MIT: Using light to propel water ~ Significant  Applications in Oil Field Production



A new system developed by engineers at MIT could make it possible to control the way water moves over a surface, using only light. This advance may open the door to technologies such as microfluidic diagnostic devices whose channels and valves could be reprogrammed on the fly, or field systems that could separate water from oil at a drilling rig, the researchers say.

The system, reported in the journal Nature Communications (“Visible light guided manipulation of liquid wettability on photoresponsive surfaces”), was developed by MIT associate professor of mechanical engineering Kripa Varanasi, School of Engineering Professor of Teaching Innovation Gareth McKinley, former postdoc Gibum Kwon, graduate student Divya Panchanathan, former research scientist Seyed Mahmoudi, and Mohammed Gondal at the King Fahd University of Petroleum and Minerals in Saudi Arabia.

 

By creating surfaces whose interactions with water — a property known as wettability — can be activated by light, the researchers found they could directly separate oil from water. The process causes individual droplets of water to coalesce and spread across the surface. (Image courtesy of the researchers)

The initial goal of the project was to find ways of separating oil from water, for example, to treat the frothy mixture of briny water and crude oil produced from certain oil wells. The more thoroughly these mixtures are intermingled — the finer the droplets are — the harder they are to separate. Sometimes electrostatic methods are used, but these are energy-intensive and don’t work when the water is highly saline, as is often the case. Instead, the team explored the use of “photoresponsive” surfaces, whose responses to water can be altered by exposure to light.

By creating surfaces whose interactions with water — a property known as wettability — could be activated by light, the researchers found they could directly separate the oil from the water by causing individual droplets of water to coalesce and spread across the surface. The more the water droplets fuse together, the more they separate from the oil.

Photoresponsive materials have been widely studied and used; one example is the active ingredient in most sunscreens, titanium dioxide, also known as titania. But most of these materials, including titania, respond primarily to ultraviolet light and hardly at all to visible light. Yet only about 5 percent of sunlight is in the ultraviolet range. So the researchers figured out a way to treat the titania surface to make it responsive to visible light.

Driving droplets of water across a surface with light


The method also be used to drive droplets of water across a surface, as the team demonstrated in a series of experiments. By selectively changing the material’s wettability using a moving beam of light, a droplet can be directed toward the more wettable area, propelling it in any desired direction with great precision. (Image courtesy of the researchers)

They did so by first using a layer-by-layer deposition technique to build up a film of polymer-bound titania particles on a layer of glass. Then they dip-coated the material with a simple organic dye. The resulting surface turned out to be highly responsive to visible light, producing a change in wettability when exposed to sunlight that is much greater than that of the titania itself.
When activated by sunlight, the material proved very effective at “demulsifying” the oil-water mixture — getting the water and oil to separate from each other.

“We were inspired by the work in photovoltaics, where dye sensitization was used to improve the efficiency of absorption of solar radiation,” says Varansi. “The coupling of the dye to titania particles allows for the generation of charge carriers upon light illumination. This creates an electric potential difference to be established between the surface and the liquid upon illumination, and leads to a change in the wetting properties.”

“Saline water spreads out on our surface under illumination, but oil doesn’t,” says Kwon, who is now an assistant professor at the University of Kansas. “We found that virtually all the seawater will spread out on the surface and get separated from crude oil, under visible light.”

The same effect could also be used to drive droplets of water across a surface, as the team demonstrated in a series of experiments. By selectively changing the material’s wettability using a moving beam of light, a droplet can be directed toward the more wettable area, propelling it in any desired direction with great precision.
Such systems could be designed to make microfluidic devices without built-in boundaries or structures. The movement of liquid — for example a blood sample in a diagnostic lab-on-a-chip — would be entirely controlled by the pattern of illumination being projected onto it.


The photoresponsive effect can be highly tuned by selecting from among thousands of available organic dyes. (Image courtesy of the researchers)

“By systematically studying the relationship between the energy levels of the dye and the wettability of the contacting liquid, we have come up with a framework for the design of these light-guided liquid manipulation systems,” Varanasi says. “By choosing the right kind of dye, we can create a significant change in droplet dynamics. It’s light-induced motion – a touchless motion of droplets.”

