 This is green fluorescent protein. You can probably imagine why I'm showing it to you It has a helix in the middle surrounded by a beta barrel This protein is interesting because it is a natural Compound that gives rise to fluorescence meaning that if we radiate it with one type of light it tends to well it emits Green light. That's why it's called green fluorescent protein if you didn't catch it Not only that by changing certain groups amino acids here and everything we can make this fluoresce in a bunch of different colors essentially by changing small groups Apart from the fact that it's fun to play with color. This has been a remarkable discovery in science This is used in a ton of biochemistry Experiments and everything just to detect whether things are for say on the inside or the outside of a cell Cheap and efficient and we don't have to introduce any artificial compounds and you can do even cooler things with it This is a jellyfish that occurs in nature that expresses clearly green fluorescent protein and again you're seeing the bioflorescence here Roger Chen came up with the idea that maybe we can take those proteins and start Injecting them in the body or so and use that for artificial applications and Roger who sadly died much too young a few years ago His lab started to expressing all these different varieties and different colors and again this small petri dish It's entirely full of green fluorescent protein in different strains What they then were able to do is that they were able to take this to the clinic in particular the surgical labs and that you can use this to Inject and really color different types of tissue because if we now combine these proteins with a receptor or something That would make say the red one bind to one type of tissue While the green one binds to a second type of tissue and the yellow one to a third type of tissue We can do this imagine you're a surgeon and you're gonna cut out a cancer tumor. Here is the cell. Please cut out the tumor That's not the entire easy right and literally this is how a surgeon see it With a lot of skills you might be able to see the tumor parts here. I certainly can't Armed with green fluorescent protein developed in Roger's lab You see this instead cuts the green parts a Five-year-old could do this, right? This is remarkably cool. There's only one problem here Among all this stuff you might have some nerve cells and you sure you definitely want to cut out the entire tumor But you would at least as far as possible. You would like to avoid inflicting nerve damage, right? So let's bring out a second copy of green fluorescent protein that binds specifically to the nerve cells so here you see well up on the upper right you see the White light pattern and I think in B here You're seeing how we call it the nerve cells and then eventually you can develop C Particular might be the yellow fluorescent protein That's bound to the Axons but basically as a surgeon you're gonna get a coloring book here So cut green but not yellow or blue. It's certainly not perfect Then you might still make a mistake, but it's completely amazing that you can color tissue