One of the most difficult types of cancer to treat is brain cancer. One of the reasons that brain cancer is so hard to treat is that the blood-brain barrier prevents most particles from getting into the brain. A group of researchers has devised a method of using nanoparticles to paint tumors in the brain of infected mice.

Once the nanoparticles cross the blood-brain barrier, they are able to attach to tumor cells and give surgeons a much clearer picture of where the tumor stops and healthy brain tissue starts. The nanoparticles cause the tumor to glow under MRI and optical imaging.

Researcher Miqin Zhand said, "If we can inject these nanoparticles with infrared dye, they will increase the contrast between the tumor tissue and the normal tissue. So during the surgery, the surgeons can see the boundary more precisely. We call it 'brain tumor illumination or brain tumor painting. The tumor will light up."

The nanoparticle the team created is devised form a component of scorpion venom called chlorotoxin. The toxin had molecules that were florescent bound to its surface.

Other researchers are using nanotubes to more effectively treat cancer. Researchers have been injecting nanotubes into tumors and then hitting the nanotubes with a laser to cause them to heat up. The process has been used to kill kidney tumors in 80% of mice. The nanotubes are exposed to laser-generated near-infrared radiation after injection, which makes the nanotubes vibrate. The vibration causes heat and kills the nearby cancer cells.

Researcher Suzy Torti form Wake Forest University School of Medicine said, "You can actually watch the tumors shrinking until, one day, they are gone. Not only did the mice survive, but they maintained their weight, didn't have any noticeable behavioral abnormalities, and experienced no obvious problems with internal tissues. As far as we can tell, other than a transient burn on the skin that didn't seem to affect the animals and eventually went away, there were no real downsides – that's very encouraging."