Like little golden assassins, 'smart' nanoparticles identify, target and kill cancer cells

Mar 08, 2010 by Anne Ju
A transmission electron microscope image of a gold hybrid nanoparticle that could be used to treat cancer. The gold in the middle is surrounded by two pieces of iron oxide. (Dickson Kirui)

Another weapon in the arsenal against cancer: Nanoparticles that identify, target and kill specific cancer cells while leaving healthy cells alone.

Led by Carl Batt, the Liberty Hyde Bailey Professor of Food Science, the researchers synthesized nanoparticles - shaped something like a dumbbell - made of gold sandwiched between two pieces of . They then attached , which target a molecule found only in colorectal cancer cells, to the particles. Once bound, the nanoparticles are engulfed by the cancer cells.

To kill the cells, the researchers use a near-infrared laser, which is a wavelength that doesn't harm normal tissue at the levels used, but the radiation is absorbed by the gold in the nanoparticles. This causes the cancer cells to heat up and die.

"This is a so-called 'smart' therapy," Batt said. "To be a smart therapy, it should be targeted, and it should have some ability to be activated only when it's there and then kills just the cancer cells."

The goal, said lead author and biomedical graduate student Dickson Kirui, is to improve the technology and make it suitable for testing in a human clinical trial. The researchers are now working on a similar experiment targeting cells.

"If, down the line, you could clinically just target the cancer cells, you could then spare the health surrounding cells from being harmed - that is the critical thing," Kirui said.

Gold has potential as a material key to fighting cancer in future smart therapies. It is biocompatible, inert and relatively easy to tweak chemically. By changing the size and shape of the gold particle, Kirui and colleagues can tune them to respond to different wavelengths of energy.

Once taken up by the researchers' gold particles, the are destroyed by heat - just a few degrees above normal body temperature - while the surrounding tissue is left unharmed. Such a low-power laser does not have any effect on surrounding cells because that particular wavelength does not heat up cells if they are not loaded up with , the researchers explained.

Using iron oxide - which is basically rust - as the other parts of the particles might one day allow scientists to also track the progress of cancer treatments using magnetic resonance imaging, Kirui said, by taking advantage of the particles' magnetic properties.

Explore further: Optically activating a cell signaling pathway using carbon nanotubes

More information: The research is reported in the Feb. 15 online edition of the journal Nanotechnology.

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User comments : 6

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5 / 5 (1) Mar 08, 2010
A better idea, forget the gold and the lasers and just use the iron oxide!
Cheap, available and deadly, read all about it here.

Another example of blinkered scientists totally unaware of the world around them.
5 / 5 (2) Mar 08, 2010
"If, down the line, you could clinically just target the cancer cells, you could then spare the health surrounding cells from being harmed - that is the critical thing," Kirui said.

I have been hearing about this for at least 4 years, we know that they are able to kill cancer cells. In 4 years there has been no progress just targeting cancer cells?
3 / 5 (4) Mar 08, 2010
I agree with you Supermegadope, this has been trumpeted for a long time now with no new insights or advancements. I first heard about the prospect of using gold nanoparticles in conjunction with an infrared laser to heat them up and destroy the cells they bind to with antibodies back in 1994. It has been over 15 years now and we are still in the same place, trumpeting the latest confirmation (YES WE KNOW IT WORKS!) and going nowhere fast. Ridiculous.
5 / 5 (1) Mar 08, 2010
A former graduate student in the research group that I joined at the beginning of this semester showed that people who were claiming to have created nanoparticle iron oxide cores with gold shells had not actually properly characterized their properties, including whether their particles were actually gold shelled and not just solid gold nanoparticles. There is also a lack of long-term stability characterization of gold nanoparticles, due to the fact that they undergo a process known as Oswald ripening, where smaller particles are broken apart and then subsumed by larger particles due to the higher surface energy of the smaller particles.

@fixer: Gold-coated iron-oxide nanoparticles have more uses than just killing cancer cells, by the way. The fact that one can excite a plasmon resonance within the gold shell provides us the opportunity to characterize the dielectric properties of every part of a biological cell.
not rated yet Mar 09, 2010
Everything worthwile in cancer research goes nowhere fast.
Too much money changes hands TREATING cancer, no one makes money CURING cancer.
A bottle of Artemisinin costs about $65.00 and thats it!
No chemo, no surgery and no radiotherapy = NO MONEY.

No chemist worth his salt is going to give up his meal ticket willingly, I refer you again to the original release.
not rated yet Mar 13, 2010
like the links that fixer share......

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