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Insulin injection.

Stem-cell implant prototypes pave the way towards life-long treatment for type 1 diabetes

New research is paving the way towards reliable, long-term treatments for type 1 diabetes. The work focused on developing implants based on stem cells that can deliver insulin directly into the bloodstream of diabetes patients.

Insulin injection.
Image credits Peter Stanic.

While the implants are not yet ready for use in a clinical role, the research does prove the viability of such systems for use in the future. The implants consist of pancreatic endoderm cells derived from human pluripotent stem cells (PSCs) and were tested with 26 patients. After more research and development, once such implants become able to secrete levels of insulin that will have a clinical effect on their recipients, they could become a viable alternative to current insulin-delivery systems and islet replacement therapies (pancreatic transplants).

Promising first steps

“The device is band-aid sized and designed to contain the lab grown islet cells for subcutaneous implant. It allows the cells within to become vascularized to permit delivery of oxygen and nutrients and release of insulin into the bloodstream. It is also readily retrievable”, said Dr. Timothy J. Kieffer of the University of British Columbia, corresponding author of the study, for ZME Science.

The team aims to provide an unlimited supply of insulin-producing cells for patients with type 1 diabetes, to mediate continuous, long-term treatment options while minimizing the invasiveness of the procedure.

Insulin is a hormone that keeps the levels of glucose (sugar) in our blood under control, and is produced by pancreatic β-cells. Type 1 diabetes is characterized by the destruction of these cells and leads to dangerously high levels of glucose building up in patients’ bloodstreams. Current treatments for this condition involve the administration of insulin directly into the bloodstream, either via manual injection or through automated systems that a patient can wear, which deliver the hormone periodically. Another possibility — although seen much more rarely in the grand scheme of things — is to treat the condition through islet transplant from donor organs.

Each of these treatment options comes with its own drawbacks. Direct injections require users to monitor their own state, remember to perform the procedure, and also carry the risk that they administer the shots imperfectly. Automated devices can be very burdensome to wear for long periods of time, are associated with long-term complications, and can malfunction. Transplants are very intrusive procedures and the supply of donor organs is very limited compared to the demand.

As such, an alternative is required, the team argues.

The current study reports on a phase I/II clinical trial involving the use of pancreatic endoderm cells as one such alternative. The team’s devices contain such cells in special capsules that allow for direct vascularization of the cells; these were implanted under the skin of the patients. The procedure did, however, run the risk of the participants’ bodies rejecting the implants, and thus involved an immunosuppressive treatment regimen that is commonly used in donor islet transplantation procedures. Possible side-effects of such treatments is an increased risk of cancer and infections in patients, as a direct consequence of their immune systems being suppressed.

That being said, the authors report that the devices worked as intended, and the cells within them started secreting insulin and delivering it directly into the participants’ bloodstreams in response to the glucose levels in their blood. Insulin expression (secretion) was recorded in 63% of the devices after they were explanted at time periods between 3 and 12 months after implantation. Insulin-secreting cells started accumulating progressively in these devices over a period of between 6 and 9 months after implantation.

Although not yet able to cover their full requirements for insulin, over a one-year study period, they reduced the amount of insulin participants needed to be administered by 20%. They also spent 13% more time in the target blood glucose range compared to pre-study periods.

“We found the implants were able to produce insulin in a meal regulated manner like normal healthy pancreatic islets, albeit at low levels,” Dr. Kieffer adds for ZME Science. “The sponsor company ViaCyte recently reported achieving clinically meaningful levels of insulin when more of these devices were implanted (8) that resulted in a dramatic reduction in the insulin injection requirements accompanied by vastly improved control of blood sugar.”

Overall, these devices were well-tolerated by their bodies and there were no severe adverse effects caused by the grafts. Two participants did experience serious adverse effects related to the immunosuppression treatment. Most of the adverse effects reported by participants, however, were related to the actual implantation/explantation surgeries, or to side-effects of the immunosuppressive treatment. All things considered, the team explains, the risk of local infection posed by the devices was very low, suggesting that the devices themselves are well-tolerated even in participants with a poor immune or healing response.

This does raise questions regarding the use of such devices over a patient’s whole life. An ideal solution to this would be an option to perform stem cell-based islet replacement therapy without the devices themselves, as this would bypass the need for immunosuppressive treatments altogether.

