Posts tagged implants

Posts tagged implants
Bionic eye prototype unveiled by Victorian scientists and designers
A team of Australian industrial designers and scientists have unveiled their prototype for the world’s first bionic eye.
It is hoped the device, which involves a microchip implanted in the skull and a digital camera attached to a pair of glasses, will allow recipients to see the outlines of their surroundings.
If successful, the bionic eye has the potential to help over 85 per cent of those people classified as legally blind. With trials beginning next year, Monash University’s Professor Mark Armstrong says the bionic eye should give recipients a degree of extra mobility.
"There’s a camera at the front and the camera is actually very similar to an iPhone camera, so it takes live action for colour," he told PM. "And then that imagery is then distilled via a very sophisticated processor down to, let’s say, a distilled signal.
"That signal is then transmitted wirelessly from what’s called a coil, which is mounted at the back of the head and inside the brain there is an implant which consists of a series of little ceramic tiles and in each tile are microscopic electrodes which actually are embedded in the visual cortex of the brain."
Professor Armstrong says is it is hoped the technology will help those who completely blind, enabling them to navigate their way around.
"What we believe the recipient will see is a sort of a low resolution dot image, but enough… [to] see, for example, the edge of a table or the silhouette of a loved one or a step into the gutter or something like that," he said.
"So the wonderful thing, if our interpretation of this is correct - because we don’t know until the first human trial - [is] it’ll of course enable people that are blind to be reconnected with their world in a way.
"There’s a number of different settings … so you could set it to floor mapping for example and it creates a silhouette around objects on the floor so that you can see where you’re going."
A challenge the designers have had to overcome is ensuring the product was lightweight, adjustable and enabled users to feel good about themselves.
"We want to make it comfortable and light weight and adjustable so that different sized heads and shapes will still manage it well and have those sort of nice aspects," Professor Armstrong said.
"We don’t want a Heath Robinson wire springs affair on somebody’s head.
"It needs to look sophisticated and appropriate, probably less like a prosthetic and more like a cool Bluetooth device."
The first implant is scheduled to go ahead next year which is expected to be followed by clinical trials, research and user feedback to the team.
The development of a bionic eye was one of the key aspirations out of the 2020 summit that was held in 2008.
Professor Armstrong says it is “amazing” that a prototype for the technology has already been achieved.
"To be honest when I heard about that 2020 conference and all of the people there, I thought it was a little bit of a hot air fest if you know what I mean," he said.
"But I’ve been proven completely wrong.
"Some of the initiatives from that, this is a major one for sure, have been brought to fruition and it’s wonderful for Australia and equally wonderful for Monash University."

Reversing Paralysis with a Restorative Gel
Some parts of the body, like the liver, can regenerate themselves after damage. But others, such as our nervous system, are considered either irreparable or slow to recover, leaving thousands with a lifetime of pain, limited mobility, or even paralysis.
Now a team of Tel Aviv University researchers, including Dr. Shimon Rochkind of TAU’s Sackler Faculty of Medicine and Tel Aviv Sourasky Medical Center and Prof. Zvi Nevo of TAU’s Department of Human Molecular Genetics and Biochemistry, has invented a method for repairing damaged peripheral nerves. Through a biodegradable implant in combination with a newly-developed Guiding Regeneration Gel (GRG) that increases nerve growth and healing, the functionality of a torn or damaged nerve could ultimately be restored.
This innovative project is now gaining international recognition. Its initial successes were reported recently at several renowned scientific congresses, including the World Federation of Neurological Societies and the European Neurological Society. And the therapy, already tested in animal models, is only a few years away from clinical use, says Dr. Rochkind.
Like healing in the womb
A nerve is like an electrical cable. When severed or otherwise damaged, power can no longer be transferred and the cable loses its functionality. Similarly, a damaged nerve loses the ability to transfer signals for movement and feeling through the nervous system.
But Dr. Rochkind and Prof. Nevo found a way to breach the gap. In their method, two severed ends of a damaged nerve are reconnected by implanting a soft, biodegradable tube, which serves as a bridge to help the nerve ends connect. The innovative gel which lines the inside of the tube nurtures nerve fibers’ growth, encouraging the nerve to reconnect the severed ends through the tube, even in cases with massive nerve damage, Dr. Rochkind says.
