Tag Archives: John Rogers

Will you be my friend? Yes, after we activate our ultraminiature, wireless, battery-free, fully implantable devices

Perhaps I’m the only one who’s disconcerted?

Here’s the research (in text form) as to why we’re watching these scampering, momentary mouse friends, from a May 10, 2021 Northwestern University news release (also on EurekAlert) by Amanda Morris,

Northwestern University researchers are building social bonds with beams of light.

For the first time ever, Northwestern engineers and neurobiologists have wirelessly programmed — and then deprogrammed — mice to socially interact with one another in real time. The advancement is thanks to a first-of-its-kind ultraminiature, wireless, battery-free and fully implantable device that uses light to activate neurons.

This study is the first optogenetics (a method for controlling neurons with light) paper exploring social interactions within groups of animals, which was previously impossible with current technologies.

The research was published May 10 [2021] in the journal Nature Neuroscience.

The thin, flexible, wireless nature of the implant allows the mice to look normal and behave normally in realistic environments, enabling researchers to observe them under natural conditions. Previous research using optogenetics required fiberoptic wires, which restrained mouse movements and caused them to become entangled during social interactions or in complex environments.

“With previous technologies, we were unable to observe multiple animals socially interacting in complex environments because they were tethered,” said Northwestern neurobiologist Yevgenia Kozorovitskiy, who designed the experiment. “The fibers would break or the animals would become entangled. In order to ask more complex questions about animal behavior in realistic environments, we needed this innovative wireless technology. It’s tremendous to get away from the tethers.”

“This paper represents the first time we’ve been able to achieve wireless, battery-free implants for optogenetics with full, independent digital control over multiple devices simultaneously in a given environment,” said Northwestern bioelectronics pioneer John A. Rogers, who led the technology development. “Brain activity in an isolated animal is interesting, but going beyond research on individuals to studies of complex, socially interacting groups is one of the most important and exciting frontiers in neuroscience. We now have the technology to investigate how bonds form and break between individuals in these groups and to examine how social hierarchies arise from these interactions.”

Kozorovitskiy is the Soretta and Henry Shapiro Research Professor of Molecular Biology and associate professor of neurobiology in Northwestern’s Weinberg College of Arts and Sciences. She also is a member of the Chemistry of Life Processes Institute. Rogers is the Louis Simpson and Kimberly Querrey Professor of Materials Science and Engineering, Biomedical Engineering and Neurological Surgery in the McCormick School of Engineering and Northwestern University Feinberg School of Medicine and the director of the Querrey Simpson Institute for Bioelectronics.

Kozorovitskiy and Rogers led the work with Yonggang Huang, the Jan and Marcia Achenbach Professor in Mechanical Engineering at McCormick, and Zhaoqian Xie, a professor of engineering mechanics at Dalian University of Technology in China. The paper’s co-first authors are Yiyuan Yang, Mingzheng Wu and Abraham Vázquez-Guardado — all at Northwestern.

Promise and problems of optogenetics

Because the human brain is a system of nearly 100 billion intertwined neurons, it’s extremely difficult to probe single — or even groups of — neurons. Introduced in animal models around 2005, optogenetics offers control of specific, genetically targeted neurons in order to probe them in unprecedented detail to study their connectivity or neurotransmitter release. Researchers first modify neurons in living mice to express a modified gene from light-sensitive algae. Then they can use external light to specifically control and monitor brain activity. Because of the genetic engineering involved, the method is not yet approved in humans.

“It sounds like sci-fi, but it’s an incredibly useful technique,” Kozorovitskiy said. “Optogenetics could someday soon be used to fix blindness or reverse paralysis.”

Previous optogenetics studies, however, were limited by the available technology to deliver light. Although researchers could easily probe one animal in isolation, it was challenging to simultaneously control neural activity in flexible patterns within groups of animals interacting socially. Fiberoptic wires typically emerged from an animal’s head, connecting to an external light source. Then a software program could be used to turn the light off and on, while monitoring the animal’s behavior.

“As they move around, the fibers tugged in different ways,” Rogers said. “As expected, these effects changed the animal’s patterns of motion. One, therefore, has to wonder: What behavior are you actually studying? Are you studying natural behaviors or behaviors associated with a physical constraint?”

Wireless control in real time

A world-renowned leader in wireless, wearable technology, Rogers and his team developed a tiny, wireless device that gently rests on the skull’s outer surface but beneath the skin and fur of a small animal. The half-millimeter-thick device connects to a fine, flexible filamentary probe with LEDs on the tip, which extend down into the brain through a tiny cranial defect.

The miniature device leverages near-field communication protocols, the same technology used in smartphones for electronic payments. Researchers wirelessly operate the light in real time with a user interface on a computer. An antenna surrounding the animals’ enclosure delivers power to the wireless device, thereby eliminating the need for a bulky, heavy battery.

Activating social connections

To establish proof of principle for Rogers’ technology, Kozorovitskiy and colleagues designed an experiment to explore an optogenetics approach to remote-control social interactions among pairs or groups of mice.

When mice were physically near one another in an enclosed environment, Kozorovitskiy’s team wirelessly synchronously activated a set of neurons in a brain region related to higher order executive function, causing them to increase the frequency and duration of social interactions. Desynchronizing the stimulation promptly decreased social interactions in the same pair of mice. In a group setting, researchers could bias an arbitrarily chosen pair to interact more than others.

“We didn’t actually think this would work,” Kozorovitskiy said. “To our knowledge, this is the first direct evaluation of a major long-standing hypothesis about neural synchrony in social behavior.”

