The dreaded rabies virus may soon have a new purpose — one that involves saving rather than taking lives. Scientists are experimenting with rabies' unique method of killing brain tissue via nerve cells to find out if the pathway can be a conduit for nanoparticles which could zap brain tumors.

The novel approach comes courtesy of researchers at Sungkyunkwan University in Suwon, South Korea, who have so far been successful with mice.

But if the mice model works well in humans, brain tumors could be directly targeted, and healthy brain tissue spared.

Rabies works its way to the brain by way of nerve cells, which effectively skirts the blood-brain barrier, a membrane that is impassable by most other pathogens — but also impassable by cancer drugs, making brain tumors deadly. This year alone, the American Brain Tumor Association predicts 17,000 people will die from brain tumors.

The virus is able to make its way to the brain because of its unique rod-like shape. The researchers in South Korea, lead by nanoparticle expert Yu Seok Youn, have mimicked this rod-like shape using gold particles (which are relatively harmless in the human body) smaller than a grain of salt. Though the particles don't carry drugs, the gold rods are the perfect conduit for laser light, which can be guided to fry cancer cells while sparing healthy ones once the particles are near the cancer cells.

The laser harmlessly passes through skin and bone heating the gold particles, which radiate the heat outward — killing tumor cells. In the test mice, two mice had their brain tumors totally eradicated after seven days; other test mice had their tumors shrunk to half their original size. Youn and his colleagues reported their findings in the journal Advanced Materials.

The approach is not without some hang-ups. The exact pathway of the gold particles was not traceable, and gold particles can take some time to clear out of the liver, which might be problematic, so the researchers are urging caution. Still, if the technology could save lives, the benefits might outweigh the risks. And the researchers are optimistic they can perfect the method in time: “Researchers need to develop . . . nanoparticles, precisely and effectively to target tumors,” Youn said. “That’s my obligation.”