Imitating nature might benefit fields from material engineering to urban planning, a group called the Biomimicry Institute says. Can it also improve artificial limbs?
Biomimicry is a design philosophy that guides an innovative merger of natural evolution and modern science. Professionals in the field start by investigating remarkable features of plants or animals. How can a kingfisher dive into water without making a splash? How do abalone create shells tougher than our most high-tech ceramics? Then they reverse-engineer or adapt those materials or mechanisms into designs that solve human problems.
The engineers who borrowed the kingfisher’s long beak to quiet the noisy Japanese bullet train are a prime example. Janine Benyus, founder of Biomimicry 3.8 (so named after “nature’s 3.8 billion years of brilliant designs and strategies”) describes the overall approach as “beginning to remember that organisms, other organisms, the rest of the natural world, are doing things very similar to what we need to do.”
The potential extends to amputees in low-income countries, according to Ana Carolina Alves. The multidisciplinary designer from Brazil is working toward an affordable, accessible prosthetic arm design for Latin America. Along with a colleague, Mexican designer Daniela Esponda, Alves intends to upgrade the next generation of artificial hands and arms — and make them available through 3D printing at low cost.
The pair began their project after earning master’s degrees in biomimicry together in 2015.
“When we look at nature, we are not trying to replace a hand, but to replace the function of a hand,” Alves says. They started by studying about 40 organisms. They also examined the movement of an already marketed prosthetic from a company called Enable. Then they tried to increase its functionality by applying the features of diverse creatures they’d researched.
“We found that the combination of the joints was actually key to make the movements of the hand,” Alves says. In the end, two animals — chiton and armadillo — were most intriguing in this regard. The chiton, a marine mollusk, has an oval body covered by an exoskeleton of eight overlapping shells. The armadillo, a mammal native to South and Central America, wears overlapping leathery armor plates. The two creatures’ shared anatomical feature offers the same benefits: toughness, smooth movement over uneven surfaces and the ability to roll up. The same characteristics factor into how joints work.
It’s a different approach than the ball-and-socket joints of some existing prostheses, but trying a new option is a big part of the point.
“I’ve worked with other methods in creating prosthetics and medical devices, like traditional design, and usually it’s hard to come up with something using the same basis,” Alves says. “So we look at people and we ask them what they want and what they need and how they want it and need it, and sometimes the client doesn’t know. This is the highest point of biomimicry brought for our project: It’s not demanding so much on clients to describe what they want, but to provide different outcomes for them.”
Making the prosthetics low cost is another formidable challenge. Around the world, teams of engineers are working toward higher-quality, lower-cost prosthetic devices — an arm or a leg that doesn’t cost an arm or a leg, in other words. So far, though, advancements have fallen into two categories: lower limbs that are high-quality, cheap and increasingly accessible, and upper limbs that are high-tech, but expensive and therefore out of reach for most people worldwide.
In recent years, leg prostheses development has brought universal access tantalizingly close to fruition. In India, home to some five and a half million amputees, a social enterprise called Jaipur Foot Organization has helped scale up care and lower the price of durable, comfortable legs. The organization has also collaborated with Stanford researchers on the design of the JaipurKnee, a low-cost option that increases stability and reduces the bobbing limp that earlier leg models created in wearers. The Stanford grads involved soon split off into design firm D-Rev. They’re now launching their next design, an $80 prosthetic joint that they say will be their first to roll out worldwide. Meanwhile, a group from MIT is also working on better prosthetic leg design.
Arm prostheses are also undergoing swift development. But unlike the leg, an upper limb prosthesis must recreate the complex movements of the human hand. New projects have aimed at increasing hand function; myoelectric models, which use electrodes to detect movements in the user’s muscles, are the main breakthrough. Offerings range from a grip partly controlled by a mobile app to a system that implants electrodes in the brain of paralyzed people . (One lucky American boy even has a prosthesis with a built-in Super Soaker .) But all of these are expensive (a myoelectric hand can be $15,000 or more), and most involve a complexity hard to implement in low-resource settings. A high-quality, low-cost arm remains out of reach of most amputees worldwide.
Biomimicry could make a difference, Alves says, by making a hand with no electrical components that is easier for the wearer to move than current options.
Although it will be a few years before their biomimetic product is available, a key technology already supports their prospect. “We wanted something that could be 3D printed,” Alves says. That process is becoming more accessible now. One open-source project allows anyone with a 3D printer to make a hand for someone in need for about $50. Although it doesn’t include myoelectric components, that price tag puts the option in reach for more people. And at least one user says it’s a better choice than a costlier, high-tech hand.
For now, Alves and Esponda are building partnerships with other individuals and organizations to plan and test their model. If the two succeed, their design could inform the next generation of 3D-printed prostheses in Latin America. “It’ll be a great opportunity to test biomimetic thinking towards such a challenge for people,” Alves says.
The “Health Horizons: Innovation and the Informal Economy” column is made possible with the support of the Rockefeller Foundation.
M. Sophia Newman is a freelance writer and an editor with a substantial background in global health and health research. She wrote Next City's Health Horizons column from 2015 to 2016 and has reported from Bangladesh, India, Nepal, Kenya, Ghana, South Africa, and the United States on a wide range of topics. See more at msophianewman.com.