Still work to be done

One of the major limitations of the study was the lack of a control group, so the findings should not be used to draw any conclusion on how effective such devices would be at treating type 1 diabetes. However, the study does show that they are relatively safe to use and validate the working principle behind their design. More research will be needed to determine the quantity of cells such implants should contain in order to produce clinically-relevant benefits for patients.

“It was very exciting to see clear meal regulated insulin production in patients following the implants and also see islet cells in the retrieved devices that looked like normal healthy pancreatic islet cells. We now have clear proof of principle data that this stem cell-based approach can work,” Dr. Kieffer adds for ZME Science.

Currently, the cells survive an average of 59 weeks after implantation. The total percentage of insulin-positive cells they contained at maturation was below the team’s ideal target, however. The researchers are now working on solutions to promote vascularization between the grafts and the patients’ bodies, and on measures to improve the survival of the cells they contain.

“Our ultimate goal is to entirely free patients from the burden of glucose monitoring and insulin injections, and without the use of any immunosuppression,” Dr. Kieffer concluded in his email for ZME Science. “We are thus very excited by the recent ViaCyte / CRISPR Therapeutics announcement that Health Canada has approved clinical testing of genetically modified cells that have been engineered to evade detection by the immune system.”

“With protocol refinements and immune-evasive cells, we hope to reach this goal.

The paper “Implanted pluripotent stem-cell-derived pancreatic endoderm cells secrete glucose-responsive C-peptide in patients with type 1 diabetes” has been published in the journal Cell Stem Cell.

One of the lab-grown blood vessels. Credit: Science Translational Medicine.

Scientists implant lab-grown blood vessels in patients who need dialysis

One of the lab-grown blood vessels. Credit: Science Translational Medicine.

One of the lab-grown blood vessels. Credit: Science Translational Medicine.

Not only have researchers grown blood vessels in the lab, but they also implanted them into the circulatory systems of patients undergoing dialysis. Since the blood vessels were grown from cells collected from the recipient’s own tissue, there are no biocompatibility issues. In time, these blood vessels grew cells of their own and became indistinguishable from other blood vessels.

The blood vessels were developed at Humacyte, a biotech company in Durham, North Carolina. Researchers grew the blood vessels using smooth muscles cells collected from the walls of arteries and veins. In the lab, the cells were placed inside a scaffold filled with a fluid that provides nutrients. Over the course of two months, this setup produced 3D networks of proteins that led to the formation of blood vessels.

In the final step, the researchers removed proteins from the newly grown vessels that might have been recognized as foreign by a recipient’s immune system. The blood vessels grew on average to 42 centimeters in length and 6 millimeters in diameter.

These blood vessels were implanted into the upper arms of 60 people with kidney failure who were undergoing dialysis. In order to connect a dialysis machine, doctors normally have to merge an artery to a vein in order to create a wider vessel that can transfer blood. However, all of the recipients were not able to undergo this procedure since their blood vessels were too narrow, which is why they were selected for blood vessel implants in the first place.

Four years after the implant, the blood vessels developed into self-healing, multi-layered tissues that looked and behaved like the recipient’s own vessels. The lab-grown vessels had no cells of their own when they were first implanted but became populated with different types of the recipient’s own cells, the authors reported in the journal Science Translational Medicine.

Blood vessels have to be replaced in many other situations such as in the event of trauma or cardiovascular disease. Usually, doctors implant synthetic tubes but these can cause scarring or lead to inflammatory reactions.

The researchers at Humacyte hope to scale their process in order to grow tens of thousands of blood vessels per year.

Doctors restore patient’s sight with stem cells, offering new hope for cure to blindness

Scientists have developed a specially engineered retinal patch to treat people with sudden, severe sight loss.

The macula lutea (an oval region at the center of the retina) is responsible for the central, high-resolution color vision that is possible in good light; when this kind of vision is impaired due to damage to the macula, the condition is called age-related macular degeneration (AMD or ARMD). Macula lutea means ‘yellow spot’ in Latin.

Picture of the back of the eye showing intermediate age-related macular degeneration.
Via Wikipedia

Douglas Waters, an 86-year-old from London, had lost his vision in July 2015 due to severe AMD. After a few months, Waters became part of a clinical trial developed by UC Santa Barbara researchers that used stem cell-derived ocular cells. He received his retinal implant at Moorfields Eye Hospital, a National Health Service (NHS) facility in London, England.