The switchable wettability of these surfaces has another benefit: They can be largely self-cleaning. When the surface is switched from water-attracting (hydrophilic) to water-repelling (hydrophobic), any water on the surface gets driven off, carrying with it any contaminants that may have built up.

Since the photoresponsive effect is based on the dye coating, it can be highly tuned by selecting from among the thousands of available organic dyes. All of the materials involved in the process are widely available, inexpensive, commodity materials, the researchers say, and the processes for making them are commonplace.

Source: By David L. Chandler, MIT

MIT: Cheap – Solar Cells – On Paper



Prof. Karen Gleason has come up with a low-cost, environmentally friendly way to make solar cells on ordinary tracing paper. Photo: Len RubensteinSpring 2012

Solar Cells on Paper

Chemical engineer Karen K. Gleason would like to paper the world with solar cells. Glued to laptops, tacked onto roof tiles, tucked into pockets, lining window shades, she envisions ultrathin, ultra-flexible solar cells going where no solar cells have gone before.

Silvery blue solar cells seem to magically generate electricity from sunlight the way Rumpelstiltskin spun straw into gold but in their present form, they’re more akin to gold than straw. 


Karen Gleason develops a low-cost, environmentally friendly way to make solar cells on tracing paper, which one day might charge a cell phone.




The cost of manufacturing crystalline and thin-film solar cells with silicon, glass, and rare earth materials like tellurium and indium is high.


LEARN MORE

MIT’s New Paper Chase: Cheap – Paper Solar Cells

Gleason, the Alexander and I. Michael Kasser Professor of Chemical Engineering, has collaborated with Vladimir Bulovic, professor of electrical engineering; former chemical engineering graduate student Miles C. Barr; and others to come up with a low-cost, environmentally friendly way to make practically indestructible solar cells on ordinary tracing paper. 


One day, a paper solar cell might help us charge a cell phone. “A paper substrate is a thousand times cheaper than silicon and glass. What’s more, these solar cells can be scrunched up, folded a thousand times, and weatherproofed,” she says.

Using abundant, inexpensive organic elements like carbon, oxygen, and copper­­ — “nothing exotic,” she says — in a vacuum chamber, layers are “printed” through a process called vapor deposition, similar to frost forming on a window. At less than 120 degrees Celsius, the method is gentler and cooler than that normally used to manufacture photovoltaic materials, allowing it to be used on delicate paper, cloth, or plastic. “We repeat that five times and you end up with a solar cell,” she says; tweaking the composition of the five layers of materials determines the cells’ energy output. 

The research is funded by MITEI founding member Eni SpA, Italy’s biggest energy company, which is pursuing new advances in biofuels, solar, and other forms of alternative energy.

“The challenge of the project appealed to me,” she says. “I also thought it would be fun.” Her students display a prototype solar cell (a sheet of paper embossed with a pinstripe and chain-link design) folded into a paper airplane as a power source for an LCD clock. 
Gleason would like to see the first commercial solar paper devices hit the market in five years, but first the cells’ efficiency has to be ramped up from nearly 4 percent to at least 10 percent. (Commercial solar cells have an efficiency of around 15 percent.) MIT engineers believe this is doable

Then, the sky’s the limit — solar cells could power iPads, generate lighting inside tents, keep ski clothing toasty. 

“The paper cells’ portability could have a big impact in developing countries, where the cost of transporting solar cells has been prohibitive.

“Rather than confining solar power to rooftops or solar farms, paper photovoltaics can be used virtually anywhere, making energy ubiquitous,” Gleason says.

MIT: Advanced thin-film technique could deliver long-lasting medication ~ Potential for Certain Types of Cancer Treatment


MIT 1-implantable-film-MIT

MIT professor Paula Hammond (right) and Bryan Hsu PhD’ 14 have developed a nanoscale film that can be used to deliver medication, either directly through injections, or by coating implantable medical devices. Photo: Dominick Reuter

Nanoscale, biodegradable drug-delivery method could provide a year or more of steady doses.