The key lies in the composition of the gel, the researchers say, which has three main components: anti-oxidants, which exhibit high anti-inflammatory activities; synthetic laminin peptides, which act as a railway or track for the nerve fibers to grow along; and hyaluronic acid, commonly found in the human fetus, which serves as a buffer against drying, a major danger for most implants. These components allow the nerve to heal the way a fetus does in the womb — quickly and smoothly.
Keeping cells safe for transplant
The implant has already been tested in animal models, and the gel by itself can be used as a stand-alone product, acting as an aid to cell therapy. GRG is not only able to preserve cells, it can support their survival while being used for therapy and transplantation, says Dr. Rochkind. When grown in the gel, cells show excellent development, as well as intensive fiber growth. This could have implications for the treatment of diseases such as Parkinson’s, for which researchers are actively exploring cell therapy as a potential solution.
Brain implants: Restoring memory with a microchip
William Gibson’s popular science fiction tale “Johnny Mnemonic” foresaw sensitive information being carried by microchips in the brain by 2021. A team of American neuroscientists could be making this fantasy world a reality.
Their motivation is different but the outcome would be somewhat similar. Hailed as one of 2013’s top ten technological breakthroughs by MIT, the work by the University of Southern California, North Carolina’s Wake Forest University and other partners has actually spanned a decade.
But the U.S.-wide team now thinks that it will see a memory device being implanted in a small number of human volunteers within two years and available to patients in five to 10 years. They can’t quite contain their excitement.
"I never thought I’d see this in my lifetime," said Ted Berger, professor of biomedical engineering at the University of Southern California in Los Angeles. "I might not benefit from it myself but my kids will."
Rob Hampson, associate professor of physiology and pharmacology at Wake Forest University, agrees. “We keep pushing forward, every time I put an estimate on it, it gets shorter and shorter.”
The scientists — who bring varied skills to the table, including mathematical modeling and psychiatry — believe they have cracked how long-term memories are made, stored and retrieved and how to replicate this process in brains that are damaged, particularly by stroke or localized injury.
Berger said they record a memory being made, in an undamaged area of the brain, then use that data to predict what a damaged area “downstream” should be doing. Electrodes are then used to stimulate the damaged area to replicate the action of the undamaged cells.
They concentrate on the hippocampus — part of the cerebral cortex which sits deep in the brain — where short-term memories become long-term ones. Berger has looked at how electrical signals travel through neurons there to form those long-term memories and has used his expertise in mathematical modeling to mimic these movements using electronics.
Hampson, whose university has done much of the animal studies, adds: “We support and reinforce the signal in the hippocampus but we are moving forward with the idea that if you can study enough of the inputs and outputs to replace the function of the hippocampus, you can bypass the hippocampus.”
The team’s experiments on rats and monkeys have shown that certain brain functions can be replaced with signals via electrodes. You would think that the work of then creating an implant for people and getting such a thing approved would be a Herculean task, but think again.
For 15 years, people have been having brain implants to provide deep brain stimulation to treat epilepsy and Parkinson’s disease — a reported 80,000 people have now had such devices placed in their brains. So many of the hurdles have already been overcome — particularly the “yuck factor” and the fear factor.
"It’s now commonly accepted that humans will have electrodes put in them — it’s done for epilepsy, deep brain stimulation, (that has made it) easier for investigative research, it’s much more acceptable now than five to 10 years ago," Hampson says.
Much of the work that remains now is in shrinking down the electronics.
"Right now it’s not a device, it’s a fair amount of equipment,"Hampson says. "We’re probably looking at devices in the five to 10 year range for human patients."
The ultimate goal in memory research would be to treat Alzheimer’s Disease but unlike in stroke or localized brain injury, Alzheimer’s tends to affect many parts of the brain, especially in its later stages, making these implants a less likely option any time soon.
Berger foresees a future, however, where drugs and implants could be used together to treat early dementia. Drugs could be used to enhance the action of cells that surround the most damaged areas, and the team’s memory implant could be used to replace a lot of the lost cells in the center of the damaged area. “I think the best strategy is going to involve both drugs and devices,” he says.
