into
beneficial applications will help researchers make better
decisions about how nanotechnology is used in
the future.
"The history of technological research and development
is full of examples of unrecognized
risks to health and the environment. Chlorofluorocarbons
and asbestos are examples," Links said. "It is
imperative to study potential risks to human health and the
environment hand in hand with benefit-driven research and
development. Doing so provides the best chance to minimize
risk, because risk
assessment can inform research and development at an early
stage, leading to alternative pathways."
Nanoparticles made of silica, for example, can be used
to deliver pharmaceuticals. But despite
the potential benefits, scientists don't have much
information on what happens to these particles
after they have offloaded their cargo. Principal
investigators from the schools of Public Health and
Engineering plan to use a protein to measure the toxicity
of silica nanoparticles in the brain cells of
rodents.
Tomas Guilarte, professor of
environmental health sciences in the Bloomberg School
and a co-
investigator on this study, said, "There is a tremendous
interest in using nanomaterials in various
aspects of medicine, including delivery of drugs to the
brain. However, the possibility that the
nanomaterial itself produces brain injury has not been
evaluated."
In another proposed study, collaborators from Public
Health and Engineering will measure how
the shape, size and function of engineered silica-silicone
hybrid nanomaterials affect cellular uptake
and response using advanced methods for cell imaging and
biomarker assessment. This research also
will address questions related to dose and exposure.
Howard Katz, professor of materials science and
engineering in the Whiting School, said, "Once
these particles reach cells, it is important to know
whether they penetrate into cells, whether cells
survive this penetration and whether the biochemistry
inside these cells is altered."
"These methods will permit us to visualize where
nanomaterials are located in cells, and the
nature of any response by these cells," added Ellen
Silbergeld, professor of environmental health
sciences in the Bloomberg School.
Multiwalled carbon nanotubes are commonly used
engineered nanoparticles that have been
exploited for their exceptional strength as well as their
chemical, optical and electrical properties.
But these particles also are known to bind toxic heavy
metals. If the nanotubes wind up in the food
chain, they could deposit toxic metals in the stomachs of
animals or humans. The fate of these metals
will be examined in an in vitro study developed by
researchers from the schools of Arts and Sciences,
Engineering and Public Health.
"Given their extremely high surface area-to-mass
ratios, small amounts of carbon nanotubes
have the potential to transport relatively large amounts of
adsorbed toxins," said William Ball,
professor of
geography and environmental engineering in the Whiting
School. "In this way, the carbon
nanotubes could effectively act as 'Trojan horses' that may
bring toxic contaminants to locations that
they may not otherwise reach."
Nanoparticles made of silver oxide, silver nitrate,
silver chloride and titanium dioxide can be
found in many household products, from the coatings on
washing machines to personal care items.
These particles may enter the ecosystem through wastewater
and affect aquatic life. Investigators
from Public Health, Arts and Sciences and Engineering will
track those particles to see if any show up
in oysters commercially harvested from the Chesapeake
Bay.
"In the water, engineered nanoparticles can alter
oyster immune defense mechanisms, making
them more susceptible to oyster diseases," said Thaddeus
Graczyk, associate professor in the
Bloomberg School. "As oysters are predominantly consumed
raw, nanoparticles recovered from the
water by oysters and retained in their tissue will enter
the human food chain."
These pilot projects represent some of the ongoing
research at the Institute for
NanoBioTechnology, which seeks to balance benefit-driven
applications of nanotechnology with risk
assessment. Findings from these investigations are expected
to have policy implications for the use of
nanoparticles. "Since inaccurately perceived risks by the
public and legislators can slow development
and adoption of beneficial technologies, accurate
assessment and timely dissemination of the actual
risks is becoming more and more critical," Links said.
"Relatively little is known about the potential
ecologic and human toxicity of nanomaterials, so INBT's
pilot project program is critical."
For a complete list of pilot programs and their
research teams, go to:
inbt.jhu.edu/health-and-the-environment-form-focus-of-lates
t-nanobio-seed-grants/2008/06
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