Here’s a citation and a link to the paper,

Wireless multilateral devices for optogenetic studies of individual and social behaviors by Yiyuan Yang, Mingzheng Wu, Amy J. Wegener, Jose G. Grajales-Reyes, Yujun Deng, Taoyi Wang, Raudel Avila, Justin A. Moreno, Samuel Minkowicz, Vasin Dumrongprechachan, Jungyup Lee, Shuangyang Zhang, Alex A. Legaria, Yuhang Ma, Sunita Mehta, Daniel Franklin, Layne Hartman, Wubin Bai, Mengdi Han, Hangbo Zhao, Wei Lu, Yongjoon Yu, Xing Sheng, Anthony Banks, Xinge Yu, Zoe R. Donaldson, Robert W. Gereau IV, Cameron H. Good, Zhaoqian Xie, Yonggang Huang, Yevgenia Kozorovitskiy and John A. Rogers. Nature Neuroscience (2021)
DOI: https://doi.org/10.1038/s41593-021-00849-x Published 10 May 2021

This paper is behind a paywall.

This latest research seems to be the continuation of research featured here in a July 16, 2019 posting: “Controlling neurons with light: no batteries or wires needed.”

Cortical spheroids (like mini-brains) could unlock (larger) brain’s mysteries

A March 19, 2021 Northwestern University news release on EurekAlert announces the creation of a device designed to monitor brain organoids (for anyone unfamiliar with brain organoids there’s more information after the news),

A team of scientists, led by researchers at Northwestern University, Shirley Ryan AbilityLab and the University of Illinois at Chicago (UIC), has developed novel technology promising to increase understanding of how brains develop, and offer answers on repairing brains in the wake of neurotrauma and neurodegenerative diseases.

Their research is the first to combine the most sophisticated 3-D bioelectronic systems with highly advanced 3-D human neural cultures. The goal is to enable precise studies of how human brain circuits develop and repair themselves in vitro. The study is the cover story for the March 19 [March 17, 2021 according to the citation] issue of Science Advances.

The cortical spheroids used in the study, akin to “mini-brains,” were derived from human-induced pluripotent stem cells. Leveraging a 3-D neural interface system that the team developed, scientists were able to create a “mini laboratory in a dish” specifically tailored to study the mini-brains and collect different types of data simultaneously. Scientists incorporated electrodes to record electrical activity. They added tiny heating elements to either keep the brain cultures warm or, in some cases, intentionally overheated the cultures to stress them. They also incorporated tiny probes — such as oxygen sensors and small LED lights — to perform optogenetic experiments. For instance, they introduced genes into the cells that allowed them to control the neural activity using different-colored light pulses.

This platform then enabled scientists to perform complex studies of human tissue without directly involving humans or performing invasive testing. In theory, any person could donate a limited number of their cells (e.g., blood sample, skin biopsy). Scientists can then reprogram these cells to produce a tiny brain spheroid that shares the person’s genetic identity. The authors believe that, by combining this technology with a personalized medicine approach using human stem cell-derived brain cultures, they will be able to glean insights faster and generate better, novel interventions.

“The advances spurred by this research will offer a new frontier in the way we study and understand the brain,” said Shirley Ryan AbilityLab’s Dr. Colin Franz, co-lead author on the paper who led the testing of the cortical spheroids. “Now that the 3-D platform has been developed and validated, we will be able to perform more targeted studies on our patients recovering from neurological injury or battling a neurodegenerative disease.”

Yoonseok Park, postdoctoral fellow at Northwestern University and co-lead author, added, “This is just the beginning of an entirely new class of miniaturized, 3-D bioelectronic systems that we can construct to expand the capacity of the regenerative medicine field. For example, our next generation of device will support the formation of even more complex neural circuits from brain to muscle, and increasingly dynamic tissues like a beating heart.”

Current electrode arrays for tissue cultures are 2-D, flat and unable to match the complex structural designs found throughout nature, such as those found in the human brain. Moreover, even when a system is 3-D, it is extremely challenging to incorporate more than one type of material into a small 3-D structure. With this advance, however, an entire class of 3-D bioelectronics devices has been tailored for the field of regenerative medicine.

“Now, with our small, soft 3-D electronics, the capacity to build devices that mimic the complex biological shapes found in the human body is finally possible, providing a much more holistic understanding of a culture,” said Northwestern’s John Rogers, who led the technology development using technology similar to that found in phones and computers. “We no longer have to compromise function to achieve the optimal form for interfacing with our biology.”

As a next step, scientists will use the devices to better understand neurological disease, test drugs and therapies that have clinical potential, and compare different patient-derived cell models. This understanding will then enable a better grasp of individual differences that may account for the wide variation of outcomes seen in neurological rehabilitation.

“As scientists, our goal is to make laboratory research as clinically relevant as possible,” said Kristen Cotton, research assistant in Dr. Franz’s lab. “This 3-D platform opens the door to new experiments, discovery and scientific advances in regenerative neurorehabilitation medicine that have never been possible.”

Caption: Three dimensional multifunctional neural interfaces for cortical spheroids and engineered assembloids Credit: Northwestern University

As for what brain ogranoids might be, Carl Zimmer in an Aug. 29, 2019 article for the New York Times provides an explanation,

Organoids Are Not Brains. How Are They Making Brain Waves?

Two hundred and fifty miles over Alysson Muotri’s head, a thousand tiny spheres of brain cells were sailing through space.

The clusters, called brain organoids, had been grown a few weeks earlier in the biologist’s lab here at the University of California, San Diego. He and his colleagues altered human skin cells into stem cells, then coaxed them to develop as brain cells do in an embryo.