Unfortunately, the team found that its method can’t help patients with advanced dementia.
"When looking at a patient with mild memory loss, there’s probably enough residual signal to work with, but not when there’s significant memory loss," Hampson said.
Constantine Lyketsos, professor of psychiatry and behavioral sciences at John Hopkins Medicine in Baltimore which is trialing a deep brain stimulator implant for Alzheimer’s patients was a little skeptical of the other team’s claims.
"The brain has a lot of redundancy, it can function pretty well if loses one or two parts. But memory involves circuits diffusely dispersed throughout the brain so it’s hard to envision." However, he added that it was more likely to be successful in helping victims of stroke or localized brain injury as indeed its makers are aiming to do.
The UK’s Alzheimer’s Society is cautiously optimistic.
"Finding ways to combat symptoms caused by changes in the brain is an ongoing battle for researchers. An implant like this one is an interesting avenue to explore," said Doug Brown, director of research and development.
Hampson says the team’s breakthrough is “like the difference between a cane, to help you walk, and a prosthetic limb — it’s two different approaches.”
It will still take time for many people to accept their findings and their claims, he says, but they don’t expect to have a shortage of volunteers stepping forward to try their implant — the project is partly funded by the U.S. military which is looking for help with battlefield injuries.
There are U.S. soldiers coming back from operations with brain trauma and a neurologist at DARPA (the Defense Advanced Research Projects Agency) is asking “what can you do for my boys?” Hampson says.
"That’s what it’s all about."

Memory Implants
A maverick neuroscientist believes he has deciphered the code by which the brain forms long-term memories.
Theodore Berger, a biomedical engineer and neuroscientist at the University of Southern California in Los Angeles, envisions a day in the not too distant future when a patient with severe memory loss can get help from an electronic implant. In people whose brains have suffered damage from Alzheimer’s, stroke, or injury, disrupted neuronal networks often prevent long-term memories from forming. For more than two decades, Berger has designed silicon chips to mimic the signal processing that those neurons do when they’re functioning properly—the work that allows us to recall experiences and knowledge for more than a minute. Ultimately, Berger wants to restore the ability to create long-term memories by implanting chips like these in the brain.
The idea is so audacious and so far outside the mainstream of neuroscience that many of his colleagues, says Berger, think of him as being just this side of crazy. “They told me I was nuts a long time ago,” he says with a laugh, sitting in a conference room that abuts one of his labs. But given the success of recent experiments carried out by his group and several close collaborators, Berger is shedding the loony label and increasingly taking on the role of a visionary pioneer.
Berger and his research partners have yet to conduct human tests of their neural prostheses, but their experiments show how a silicon chip externally connected to rat and monkey brains by electrodes can process information just like actual neurons. “We’re not putting individual memories back into the brain,” he says. “We’re putting in the capacity to generate memories.” In an impressive experiment published last fall, Berger and his coworkers demonstrated that they could also help monkeys retrieve long-term memories from a part of the brain that stores them.
If a memory implant sounds farfetched, Berger points to other recent successes in neuroprosthetics. Cochlear implants now help more than 200,000 deaf people hear by converting sound into electrical signals and sending them to the auditory nerve. Meanwhile, early experiments have shown that implanted electrodes can allow paralyzed people to move robotic arms with their thoughts. Other researchers have had preliminary success with artificial retinas in blind people.
Still, restoring a form of cognition in the brain is far more difficult than any of those achievements. Berger has spent much of the past 35 years trying to understand fundamental questions about the behavior of neurons in the hippocampus, a part of the brain known to be involved in forming memory. “It’s very clear,” he says. “The hippocampus makes short-term memories into long-term memories.”
What has been anything but clear is how the hippocampus accomplishes this complicated feat. Berger has developed mathematical theorems that describe how electrical signals move through the neurons of the hippocampus to form a long-term memory, and he has proved that his equations match reality. “You don’t have to do everything the brain does, but can you mimic at least some of the things the real brain does?” he asks. “Can you model it and put it into a device? Can you get that device to work in any brain? It’s those three things that lead people to think I’m crazy. They just think it’s too hard.”
