nanotehnoloogia, nanoteknologia, nanotechnologija, nanotehnologijas, nanoteknologija,
nanotechnologii, nanotecnologia, nanotehnologijo, nanoteknik
Nano Geneeskunde...Nano Medicína
Nanorods May Make Safer Cancer Treatment
Nanorods Show Benefits Over Nanospheres in Noninvasive
Atlanta (March 14, 2006) Researchers at the Georgia Institute of Technology
and the University of California, San Francisco, have found an even more effective
and safer way to detect and kill cancer cells. By changing the shapes of gold
nanospheres into cylindrical gold nanorods, they can detect malignant tumors
hidden deeper under the skin, like breast cancer, and selectively destroy them
with lasers only half as powerful as before without harming the healthy cells.
The method, which allows for a safer, deeper penetrating noninvasive cancer
treatment, has just appeared in the Journal of the American Chemical Society,
Image of cancer cell illuminated by gold nanorods
bound to anti-EFGR.
year, the father and son research team of Mostafa El-Sayed
and Ivan El-Sayed, showed that gold nanoparticles coated
with a cancer antibody were very effective at binding
to tumor cells. When bound to the gold, the cancer
cells scattered light, making it very easy to identify
the noncancerous cells from the malignant ones. The
nanoparticles also absorbed the laser light more easily,
so that the coated malignant cells only required half
the laser energy to be killed compared to the benign
cells. This makes it relatively easy to ensure that
only the malignant cells are being destroyed.
Now, they've discovered that by changing the spheres into rods, they can lower
the frequency to which the nanoparticles respond from the visible light spectrum
used by the nanospheres to the near-infrared spectrum. Since these lasers can
penetrate deeper under the skin than lasers in the visible spectrum, they can
reach tumors that are inaccessible to visible lasers.
"With the nanospheres we're using visible lasers, but most of the solid cancer
is under the tissues and visible light doesn't go but a few millimeters deep.
But by using the nanorods we can tune them to react to the infrared lasers, which
can penetrate the tumor without being absorbed by the tissues, said Mostafa
El-Sayed, director of the Laser Dyanamics Laboratory and Regents' professor of
chemistry at Georgia Tech.
Image of nonmalignant cells after incubation with
gold nanorods bound with anti-EFGR.
cancer cells have a protein, known as Epidermal Growth
Factor Receptor (EFGR), all over their surface, while
healthy cells typically do not express the protein
as strongly. By conjugating, or binding, the gold
nanorods to an antibody for EFGR, suitably named
anti-EFGR, researchers were able to get the nanoparticles
to attach themselves to the cancer cells.
In this latest study, researchers incubated two malignant oral epithelial cell
lines and one benign epithelial cell lines with nanorods conjugated to anti-EFGR.
Not only were the malignant lines clearly identifiable as such under a simple
optical microscope, but after being exposed to a continuous sapphire laser
in the near infrared spectrum, the malignant lines only required half the laser
energy to kill them as the healthy cells.
"This makes it more practical than the sphere in terms of treating cancer, said
Mostafa El-Sayed. For laser phototherapy treatment of skin cancer or, for diagnostic
biopsies, the spheres are fine, but for phototherapy of cancer deep under the
skin, like breast cancer, then one really needs to use the nanorods treatment.
Georgia Institute of Technology is one of the nation's
premiere research universities. Ranked ninth among
U.S. News & World Report 's top public universities,
Georgia Tech educates more than 17,000 students every
year through its Colleges of Architecture, Computing,
Engineering, Liberal Arts, Management and Sciences.
Tech maintains a diverse campus and is among the
nation's top producers of women and African-American
engineers. The Institute offers research opportunities
to both undergraduate and graduate students and is
home to more than 100 interdisciplinary units plus
the Georgia Tech Research Institute. During the 2004-2005
academic year, Georgia Tech reached $357 million
in new research award funding. The Institute also
maintains an international presence with campuses
in France and Singapore and partnerships throughout
story has been adapted from a news release
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