Medical physicists at the University of Virginia have created a novel way to kill tumor cells using nanoparticles and light. The technique, devised by Wensha Yang, an instructor in radiation oncology at the University of Virginia, and colleagues Ke Sheng, Paul W. Read, James M. Larner, and Brian P. Helmke, employs quantum dots. Quantum dots are semiconductor nanostructures, 25 billionths of a meter in diameter, which can confine electrons in three dimensions and emit light when exposed to ultraviolet radiation.

Yang and his colleagues realized that quantum dots also give off light when exposed to megavoltage x-rays, such as those used in cancer radiotherapy. That property, the scientists realized, makes quantum dots an ideal mediator in therapies employing light-activated compounds to treat cancer.

A compound called Photofrin is the only photosensitizer currently approved by the FDA. Photofrin is absorbed by cancer cells and, upon exposure to light, becomes active and kills cells. It is currently used to treat certain kinds of shallowly located tumors, but Yang and his colleagues realized that combing Photofrin with quantum dots could create an efficient method to kill even deeply seated cancer cells.   Read More...