Before the surgery, Water’s sight was very poor, and he wasn’t able to see anything with his right eye. After the surgery, his vision improved so much that he could read the newspaper and help his wife in the garden.

The study, published in Nature Biotechnology, shows groundbreaking results. Researchers could safely and effective implant a specially engineered patch of retinal pigment epithelium cells derived from stem cells to treat people with sudden severe sight loss from wet AMD. This is the first time a completely engineered tissue has been successfully transplanted in this manner.

“This study represents real progress in regenerative medicine and opens the door on new treatment options for people with age-related macular degeneration,” said co-author Peter Coffey, a professor at UCSB’s Neuroscience Research Institute and co-director of the campus’s Center for Stem Cell Biology & Engineering.

Douglas Waters was struggling to see up close after developing severe macular degeneration, but 12 months on he is able to read a newspaper again

AMD usually affects people over the age of 50 and accounts for almost 50% of all visual impairment in the developed world. The condition disturbs central vision responsible for reading, leaving the surrounding eyesight normal. Wet AMD is caused by hemorrhage or liquid accumulation into the region of the macula, in the center of the retina. Wet AMD almost always starts as dry AMD. Researchers believe that this new technique will be the future cure for dry AMD.

Scientists wanted to see whether the diseased retinal cells could be replenished using the stem cell patch. They used a specially engineered surgical tool to insert the patch under the affected retina. The operation lasted almost two hours.

Besides Water, another patient, a 60-year-old woman who also suffered from wet AMD, underwent the surgery. The two patients were observed for one year and reported improvements to their vision. The results were incredible — the patients went from being almost blind to reading 60 to 80 words per minute with normal reading glasses.

“We hope this will lead to an affordable ‘off-the-shelf’ therapy that could be made available to NHS patients within the next five years,” said Coffey, who founded the London Project to Cure Blindness more than a decade ago.

 

 

turtle titanium 3d printed jaw

Sea Turtle gets a new 3D-printed titanium jaw after being hit by a boat’s propeller

turtle titanium 3d printed jaw

A turtle named Akut-3 was fitted with a new, custom made 3-D printed jaw by doctors at the Research, Rescue and Rehabilitation centre at Pamukkale University in Denizli, Turkey. The reptile was found badly injured at sea and brought to the center for rehabilitation. At first, the doctors healed the turtle’s wounds and hand fed her, but they knew they had to turn to something more drastic if the animal was to ever fend for herself in the wild again. They turned to a company in Turkey known for custom made prostheses, gave them a detailed CT scan of the turtle’s skull, then received a new beak made out of medical-grade titanium. The prosthesis perfectly fit Akut-3, who is aptly named like a cyborg.

This is the first time a turtle, or a reptile for that matter, received a 3-D printed medical implant. In 2012, ZME Science reported how an 83-year old woman had her lower jaw replaced by an exact 3D printed replica made out of titanium. Now, veterinarians are making good use of these implants, or prostheses. For instance, this dog can now walk again after being fitted with some custom-made 3-D printed braces.

Cleopatra was fitted with a 3-D printed shell by a student at Colorado Technical University. The original one was destroyed by a poor diet.

Cleopatra was fitted with a 3-D printed shell by a student at Colorado Technical University. The original one was destroyed by a poor diet.

Of the tiny tracheobronchial splints used to restore normal breathing to babies. Image: Morrison et al., Science Translational Medicine

Three babies’ lives saved by 4-D printed implant from otherwise incurable breathing disease

Three babies aged six to eighteen months suffering from an incurable breathing condition were saved by doctors who printed a 3-D implant. The implant is made out of a special biodegradable plastic that dissolves in three years (just enough incidentally for kids to be out of harms way permanently). It’s also designed to grow and expand as the babies age, hence it’s called a 4-D printed implant since time is considered an additional dimension, in this case.

Of the tiny  tracheobronchial splints used to restore normal breathing to babies. Image: Morrison et al., Science Translational Medicine

Of the tiny tracheobronchial splints used to restore normal breathing to babies. Image: Morrison et al., Science Translational Medicine

The kids were suffering from a severe form of tracheobronchomalacia, which affects about 1 in 2,000 children around the world. The disease regularly causes the windpipe to collapse, blocking breathing. There is no cure for the disease, and the children in question had a life expectancy estimated at days to weeks. Prior to surgery, the children had tubes attached to their necks and were placed in a permanently ventilated enclosure. At times, the babies suffered severe complications and had to be resuscitated.

