 I'd like to start with an image suggested to me by a friend and colleague at Princeton, Cliff Cranquin, which is that we can imagine an alien spaceship landing here at the World Economic Forum full of the most amazing technology, right? Self-healing materials that can be reprogrammed over and over again to carry out different functions and produce different sorts of structures. And if this happened, we would all be desperate to understand how this amazing alien technology works. So this is indeed the world that we live in, and that alien technology is biology itself. So as a biological engineer, I really view cells as programmable devices. Every cell in our body is a programmable device that we can use to carry out complex functions. Cells can be reprogrammed and undergo huge structural changes during life, and they can produce materials like spider silk that are even tougher than Kevlar. Also, these sorts of approaches are actually really relevant already in the clinic. So in this amazing new technique of T-cell immunotherapy, it's possible to take cells out of a patient, introduce designer receptors that allow them to hunt down and track cancer cells, and put them back into the patient, in some case just melting tumors away. But how do we actually go about programming biology? How do we go about giving instructions to a cell to tell it to move to a certain location? And when it gets there, divide or differentiate to say a muscle cell or a neuron, this is really challenging because cells are, in some sense, wet computers whose programming language we're only beginning to understand. And instead of transistors, the circuits in these cells are proteins that might wink on and off or move from one location to another or assemble in little miniature machines and little nanoclusters like oil and water. And moreover, even if we knew what program to deliver, the tools that we have in biology to actually program inputs are incredibly rudimentary. So using even the best drugs, we can't add a drug to one cell and not affect its neighbors to turn things on only in that cell at one time. And even with the amazing revolution of genome editing, we still are not able to do anything other than make a permanent modification. So we can't control this when and where we want. What if instead we could use light as an input to cell biology? Light can be focused with exquisite precision and can be turned on and off as quickly as we please. And due to decades of research by plant biologists, we have a huge toolbox of light-sensitive proteins that we can modify and put into any cell and tissue of interest. For some of you, this might sound familiar. Light control in biology is what's called optogenetics, and it's really made amazing revolutions already in neuroscience. Using light-gated ion channels in brain, we can actually control movements, memories, and many more things inside animals and potentially even in people. But of course, the power of optogenetics goes far beyond in neuroscience. There are many more types of cells out there than neurons and many other processes than in the brain. And so my laboratory uses light-gated proteins to actually move, to stick to each other or catalyze chemical reactions to be able to move proteins around inside a cell or even assemble miniature factories to synthesize natural products of interest. And of course, the next step, once you have a light-gated protein, is to be able to wire this up to control any cell behavior that you're interested in. So one example is that we might be able to take a protein that controls cell motility and cell movement, wire it to a light-sensitive module, and then every time we shine light on a cell, we can move it when and where we want, like a cat following a laser pointer. So I'm gonna tell you a little bit now about how we can use these sorts of approaches for a couple of different applications in tissue engineering and cancer and even in metabolic engineering. One of the things my lab would really like to do in a long-term sense is the idea of being able to program and repair tissues and organs. For that, we actually look to nature and how this naturally happens during embryogenesis. In the embryo, there are proteins that actually act as sort of zip code proteins or compass proteins that tell cells where they are and then therefore what to become. So one of our immediate goals was to actually be able to make light-controlled versions of these zip code proteins so we could turn on different organizational programs when and where we want in the embryo. So here are examples of two of those zip code proteins that now with just a projector screen and an LED and a microscope, we can actually turn them on when and where we would like to. And this has already taught us some basic rules now about how to actually build an animal. So it turns out that during natural development, the embryo undergoes a series of very complex but very reproducible folds and shape changes in order to sort of build the structure of the adult animal. We found that one of these zip code proteins that we can control actually controls when and where those folds happen. And so now by shining light on different areas of a live embryo, we can actually play origami with it and sort of fold it up in any novel pattern that we want to to see how that will affect the organism's development. Another application we're thinking about a lot is in the context of diagnosis and treatment of cancer. So it turns out that cancer is a disease in which the pathways that control cell growth become rewired so that a cell will grow in environments where it normally wouldn't. And we imagine that we might be able to diagnosis by actually probing the inputs to these growth pathways with light, measuring responses, and seeing cases where the inputs and outputs differ in a normal and cancer cell. We indeed found examples where normal and cancer cells differ and where treatment with appropriate chemotherapy drugs actually could turn the cancer cell signal processing back to that of a normal cell. And now we can envision all optical diagnosis where we might be able to probe entire functional processes in a cancer cell, even detecting mutations that we haven't yet identified in other methods to be able to identify which drug optimally take. Of course, this is only the beginning of this very exciting new field. There are many other approaches we can imagine in the future. Right now it's very exciting to think that we can go beyond light to other sorts of fields like magnetic fields or ultrasound to be able to address cells deep inside an organism and program their behavior, or even to do away with this input control altogether and upload our inputs directly using synthetic biology, which I'd be happy to talk about later. Thank you very much.