The organoids grew into balls about the size of a pinhead, each containing hundreds of thousands of cells in a variety of types, each type producing the same chemicals and electrical signals as those cells do in our own brains.

In July, NASA packed the organoids aboard a rocket and sent them to the International Space Station to see how they develop in zero gravity.

Now the organoids were stowed inside a metal box, fed by bags of nutritious broth. “I think they are replicating like crazy at this stage, and so we’re going to have bigger organoids,” Dr. Muotri said in a recent interview in his office overlooking the Pacific.

What, exactly, are they growing into? That’s a question that has scientists and philosophers alike scratching their heads.

On Thursday, Dr. Muotri and his colleagues reported that they  have recorded simple brain waves in these organoids. In mature human brains, such waves are produced by widespread networks of neurons firing in synchrony. Particular wave patterns are linked to particular forms of brain activity, like retrieving memories and dreaming.

As the organoids mature, the researchers also found, the waves change in ways that resemble the changes in the developing brains of premature babies.

“It’s pretty amazing,” said Giorgia Quadrato, a neurobiologist at the University of Southern California who was not involved in the new study. “No one really knew if that was possible.”

But Dr. Quadrato stressed it was important not to read too much into the parallels. What she, Dr. Muotri and other brain organoid experts build are clusters of replicating brain cells, not actual brains.

If you have the time, I recommend reading Zimmer’s article in its entirety. Perhaps not coincidentally, Zimmer has an excerpt titled “Lab-Grown Brain Organoids Aren’t Alive. But They’re Not Not Alive, Either.” published in Slate.com,

From Life’s Edge: The Search For What It Means To Be Alive by Carl Zimmer, published by Dutton, an imprint of Penguin Publishing Group, a division of Penguin Random House, LLC. Copyright © 2021 by Carl Zimmer.

Cleber Trujillo led me to a windowless room banked with refrigerators, incubators, and microscopes. He extended his blue-gloved hands to either side and nearly touched the walls. “This is where we spend half our day,” he said.

In that room Trujillo and a team of graduate students raised a special kind of life. He opened an incubator and picked out a clear plastic box. Raising it above his head, he had me look up at it through its base. Inside the box were six circular wells, each the width of a cookie and filled with what looked like watered-down grape juice. In each well 100 pale globes floated, each the size of a housefly head.

Getting back to the research about monitoring brain organoids, here’s a link to and a citation for the paper about cortical spheroids,

Three-dimensional, multifunctional neural interfaces for cortical spheroids and engineered assembloids by Yoonseok Park, Colin K. Franz, Hanjun Ryu, Haiwen Luan, Kristen Y. Cotton, Jong Uk Kim, Ted S. Chung, Shiwei Zhao, Abraham Vazquez-Guardado, Da Som Yang, Kan Li, Raudel Avila, Jack K. Phillips, Maria J. Quezada, Hokyung Jang, Sung Soo Kwak, Sang Min Won, Kyeongha Kwon, Hyoyoung Jeong, Amay J. Bandodkar, Mengdi Han, Hangbo Zhao, Gabrielle R. Osher, Heling Wang, KunHyuck Lee, Yihui Zhang, Yonggang Huang, John D. Finan and John A. Rogers. Science Advances 17 Mar 2021: Vol. 7, no. 12, eabf9153 DOI: 10.1126/sciadv.abf9153

This paper appears to be open access.

According to a March 22, 2021 posting on the Shirley Riley AbilityLab website, the paper is featured on the front cover of Science Advances (vol. 7 no. 12).

L’Oréal introduces new wearable technology (UV sensor) as nail art?

Downloaded from https://inhabitat.com/tiny-yves-behar-designed-wearable-warns-you-when-youve-had-too-much-sun/uv-sense-by-loreal-and-yves-behar-2

(I should have published this a while ago but I think the content holds up even if it is a bit dated.) What you see on the model’s thumbnail (in the image above) is L’Oréal’s latest wearable tech as Lucy Wang notes in her January 8, 2018 preview article for inhabitat. (Note: The article is posted in a slide show, which offers quite a bit of detail (some of it technical) including this (Note: Links have been removed),

A tiny piece of innovative tech wants to help you stay away from sun-induced skin cancer. Global beauty leader L’Oréal teamed up with prolific designer Yves Behar of fuseproject to create UV Sense, the first battery-free wearable electronic UV sensor. Soon to be unveiled at the 2018 Consumer Electronics Show [CES] kicking off tomorrow [January 9, 2018], this innovative technology collects and shares real-time data on individual UV exposure within a wearable so small and thin it fits on a fingernail.

Christina Bonnington in a January 28, 2018 article for Fast Company offers less technical detail while offering many other useful tidbits (Note: Links have been removed),

… in 2016, beauty brand L’Oreal entered the space with another solution: a stretchable UV-sensing skin patch developed by the company’s technology incubator. The My UV Patch was an experiment in giving beauty consumers access to their sun-exposure data. A heart-shaped design on the patch changed colors depending on your sun exposure, which could then be analyzed via photograph in its accompanying app. L’Oreal distributed more than 1 million of the patches to consumers for free and was surprised by the level of engagement and effectiveness of the project: 34 percent of users reported wearing sunscreen more often, and 37 percent tried to stay in the shade more frequently.

Now, L’Oreal has a new wearable device for people like me—people concerned with their long-term sun-exposure risks, people at risk for melanoma, and people who want to know if they should be wearing more sunscreen or reapplying more often. But calling it a device is a bit of a stretch. The UV Sense is a circular, nail-sized sticker that’s little more than a UV sensor and an antenna. Unlike most other wearables, it’s completely batteryless; the sensor is powered by near-field communications and only transmits data when you place your phone near the sensor. Developed in partnership with Northwestern University, UV Sense now boasts the title of world’s smallest wearable.

