 Today I'm going to talk about the emerging field of human bionics. Specifically, I'll describe research underway to advance bionic limbs and the implications of such research on disability and human augmentation. How is human bionics defined? Human bionics seeks to advance biologic or synthetic constructs that attach to the body or implanted inside the body that normalize or extend physiological function. Bionic researchers contemplate a future in which technology is no longer comprises lifeless tools from our minds and bodies. A future in which our built world has been carefully integrated into nature. A world in which what is biological and what is not, what is human and what is not, what is nature and what is not will be forever blurred. You know, it's interesting. We understand the synthetic world more than we understand the cells and tissues that make up our bodies. Years ago with my colleague Bob Dennis, a tissue engineer, we set up to build what we called an actin-miasa machine, a swimming robot. It's a hybrid machine. It's unusual because it's powered by living muscle tissue. Because the science of organ maintenance had not been perfected, our machine only lived for 48 hours. I predict one day we will understand biologic constructs as well as today we understand synthetics. In that future, when the architect designs and builds, she will ask, should this part of the device be polymer or should it be skin? Should this part of the device be shape-memory alloy or should it be skeletal muscle? In that future, hybrid machines such as our actin-miasa machine will live on as part of the built world, the built environment, a new nature. Today we live in a world where disability is commonplace. The level of human suffering is beyond all comprehension in the world. So many people have disabilities and a poorer quality of life than they seek. The field of bonnix imagines a future where that's not the case, where largely disability has been solved. The science and technology that will enable the elimination of disability after disability will also, I believe, set the technological foundation for human augmentation. Recently with colleagues Ed Boyden, Bob Langer, and Joe Jacobson, we've established at MIT the Center for Extreme Bonnix. The center has been and will continue to focus on four critical areas to mitigate disability. Program Mon is brain IO, getting information in and out of the brain. Boyden is developing very dense arrays that will go into the brain. Second program is getting information out of the body. A goal there is an interface to peripheral nerves to get high fidelity, efferent afference signaling, mainly for the control of external artificial limbs. And thirdly is how do you build synthetic body parts that emulate the mass and dynamics of the biological counterpart? So, bonnix arms, legs are examples. And fourthly is the area of regenerative medicine. For example, how can one repair a spinal cord lesion to restore functionality, as was shown in this animal model. It's critically important to deeply understand how humans work from our limbs to our brain. How does it all work? As you can see, I'm wearing two artificial limbs. I'd like to describe how they work today. And then I'm going to kind of talk to you about how I want them to work. 20 years ago what I'm wearing here will just simply be laughable, but it's a start. So the legs have six microprocessors, small computers, and 24 sensors that measure positions and accelerations and forces and whatnot. That sensory data goes into those computers as microprocessors. And the microprocessors run algorithms that control a muscle tendon-like artificial actuator, a motor with a series compliance. And when I walk, what we've done is put forth algorithms that enable me to walk without much training. It's very natural and very simple for me to walk. So how did we do that? Again, the science is very important. We advance mathematical descriptions, and we ask questions such as what are the muscles doing in the leg? How much energy is the tendon storing? How the muscle is being controlled by the nervous system? And that informs what we build and how we program what we build. Here's part of the control circuitry that's running in the leg. We have a physical description of the muscle tendon, and we input sensed position and speed of the bonnet joint into that, and it informs us what this virtual muscle, its length, and its speed. And then we have a reflex control. We know scientifically that the dominant reflex of the human calf muscle is a positive force feedback when the foot is in contact with the ground. Simply works as the greater the force born on the calf muscle in the Achilles tendon, the greater is the activation of that muscle. So we actually program that on chip in the bonnet limb in the synthetics. The greater the torque that I apply on the device, the greater is the force of those virtual muscles. The greater is the muscle activation, and then we tell the motor to output more current. So even though the limbs are obviously synthetic, they move somewhat like a natural limb. That's the goal, that it doesn't really matter that they're synthetic because they move like flesh and bone. This is a really compelling strategy. One reason is one gets emergent behaviors. We didn't study running at this time. We studied walking, but it turns out those reflexes are really effective in running and well. This is a US soldier lost a limb, and this video is taken shortly after he was fitted with a prosthesis. Those same reflexive capabilities gave him that functionality. So you get this emergent rich behavior when you carefully look at the