Their lives was saved however by a tiny white tube no thicker than a pencil’s lead. To make the implant, the team at  Michigan’s C.S. Mott Children’s Hospital first made CT scans of the babies’ necks to build a model of the collapsed airways. Then a computer program used this geometry to design a 3-D model of the splint which would expand the airway and allow normal breathing. It was only a matter of printing the implant, using a laser 3-D printer which deposits polycaprolactone. So, every implant was custom made to fit inside the baby’s necks perfectly. Each for $10 and a couple of hours of design work.

“This is the first 3D-printed implant specifically designed to change shape over time, the fourth dimension, to allow for a child’s growth,”  Dr. Glenn Green, associate professor of pediatric otolaryngology at C.S. Mott Children’s Hospital in Michigan.

“Holidays are not spent in the hospital anymore,” Green said. “Instead of lying flat on their backs for weeks on end, these children are learning to sit and stand and run.”

“I honestly don’t think we can ever thank Dr. Green and his team in Michigan enough,” Natalie Peterson, mother of sixteen-month-old Garrett Peterson, said. “We know that without this procedure, Garrett was a month or so from passing away.”

Two renderings of the tracheobronchial splint, which is placed over the collapsed airway. The design parameters (inner diameter, length, wall thickness, and number and spacing of suture holes) were adjusted according to the patient's specific anatomy. (Morrison et al., Science Translational Medicine)

Two renderings of the tracheobronchial splint, which is placed over the collapsed airway. The design parameters (inner diameter, length, wall thickness, and number and spacing of suture holes) were adjusted according to the patient’s specific anatomy. (Morrison et al., Science Translational Medicine)

If children survive past age three, they’ll eventually get strong enough to get rid of  tracheobronchomalacia with no sign they ever had the disease which nearly wiped them out as newborns.

“We were honestly terrified, just hoping that we were making the right decision,” the mother of  five-month-old Ian Orbich , Meghan Orbich, said in a statement. “I am thankful every single day that this splint was developed. It has meant our son’s life. I am certain that if we hadn’t had the opportunity to bring Ian to Mott, he would not be here with us today.”

Their work was described in a paper published in the journal Science Translational Medicine.

 

 

 

A paralyzed women controlled a F-35 simulator with her thoughts. AFP Photo / HO

Paralyzed woman flies fighter jet with nothing but her thoughts

A crowd gathered for the New America Foundation’s first annual Future of War conference was told by DARPA’s director that a woman was able to control  F-35 flight simulator without touching the joystick. The woman controlled the simulation only with her thoughts, which were relayed and processed to the simulator by a neural implant embedded in her left cortex.

A mind, sky high

A paralyzed women controlled a F-35 simulator with her thoughts. AFP Photo / HO

A paralyzed women controlled a F-35 simulator with her thoughts. AFP Photo / HO

ZME Science previously reported the story of Jan Scheuermann, a quadriplegic woman, who despite being paralyzed from the neck down was able to control a robotic arm to flex, point or grab objects. It’s an amazing achievement from behalf of DARPA scientists who are truly raising the bar for brain-computer interfaces. Speaking about their work, Defense Advanced Research Projects Agency Director Arati Prabhakar said:

“It’s so moving to see what an impact it has on people to be even able to experiment with a technology like that from with the perspective of restoration. In doing this work … we can now see a future where we can free the brain from the limitations of the human body.”

At the Future of War conference, Prabhakar disclosed to the audience how one day Schaeuermann made an unlikely request. The paralyzed women asked if it was possible to fly using her thoughts, under the same principles that allowed her to control the 10 degrees of freedom mechanical arm.

 “Instead of thinking about controlling a joystick, which is what our ace pilots do when they’re driving this thing, Jan’s thinking about controlling the airplane directly. For someone who’s never flown — she’s not a pilot in real life — she’s flying that simulator directly from her neural signaling.”

The details are sketchy, so we don’t know how well Schaeuermann performed. But the talk, which you can view below, hints of some exciting developments for the future. We know drones and driverless cars are a hot thing now, but it’s insight like this that suggest these might truly become mainstream soon enough.

