at Temple University are using protein structures
to design and assemble metal oxide nanoparticles that
could be used in environmental remediation.
will present their research, "Inorganic nanoparticles
synthesized from biological precursors as nanocatalysts
for environmental applications," at the 228th
American Chemical Society national meeting, Aug. 22-26,
researchers have been exploring how these nanoparticles
can be used in environmental remediation, such as
helping to transform toxic metals in lakes, rivers
or streams, and in groundwater for easier cleanup.
"The protein we use to make these particles is
ferritin, which is a protein we carry around in our
blood," says Daniel R. Strongin, Ph.D., professor
of chemistry at Temple. "It's an iron storage
protein, so if there's extra iron in our blood, it
typically gets stored in ferritin. Then, when our
body needs iron, the ferritin releases what has been
and his collaborators, Hazel Ann Hosein, a doctoral
student in chemistry at Temple, and Trevor Douglas,
an associate professor of chemistry at Montana State
University, have been loading horse spleen ferritin
with iron in the laboratory to create the nanoparticles.
By varying the amount of iron they load, they can
vary the size of the particles.
example, there are certain oxidation states that would
make the metals precipitate in solution, or fall out
of solution so they can't be carried downstream or
by groundwater," explains Strongin. "In
one case, we've been looking at the reduction of toxic
Chromium-6 (or hexavalent chromium), one that the
U.S. Environmental Protection Agency has on their
toxic metal list for groundwater."
applying the nanoparticles to Chromium-6, and with
the aid of visible light or solar radiation to activate
the particles-the particles are photocatalytic-the
researchers were able to reduce the chromium from
hexavalent to trivalent, which is insoluble in water.
chromium is much easier to clean," says Strongin.
"You can filter it much more easily in this state."
says that their results have been encouraging enough
that the researchers believe that the nanoparticles
they are creating could have an impact on other toxic
metals, such as Technetium-7, which is a problem at
the nuclear waste site in the state of Washington.
large canisters of nuclear waste have been sitting
there since the 1940s and '50s, and they are slowly
leaking," he says. "People are worried about
it getting into the groundwater. But we believe that
this method of using nanoparticles could play a role
in preventing the spread in groundwater and help facilitate
cleaning it up."
says the researchers are attempting to do chemistry
with these nanoparticles that could not otherwise
be done with larger bulk materials.
have a pretty novel approach in using proteins to
assemble these particles," he says. "Nature
does this, and we're just harnessing that ability."
for this research was provided by the U.S. Environmental
Protection Agency and the American Chemical Society.
Science and Technolgy Writer