The technique works by inserting microscopic synthetic rods called carbon nanotubules into cancer cells. When the rods are exposed to near-infra red light from a laser they heat up, killing the cell, while cells without rods are left unscathed. Details of the Stanford University work are published by Proceedings of the National Academy of Sciences. The next step was to find a way to introduce the nantubules into cancer cells, but not healthy cells. The researchers did this by taking advantage of the fact that, unlike normal cells, the surface of cancer cells is covered with receptors for a vitamin known as folate. They coated the nanotubules with folate molecules, making it easy for them to pass into cancer cells, but unable to bind with their healthy cousins. Exposure to the laser duly killed off the diseased cells, but left the healthy ones untouched.