Prosthetic body parts have been around in many shapes and forms for thousands of years. But up until just a few decades ago, they were often uncomfortable, provided little to no control for the user and didn't look all that great either.
Fast-forward to the present day and thanks to advances in medicine, robotics and neuroscience, a number of bionic body parts have been developed that have the power to be truly life-changing for those who need them the most, from a bionic eye to an artificial kidney to a thought-controlled robotic leg.
The most advanced bionic body parts tend to be arms and legs, because they're the easiest to develop and there's the most need for them. But over the past few years scientists have created fully working body parts that provide sensory feedback, like a bionic ear, as well as bionic organs, like a pancreas and kidney.
Separating bionic fact from bionic fiction
Many of these bionic body parts are still in the early stages of production and are far from being rolled out to those that need them. That's because there are all kinds of challenges to consider – not only the materials the body part is made from, but also integrating it into our bodies so it isn't rejected, as well as developing ways for it to become part of our nervous system, so it behaves like any other limb or organ.
Add to that the huge raft of financial, ethical, moral and political implications of enhancing our bodies with the help of technology. But it's easy to overlook all of these concerns when the tech sounds so exciting, promising and like the robotic hands, arms and whole bodies of our sci-fi dreams.
"The public perception of bionics is vastly different from the reality of prosthetics," Kia Nazarpour, director of expertise in bio and environmental engineering, at Newcastle University, told us. "That's thanks to science writers and researchers who showcase their work in a sci-fi oriented way to increase publicity."
With that in mind, we've collected together just a few of the most interesting advances in bionics, from the life-changing to the cheap and effective.
The Bionic Eye
Scientists and researchers have been creating prototypes for bionic eyes since the early 80s. Right now there's no smart eyeball you can simply switch out for your own. Instead, there's what's known as retinal implants or retinal prosthetics. A few companies, including US-based Second Sight and German company Retinal Implant, have been tirelessly testing combinations of smart lenses and brain implants in a bid to restore the sight of blind patients to varying degrees of success.
Second Sight's most recent foray into the bionic vision space is a system called Orion, which consists of a miniature video camera mounted on a patient's glasses. The device then sends images via a series of electrical pulses, which are transmitted wirelessly to an array of electrodes on the surface of the patient's visual cortex.
Orion isn't being rolled out to the general public quite yet, but early trials have shown that the system can result in the perception of patterns of light. By bypassing the retina and optic nerve, the system can restore useful vision to patients who are completely blind because of causes such as cancer, trauma, glaucoma or diabetic retinopathy.
There have also been a number of other bionic enhancements made to benefit our eyes, but that are focused much more on what's going on at the front of our eyeballs than behind them.
A company called Acumetics Technology Corporation has been testing a Bionic Lens. If you're squeamish look away now, because this lens has been engineered to replace the lens that sits on our eyes. Those fitted with a new Bionic Lens will experience a number of improvements to their vision, including perfect eyesight and crystal clear vision – even at a distance. The company hopes to add more futuristic features over time too, like displaying your smartphone screen directly on your eye.
Although some of these benefits are meant to supercharge the eyesight of someone who doesn't have any current problems with their vision, it's also expected to vastly improve the vision of those who suffer from eye problems directly associated with the lens, such as cataracts or glaucoma.
The Hero Arm
Lots of bionic arms have made headlines over the past few years, most notably the i-Limb Ultra from Touch Bionics. But one that's caught our eye for different reasons is the Hero Arm from Open Bionics, due to its focus on bringing advanced, light and low cost prosthetics to people that really need it.
According to Open Bionics, the Hero Arm aims to be three times more affordable than other multi-grip bionic arms. Granted that's still bound to be too expensive for many people, especially those in developing countries, but it's a solid step in the right direction.
The arm itself is custom-built and can be made to fit amputees as young as eight years old. Although it's a considerably cheaper option than other bionic arms, a lot of the most important functionality is built inside the prosthesis, including sensors inside to detect muscle movement, giving users control over the arm, plus lights, sounds and vibrations to provide feedback – all weighing less than 1kg.
What's more, Hero Arm is one of the few advances on the list that'll be widely available to buy in the coming months and has already been tested in the US and Canada.
The Bionic Fingertip
Although there are advanced bionic hands and arms more readily now than ever before, something that's tricky to replicate is our sense of touch.
Prostheses like the Hero Arm are available to provide some touch feedback through the use of lights and vibrations, but it's much more of a challenge to actually replicate that sense of touch in someone's brain.
Back in 2016, scientists from EPFL (Swiss Federal Institute of Technology) and SSSA (Sant'Anna School of Advanced Studies) in Italy were successful in giving an amputee a bionic fingertip, which allowed him to feel the sensations of rough and smooth textures.
The fingertip was connected to a series of electrodes that had been surgically implanted into the nerves in his upper arm. So when his fingertip moved over a rough surface, its sensors inside were able to generate an electrical signal that was then translated into a series of electrical signals in order to 'mimic' the language of the nervous system.
The Bionic Knee Brace
Granted it may not sound like the most exciting bionic body part, but with huge numbers of the population suffering from knee problems, this could well be the most needed.
