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Researchers use Nanoparticles as Destructive
Beacons to zap Tumors
Newswise, July 2010 — A group of researchers
from Wake Forest University Baptist Medical
Center (WFUBMC) is developing a way to treat
cancer by using lasers to light up tiny
nanoparticles and destroy tumors with the
ensuing heat.
At the 52nd Annual Meeting of the American
Association of Physicists in Medicine (AAPM)
in Philadelphia, they described the latest
development for this technology:
iron-containing Multi-Walled Carbon
Nanotubes (MWCNTs) -- threads of hollow
carbon that are 10 thousand times thinner
than a human hair.
In laboratory experiments, the team showed
that by using an MRI scanner, they could
image these particles in living tissue,
watch as they approached a tumor, zap them
with a laser, and destroy the tumor in the
process.
If this sounds like science fiction, it is
not. The work builds on an experimental
technique for treating cancer called
laser-induced thermal therapy (LITT), which
uses energy from lasers to heat and destroy
tumors.
LITT works by virtue of the fact
that certain nanoparticles like MWCNTs can
absorb the energy of a laser and then
convert it into heat. If the nanoparticles
are zapped while within a tumor, they will
boil off the energy as heat and kill the
cancerous cells.
The problem with LITT, however, is that
while a tumor may be clearly visible in a
medical scan, the particles are not. They
cannot be tracked once injected, which could
put a patient in danger if the nanoparticles
were zapped away from the tumor because the
aberrant heating could destroy healthy
tissue.
Now the team from Wake Forest Baptist has
shown for the first time that it is possible
to make the particles visible in the MRI
scanner to allow imaging and heating at the
same time. By loading the MWCNT particles
with iron, they become visible in an MRI
scanner. Using tissue containing mouse
tumors, they showed that these
iron-containing MWCNT particles could
destroy the tumors when hit with a laser.
"To find the exact location of the
nanoparticle in the human body is very
important to the treatment," says Xuanfeng
Ding, M.S., who is presenting the work today
in Philadelphia. "It is really exciting to
watch the tumor labeled with the nanotubes
begin to shrink after the treatment."
The results are part of Ding's ongoing Ph.D.
thesis work -- a multi-disciplinary project
led by Suzy Torti, Ph.D., professor of
biochemistry at Wake Forest Baptist, and
David Carroll, Ph.D., director of the Wake
Forest University Center for Nanotechnology
and Molecular Materials, that also includes
the WFUBMC Departments of Physics, Radiation
Oncology, Cancer Biology, and Biochemistry.
A previous study by the same group showed
that laser-induced thermal therapy using a
closely-related nanoparticle actually
increased the long-term survival of mice
with tumors. The next step in this project
is to see if the iron-loaded nanoparticles
can do the same thing.
If the work proves successful, it may one
day help people with cancer, though the
technology would have to prove safe and
effective in clinical trials.
Dan Bourland, Ph.D., associate professor of
radiation oncology and Ding’s advisor,
praises the high quality of Ding's work and
says that the project is a strong example of
today’s "team science" that is needed for
success in the biomedical fields.