About one in four older adults suffers from chronic pain. Many of those people take medication, usually as pills. But this is not an ideal way of treating pain: Patients must take medicine frequently, and can suffer side effects, since the contents of pills spread through the bloodstream to the whole body.

Now researchers at MIT have refined a technique that could enable pain medication and other drugs to be released directly to specific parts of the body — and in steady doses over a period of up to 14 months.  The method uses biodegradable, nanoscale “thin films” laden with drug molecules that are absorbed into the body in an incremental process.

“It’s been hard to develop something that releases [medication] for more than a couple of months,” says Paula Hammond, the David H. Koch Professor in Engineering at MIT, and a co-author of a new paper on the advance. “Now we’re looking at a way of creating an extremely thin film or coating that’s very dense with a drug, and yet releases at a constant rate for very long time periods.”

In the paper, published today in the Proceedings of the National Academy of Sciences, the researchers describe the method used in the new drug-delivery system, which significantly exceeds the release duration achieved by most commercial controlled-release biodegradable films.

“You can potentially implant it and release the drug for more than a year without having to go in and do anything about it,” says Bryan Hsu PhD ’14, who helped develop the project as a doctoral student in Hammond’s lab. “You don’t have to go recover it. Normally to get long-term drug release, you need a reservoir or device, something that can hold back the drug. And it’s typically nondegradable. It will release slowly, but it will either sit there and you have this foreign object retained in the body, or you have to go recover it.”

Layer by layer

The paper was co-authored by Hsu, Myoung-Hwan Park of Shamyook University in South Korea, Samantha Hagerman ’14, and Hammond, whose lab is in the Koch Institute for Integrative Cancer Research at MIT.

The research project tackles a difficult problem in localized drug delivery: Any biodegradable mechanism intended to release a drug over a long time period must be sturdy enough to limit hydrolysis, a process by which the body’s water breaks down the bonds in a drug molecule. If too much hydrolysis occurs too quickly, the drug will not remain intact for long periods in the body. Yet the drug-release mechanism needs to be designed such that a drug molecule does, in fact, decompose in steady increments.

To address this, the researchers developed what they call a “layer-by-layer” technique, in which drug molecules are effectively attached to layers of thin-film coating. In this specific case, the researchers used diclofenac, a nonsteroidal anti-inflammatory drug that is often prescribed for osteoarthritis and other pain or inflammatory conditions. They then bound it to thin layers of poly-L-glutamatic acid, which consists of an amino acid the body reabsorbs, and two other organic compounds. The film can be applied onto degradable nanoparticles for injection into local sites or used to coat permanent devices, such as orthopedic implants.

In tests, the research team found that the diclofenac was steadily released over 14 months. Because the effectiveness of pain medication is subjective, they evaluated the efficacy of the method by seeing how well the diclofenac blocked the activity of cyclooxygenase (COX), an enzyme central to inflammation in the body.

“We found that it remains active after being released,” Hsu says, meaning that the new method does not damage the efficacy of the drug. Or, as the paper notes, the layer-by-layer method produced “substantial COX inhibition at a similar level” to pills.

The method also allows the researchers to adjust the quantity of the drug being delivered, essentially by adding more layers of the ultrathin coating.

A viable strategy for many drugs

Hammond and Hsu note that the technique could be used for other kinds of medication; an illness such as tuberculosis, for instance, requires at least six months of drug therapy.

“It’s not only viable for diclofenac,” Hsu says. “This strategy can be applied to a number of drugs.”

Indeed, other researchers who have looked at the paper say the potential medical versatility of the thin-film technique is of considerable interest.

“I find it really intriguing because it’s broadly applicable to a lot of systems,” says Kathryn Uhrich, a professor in the Department of Chemistry and Chemical Biology at Rutgers University, adding that the research is “really a nice piece of work.”

To be sure, in each case, researchers will have to figure out how best to bind the drug molecule in question to a biodegradable thin-film coating. The next steps for the researchers include studies to optimize these properties in different bodily environments and more tests, perhaps with medications for both chronic pain and inflammation.

