Illustration of the American chemist Roger Y Tsien (1952-2016). In 2008 Tsien was awarded the Nobel Prize in Chemistry along with Osamu Shimomura and Martin Chalfie for the discovery and development of the green fluorescent protein (GFP). This glowing protein has been used widely as a research tool in biology and medicine. The gene coding for it can be tagged to the genes of other proteins or viruses to study their movements within cells. They can also be used to tag cancer cells to track their spread through the body. Tsien discovered how to make GFP glow with different colours, allowing the tracking of multiple process at once.