Guive Balooch, the global vice president of L’Oréal’s technology incubator, said that the company wanted to make sure the sensor was comfortable for longtime wear. My UV Patch, L’Oreal’s first tech-centric UV-sensing product, was a disposable: You wore it for up to three days, then threw it away. The UV Sense, by contrast, lasts as long as any other wearable on the market. And besides just being small, it’s notable for its unique form factor. Its tiny size—about as thick as a credit card and lighter than a Tic Tac—makes it ideal as a stick-on nail applique. “We knew that nail art was booming,” Balooch said. “We thought that could be really interesting.” However, it’s not exclusively a nail sticker—it can just as easily be positioned on a pair of sunglasses or on another accessory you typically wear outdoors, such as a watch. On a nail, the sensor lasts for two weeks, then it needs to be readhered. (“The reason is more for the nail than the sensor,” Balooch said. “The nail is a living part of your body. UV gel or nail art normally lasts about two weeks.”)

For anyone who’d like to bear down on the technical detail, there’s Daniel Cooper’s January 7, 2018 article for engadget (Note: Links have been removed),

L’Oreal is working with MC10, a medical technology wearables outfit established by professor John Rogers at Northwestern University. Rogers is famous for developing the “wearable tattoo,” circuit boards no thicker than a band-aid that attach to people’s skin. The eventual goal for such technology is that it will replace the bulky and invasive monitors strapped onto hospital patients.

Interesting, yes? And as the writers note it’s not L’Oréal’s first foray into wearable tech. For anyone interested in the 2016 version, there’s my January 6, 2016 posting about ‘my UV patch”  and its introduction a the 2016 CES.  As for John Rogers, one of my latest postings on him and his work is a May 15, 2015 posting.  You can find more using “John Rogers” as your blog search term.

Swallow your technology and wear it inside (wearable tech: 2 of 3)

While there are a number of wearable and fashionable pieces of technology that monitor heart rate and breathing, they are all worn on the outside of your body. Researchers are working on an alternative that can be swallowed and will monitor vital signs from within the gastrointestinal tract. I believe this is a prototype of the device,

This ingestible electronic device invented at MIT can measure heart rate and respiratory rate from inside the gastrointestinal tract. Courtesy: MIT

This ingestible electronic device invented at MIT can measure heart rate and respiratory rate from inside the gastrointestinal tract. Image: Albert Swiston/MIT Lincoln Laboratory Courtesy: MIT

From a Nov. 18, 2015 news item on phys.org,

This type of sensor could make it easier to assess trauma patients, monitor soldiers in battle, perform long-term evaluation of patients with chronic illnesses, or improve training for professional and amateur athletes, the researchers say.

The new sensor calculates heart and breathing rates from the distinctive sound waves produced by the beating of the heart and the inhalation and exhalation of the lungs.

“Through characterization of the acoustic wave, recorded from different parts of the GI tract, we found that we could measure both heart rate and respiratory rate with good accuracy,” says Giovanni Traverso, a research affiliate at MIT’s Koch Institute for Integrative Cancer Research, a gastroenterologist at Massachusetts General Hospital, and one of the lead authors of a paper describing the device in the Nov. 18 issue of the journal PLOS One.

A Nov. 18, 2015 Massachusetts Institute of Technology (MIT) news release by Anne Trafton, which originated the news item, further explains the research,

Doctors currently measure vital signs such as heart and respiratory rate using techniques including electrocardiograms (ECG) and pulse oximetry, which require contact with the patient’s skin. These vital signs can also be measured with wearable monitors, but those are often uncomfortable to wear.

Inspired by existing ingestible devices that can measure body temperature, and others that take internal digestive-tract images, the researchers set out to design a sensor that would measure heart and respiratory rate, as well as temperature, from inside the digestive tract.

The simplest way to achieve this, they decided, would be to listen to the body using a small microphone. Listening to the sounds of the chest is one of the oldest medical diagnostic techniques, practiced by Hippocrates in ancient Greece. Since the 1800s, doctors have used stethoscopes to listen to these sounds.

The researchers essentially created “an extremely tiny stethoscope that you can swallow,” Swiston says. “Using the same sensor, we can collect both your heart sounds and your lung sounds. That’s one of the advantages of our approach — we can use one sensor to get two pieces of information.”

To translate these acoustic data into heart and breathing rates, the researchers had to devise signal processing systems that distinguish the sounds produced by the heart and lungs from each other, as well as from background noise produced by the digestive tract and other parts of the body.

The entire sensor is about the size of a multivitamin pill and consists of a tiny microphone packaged in a silicone capsule, along with electronics that process the sound and wirelessly send radio signals to an external receiver, with a range of about 3 meters.

In tests along the GI tract of pigs, the researchers found that the device could accurately pick up heart rate and respiratory rate, even when conditions such as the amount of food being digested were varied.

“The authors introduce some interesting and radically different approaches to wearable physiological status monitors, in which the devices are not worn on the skin or on clothing, but instead reside, in a transient fashion, inside the gastrointestinal tract. The resulting capabilities provide a powerful complement to those found in wearable technologies as traditionally conceived,” says John Rogers, a professor of materials science and engineering at the University of Illinois who was not part of the research team.

Better diagnosis

The researchers expect that the device would remain in the digestive tract for only a day or two, so for longer-term monitoring, patients would swallow new capsules as needed.

For the military, this kind of ingestible device could be useful for monitoring soldiers for fatigue, dehydration, tachycardia, or shock, the researchers say. When combined with a temperature sensor, it could also detect hypothermia, hyperthermia, or fever from infections.