biophysics and design the mechanism based on that science. So what about a neural signal? What would we do if we could have information from muscles and nerves and maybe even the brain? How would we use it? Well, what we're exploring is taking the same control, reflexive control framework and using the neural signal to affect the sensitivity of the model reflexes. So how this might work is I am amputated here. My biological leg comes to here. If I relax my remaining calf musclature, the sensitivity is very, very low. I don't get power from my bionic limb, but if I really fire my muscles, I get a lot of power and energy, and I can really get a lot of energy if I run. Predominantly in the field, that neural signal from the peripheral is gotten using a surface electrode, which has many, many issues. The most obvious is if I were to leave this stage and if I were to run for 30 minutes or so a few miles and come back here, I could fill an entire glass with sweat. So it's hard to imagine a surface electrode working in that environment. So we want to go inside the body. We want to develop, as a field, we want to develop implants that get these signals. So there's a compelling biological phenomena. If you take a muscle shown here as M, a muscle that needs a nerve, a denervated muscle, and you put a nerve next to that muscle that's transected, that's been cut, time and time again the nerve will grow again, regenerate, and innervate that muscle. It's a very robust phenomena. So you see the nerve stump, and you see the sprouting going to muscle M. So we want to exploit that capability. So here's a set of experiments where a nerve is cut and we took skin and muscle cells, put it next to the transected nerve. The nerve grows, does accrued segregation, and innervates the skin and muscle end organs. The idea here is that the muscle amplifies the nerve signal. We can get motor information from the muscle side, and in principle potentially stimulate the cutaneous side, take measurements on the bionic limb, stimulate, and hopefully in the future give a person with limb amputation this sense of contact or touch. Imagine a large tube with a bunch of very, very small tubes inside, and each of the small tubes have a diameter of about 100 microns. So you have a proximal transected nerve. On the other end of the array we put those tissues, skin cells, muscle cells. What we want is the nerve to grow through the array attached to the end organs. Within each channel we can put electrodes that sense motor information coming down from the spinal cord. Adjacent channels might be sensory, where we can stimulate and reflect sensory information on the external device into the nervous system, closing the loop between the human machine. This just shows a section of the array showing that we in fact can produce growth through these channels, and re-intervention of a target end organ on the other side. How do we plan to get information in and out of the body? Is it going to be wired? Is it going to be wireless? I think a wired approach is very, very compelling for a number of reasons. One is the enormous ease with which one can get data in and out of the human body. This is an approach that's been long pursued in the field called osteointegration. The idea here is to take a synthetic implant, say like titanium, and insert it into the residual skeleton. One advantage of that is you can do mechanical loading directly into the skeleton and not use what I'm using here today, an external socket, to exert those forces on the residual end. Working with a collaborator Mark Picken, we believe we've solved the infection problem. Where the titanium has an optimal geometry, where the skin cells would adhere to that titanium surface. Also compelling about this approach, you can make that titanium shaft hollow and run wires through it. You can run wires from muscles inside the body out to the bionic limb, and from the bionic limb through the conduit into the body for that bi-directional communication. Here's a kitty cat that is missing a hind limb and using this skeletal conduit. A lot of pets lose limbs, so what I'm saying will not only benefit humans in the long term, but also cats and dogs. Now I'm going to transition from prosthetics to orthotics and exoskeletons, so what is that? An exoskeleton is a robot that wraps around a limb. That limb can be a limb of normal physiology, or it can be a limb with some pathology. I'd love this photo. I found this on the internet. To me it says, okay, we've invested so many dollars in society to make wheeled vehicles better and better and better. Carves, wheelchairs, segues and whatnot. My hope is in this century we invest more dollars to make our own bodies, our own morphologies, more efficient, stronger. So there's different types of exoskeletons. One is in series with the leg. It lengthens the leg. This is the power skip. It was developed by some inventors here in Europe. Clearly, if you're crazy enough, it augments jumping. If you take that person and measure their amount of food energy to go from point H to point B, wearing these devices, it'll be higher than if the devices were not worn. So as a transportation device, it's a problem. Also, it's difficult for me to imagine anyway, strapping these on and running across a very rough terrain, a rocky path with logs and without tripping, because the foot-ankle, foot-ground interaction has been disrupted. One can have a series device lengthening the leg that does not disrupt stability. Often, the amount of energy storage and actuation is limited. This is a shoe that I developed years ago, and after about a decade of research, we only got a few percent