Directed Radiotherapy Using Carbon Nanotubes

A new method for specifically targeting cancer cells with radio-frequency waves was developed by researchers at University of Texas M. D. Anderson Cancer Center in Houston. The method uses carbon based nanotubes to enter the cancerous cells and vibrate at a high frequency. The nanotubes’ vibrations, which are generated as a result of radio waves, cause the cancer cells to overheat, leading to their destruction.
Dr. Steven Curley (Credit: University of Texas)
Dr. Steven Curley
(Credit: University of Texas)

Radiotherapy is a common therapeutic pathway for various types of cancer. The major problem with radiotherapy is that it’s not tissue specific, meaning that it kills other cells in addition to the cancer cells. Much effort has been made to make radiotherapy more specific. One technology recently covered by TFOT uses alpha particles instead of the broadly used beta particles. The Texas University research team chose a different pathway, using carbon nanotubes to specifically destroy cancer cells.

The nanotubes, injected into the tumor, act as conductors for the radio-waves. The use of nanotubes is not innovative, since carbon nanotubes designed to react to near-infrared waves were used before for cancer treatment. However, the near infrared waves can only penetrate the top four centimeters of the skin. A major achievement of the current project is that the scientists succeeded in finding a way of using radio-frequency waves (which penetrate the body easily) to vibrate the carbon nanotubes.

The concept was proven practical in successfully conducted experiments on a tumor in a rabbit’s liver. The nanotubes were injected into the tumor and treated with a radio-frequency for two minutes. As a result, the cancerous cells were killed. This was the first time carbon nanotubes were used in a living creature rather than on a cell culture.

There are still some unresolved issues that must be overcome before this development can be put into use. The main problem of this technique is the killing radius; this radiotherapy treatment kills cells in a radius of 2-3 millimeters around the tumor, a killing zone that must be decreased. Another issue is the specific targeting of the nanotubes to the cancer cells. In this experiment, the nanotubes were injected into the tumor. Injection might not always be practical or accurate. Therefore, another way of targeting the nanotubes, such as using specific antibodies, is currently under research.

The targeted radiotherapy using carbon nanotubes will probably reach the clinical trials phase in 3-4 years. So far, only a proof of concept experiment was demonstrated and more research needs to be conducted before the method can be widely used.

More information on the research can be found on the Texas M. D. Anderson Cancer Center website.