麻豆传媒

(Image: Chris Crisman)

Tell me about your bionic legs鈥�
I have a company that produces what I鈥檓 wearing: the . For the first time in history we鈥檝e normalised walking speed and its energy cost. In other words, if you simply measure a user鈥檚 speed and metabolic energy expenditure, you can鈥檛 tell whether they have bionic legs or biological legs. That鈥檚 especially important because conventional technology used on people with leg amputation makes them limp, which causes musculoskeletal stresses that lead to joint disease and many other secondary conditions. True limb bionics eliminate limping and solve these very costly secondary conditions. Typically when we fit the BiOM prosthesis to a person, if they have hip pain, knee pain or back pain it is reduced in days.

Could such bionics benefit people in general?
Actually, we have developed bionic technology for people with complete biological limbs. Last year, we were the first research group to build an autonomous leg exoskeleton that significantly reduces the metabolic cost of walking to a person without a leg condition. It鈥檚 an artificial calf muscle, which supplies about 80 per cent of the power to walk. So a person with a normal physiology could put on these exoskeletons and walk using substantially less energy.

It鈥檚 so profound in its augmentation that if you wear it just for 20 minutes and take it off, your legs feel heavy and awkward.

Who do you see using these?
Soldiers, hikers, athletes, anyone. Imagine a world where our physicality doesn鈥檛 decrease as we age. The number one reason your grandparents can鈥檛 get around is knee osteoarthritis, and the biomechanical cause is believed to be a degradation of calf muscle power. With bionics, we can put 18-year-old calf muscles in (or on) everyone, regardless of their age, and potentially solve this big mobility problem in the elderly. If our biology continues to have the typical age-related degeneration, bionic technology can make up the differential.

The best marathon time of your life could be when you鈥檙e 60, after you started running marathons when you were 20. Imagine how such future technology will affect running times, jumping heights and all types of athletic performances.

Isn鈥檛 it cheating to use technology like that?
The idea here is to use technology to maintain a human鈥檚 inherent biological physicality, a notion that most people would accept. One can imagine a world where people wear bionics just so that when they run and train they don鈥檛 have enormous stresses on their biological joints. We are clueless about our own bodies. We have no idea when we鈥檙e about to injure ourselves. Sensors in the machines can give us that awareness and tell us that we need to stop or do something different 鈥� or they can lower the physical stress for us.

Tell me about your vision to connect bionic devices directly to the human nervous system.
Prostheses and exoskeletons are conventionally controlled by electrodes on the skin that detect the electrical activity of muscles. But this approach is kind of a laboratory trick, with limited functionality for clinical applications. One reason is that if I left here and ran two miles, I could fill a whole glass with my sweat. Current skin-surface interfaces will not survive, or produce consistent signals, in such a harsh environment. So our goal is to get information in and out of the peripheral nervous system in a more direct manner 鈥� invasively.

Aren鈥檛 other groups are already doing this, by implanting electrodes directly into nerves?
The problem with approaches that pierce the nerve is that nerves complain loudly. It鈥檚 just not a viable, sustainable option in my view.

So what鈥檚 your solution?
What we are discovering is that you don鈥檛 need to pierce the nerve, because the peripheral system is remarkably flexible. If you take a muscle that doesn鈥檛 have a nerve and then you place a cut nerve close to that muscle, the nerve will grow and sprout and innervate the muscle. It鈥檚 a very robust and repeatable phenomenon. So we are creating an interface that exploits biology by growing nervous tissue through or around synthetic materials, closing the loop between human and machine. The interface would detect nerve signals that reveal a user鈥檚 intent to move a prosthesis, for example, or could transmit sensory information from a prosthesis into the body through the nerve.

鈥淥ur interface uses biology to close the loop between human and machine鈥�

How would the signals from the nerve connect to the artificial limb?
That鈥檚 a key question. Once you have an interface to the nerve, you鈥檙e going to end up with a bundle of wires, so how do you get the information in and out of the body? Many researchers are pursuing a wireless approach, where implanted electronics communicate wirelessly with a wearable robot.

I think it鈥檚 compelling to consider wired approaches, because you could transmit information at an enormous rate. Then there would be an external skin patch where all the communication and processing takes place. And you could make the patch beautiful; it could be like a tattoo, right? In my own body I would want such a patch on my thigh. I鈥檇 have wires in and out of my peripheral nervous system passing to and from the patch, providing two-way, wired connectivity to any external machine.

What other conditions might your devices be useful for?
We鈥檙e also doing work with other limb disabilities, such as paralysis. For a person with a spinal cord lesion, you could in principle put stimulation technology on nerves for muscle activation, along with muscle sensors that we鈥檙e also working on to measure muscle dynamics. You could have a synthetic, external spinal cord.

This sounds incredibly futuristic鈥�
Bionics is just getting started. What I鈥檓 wearing here is going to be laughable 20 years from now 鈥� absolutely laughable. So if you think stuff is cool now, it will become extraordinary 鈥� and disability will end, I鈥檇 say, by the end of this century. And I think that鈥檚 a very conservative statement. At the rate technology is progressing, most disability will be gone in 50 years.

Some people might take offence at the idea of having to fix all disability.
I鈥檓 upset today when you have a human being who is blind, can鈥檛 hear, can鈥檛 move. Such human limitation is what I find deeply offensive. If a person desires to be hearing impaired and loves that culture, wonderful. A person can choose not to use hearing prostheses. But if a person wishes to hear Mozart, I think society should work hard to give them that freedom. It鈥檚 about human rights. If a person wants to run but has paralysed limbs, let鈥檚 give her that right.

This article appeared in print under the headline 鈥淲elcome to the bionic dawn鈥