decrease in metabolic rate. The exciting stuff happens when the exoskeleton runs in parallel with the leg. This is my favorite patent I've ever found. It was at the U.S. Patent Office and came across this. The inventor is Yagin. You see the date 1890. So Yagin had this vision of these exoskeletal body suits, and his goal was to augment the Russian army. He actually worked before communism under Zoroastrian. What you see here are highly compliant leaf springs running up the legs, and then underneath the forum there is a clutch, and Yagin envisioned that as a person would run and enter in the aerial phase of running, they would unlock the clutch, which disengages the spring so a person could retract their legs or flex their legs for foot clearance. To my knowledge, this was never built, you know, microprocessors and sensors and whatnot did not exist in 1890. This mission of to build an exoskeleton, then augment something as common as human walking and running is over 100 years old. Recently, at my lab at MIT, the Center for Extreme Bionics, we actually succeeded in this goal. This is a foot ankle exoskeleton. This, the human wear has no limb pathology whatsoever, a completely normal physiology. But nonetheless, these exoskeletal structures augmenting the extension of the ankle, power plant reflection, injecting lots of mechanical power into the gate, reduce the amount of food energy to walk by about 10%. The augmentation is so profound that when a person wears this device, after only 20 minutes of walking around, when they take it off, their own normal limbs feel heavy and awkward. So these future exoskeletons, we want to be like the bicycle. They have an augmentative effect, but the human inside does not degrade. This is just a graph showing how the device works and some data. The device inputs a lot of mechanical power, similar to a normal biological ankle. So when you inject that mechanical energy into the gate, there's a reduction in metabolic cost. How do we control this thing? Again, I imagine virtual muscles and tendons controlled reflexively. But here, because it's an exoskeleton, there's already a biological limb there. So you can imagine putting virtual muscles on the outside of the body, but they behave and are controlled similar to physical muscles. For this foot ankle device, we're looking at the soleus, attaching a virtual soleus in the external body so that the actual soleus of the human can turn off in an output less energy. We're also looking into running. Again, this person does not have a disability. The goal here is to reduce stress throughout the muscle skeletal system. Hopefully in the future, people wear these devices as a preventative measure to reduce the chance of getting a knee injury, for example, or if one has a knee injury to continue one's athletic career by having an exoskeleton that reduces the loads. I believe in a decade or two when we walk down the street, we'll routinely see people wearing machines, exoskeletons. How does all this current technology and the technology that's coming down the pike, how will affect human identity? How a person sees their own body and that body may be unusual with limb amputation or paralysis or whatnot? And how society views person's unusual bodies. So this is an image taken of me shortly after my limbs are amputated in 1982. What do you see here? Do you see a crippled? Do you see weakness? Or do you see extraordinarily exciting potential? I asked my rehab doctor a few weeks after my limbs are amputated. What would I be able to do with my new body? And I told him I want to be able to ride my bicycle. I want to be able to drive my car. I want to be able to return to my chosen sport of mountain climbing. And he quickly said you'll be able to drive a car but you'll need hand controls. And he said but you will not be able to ride a bicycle nor return to climbing mountains. He was wrong from my perspective today because he viewed my body as broken. And he viewed technology, current technology is forever stagnant, will never be upgraded, will never change. I was very upset obviously when he said I wouldn't be able to do all these things I wanted to do. But quickly I realized that the artificial part of my body was represented potential. It could be anything that I could imagine or the scientific world could imagine. Perhaps one day they may be so sophisticated these bionic limbs that I'll be able to run and run faster than persons with biological limbs. Perhaps the limbs one day will not only have a human-like structure or shape, maybe they'll have wings and I'll be able to fly. So as a young man I had all these dreams and began imagining beyond limitation maybe technology will become so advanced that we can eliminate disability across many forms of brain and body condition. So because of inadequate technology today disability is just commonplace. The basic science of technology that will enable the elimination of disability will also enable, I predict, human augmentation. The ability to use technology to extend beyond innate capabilities. Bionics indeed has tremendous potential for society but not without risk. As a society in my view we need to put forth public policy at a rate commensurate with this ever-expanding augmentation technology to further incentivize bionics that improve quality of life but also to mitigate unattended nefarious uses of augmentation technology. We the people have in our creative power the authority to end disability in this century and simultaneously adhere with absolute obedience to the principles of human diversity and individual freedoms. So I'll put a period there and I'd love to begin a conversation.