Wireless, implanted sensor broadens range of brain research
A compact, self-contained sensor recorded and transmitted brain activity data wirelessly for more than a year in early stage animal tests, according to a study funded by the National Institutes of Health. In addition to allowing for more natural studies of brain activity in moving subjects, this implantable device represents a potential major step toward cord-free control of advanced prosthetics that move with the power of thought. The report is in the April 2013 issue of the Journal of Neural Engineering.
“For people who have sustained paralysis or limb amputation, rehabilitation can be slow and frustrating because they have to learn a new way of doing things that the rest of us do without actively thinking about it,” said Grace Peng, Ph.D., who oversees the Rehabilitation Engineering Program of the National Institute of Biomedical Imaging and Bioengineering (NIBIB), part of NIH. “Brain-computer interfaces harness existing brain circuitry, which may offer a more intuitive rehab experience, and ultimately, a better quality of life for people who have already faced serious challenges.”
Recent advances in brain-computer interfaces (BCI) have shown that it is possible for a person to control a robotic arm through implanted brain sensors linked to powerful external computers. However, such devices have relied on wired connections, which pose infection risks and restrict movement, or were wireless but had very limited computing power.
Building on this line of research, David Borton, Ph.D., and Ming Yin, Ph.D., of Brown University, Providence, R.I., and colleagues surmounted several major barriers in developing their sensor. To be fully implantable within the brain, the device needed to be very small and completely sealed off to protect the delicate machinery inside the device and the even more delicate tissue surrounding it. At the same time, it had to be powerful enough to convert the brain’s subtle electrical activity into digital signals that could be used by a computer, and then boost those signals to a level that could be detected by a wireless receiver located some distance outside the body. Like all cordless machines, the device had to be rechargeable, but in the case of an implanted brain sensor, recharging must also be done wirelessly.
The researchers consulted with brain surgeons on the shape and size of the sensor, which they built out of titanium, commonly used in joint replacements and other medical implants. They also fitted the device with a window made of sapphire, which electromagnetic signals pass through more easily than other materials, to assist with wireless transmission and inductive charging, a method of recharging also used in electronic toothbrushes. Inside, the device was densely packed with the electronics specifically designed to function on low power to reduce the amount of heat generated by the device and to extend the time it could work on battery power.
Testing the device in animal models — two pigs and two rhesus macaques — the researchers were able to receive and record data from the implanted sensors in real time over a broadband wireless connection. The sensors could transmit signals more than three feet and have continued to perform for over a year with little degradation in quality or performance.
The ability to remotely record brain activity data as an animal interacts naturally with its environment may help inform studies on muscle control and the movement-related brain circuits, the researchers say. While testing of the current devices continues, the researchers plan to refine the sensor for better heat management and data transmission, with use in human medical care as the goal.
“Clinical applications may include thought-controlled prostheses for severely neurologically impaired patients, wireless access to motorized wheelchairs or other assistive technologies, and diagnostic monitoring such as in epilepsy, where patients currently are tethered to the bedside during assessment,” said Borton.
Patient has 75 per cent of his skull replaced by 3D-printed implant
A man has had 75 per cent of his skull replaced with a custom-made 3D-printed implant.
The un-named patient in the United States had his head imaged by a 3D scanner before the plastic prosthetic was crafted to suit his features.
Oxford Performance Materials in Connecticut then gained approval from US regulators before the printed bone replacement was inserted in his skull during a surgical procedure earlier this week.
The ground-breaking operation has only now been revealed.
The company says it can now provide the 3D printouts to replace bone damaged by disease or trauma after the US Food and Drug Administration granted approval on February 18.
The implant is more than a simple moulded plastic plate: Tiny surface details are etched into the polyetherketoneketone to encourage the growth of cells and bone.
The company says about 500 people in the US could make use of the technology each month, with recipients ranging from injured construction workers through to wounded soldiers.
It says it can produce an implant within two weeks of obtaining 3D scans of the affected area.
Clever Battery Completes Stretchable Electronics Package
Northwestern University’s Yonggang Huang and the University of Illinois’ John A. Rogers are the first to demonstrate a stretchable lithium-ion battery — a flexible device capable of powering their innovative stretchable electronics.
