Chemical & Engineering News Digital Edition - Institute of Materia ...

TROY BENN
Electron
microscopy
confirmed presence
of spherical silver
nanoparticles in six
brands of socks.
Japan’s Takeda Pharmaceutical will spend
$8.8 billion in cash to acquire Millennium
Pharmaceuticals of Cambridge, Mass.
“Millennium has strong discovery,
development, and commercial capabilities
led by a well-established management
team,” Takeda President Yasuchika
Hasegawa says. “Our strong desire is to
retain Millennium employees, who have
created an entrepreneurial and innovative
culture.”
Already the largest pharmaceutical
company in Japan with nearly $11 billion
in annual sales, Takeda sees its purchase
of a U.S. biotechnology company as a
way to expand its worldwide position in
NEWS OF THE WEEK
TOXIC SOCKS
ACS MEETING NEWS: Silver
nanoparticles intended to control
odor release in the wash
ARIZONA STATE UNIVERSITY researchers
have found that socks impregnated with odorfighting
silver nanoparticles release the nanoparticles
when washed. This study, the first to examine
how nanoparticles are released from commercially
available clothing,
raises concerns about
silver particles leaching
into wastewater and the
environment.
Troy M. Benn, a
graduate student at ASU,
presented these results
to the Division of Environmental
Chemistry at
last week’s ACS national
meeting in New Orleans.
Details of the work,
which Benn carried out
with ASU professor of civil and environmental engineering
Paul Westerhoff, recently appeared in Environmental
Science & Technology (DOI: 10.1021/es7032718).
Various nanoparticles are increasingly used to make
clothing free of wrinkles and resistant to stains, but
little is known about what happens to nanoparticles in
the laundry. The study is significant because it examines
whether such products release nanoparticles during
use, Mark R. Wiesner, an environmental engineer at
Duke University, said.
Benn and Westerhoff reasoned that the sock manu-
PHARMACEUTICALS Takeda buys Millennium to build U.S. business
the oncology drug market. Similar moves
were made in late 2007 by the Japanese
drug firms Eisai, which acquired MGI
Pharma, and Astellas Pharma, which
bought Agensys (C&EN, Dec. 17, 2007,
page 8).
Takeda, however, is spending significantly
more than its Japanese competitors
to buy a profitable, midsized
U.S. biotech business. The 15-year-old
Millennium had revenues of $528 million
in 2007; $265 million came from its
U.S. sales of the multiple myeloma drug
Velcade, and $167 million was royalties
on non-U.S. Velcade sales by its partner,
Johnson & Johnson.
WWW.CEN-ONLINE.ORG 10 APRIL 14, 2008
facturing process may control how much silver is
released during washing because the amounts varied
widely among the socks they tested.
Juan P. Hinestroza, assistant professor of fiber science
at Cornell University, agrees. He said the varying
amounts and morphologies of the silver released are
indeed functions of different processes used to deposit
the silver onto the textile material and the properties
of the textile substrate. He hopes this study will
motivate scientists to develop synthetic routes that
take advantage of the properties of silver nanoparticles
in textiles while preventing leaching into wastewater
streams.
The ASU researchers shook each of six brands of
socks in one-half liter of distilled water with no detergent
for one hour and then analyzed the effluent with
electron microscopy. The socks contained up to 1,360
μg of silver per gram of socks, and released as much as
650 μg of silver in both ionic and colloidal forms. “In
the environment, both ionic and nanosilver exhibit
adverse effects to aquatic organisms, although through
what appear to be different biological mechanisms,”
Westerhoff said.
The ASU researchers’ model indicated that both
kinds of silver would be trapped in biosolids in wastewater
treatment facilities. They said increased use
of nanoproducts could produce increased amounts of
silver in these biosolids, which could limit the use of
such biosolids as agricultural fertilizer. Benn added
that the Environmental Protection Agency doesn’t
currently regulate silver levels in biosolids from
wastewater treatment but does, for example,
list maximum concentrations for drinking water.
And in 2006, EPA officials announced that the agency
would begin regulating as a pesticide the silver ions
released in a washing machine that are intended to
kill bacteria (C&EN, Dec. 4, 2006, page 14).—RACHEL
PETKEWICH
Takeda has made other globalization
moves as well. In February, it set up a
$1.2 billion deal with Amgen to gain access
to 13 molecules in Amgen’s drug
development pipeline.
And the Japanese company recently
restructured its U.S. operations, in part
by dissolving and dividing up its 30-yearold
TAP Pharmaceutical Products joint
venture with Abbott Laboratories. If both
shareholders and regulators approve of
Takeda’s offer for Millennium—both companies’
boards have already approved
the deal—the biotech firm will become a
stand-alone subsidiary of Takeda.—ANN
THAYER