A major motivation for the work, Hammond notes, is “the whole idea that we might be able to design something using these kinds of approaches that could create an [easier] lifestyle” for people with chronic pain and inflammation.

Hsu and Hammond were involved in all aspects of the project and wrote the paper, while Hagerman and Park helped perform the research, and Park helped analyze the data.

The research described in the paper was supported by funding from the U.S. Army and the U.S. Air Force.

MIT: Entirely New Approach to Graphene Semiconductors creates a ‘copy machine’ for cheap semiconductor wafers


Graphene Copy Machine 58f786adf3e74This image shows LEDs grown on graphene and then peeled.

 

In 2016, annual global semiconductor sales reached their highest-ever point, at $339 billion worldwide. In that same year, the semiconductor industry spent about $7.2 billion worldwide on wafers that serve as the substrates for microelectronics components, which can be turned into transistors, light-emitting diodes, and other electronic and photonic devices.

A developed by MIT engineers may vastly reduce the overall cost of wafer technology and enable devices made from more exotic, higher-performing than conventional silicon.

The new method, reported today in Nature, uses graphene—single-atom-thin sheets of graphite—as a sort of “copy machine” to transfer intricate crystalline patterns from an underlying to a top layer of identical material.

The engineers worked out carefully controlled procedures to place single sheets of graphene onto an expensive wafer. They then grew semiconducting material over the graphene layer. They found that graphene is thin enough to appear electrically invisible, allowing the top layer to see through the graphene to the underlying crystalline wafer, imprinting its patterns without being influenced by the graphene.

Graphene is also rather “slippery” and does not tend to stick to other materials easily, enabling the engineers to simply peel the top semiconducting layer from the wafer after its structures have been imprinted.

Jeehwan Kim, the Class of 1947 Career Development Assistant Professor in the departments of Mechanical Engineering and Materials Science and Engineering, says that in conventional semiconductor manufacturing, the wafer, once its crystalline pattern is transferred, is so strongly bonded to the semiconductor that it is almost impossible to separate without damaging both layers.MIT-Slippery-Graphene-1_0

“You end up having to sacrifice the wafer—it becomes part of the device,” Kim says.

With the group’s new technique, Kim says manufacturers can now use graphene as an intermediate layer, allowing them to copy and paste the wafer, separate a copied film from the wafer, and reuse the wafer many times over. In addition to saving on the cost of wafers, Kim says this opens opportunities for exploring more exotic semiconductor materials.

“The industry has been stuck on silicon, and even though we’ve known about better performing semiconductors, we haven’t been able to use them, because of their cost,” Kim says. “This gives the industry freedom in choosing by performance and not cost.”

Kim’s research team discovered this new technique at MIT’s Research Laboratory of Electronics. Kim’s MIT co-authors are first author and graduate student Yunjo Kim; graduate students Samuel Cruz, Babatunde Alawonde, Chris Heidelberger, Yi Song, and Kuan Qiao; postdocs Kyusang Lee, Shinhyun Choi, and Wei Kong; visiting research scholar Chanyeol Choi; Merton C. Flemings-SMA Professor of Materials Science and Engineering Eugene Fitzgerald; professor of electrical engineering and computer science Jing Kong; and assistant professor of mechanical engineering Alexie Kolpak; along with Jared Johnson and Jinwoo Hwang from Ohio State University, and Ibraheem Almansouri of Masdar Institute of Science and Technology.

Graphene Copy II imagesGraphene shift

Since graphene’s discovery in 2004, researchers have been investigating its exceptional electrical properties in hopes of improving the performance and cost of electronic devices. Graphene is an extremely good conductor of electricity, as electrons flow through graphene with virtually no friction. Researchers, therefore, have been intent on finding ways to adapt graphene as a cheap, high-performance semiconducting material.

“People were so hopeful that we might make really fast electronic devices from graphene,” Kim says. “But it turns out it’s really hard to make a good graphene transistor.”