No longer needing to be connected by a cord to an electrical outlet, the stretchable electronic devices now could be used anywhere, including inside the human body. The implantable electronics could monitor anything from brain waves to heart activity, succeeding where flat, rigid batteries would fail.
Huang and Rogers have demonstrated a battery that continues to work — powering a commercial light-emitting diode (LED) — even when stretched, folded, twisted and mounted on a human elbow. The battery can work for eight to nine hours before it needs recharging, which can be done wirelessly.
The new battery enables true integration of electronics and power into a small, stretchable package. Details are published by the online journal Nature Communications.
“We start with a lot of battery components side by side in a very small space, and we connect them with tightly packed, long wavy lines,” said Huang, a corresponding author of the paper. “These wires provide the flexibility. When we stretch the battery, the wavy interconnecting lines unfurl, much like yarn unspooling. And we can stretch the device a great deal and still have a working battery.”
Huang led the portion of the research focused on theory, design and modeling. He is the Joseph Cummings Professor of Civil and Environmental Engineering and Mechanical Engineering at Northwestern’s McCormick School of Engineering and Applied Science.
The power and voltage of the stretchable battery are similar to a conventional lithium-ion battery of the same size, but the flexible battery can stretch up to 300 percent of its original size and still function.

A team of neuroengineers based at Brown University has developed a fully implantable and rechargeable wireless brain sensor capable of relaying real-time broadband signals from up to 100 neurons in freely moving subjects. Several copies of the novel low-power device, described in the Journal of Neural Engineering, have been performing well in animal models for more than year, a first in the brain-computer interface field. Brain-computer interfaces could help people with severe paralysis control devices with their thoughts.
Arto Nurmikko, professor of engineering at Brown University who oversaw the device’s invention, is presenting it this week at the 2013 International Workshop on Clinical Brain-Machine Interface Systems in Houston.
“This has features that are somewhat akin to a cell phone, except the conversation that is being sent out is the brain talking wirelessly,” Nurmikko said.
Neuroscientists can use such a device to observe, record, and analyze the signals emitted by scores of neurons in particular parts of the animal model’s brain.
Meanwhile, wired systems using similar implantable sensing electrodes are being investigated in brain-computer interface research to assess the feasibility of people with severe paralysis moving assistive devices like robotic arms or computer cursors by thinking about moving their arms and hands.
This wireless system addresses a major need for the next step in providing a practical brain-computer interface,” said neuroscientist John Donoghue, the Wriston Professor of Neuroscience at Brown University and director of the Brown Institute for Brain Science.
Tightly packed technology
In the device, a pill-sized chip of electrodes implanted on the cortex sends signals through uniquely designed electrical connections into the device’s laser-welded, hermetically sealed titanium “can.” The can measures 2.2 inches (56 mm) long, 1.65 inches (42 mm) wide, and 0.35 inches (9 mm) thick. That small volume houses an entire signal processing system: a lithium ion battery, ultralow-power integrated circuits designed at Brown for signal processing and conversion, wireless radio and infrared transmitters, and a copper coil for recharging — a “brain radio.” All the wireless and charging signals pass through an electromagnetically transparent sapphire window.
In all, the device looks like a miniature sardine can with a porthole.
But what the team has packed inside makes it a major advance among brain-machine interfaces, said lead author David Borton, a former Brown graduate student and postdoctoral research associate who is now at Ecole Polytechnique Federale Lausanne in Switzerland.
“What makes the achievement discussed in this paper unique is how it integrated many individual innovations into a complete system with potential for neuroscientific gain greater than the sum of its parts,” Borton said. “Most importantly, we show the first fully implanted microsystem operated wirelessly for more than 12 months in large animal models — a milestone for potential [human] clinical translation.”
The device transmits data at 24 Mbps via 3.2 and 3.8 Ghz microwave frequencies to an external receiver. After a two-hour charge, delivered wirelessly through the scalp via induction, it can operate for more than six hours.
“The device uses less than 100 milliwatts of power, a key figure of merit,” Nurmikko said.
Co-author Ming Yin, a Brown postdoctoral scholar and electrical engineer, said one of the major challenges that the team overcame in building the device was optimizing its performance given the requirements that the implant device be small, low-power and leak-proof, potentially for decades.
