Biomedical Breakthroughs: Bionerves and Restored Sensation

restoring_mobilityThese days, advances in prosthetic devices, bionic limbs and exoskeletons continue to advance and amaze. Not only are doctors and medical researchers able to restore mobility and sensation to patients suffering from missing limbs, they are now crossing a threshold where they are able to restore these abilities and faculties to patients suffering from partial or total paralysis.

This should come as no surprise, seeing as how the latest biomedical advances – which involve controlling robotic limbs with brain-computer interfacing – offer a very obvious solution for paralyzed individuals. In their case, no robotic limbs or bionic attachments are necessary to restore ambulatory motion since these were not lost. Instead, what is needed is to restore motor control to compensate for the severed nerves.

braingate1Thanks to researchers working at Case Western University in Ohio, a way forward is being proposed. Here, a biomedical team is gearing up to combine the Braingate cortical chip, developed at Brown University, with their own Functional Electric Stimulation (FES) platform. Through this combination, they hope to remove robots from the equation entirely and go right to the source.

It has long been known that electrical stimulation can directly control muscles, but attempts to do this in the past artificially has often been inaccurate (and therefore painful and potentially damaging) to the patient. Stimulating the nerves directly using precisely positioned arrays is a much better approach, something that another team at Case Western recently demonstrated thought their “nerve cuff electrode”.

cuff-electrodeThis electrode is a direct stimulation device that is small enough to be placed around small segments of nerve. The Western team used the cuff to provide an interface for sending data from sensors in the hand back to the brain using sensory nerves in the arm. With FES, the same kind of cuff electrode can also be used to stimulate nerves going the other direction, in other words, to the muscles.

The difficulty in such a scheme, is that even if the motor nerves can be physically separated from the sensory nerves and traced to specific muscles, the exact stimulation sequences needed to make a proper movement are hard to find. To achieve this, another group at Case Western has developed a detailed simulation of how different muscles work together to control the arm and hand.

braingate2-img_assist_custom-500x288Their model consists of 138 muscle elements distributed over 29 muscles, which act on 11 joints. The operational procedure is for the patient to watch the image of the virtual arm while they naturally generate neural commands that the BrainGate chip picks up to move the arm. In practice, this means trying to make the virtual arm touch a red spot to make it turn green.

Currently in clinical trials, the Braingate2 chip is being developed with the hope of not only stimulating muscles, but generating the same kinds of feedback and interaction that real muscle movement creates. The eventual plan is that the patient and the control algorithm will learn together in tandem so that a training screen will not be needed at all and a patient will be able to move on their own without calibrating the device.

bionic-handBut at the same time, biotech enhancements that are restoring sensation to amputee victims are also improving apace. Consider the bionic hand developed by Silvestro Micerna of the École Polytechnique Fédérale de Lausanne in Switzerland. Unlike previous bionic hands, which rely on electrodes to receive nerve signals to control the hand’s movement, his device sends electronic signals back to simulate the feeling of touch.

Back in February of 2013, Micerna and his research team began testing their bionic hand, and began clinical trials on a volunteer just last month. Their volunteer, a man named Dennis Aabo Sørensen from Denmark, lost his arm in a car accident nine years ago, and has since become the first amputee to experience artificially-induced sensation in real-time.

prosthetic_originalIn a laboratory setting wearing a blindfold and earplugs, Sørensen was able to detect how strongly he was grasping, as well as the shape and consistency of different objects he picked up with his prosthetic. Afterwards, Sørensen described the experience to reporters, saying:

The sensory feedback was incredible. I could feel things that I hadn’t been able to feel in over nine years. When I held an object, I could feel if it was soft or hard, round or square.

The next step will involve miniaturizing the sensory feedback electronics for a portable prosthetic, as well as fine-tuning the sensory technology for better touch resolution and increased awareness about the movement of fingers. They will also need to assess how long the electrodes can remain implanted and functional in the patient’s nervous system, though Micerna’s team is confident that they would last for many years.

bionic-hand-trialMicerna and his team were also quick to point out that Sørensen’s psychological strength was a major asset in the clinical trial. Not only has he been forced to adapt to the loss of his arm nine years ago, he was also extremely willing to face the challenge of having experienced touch again, but for only a short period of time. But as he himself put it:

I was more than happy to volunteer for the clinical trial, not only for myself, but to help other amputees as well… There are two ways you can view this. You can sit in the corner and feel sorry for yourself. Or, you can get up and feel grateful for what you have.

The study was published in the February 5, 2014 edition of Science Translational Medicine, and represents a collaboration called Lifehand 2 between several European universities and hospitals. And although a commercially-available sensory-enhanced prosthetic may still be years away, the study provides the first step towards a fully-realizable bionic hand.

braingate_drinkassistYes, between implantable electronics that can read out brainwaves and nerve impulses, computers programs that are capable of making sense of it all, and robotic limbs that are integrated to these machines and our bodies, the future is looking very interesting indeed. In addition to restoring ambulatory motion and sensation, we could be looking at an age where there is no such thing as “permanent injury”.

And in the meantime, be sure to check out this video of Sørensen’s clinical trial with the EPFL’s bionic hand:


Sources:
extremetech.com, actu.epfl.ch, neurotechnology.com

The Future of Medicine: Engineered Viruses, Nanoparticles and Bio-Absorbable Circuits

medtechThe future that is fast approaching us is one filled with possibilities, many of which were once thought to be the province of science fiction. Between tricorders and other new devices that can detect cancer sooner and at a fraction of the cost, HIV vaccines and cures, health monitoring tattoos and bionic limbs, we could be moving into an age where all known diseases are curable and physical handicaps will be non-existent.