Across the ocean, in Germany, researchers at  the Institute for Flight System Dynamics of the Technische Universität München (TUM) are working on ways in which brain controlled flight might work in the EU-funded project “Brainflight.” The test runs they’ve made so far demonstrate an amazing precision for such an infant technology. One of the subjects was able to follow eight out of ten target headings with a deviation of only 10 degrees, the German researchers report. Several of the subjects also managed the landing approach under poor visibility. One test pilot even landed within only few meters of the centerline.

One minds are amazing things, too bad our bodies come in the way sometimes. Not for long.

Footage of a paralyzed rat using his hind legs, which normally should have been completely numb. This from experiments performed last year, so this is an old implant - not the newly developed e-Dura. Image: CNET

Paralyzed rats regain use of hind legs with flexible spinal cord implant. Humans to follow

Footage of a paralyzed rat using his hind legs, which normally should have been completely numb. This from experiments performed last year, so this is an old implant - not the newly developed e-Dura. Image: CNET

Footage of a paralyzed rat using his hind legs, which normally should have been completely numb. This from experiments performed last year, so this is an old implant – not the newly developed e-Dura. Image: CNET

Swiss scientists demonstrated a flexible ribbon-like implant that attaches itself to a paralyzed rat’s spinal cord, allowing the animal to walk again. The prosthetic, described by foremost experts in the field as ‘remarkable’, works by delivering timed electrical impulses and drugs along the spinal cord. In this particular case, rats aren’t that different from humans, and true enough clinical trials are now one step closer. In the future, paralysis might just be another word for “walking funny.”

A breakthrough in medicine

The technology was first introduced by researchers at the Ecole polytechnique federale de Lausanne, Switzerland last year, when it was shown how a rat with a severed spinal cord could walk again after a system of electrical impulses and chemical reactions was introduced.  The brain moves the body by sending electrical signals down the spinal cord and into the nervous system. When the spinal cord is severed, the signals can no longer reach that part of the spine, paralyzing that part of the body. The idea is to direct electrical impulses below the cut, where signal from the brain discontinued. This is done via electrodes that take the place of the brain signal, along with neurotransmitting drugs to reanimate the nerve cells beneath the injured tissue. If you find this amazing, you’re not alone. Paralysis might become a thing of the past in just a few decades.

This is how the flexible e-Dura implant looks like. The implant is so effective because it mimics the soft tissue around the spine so that the body does not reject its presence. Image: EPFL

This is how the flexible e-Dura implant looks like. The implant is so effective because it mimics the soft tissue around the spine so that the body does not reject its presence. Image: EPFL

In practical terms, however, a surface implant on a human’s spinal cord is extremely tricky. Because it’s rigid, the constant friction causes local inflammation, damaging the surrounding area. The latest updates features a flexible implant specifically designed to integrate with the patient’s spine, minimizing the risk of rejection and further damage. Called E-Dura, the implant mimics the soft tissue around the spine – known as the dura mater – reducing the risk of inflammation, friction and abrasion.

[RELATED] Paralyzed rats regain control of their bladder

“Our e-Dura implant can remain for a long period of time on the spinal cord or cortex,” said Professor Stéphanie Lacour.

“This opens up new therapeutic possibilities for patients suffering from neurological trauma or disorders, particularly individuals who have become paralyzed following spinal cord injury.”

After implanting e-Dura in rats, researchers found there was no sign of damage or rejection following two months of observation. It goes without saying the the rats could walk once the implant was set.

e-dura2

The implant is made of silicon and covered with gold electric conducting tracks that can be pulled and stretched along with the silicon material. The electrodes, a new composite made of silicon and platinum microbeads, can be pulled in any direction. The two components act together and direct electrical signals to the spinal cord in the same manner as the brain would. Meanwhile, tiny microfluid channel embedded in the implant deliver neurotransmitter drugs.

“Soft flexible nerves connected to unyielding silicon and metal – the combination has spawned many a Hollywood cyborg,” wrote science writer Robert Service in Science.

“The implants Lacour’s team created still have to be wired to the out- side world to operate, but she and her colleagues are designing wireless versions of the technology. Watch out, Hollywood, reality is catching up.”

It’s heartwarming to hear that this isn’t the only effort that seeks to abolish paralysis. There are many projects worldwide hard at work developing the next generation of implants and drugs that will make paralysis a thing of history. For instance, another group at Cambridge University has restored movement in the hind legs of 23 dogs after they transplanted nerve cells from the animals’ noses.