“We tried to make the best tradeoff between the critical specifications of the device, such as power consumption, noise performance, wireless bandwidth and operational range,” Yin said. “Another major challenge we encountered was to integrate and assemble all the electronics of the device into a miniaturized package that provides long-term hermeticity (water-proofing) and biocompatibility as well as transparency to the wireless data, power, and on-off switch signals.”
With early contributions by electrical engineer William Patterson at Brown, Yin helped to design the custom chips for converting neural signals into digital data. The conversion has to be done within the device, because brain signals are not produced in the ones and zeros of computer data.
Ample applications
The team worked closely with neurosurgeons to implant the device in three pigs and three rhesus macaque monkeys. The research in these six animals has been helping scientists better observe complex neural signals for as long as 16 months so far. In the new paper, the team shows some of the rich neural signals they have been able to record in the lab. Ultimately this could translate to significant advances that can also inform human neuroscience.
Current wired systems constrain the actions of research subjects, Nurmikko said. The value of wireless transmission is that it frees subjects to move however they intend, allowing them to produce a wider variety of more realistic behaviors. If neuroscientists want to observe the brain signals produced during some running or foraging behaviors, for instance, they can’t use a cabled sensor to study how neural circuits would form those plans for action and execution or strategize in decision making.
In the experiments in the new paper, the device is connected to one array of 100 cortical electrodes, the microscale individual neural listening posts, but the new device design allows for multiple arrays to be connected, Nurmikko said. That would allow scientists to observe ensembles of neurons in multiple related areas of a brain network.
The new wireless device is not approved for use in humans and is not used in clinical trials of brain-computer interfaces. It was designed, however, with that translational motivation.
“This was conceived very much in concert with the larger BrainGate* team, including neurosurgeons and neurologists giving us advice as to what were appropriate strategies for eventual clinical applications,” said Nurmikko, who is also affiliated with the Brown Institute for Brain Science.
Borton is now spearheading the development of a collaboration between EPFL and Brown to use a version of the device to study the role of the motor cortex in an animal model of Parkinson’s disease.
Meanwhile the Brown team is continuing work on advancing the device for even larger amounts of neural data transmission, reducing its size even further, and improving other aspects of the device’s safety and reliability so that it can someday be considered for clinical application in people with movement disabilities.
(Source: news.brown.edu)
World premiere of muscle and nerve controlled arm prosthesis
For the first time an operation has been conducted, at Sahlgrenska University Hospital, where electrodes have been permanently implanted in nerves and muscles of an amputee to directly control an arm prosthesis. The result allows natural control of an advanced robotic prosthesis, similarly to the motions of a natural limb.
A surgical team led by Dr Rickard Brånemark, Sahlgrenska University Hospital, has carried out the first operation of its kind, where neuromuscular electrodes have been permanently implanted in an amputee. The operation was possible thanks to new advanced technology developed by Max Ortiz Catalan, supervised by Rickard Brånemark at Sahlgrenska University Hospital and Bo Håkansson at Chalmers University of Technology.
“The new technology is a major breakthrough that has many advantages over current technology, which provides very limited functionality to patients with missing limbs,” says Rickard Brånemark.
Big challenges
There have been two major issues on the advancement of robotic prostheses: 1) how to firmly attach an artificial limb to the human body; 2) how to intuitively and efficiently control the prosthesis in order to be truly useful and regain lost functionality.
“This technology solves both these problems by combining a bone anchored prosthesis with implanted electrodes,” said Rickard Brånemark, who along with his team has developed a pioneering implant system called Opra, Osseointegrated Prostheses for the Rehabilitation of Amputees.
A titanium screw, so-called osseointegrated implant, is used to anchor the prosthesis directly to the stump, which provides many advantages over a traditionally used socket prosthesis.
“It allows complete degree of motion for the patient, fewer skin related problems and a more natural feeling that the prosthesis is part of the body. Overall, it brings better quality of life to people who are amputees,” says Rickard Brånemark.
