Quyen Nguyen: Color-coded surgery TED Video

Surgeons are taught from textbooks which conveniently color-code the types of tissues, but that's not what it looks like in real life -- until now. At TEDMED Quyen Nguyen demonstrates how a molecular marker can make tumors light up in neon green, showing surgeons exactly where to cut.

Also, if by Green Fluorescent Protein you mean GFP this is also a remarkable tool but was adapted from a jellyfish rather than invented from scratch.

In 2009, a new kind of IFP was developed by Tsien's group, and further reported and described by Science. The new IFPs are developed from bacterial phytochromes instead of from multicellular organism like jellyfish. Under normal conditions, bacterial phytochromes absorb light for signaling instead of fluorescence, but they can be turned fluorescent after deleting some of the signaling parts by genetic means such as site-directed mutagenesis. In order to fluorescence, tetrapyrrole is also required, however, it's abundant in living bodies.[