These treatments attack both cancer cells and healthy cells, exposing patients to serious side effects. They’ve developed materials capable of converting near-infrared light, or NIR, efficiently and safely into heat that can be highly targeted against cancer cells. Their materials are tin oxide (SnO x ) nanoflakes, tiny particles that have a thickness of less than 20 nanometers (a nanometer is one-thousand-millionth of a meter). A photothermal therapy is a noninvasive procedure that heats up cancer cells in order to destroy them. It works by infiltrating cancer cells with materials that absorb light and turn it into heat—in this case, the SnO x nanoflakes—which can be designed so that they accumulate specifically in tumor tissues.