In the future, the researchers plan to design sensors that could diagnose heart conditions such as abnormal heart rhythms (arrhythmias), or breathing problems including emphysema or asthma. Currently doctors require patients to wear a harness (Holter) monitor for up to a week to detect such problems, but these often fail to produce a diagnosis because patients are uncomfortable wearing them 24 hours a day.

“If you could ingest a device that would listen for those pathological sounds, rather than wearing an electrical monitor, that would improve patient compliance,” Swiston says.

The researchers also hope to create sensors that would not only diagnose a problem but also deliver a drug to treat it.

“We hope that one day we’re able to detect certain molecules or a pathogen and then deliver an antibiotic, for example,” Traverso says. “This development provides the foundation for that kind of system down the line.”

MIT has provided a video with two of the researchers describing their work and and plans for its future development,

Here’s a link to and a citation for the paper,

Physiologic Status Monitoring via the Gastrointestinal Tract by G. Traverso, G. Ciccarelli, S. Schwartz, T. Hughes, T. Boettcher, R. Barman, R. Langer, & A. Swiston. PLOS DOI: 10.1371/journal.pone.0141666 Published: November 18, 2015

This paper is open access.

Note added Nov. 25, 2015 at 1625 hours PDT: US National Public Radio (NPR) has a story on this research. You can find Nov. 23, 2015 podcast (about six minutes) and a series of textual excerpts featuring Albert Swiston, biomaterials scientist at MIT, and Stephen Shankland, senior writer for CNET covering digital technology, from the podcast here.

Norway and degradable electronics

It’s a bit higgledy-piggledy but a Nov. 20, 2014 news item on Nanowerk highlights some work with degradable electronics taking place in Norway,

When the FM frequencies are removed in Norway in 2017, all old-fashioned radios will become obsolete, leaving the biggest collection of redundant electronics ever seen – a mountain of waste weighing something between 25,000 and 30,000 tonnes.

The same thing is happening with today’s mobile telephones, PCs and tablets, all of which are constantly being updated and replaced faster than the blink of an eye. The old devices end up on waste tips, and even though we in the west recover some materials for recycling, this is only a small proportion of the whole.

And nor does the future bode well with waste in mind. Technologists’ vision of the future is the “Internet of Things”. Electronics are currently printed onto plastics. All products are fitted with sensors designed to measure something, and to make it possible to talk to other devices around them. Davor Sutija is General Manager at the electronics firm Thin Film, and he predicts that in the course of a few years each of us will progress from having a single sensor to having between a hundred and a thousand. This in turn will mean that billions of devices with electronic bar codes will be released onto the market.

Researchers are now getting to grips with this problem. Their aim is to develop processes in which electronics are manufactured in such a way that their entire life cycle is controlled, including their ultimate disappearance.

A Nov. 20, 2014 article by Åse Dragland for the Gemini newsletter (also found as a Nov. 20, 2014 news release on SINTEF [Norwegian: Stiftelsen for industriell og teknisk forskning]), describes the inspiration for the work in Norway while pointing out some signficant differences from US researchers in the approach to creating a commercial application,

In New Orleans in the USA, researchers have made electronic circuits which they implant into surgical wounds following operations on rats. Each wound is sewn up and the electricity in the circuits then accelerates the healing process. After a few weeks, the electronics are dissolved by the body fluids, making it unnecessary to re-open the wound to remove them manually.

In Norway, researchers at SINTEF have now succeeded in making components containing magnesium circuits designed to transfer energy. These are soluble in water and disappear after a few hours.

“We make no secret of the fact that we are putting our faith in the research results coming out of the USA”, says Karsten Husby at SINTEF ICT. “The Americans have made amazing contributions both in relation to medical applications, and towards resolving the issue of waste. We want to try to find alternative approaches to the same problem”, he says.

The circuit containing the small components is printed on a silicon wafer. At only a few nanometres thick, the circuits are extremely thin, and this enables them to dissolve more effectively. Some of the circuit components are made of magnesium, others of silicon, and others of silicon with a magnesium additive.

But the journey to the researchers’ goal from their current position leaves them with more than enough work to do. Making the ultra-thin circuits is a challenge enough in itself, but they also have to find a “coating” or “film” which will act as a protective packaging around the circuits.

The Americans use silk as their coating material, but the Norwegians are not in favour of this. The silk used is made as part of a process which involves the substance lithium, which is banned at MiNaLab – the laboratory where the SINTEF researchers work.

“Lithium generates a technical problem for our lab”, says Geir Uri Jensen, “so we’re considering alternatives, including a variety of plastics”, he says. “In order to achieve this, we’ve brought in some materials scientists here at SINTEF who are very skilled in this field”, he says.

The nature of the coating must be tailored to the time at which the electronics are required to degrade. In some cases this is just one week – in others, four. For example, if the circuit package is designed to be used in seawater, and fitted with sensors for taking measurements from oil spills, the film must be made so that it remains in place for the weeks in which the measurements are being taken.

“When the external fluids penetrate to the “guts” inside the packaging, the circuits begin to degrade. The job must be completed before this happens”, says Karsten Husby.

Geir Uri Jensen makes a sketch and explains how the nano researchers use horizontal and vertical etching processes in the lab to deposit all the layers onto the silicon circuits. And then – how they have to etch and lift the circuit loose from the silicon wafer in order later to transfer it across to the film.

“This works well enough using sensors at full scale”, he says, “but when the wafers are as thin as this, things become more tricky”. Jensen shrugs. “Even if the angle is just a little off, the whole assembly will snap”, he says.