Developed by Spring Loaded, the bionic knee brace isn't an all-singing, all-dancing robot knee. Instead, what makes it effective is its simplicity, using the body's own weight and movements to power it. So when you bend your knee it stores the energy, then returns it to your leg as you straighten it back out again.
That process sounds simple, but trials show the brace can reduce load on the knee joint by 64%. That can lead to all kinds of uses, from reducing fatigue and preventing injury for minor problems through to reducing pain and dramatically improving mobility for those with more serious, long-term knee problems.
"Our team took inspiration from aircraft landing gear to develop a unique hinge mechanism powered by a miniature liquid spring that reduces forces across all three compartments of the knee while enhancing strength," Keith Gordon, director of marketing at Spring Loaded, told us.
"Our technology circumvents many of the challenges relating to price and convenience faced by externally-powered alternatives like exoskeletons by redirecting energy created by the wearer's own body to help at crucial moments," Gordon explained.
Although the bionic knee brace isn't the most sci-fi bionic body piece of tech being developed, its design is more affordable and convenient than other solutions, which is what's important when it comes to improving the most lives.
It's all well and good creating new limbs and new eyes, but if they don't connect up to our brains in the right way, they're not going to feel natural or effectively provide amputees or people with disabilities with the mobility and sensations they need.
Enter brain-computer interfaces. Put simply, a brain-computer interface (BCI) is a communication pathway between an enhanced brain or wired brain and an external device.
Building brain-computer interfaces, also known as neuroprosthetics, is central to creating prosthetics that play nice with your brain, enabling users to feel (or see, or touch, or smell, or taste) the world around them with the prosthetics, just like they would with their own limb or organ.
We spoke to Dr. Steven M. Chase, an associate professor at the Center for the Neural Basis of Cognition from Carnegie Mellon University, about how he's currently working to make prosthetics behave like they're a part of our bodies.
"We're using brain-computer interfaces to study learning," he explains. "We are finding that, given enough time, we can teach subjects to generate entirely new patterns of neural activity."
It's this new neural activity that's a central component in adding new body parts that can be controlled by the brain. These electrical, neural signals can convince your brain the body part is yours, allowing you to move it and, in some cases, even feel the world around you.
"We are also working on something we're calling a 'neural signal stabiliser' that can reduce, and potentially eliminate, the need to re-calibrate a brain-computer interface," Chase tells us.
Although many other researchers have created interfaces between someone's brain and their prosthetic limb, this connection is often short-lived or doesn't work the way you'd need it to day-in and day-out.
"Every brain-computer interface needs to be calibrated, which is the process of specifying exactly how neural signals will translate into movement of the device. Instabilities in the recorded neural signals cause the interface to stop working – sometimes in as little as a few hours – until the device is re-calibrated," Chase says. "This is time-consuming. We are working on a method that can extract stable signals from the unstable recordings, and thus eliminate the need for re-calibration."
The 3D Printed Heart
Bioprinting is a process that allows scientists and medical professionals to use 3D printing methods to 'print' cells and biological tissues. Over the past few years, a number of body parts have been created using bioprinting techniques, including a thyroid gland and a tibia replacement.
One of the most impressive, and life-changing, examples has been the creation of a 3D printed heart. Or a patch of heart cells, to be more exact. A team of researchers from the Heart Research Institute (HRI) in Australia have developed a way of taking cells from a patient's skin, then using them to generate stem cells, which can go on to grow into heart cells.
This patch of cells is then stuck onto a patient's heart following a heart attack. The cells actually beat, behaving just like a real heart, which enables them to repair some of the damage done by a heart attack or sudden cardiac arrest.
Bioprinting, especially of such complex organs, is still very much in its infancy and will take a long time to be rolled out more widely. As you might expect, the process of collecting skin cells, growing stem cells and printing some new heart cells is costly.
Looking to our tech-enabled future
It's easy to get swept away by some of these bionic developments. But let's not go daydreaming about a Luke Skywalker hand or perfect vision with a new eyeball just yet. Newcastle Univeristy's Kia Nazarpour warns us it's still early days. "There's a lack of evidence about what bionics work and what doesn't," he tells us. "In development of a drug, we test various versions of it in multiple clinical trials. In the bionics, trials are limited to a couple of participants."
Although there are a lot of hurdles to overcome, it'd be short-sighted to not see just how life-changing bionics could be for people all over the globe. "I'm excited about the future for this field," said Dr. Steven Chase. "We're seeing more clinical trials, and people are beginning to tackle the really hard problems of creating limbs that you can sense and feel."
Like many other experts we spoke to, Chase reiterated that one of the main hurdles right now is financial backing. "What needs to happen to make these devices a clinical reality is continued funding from scientific agencies," he says.
What's important is that financial backing and development shouldn't just be pumped into the projects that excite us, but the ones that will make the biggest difference. That's the view of Norbert Kang, a plastic and reconstructive surgeon at the Royal Free Hospital in London.
"Amputees, especially ones with multiple injuries, don't get a lot of airtime and aren't always top of the agenda," Kang explains. "This means there's no one to speak on their behalf at the highest levels of government or society. So, if anything needs to evolve, it is attitudes and financial support for this relatively un-glamorous but essential work."
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