The human trials may start as early as June of this year, at a special facility called the called the Gait Platform, housed in the University Hospital of Lausanne, Switzerland. The e-Dura implant was described in a paper published in Science.

3D printed skull implant is ready for surgery

3D printing is the stuff of the future – today. It’s one of the most stunning pieces of relatively accessible technology; most notably in medicine, the precision offered by 3-D printing can make tiny surface details on the replacement part that encourage the growth of cells and allow the bone to attach more easily. In a specific case, 3D printing technology has helped replace 3/4 of a patient’s skull.

3-d-printed-skull-660

This technology could help replace the bone in people’s skulls damaged by disease or trauma – much better than existing solutions. But not only is this technology available and can do wonders for patients, but it was also regulated by the FDA – something which usually takes much more time, especially with something like this, which will virtually impact the entirety of orthopedics.

“We see no part of the orthopedic industry being untouched by this,” said Scott DeFelice, president of Oxford Performance Materials.

DeFelice’s company is already selling 3D-printed implants overseas as a contract manufacturer, but now the big door to the US has opened – according to DeFelice, some 300-500 people would need such an implant every month, either due to some type of bone cancer or trauma.

3D printing brings a big advantage to the table: it basically digitally scans an object and then prints out a matching, 3D replica, layer by layer, with very high fidelity and detail level.

Via Discovery

This implantable medical device. (c) M. Scott Brauer/MIT

A pharmacy under your skin – microchip implanted in patients delivers drugs

The prospect of medical implants capable of delivering drugs directly to the patient’s blood stream or tissue has been an important subject for research. Recently, a microchip was implanted in 8 women, with the sole role of delivering an osteoporosis treating drug. The human trial is the culmination of 15 years worth of development work by MIT scientists.

Just  5 cm long and 3 cm wide, the microchip was implanted in less than 30 minutes, as the patients were under local anesthesia. The device has 20 tiny  reservoirs, each holding 600-nanoliters of drug solution, at the bottom of which a thin layer of platinum or titanium was coated. When the payload had to be released, an electrical current passed through the reservoir, melting the bottom layer. This action could be programmed or triggered manually via a wireless command. Concerning treatment reports, the patients who had their drugs delivered via the implant fared just as well as those who had it injected. Due to its bidirectional nature, this allowed the researchers to both notice whether the device functioned properly or not, and monitor its performance.

The project was made possible thanks to the vision of  Michael Cima and Robert Langer, both MIT scientists, who had worked on the microchip drug delivery solution for the past 15 years, and described it in a recent edition of the journal Science Translational Medicine.

This implantable medical device. (c) M. Scott Brauer/MIT

This implantable medical device. (c) M. Scott Brauer/MIT

The demand for an automated drug delivery solution has been at large for a while now, as it’s considered it can address a number of issues which inherently come along with traditional medical treatment. One big problem that interferes with a successful treatment is the patient himself. It’s imperetive for a patient to follow his prescribed drug treatment clockwise for the whole duration of it, otherwise, most often, the whole treatment will render poor results.

The tiny pharmacist

For this human trial, all of the implanted women suffered from  osteoporosis. The drug treatment delivered through the microchip needs to be administered once a day for 20 days, hence the number of reservoirs in the device. Unfortunately, only one in four osteoporosis patients actually stick to their daily dose, the rest ending up ruining their treatment. Inevitably, more or less similar statistics in failure to stick to a treatment’s schedule has been reported for other diseases as well. The microchip drug delivery solution seeks to wipe this kind of problem all together. Also, it comes without the hassle of having to make regular hospital trips or face the needle on day-to-day basis.

“Compliance is very important in a lot of drug regimens, and it can be very difficult to get patients to accept a drug regimen where they have to give themselves injections,” says Cima, the David H. Koch Professor of Engineering at MIT. “This avoids the compliance issue completely, and points to a future where you have fully automated drug regimens.”

