Scientists zap tumours with laser

August 5th, 2009 - 3:22 pm ICT by IANS  

Washington, Aug 5 (IANS) By injecting nanotubes into tumours and zapping them with a quick, 30-second laser burst, scientists have killed kidney tumours in nearly 80 percent of mice. Their success suggests a potential future cancer treatment for humans.

The result is a collaborative effort between Wake Forest University School of Medicine (WFUSM), Rice University and Virginia Tech.

“When dealing with cancer, survival is the endpoint you are searching for,” said Suzy Torti, lead study investigator and professor of biochemistry at Wake Forest.

“It’s great if you can get the tumour to shrink, but the gold standard is to make the tumour shrink or disappear and not come back. It appears that we’ve found a way to do that,” said Torti.

Nanotubes are long, thin, sub-microscopic tubes made of carbon. For the study, researchers used multi-walled nanotubes (MWCNTs), which contain several nanotubes nestled within each other.

The tubes, when non-invasively exposed to laser-generated near-infrared radiation, respond by vibrating, creating heat. If enough heat is conducted, tumour cells near the tubes begin to shrink and die.

Using a mouse model, researchers injected kidney tumours with different quantities of MWCNTs and exposed the area to a three-watt laser for 30 seconds.

Researchers found that the mice who received no treatment for their tumours died about 30 days into the study.

Mice who received the nanotubes alone or laser treatment alone survived for a similar length of time. However, the group that received the highest dose of such nanotubes, the tumours completely disappeared in 80 percent of the mice.

Many of those mice continued to live tumour-free through the completion of the study, which was about nine months later.

“You can actually watch the tumours shrinking until, one day, they are gone,” Torti said.

Before the treatment can be tested in humans, however, studies need to be done to test the toxicity and safety, looking to see if the treatment causes any changes in organs over time, as well as the pharmacology of the treatment, looking at things such as what happens to the nanotubes, which are synthetic materials, over time.

The study appeared in the August issue of the Proceedings of the National Academy of Sciences.

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