How it works
Presently, robotic prostheses rely on electrodes over the skin to pick up the muscles electrical activity to drive few actions by the prosthesis. The problem with this approach is that normally only two functions are regained out of the tens of different movements an able-body is capable of. By using implanted electrodes, more signals can be retrieved, and therefore control of more movements is possible. Furthermore, it is also possible to provide the patient with natural perception, or “feeling”, through neural stimulation.
“We believe that implanted electrodes, together with a long-term stable human-machine interface provided by the osseointegrated implant, is a breakthrough that will pave the way for a new era in limb replacement,” says Rickard Brånemark.
The patient
The first patient has recently been treated with this technology, and the first tests gave excellent results. The patient, a previous user of a robotic hand, reported major difficulties in operating that device in cold and hot environments and interference from shoulder muscles. These issues have now disappeared, thanks to the new system, and the patient has now reported that almost no effort is required to generate control signals. Moreover, tests have shown that more movements may be performed in a coordinated way, and that several movements can be performed simultaneously.
“The next step will be to test electrical stimulation of nerves to see if the patient can sense environmental stimuli, that is, get an artificial sensation. The ultimate goal is to make a more natural way to replace a lost limb, to improve the quality of life for people with amputations,” says Rickard Brånemark.
Bioengineers print ears that look and act like the real thing
Cornell bioengineers and physicians have created an artificial ear that looks and acts like a natural ear, giving new hope to thousands of children born with a congenital deformity called microtia.
In a study published online Feb. 20 in PLOS One, Cornell biomedical engineers and Weill Cornell Medical College physicians described how 3-D printing and injectable gels made of living cells can fashion ears that are practically identical to a human ear. Over a three-month period, these flexible ears grew cartilage to replace the collagen that was used to mold them.
"This is such a win-win for both medicine and basic science, demonstrating what we can achieve when we work together," said co-lead author Lawrence Bonassar, associate professor of biomedical engineering.
The novel ear may be the solution reconstructive surgeons have long wished for to help children born with ear deformity, said co-lead author Dr. Jason Spector, director of the Laboratory for Bioregenerative Medicine and Surgery and associate professor of plastic surgery at Weill Cornell.
"A bioengineered ear replacement like this would also help individuals who have lost part or all of their external ear in an accident or from cancer," Spector said.
Replacement ears are usually constructed with materials that have a Styrofoam-like consistency, or sometimes, surgeons build ears from a patient’s harvested rib. This option is challenging and painful for children, and the ears rarely look completely natural or perform well, Spector said.
To make the ears, Bonassar and colleagues started with a digitized 3-D image of a human subject’s ear and converted the image into a digitized “solid” ear using a 3-D printer to assemble a mold.
They injected the mold with collagen derived from rat tails, and then added 250 million cartilage cells from the ears of cows. This Cornell-developed, high-density gel is similar to the consistency of Jell-O when the mold is removed. The collagen served as a scaffold upon which cartilage could grow.
The process is also fast, Bonassar added: “It takes half a day to design the mold, a day or so to print it, 30 minutes to inject the gel, and we can remove the ear 15 minutes later. We trim the ear and then let it culture for several days in nourishing cell culture media before it is implanted.”
The incidence of microtia, which is when the external ear is not fully developed, varies from almost 1 to more than 4 per 10,000 births each year. Many children born with microtia have an intact inner ear, but experience hearing loss due to the missing external structure.
Bonassar and Spector have been collaborating on bioengineered human replacement parts since 2007. Bonassar has also worked with Weill Cornell neurological surgeon Dr. Roger Härtl on bioengineered disc replacements using some of the same techniques demonstrated in the PLOS One study.
The researchers specifically work on replacement human structures that are primarily made of cartilage — joints, trachea, spine, nose — because cartilage does not need to be vascularized with a blood supply in order to survive.
They are now looking at ways to expand populations of human ear cartilage cells in the laboratory so that these cells can be used in the mold, instead of cow cartilage.
"Using human cells, specifically those from the same patient, would reduce any possibility of rejection," Spector said.
He added that the best time to implant a bioengineered ear on a child would be when they are about 5 or 6 years old. At that age, ears are 80 percent of their adult size.
If all future safety and efficacy tests work out, it might be possible to try the first human implant of a Cornell bioengineered ear in as little as three years, Spector said.