It might take a while before microchip implants will take off, though, as a lot more trials have to be completed and researchers need to ensure that  the device is absolutely fail proof. Some concerns existed whether the microchip would be biocompatible or not, but luckily it performed magnificently in this respect. Still, the device is in its infancy and is a long way from proving it’s truly reliable, and to ensure this, a myriad of test runs have to be made. A glitch in the system might cause the entire drug payload, maybe worth a whole month’s treatment, to be released – this needs to be avoided at all costs. Also, what’s worse maybe, is having the device not do anything at all. If the microchip were to be employed to deliver drugs for diabetes patients, whose life depend on a regular and successful insulin injection, and it would stop working,   then unexpected events of dramatic consequences might occur. Such a thing isn’t unthinkable, as for the current human test trial, out of the 8 individual implants, one didn’t work at all and was ruled out of the study. Hopefully, all of these issues, as well as all other foreseen by the researchers at the moment, will be resolved in the future.

 

 

The self-propelled wirelessly powered prototype developed by Stanford scientists, 3mm wide and 4mm long, showed resting upon one of the researcher's hand. (c) Stanford University

Revolutionary wireless powered tiny device can swim through blood streams

Implantable medical devices, capable of delivering drugs or performing micro-surgery from inside the body, have been the subject of scientific research for decades now. A number of exciting prototypes have been developed in the past few years, as miniaturization allowed it, however reliability flaws rendered them unpractical. A new tiny device developed by Stanford electrical engineers, was presented this week at the International Solid-State Circuits Conference by lead researcher Ada Poon, which is powered without wires or batteries and is small enough to travel through human blood streams.

“Such devices could revolutionize medical technology,” said Poon, an Electrical Engineering Assistant Professor. “Applications include everything from diagnostics to minimally invasive surgeries.”

The self-propelled wirelessly powered prototype developed by Stanford scientists, 3mm wide and 4mm long, showed resting upon one of the researcher's hand. (c) Stanford University

The self-propelled wirelessly powered prototype developed by Stanford scientists, 3mm wide and 4mm long, showed resting upon one of the researcher's hand. (c) Stanford University

In front of the conference audience, Poon demonstrated the working device, just a few millimeters in size and wirelessly powered, capable of controlled motion through a fluid, including blood. This could be the first of a new class of working medical implants, which could deliver drugs, perform analyses, and perhaps even zap blood clots or remove plaque from sclerotic arteries all from inside the human body. Since its power is derived wirelessly using electromagnetic radio waves, the device escapes all the reliability issues other implants meant for similar applications encountered. No batteries or wires means that the device can travel through the blood stream without risk of power failure and a dramatic scale down in size (batteries amount to most of the volume of such devices).

“While we have gotten very good at shrinking electronic and mechanical components of implants, energy storage has lagged in the move to miniaturize,” said co-author Teresa Meng, a professor of electrical engineering and computer science. “This hinders us in where we can place implants within the body and also creates the risk of corrosion or broken wires, not to mention replacing aging batteries.”

A tiny surgeon inside your blood vessels

Scientists have been trying to devise such medical wirelessly powered implants for 50 years now, but it seems the approach taken in the past was wrong, all because of one flawed assumption – that the human tissue is a good electrical conductor. Couldn’t been farther from the truth. With this inaccurate model in mind, high-frequency waves dissipate in the human tissue, dissipating as the device travels further.

Poon took a different approach, and considered the human tissue as a dielectric, a type of insulator – quite the opposite of previous assumptions! In a dielectric, the signal is conveyed as waves of shifting polarization of atoms within cells, which renders radio waves propagation possible. Moreover, the human tissue has been found to be “low-loss” dielectric, which means signal loss is minimal. Again, the opposite of past assumptions. These have all been demonstrate experimentally and mathematically.

“When we extended things to higher frequencies using a simple model of tissue, we realized that the optimal frequency for wireless powering is actually around one gigahertz,” said Poon, “about 100 times higher than previously thought.”

This revelation was instrumental to the researchers’ development, since it allowed them to build the device 100 times smaller and yet deliver the power needed by the medical device. This is why the antenna is just 2mm in size – small enough to travel through blood streams.

[RELATED] Nanotech powered by your breath

Two types of self-propelled devices were developed and demoed. One generates direction force to push itself forward by driving electrical current directly through the blood stream, allowing for velocity of around half a centimeter per second. The other, moves similar to the way a kayaker paddles upstream, switching current back and forth through a wire loop.

“There is considerable room for improvement and much work remains before such devices are ready for medical applications,” said Poon. “But for the first time in decades the possibility seems closer than ever.”

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