In order for a transistor to work, it must be able to turn a flow of electrons on and off, to generate a pattern of ones and zeros, instructing a device on how to carry out a set of computations. As it happens, it is very hard to stop the flow of electrons through graphene, making it an excellent conductor but a poor semiconductor.

Kim’s group took an entirely new approach to using graphene in semiconductors. Instead of focusing on graphene’s electrical properties, the researchers looked at the material’s mechanical features.

“We’ve had a strong belief in graphene, because it is a very robust, ultrathin, material and forms very strong covalent bonding between its atoms in the horizontal direction,” Kim says. “Interestingly, it has very weak Van der Waals forces, meaning it doesn’t react with anything vertically, which makes graphene’s surface very slippery.”

Copy and peel

The team now reports that graphene, with its ultrathin, Teflon-like properties, can be sandwiched between a wafer and its semiconducting layer, providing a barely perceptible, nonstick surface through which the semiconducting material’s atoms can still rearrange in the pattern of the wafer’s crystals. The material, once imprinted, can simply be peeled off from the graphene surface, allowing manufacturers to reuse the original wafer.

The team found that its technique, which they term “remote epitaxy,” was successful in copying and peeling off layers of semiconductors from the same semiconductor wafers. The researchers had success in applying their technique to exotic wafer and semiconducting materials, including indium phosphide, gallium arsenenide, and gallium phosphide—materials that are 50 to 100 times more expensive than silicon.

Kim says that this new technique makes it possible for manufacturers to reuse wafers—of silicon and higher-performing materials—”conceptually, ad infinitum.”

An exotic future

The group’s graphene-based peel-off technique may also advance the field of flexible electronics. In general, wafers are very rigid, making the devices they are fused to similarly inflexible. Kim says now, semiconductor devices such as LEDs and solar cells can be made to bend and twist. In fact, the group demonstrated this possibility by fabricating a flexible LED display, patterned in the MIT logo, using their technique.

“Let’s say you want to install solar cells on your car, which is not completely flat—the body has curves,” Kim says. “Can you coat your semiconductor on top of it? It’s impossible now, because it sticks to the thick wafer. Now, we can peel off, bend, and you can do conformal coating on cars, and even clothing.”

Going forward, the researchers plan to design a reusable “mother wafer” with regions made from different exotic materials. Using as an intermediary, they hope to create multifunctional, high-performance devices. They are also investigating mixing and matching various semiconductors and stacking them up as a multimaterial structure.

“Now, exotic materials can be popular to use,” Kim says. “You don’t have to worry about the cost of the wafer. Let us give you the copy machine. You can grow your semiconductor device, peel it off, and reuse the .”

Explore further: Researchers ‘iron out’ graphene’s wrinkles

More information: Remote epitaxy through graphene enables two-dimensional material-based layer transfer, Natur

MIT: Light-emitting particles (quantum dots) open new window for biological imaging


QD Bio Image V images

‘Quantum dots’ that emit infrared light enable highly detailed images of internal body structures

For certain frequencies of short-wave infrared light, most biological tissues are nearly as transparent as glass. Now, researchers have made tiny particles that can be injected into the body, where they emit those penetrating frequencies. The advance may provide a new way of making detailed images of internal body structures such as fine networks of blood vessels.

The new findings, based on the use of light-emitting particles called quantum dots, is described in a paper in the journal Nature Biomedical Engineering, by MIT research scientist Oliver Bruns, recent graduate Thomas Bischof PhD ’15, professor of chemistry Moungi Bawendi, and 21 others.

Near-infrared imaging for research on biological tissues, with wavelengths between 700 and 900 nanometers (billionths of a meter), is widely used, but wavelengths of around 1,000 to 2,000 nanometers have the potential to provide even better results, because body tissues are more transparent to that light. “We knew that this imaging mode would be better” than existing methods, Bruns explains, “but we were lacking high-quality emitters” — that is, light-emitting materials that could produce these precise wavelengths.