There’s no doubt that as the use of consumer electronics increases, so too does the need to remove obsolete electronic products. Just think of all the cheap electronics built into children’s toys which are thrown away every year.

The removal of “outdated electronics” can also be a very labour-intensive process. Every day, surgeons place implants fitted with sensors into our bodies in order to measure everything from blood pressure and pressure on the brain, to how our hip implants are working. Some weeks later they have to operate again in order to remove the electronics.

But not everyone is interested in the new technologies developing in this field. Electronics companies which manufacture circuits are more interested in selling their products than in investing in research that results in their products disappearing. And companies which rely on recycling for their revenues may regard these new ideas as a threat to their existence.
Eco-friendly electronics are on the way

“It’s important to make it clear that we’re not manufacturing a final product, but a demo that can show that an electronic component can be made with properties that make it degradable”, says Husby. “Our project is now in its second year, but we’ll need a partner active in the industry and more funding in the years ahead if we’re to meet our objectives. There’s no doubt that eco-friendly electronics is a field which will come into its own, also here in Norway. And we’ve made it our mission to reach our goals”, he says.

Here’s an image of dissolving electronic circuits made available by the researchers,

Electronic circuits can be implanted into surgical wounds and assist the healing process by accelerating wound closure. After a few weeks, the electronics are dissolved by the body fluids, making it unnecessary to re-open the wound to remove them manually. Photos: Werner Juvik/SINTEF - See more at: http://gemini.no/en/2014/11/tomorrows-degradable-electronics/#sthash.Erh1sZp2.dpuf

Electronic circuits can be implanted into surgical wounds and assist the healing process by accelerating wound closure. After a few weeks, the electronics are dissolved by the body fluids, making it unnecessary to re-open the wound to remove them manually. Photos: Werner Juvik/SINTEF – See more at: http://gemini.no/en/2014/11/tomorrows-degradable-electronics/#sthash.Erh1sZp2.dpuf

The researcher most associated with this kind of work is John Rogers at the University of Illinois at Urbana-Champaign and you can read more about biodegradable/dissolving electronics in a Sept. 27, 2012 article (open access) by Katherine Bourzac for Nature magazine. You can find more information about Thin Film Electronics or Thinfilm Electronics (mentioned in the third paragraph of the news item on Nanowerk) website here.

Dimpling can be more than cute, morphable surfaces (smorphs) from MIT (Massachusetts Institute of Technology)

A morphable surface developed by an MIT team can change surface texture — from smooth to dimply, and back again — through changes in pressure. When the inside pressure is reduced, the flexible material shrinks, and the stiffer outer layer wrinkles. Increasing pressure returns the surface to a smooth state.

A June 24, 2014 news item on Nanowerk features a story about the origins of the dimpled golf ball, aerodynamics, and some very pink material (Note: A link has been removed),

There is a story about how the modern golf ball, with its dimpled surface, came to be: In the mid-1800s, it is said, new golf balls were smooth, but became dimpled over time as impacts left permanent dents. Smooth new balls were typically used for tournament play, but in one match, a player ran short, had to use an old, dented one, and realized that he could drive this dimpled ball much further than a smooth one.

Whether that story is true or not, testing over the years has proved that a golf ball’s irregular surface really does dramatically increase the distance it travels, because it can cut the drag caused by air resistance in half. Now researchers at MIT are aiming to harness that same effect to reduce drag on a variety of surfaces — including domes that sometimes crumple in high winds, or perhaps even vehicles.

Detailed studies of aerodynamics have shown that while a ball with a dimpled surface has half the drag of a smooth one at lower speeds, at higher speeds that advantage reverses. So the ideal would be a surface whose smoothness can be altered, literally, on the fly — and that’s what the MIT team has developed.

The new work is described in a paper in the journal Advanced Materials (“Smart Morphable Surfaces for Aerodynamic Drag Control”) by MIT’s Pedro Reis and former MIT postdocs Denis Terwagne (now at the Université Libre de Bruxelles in Belgium) and Miha Brojan (now at the University of Ljubljana in Slovenia).

esearchers made this sphere to test their concept of morphable surfaces. Made of soft polymer with a hollow center, and a thin coating of a stiffer polymer, the sphere becomes dimpled when the air is pumped out of the hollow center, causing it to shrink. (Photo courtesy of the MIT researchers)

Researchers made this sphere to test their concept of morphable surfaces. Made of soft polymer with a hollow center, and a thin coating of a stiffer polymer, the sphere becomes dimpled when the air is pumped out of the hollow center, causing it to shrink. (Photo courtesy of the MIT researchers)

A June 24, 2014 MIT (Massachusetts Institute of Technology) news release (also on EurekAlert) by David Chandler, which originated the news item, provides more detail about the work,

The ability to change the surface in real time comes from the use of a multilayer material with a stiff skin and a soft interior — the same basic configuration that causes smooth plums to dry into wrinkly prunes. To mimic that process, Reis and his team made a hollow ball of soft material with a stiff skin — with both layers made of rubberlike materials — then extracted air from the hollow interior to make the ball shrink and its surface wrinkle.

“Numerous studies of wrinkling have been done on flat surfaces,” says Reis, an assistant professor of mechanical engineering and civil and environmental engineering. “Less is known about what happens when you curve the surface. How does that affect the whole wrinkling process?”

The answer, it turns out, is that at a certain degree of shrinkage, the surface can produce a dimpled pattern that’s very similar to that of a golf ball — and with the same aerodynamic properties.