And in the past few months, more stories have emerged with provide hope for millions of people living with diseases, injuries and disabilities. The first came just over three weeks ago from University of California, Berkley, where researchers have been working with an engineered virus which they claim could help cure blindness. As part of a gene therapy program, this treatment has been shown to effectively correct a rare form of inherited blindness.

virus-sight1For the past six years, medical science has been using adeno-associated viruses (AAV) as part of a gene therapy treatment to correct inherited retinal degenerative disease. However, the process has always been seen as invasive, since it involves injected the AAVs directly into a person’s retina with a needle. What’s more, the rpocess has shown itself to be limited, in that the injected virus does not reach all the retinal cells that need repair.

But as Professor David Schaffer, the lead researcher on the project, stated in an interview with Science Translational Medicine:

[D]octors have no choice because none of the gene delivery viruses can travel all the way through the back of the eye to reach the photoreceptors – the light sensitive cells that need the therapeutic gene.

Building on this and many more years of research, Prof David Schaffer and his colleagues developed a new process where they generated around 100 million variants of AAV and then selected five that were effective in penetrating the retina. They then used the best of these, a strain known as 7m8, to transport genes to cure two types of hereditary blindness on a group of mice.

virus-sightIn each case, the engineered virus delivered the corrective gene to all areas of the retina and restored retinal cells nearly to normal. But more importantly, the virus’ ability to penetrate the retina on its own makes the process far less invasive, and will likely be far more cost-effective when adapted to humans. And the process is apparently very convenient:

[W]e have now created a virus that you just inject into the liquid vitreous humor inside the eye and it delivers genes to a very difficult-to-reach population of delicate cells in a way that is surgically non-invasive and safe. It’s a 15-minute procedure, and you can likely go home that day.

Naturally, clinical trials are still needed, but the results are encouraging and Professor Schaffer indicated that his team are busy at work, now collaborating with physicians to identify the patients most likely to benefit from this gene-delivery technique.

nanoparticles_miceNext up, there was the announcement back at the end of May that researchers from North Carolina State and University of North Carolina Chapel Hill had found yet another medical use for nanoparticles. In there case, this consisted of combating a major health concern, especially amongst young people today: diabetes.

In a study that was published in the Journal of Agricultural and Food Chemistry, the collaborating teams indicated that their solution of nanoparticles was able to monitor blood sugar levels in a group of mice and released insulin when their sugar levels got too high. Based on the results, the researchers claim that their method will also work for human beings with type 1 diabetes.

image descriptionEach of the nanoparticles have a core of insulin that is contained with a degradable shell. When glucose levels in the blood reach high concentrations spike, the shell dissolves, releasing insulin and lowering the subject’s blood sugar. The degradable nano-network was shown to work in mice where a single injection kept blood glucose levels normal for a minimum of 10 days.

While the exact cause of this kind of diabetes is unknown, the effects certainly are. Patients living with this genetically-acquired form of the disease require several shots of insulin a day to keep their blood sugar levels under control. And even then, blindness, depression and even death can still result. What’s more, if the insulin shots are specifically calculated for the individual in question, side-effects can occur.

???????????????????????????????Hence the genius behind this new method. Not only would it relieve people who have type 1 diabetes from constantly injecting themselves, it would also remove the need to monitor their own blood sugar levels since the nanoparticles would be controlling them automatically.

In a study published recently in the Journal of Agricultural and Food Chemistry, Zhen Gu, lead author of the study claimed that the technology functions essentially the same as a pancreas. Hence another benefit of the new method, in that it could make pancreatic transplants – which are often necessary for patients with diabetes – unnecessary.

biocircuitsAnd last, but certainly not least, comes from the University of Illinois where John Rogers are developing a series of bio-absorbable electronic circuits that could help us win the war on drug-resistant bacteria. As part of a growing trend of biodegradable, flexible electronic circuits that operate wirelessly, fighting “superbugs” is just one application for this technology, but a very valuable one.

For some time now, bacteria that is resistant to antibiotics has been spreading, threatening to put the clock back 100 years to the time when routine, minor surgery was life-threatening. Some medical experts are warning that otherwise straightforward operations could soon become deadly unless new ways to fend off these infections are found. And though bacteria can evolve ways of evading chemical assaults, they are still vulnerable to direct assault.

electronics_dissolvingThis is how the new bio-absorbable circuits work: by heating up the virus. Each circuit is essentially a miniature electric heater that can be implanted into wounds and powered wirelessly to fry bacteria during healing before dissolving harmlessly into body fluids once their job is done. While this might sound dangerous, keep in mind that it takes only a relatively mild warming to kill bugs without causing discomfort or harm to surrounding tissues.

To fashion the circuits, Rogers and his colleagues used layers of utra-thin wafers and silk, material so thin that they disintegrate in water or body fluids or (in the case of silk) are known to dissolve anyway. For the metal parts, they used extra-thin films of magnesium, which is not only harmless but in fact an essential nutrient. For semiconductors, they used silicon membranes 300 nanometres thick, which also dissolve in water.

In addition to deterring bacteria, Rogers says that implantable, bio-absorbable RF electronics could be used to stimulate nerves for pain relief, and to stimulate bone re-growth, a process long proven to work when electrodes are placed on the skin or directly on the bone. Conceivably they could also be used to precisely control drug release from implanted reservoirs.

In other words, this is just the beginning. When it comes to the future of medicine, just about any barrier that was once considered impassable are suddenly looking quite porous…

Sources: sci-news.com, stm.sciencemag.org, singularityhub.com, bbc.com/future