The aerodynamic properties of dimpled balls can be a bit counterintuitive: One might expect that a ball with a smooth surface would sail through the air more easily than one with an irregular surface. The reason for the opposite result has to do with the nature of a small layer of the air next to the surface of the ball. The irregular surface, it turns out, holds the airflow close to the ball’s surface longer, delaying the separation of this boundary layer. This reduces the size of the wake — the zone of turbulence behind the ball — which is the primary cause of drag for blunt objects.

When the researchers saw the wrinkled outcomes of their initial tests with their multilayer spheres, “We realized that these samples look just like golf balls,” Reis says. “We systematically tested them in a wind tunnel, and we saw a reduction in drag very similar to that of golf balls.”

Because the surface texture can be controlled by adjusting the balls’ interior pressure, the degree of drag reduction can be controlled at will. “We can generate that surface topography, or erase it,” Reis says. “That reversibility is why this is pretty interesting; you can switch the drag-reducing effect on and off, and tune it.”

As a result of that variability, the team refers to these as “smart morphable surfaces” — or “smorphs,” for short. The pun is intentional, Reis says: The paper’s lead author — Terwagne, a Belgian comics fan — pointed out that one characteristic of Smurfs cartoon characters is that no matter how old they get, they never develop wrinkles.

Terwagne says that making the morphable surfaces for lab testing required a great deal of trial-and-error — work that ultimately yielded a simple and efficient fabrication process. “This beautiful simplicity to achieve a complex functionality is often used by nature,” he says, “and really inspired me to investigate further.”

Many researchers have studied various kinds of wrinkled surfaces, with possible applications in areas such as adhesion, or even unusual optical properties. “But we are the first to use wrinkling for aerodynamic properties,” Reis says.

The drag reduction of a textured surface has already expanded beyond golf balls: The soccer ball being used at this year’s World Cup, for example, uses a similar effect; so do some track suits worn by competitive runners. For many purposes, such as in golf and soccer, constant dimpling is adequate, Reis says.

But in other uses, the ability to alter a surface could prove useful: For example, many radar antennas are housed in spherical domes, which can collapse catastrophically in very high winds. A dome that could alter its surface to reduce drag when strong winds are expected might avert such failures, Reis suggests. Another application could be the exterior of automobiles, where the ability to adjust the texture of panels to minimize drag at different speeds could increase fuel efficiency, he says.

Delightful is not the first adjective that jumps to my mind when describing this work but I’m not an engineer (from the news release),

John Rogers, a professor of materials research and engineering at the University of Illinois at Urbana-Champaign who was not involved in this work, says, “It represents a delightful example of how controlled processes of mechanical buckling can be used to create three-dimensional structures with interesting aerodynamic properties. The type of dynamic tuning of sophisticated surface morphologies made possible by this approach would be difficult or impossible to achieve in any other way.”

Here’s a link to and a citation for the paper,

Smart Morphable Surfaces for Aerodynamic Drag Control by Denis Terwagne, Miha Brojan, and Pedro M. Reis. Advanced Materials DOI: 10.1002/adma.201401403 Article first published online: 23 JUN 2014

© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

This paper is behind a paywall.

Surgery with fingertip control

In the future, ‘surgery at your fingertips’ could be literally true. Researchers at the University of Illinois at Urbana-Champaign have created a silicon nanomembrane that can be fitted onto the fingertips and could, one day, be used in surgical procedures. From the Aug. 9, 2012 news item on ScienceDaily,

The intricate properties of the fingertips have been mimicked and recreated using semiconductor devices in what researchers hope will lead to the development of advanced surgical gloves.

The devices, shown to be capable of responding with high precision to the stresses and strains associated with touch and finger movement, are a step towards the creation of surgical gloves for use in medical procedures such as local ablations [excising or removing tissue] and ultrasound scans.

Researchers from the University of Illinois at Urbana-Champaign, Northwestern University and Dalian University of Technology have published their study August 10, in IOP [Institute of Physics] Publishing’s journal Nanotechnology.

The Aug. 10,2012 posting on the IOP website  offers this detail about the research,

The electronic circuit on the ‘skin’ is made of patterns of gold conductive lines and ultrathin sheets of silicon, integrated onto a flexible polymer called polyimide. The sheet is then etched into an open mesh geometry and transferred to a thin sheet of silicone rubber moulded into the precise shape of a finger.

This electronic ‘skin’, or finger cuff, was designed to measure the stresses and strains at the fingertip by measuring the change in capacitance – the ability to store electrical charge – of pairs of microelectrodes in the circuit.  Applied forces decreased the spacing in the skin which, in turn, increased the capacitance.

The fingertip device could also be fitted with sensors for measuring motion and temperature, with small-scale heaters as actuators for ablation and other related operations

The researchers experimented with having the electronics on the inside of the device, in contact with wearer’s skin, and also on the outside. They believe that because the device exploits materials and fabrication techniques adopted from the established semiconductor industry, the processes can be scaled for realistic use at reasonable cost.

“Perhaps the most important result is that we are able to incorporate multifunctional, silicon semiconductor device technologies into the form of soft, three-dimensional, form-fitting skins, suitable for integration not only with the fingertips but also other parts of the body,” continued Professor Rogers [John Rogers, co-author of the study].

Here’s what an image of these e-fingertips,

Virtual touch. Electronic fingertips could one day allow us to feel virtual sensations. Credit: John Rogers/University of Illinois at Urbana-Champaign

Krystnell A offers a more detailed description of the e-fingetips in an Aug. 9, 2012 story for Science NOW,

Hoping to create circuits with the flexibility of skin, materials scientist John Rogers of the University of Illinois, Urbana-Champaign, and colleagues cut up nanometer-sized strips of silicon; implanted thin, wavy strips of gold to conduct electricity; and mounted the entire circuit in a stretchable, spider web-type mesh of polymer as a support. They then embedded the circuit-polyimide structure onto a hollow tube of silicone that had been fashioned in the shape of a finger. Just like turning a sock inside out, the researchers flipped the structure so that the circuit, which was once on the outside of the tube, was on the inside where it could touch a finger placed against it.

To test the electronic fingers, the researchers put them on and pressed flat objects, such as the top of their desks. The pressure created electric currents that were transferred to the skin, which the researchers felt as mild tingling. That’s a first step in creating electrical signals that could be sent to the fingers, which could virtually recreate sensations such as heat, pressure, and texture, the team reports online today in Nanotechnology.

Rogers says another application of the technology is to custom fit the “electronic skin” around entire organs, allowing doctors to remotely monitor changes in temperature and blood flow. Electronic skin could also restore sensation to people who have lost their natural skin, he says, such as burn victims or amputees.

Here’s a link to the article which is freely accessible for 30 days after publication, from the Aug. 9, 2012 news item on ScienceDaily,

Ming Ying, Andrew P Bonifas, Nanshu Lu, Yewang Su, Rui Li, Huanyu Cheng, Abid Ameen, Yonggang Huang, John A Rogers. Silicon nanomembranes for fingertip electronics. Nanotechnology, 2012; 23 (34): 344004 DOI: 10.1088/0957-4484/23/34/344004

My best guess is that free access will no longer be available by Sept. 7 (or so) , 2012. I last wrote about John Rogers’ work in an Aug. 12, 2011 posting about electronic tattoos.

Electronic tattoos

Yes, you can temporarily apply electronics that look like tattoos to your skin. From the August 11, 2011 news item on physorg.com,

Engineers have developed a device platform that combines electronic components for sensing, medical diagnostics, communications and human-machine interfaces, all on an ultrathin skin-like patch that mounts directly onto the skin with the ease, flexibility and comfort of a temporary tattoo.

The team led by professor John Rogers at the University of Illinois has create wearable electronics.

The patches are initially mounted on a thin sheet of water-soluble plastic, then laminated to the skin with water – just like applying a temporary tattoo. Alternately, the electronic components can be applied directly to a temporary tattoo itself, providing concealment for the electronics.

Here’s a video released by the University of Illinois featuring Rogers and his colleague, lead author Dae-Hyeong Kim, describing their work,
http://www.youtube.com/watch?v=tOk7OWZ-Lck

(ETA April 7, 2014: This link leads to a notice that the video is no long available.)

Possible applications for this technology include (from the news item on physorg.com),

In addition to gathering data, skin-mounted electronics could provide the wearers with added capabilities. For example, patients with muscular or neurological disorders, such as ALS, could use them to communicate or to interface with computers. The researchers found that, when applied to the skin of the throat, the sensors could distinguish muscle movement for simple speech. The researchers have even used the electronic patches to control a video game, demonstrating the potential for human-computer interfacing.

The August 11, 2011 news item about this research on Nanwerk features some technical details [Note: The news item on physorg.com also offers technical information but the Nanowerk item from the National Science Foundation offered some additional details.],

The researchers have created a new class of micro-electronics with a technology that they call an epidermal electronic system (EES). They have incorporated miniature sensors, light-emitting diodes, tiny transmitters and receivers, and networks of carefully crafted wire filaments into their initial designs.

The technology is presented—along with initial measurements that researchers captured using the EES—in a paper by lead author Dae-Hyeong Kim of the University of Illinois and colleagues in the August 12, 2011, issue of Science (“Epidermal Electronics “).

While existing technologies accurately measure heart rate, brain waves and muscle activity, EES devices offer the opportunity to seamlessly apply sensors that have almost no weight, no external wires and require negligible power.

Because of the small power requirements, the devices can draw power from stray (or transmitted) electromagnetic radiation through the process of induction and can harvest a portion of their energy requirements from miniature solar collectors.

The EES designs yield flat devices that are less than 50-microns thick—thinner than the diameter of a human hair—which are integrated onto the polyester backing familiar from stick-on tattoos.

The devices are so thin that close-contact forces called van der Waals interactions dominate the adhesion at the molecular level, so the electronic tattoos adhere to the skin without any glues and stay in place for hours. The recent study demonstrated device lifetimes of up to 24 hours under ideal conditions.

In light of today’s earlier posting on surveillance, I’m torn between appreciating the technological advance with its attendant possibilities and my concerns over increased monitoring.

Adding to my disconcertment is this comment from one of Rogers’ other colleagues (from the news item on physorg.com),

“The blurring of electronics and biology is really the key point here,” Huang [Northwestern University engineering professor Yonggang Huang] said. “All established forms of electronics are hard, rigid. Biology is soft, elastic. It’s two different worlds. This is a way to truly integrate them.”

Engineers never talk about the social implications of these concepts (integrating biology and electronics) which can be quite frightening and upsetting to some folks depending on how they are introduced to the concept.

While existing technologies accurately measure heart rate, brain waves and muscle activity, EES devices offer the opportunity to seamlessly apply sensors that have almost no weight, no external wires and require negligible power.
Because of the small power requirements, the devices can draw power from stray (or transmitted) electromagnetic radiation through the process of induction and can harvest a portion of their energy requirements from miniature solar collectors.
The EES designs yield flat devices that are less than 50-microns thick—thinner than the diameter of a human hair—which are integrated onto the polyester backing familiar from stick-on tattoos.
The devices are so thin that close-contact forces called van der Waals interactions dominate the adhesion at the molecular level, so the electronic tattoos adhere to the skin without any glues and stay in place for hours. The recent study demonstrated device lifetimes of up to 24 hours under ideal conditions.