QD bio Image II imagesLight-emitting particles have been a specialty of Bawendi, the Lester Wolf Professor of Chemistry, whose lab has over the years developed new ways of making quantum dots. These nanocrystals, made of semiconductor materials, emit light whose frequency can be precisely tuned by controlling the exact size and composition of the particles.

The key was to develop versions of these quantum dots whose emissions matched the desired short-wave infrared frequencies and were bright enough to then be easily detected through the surrounding skin and muscle tissues. The team succeeded in making particles that are “orders of magnitude better than previous materials, and that allow unprecedented detail in biological imaging,” Bruns says. The synthesis of these new particles was initially described in a paper by graduate student Daniel Franke and others from the Bawendi group in Nature Communications last year.

The quantum dots the team produced are so bright that their emissions can be captured with very short exposure times, he says. This makes it possible to produce not just single images but video that captures details of motion, such as the flow of blood, making it possible to distinguish between veins and arteries.

QD Bio Image IV GAAlso Read About

Graphene Quantum Dots Expand Role In Cancer Treatment And Bio-Imaging

 

 

The new light-emitting particles are also the first that are bright enough to allow imaging of internal organs in mice that are awake and moving, as opposed to previous methods that required them to be anesthetized, Bruns says. Initial applications would be for preclinical research in animals, as the compounds contain some materials that are unlikely to be approved for use in humans. The researchers are also working on developing versions that would be safer for humans.QD Bio Image III 4260773298_1497232bef

 

The method also relies on the use of a newly developed camera that is highly sensitive to this particular range of short-wave infrared light. The camera is a commercially developed product, Bruns says, but his team was the first customer for the camera’s specialized detector, made of indium-gallium-arsenide. Though this camera was developed for research purposes, these frequencies of infrared light are also used as a way of seeing through fog or smoke.

Not only can the new method determine the direction of blood flow, Bruns says, it is detailed enough to track individual blood cells within that flow. “We can track the flow in each and every capillary, at super high speed,” he says. “We can get a quantitative measure of flow, and we can do such flow measurements at very high resolution, over large areas.”

Such imaging could potentially be used, for example, to study how the blood flow pattern in a tumor changes as the tumor develops, which might lead to new ways of monitoring disease progression or responsiveness to a drug treatment. “This could give a good indication of how treatments are working that was not possible before,” he says.

###

The team included members from MIT’s departments of Chemistry, Chemical Engineering, Biological Engineering, and Mechanical Engineering, as well as from Harvard Medical School, the Harvard T.H. Chan School of Public Health, Raytheon Vision Systems, and University Medical Center in Hamburg, Germany. The work was supported by the National Institutes of Health, the National Cancer Institute, the National Foundation for Cancer Research, the Warshaw Institute for Pancreatic Cancer Research, the Massachusetts General Hospital Executive Committee on Research, the Army Research Office through the Institute for Soldier Nanotechnologies at MIT, the U.S. Department of Defense, and the National Science Foundation.

Additional background

ARCHIVE: A new contrast agent for MRI http://news.mit.edu/2017/iron-oxide-nanoparticles-contrast-agent-mri-0214

ARCHIVE: A new eye on the middle ear http://news.mit.edu/2016/shortwave-infrared-instrument-ear-infection-0822

ARCHIVE: Chemists design a quantum-dot spectrometer http://news.mit.edu/2015/quantum-dot-spectrometer-smartphone-0701

ARCHIVE: Running the color gamut http://news.mit.edu/2014/startup-quantum-dot-tv-displays-1119

ARCHIVE: Fine-tuning emissions from quantum dots http://news.mit.edu/2013/fine-tuning-emissions-from-quantum-dots-0602

MIT: “Ironing out” graphene’s wrinkles to make ‘Pristine Graphene’ ~ Promising Successor to Silicon (at the ‘Speed of Light’)


MIT-Wrinkle Single-Domain_0.jpg

Researchers at MIT have found a way to make graphene with fewer wrinkles, and to iron out the wrinkles that do appear. They found each wafer exhibited uniform performance, meaning that electrons flowed freely across each wafer, at similar speeds, even across previously wrinkled regions.

New technique produces highly conductive graphene wafers.

” … electrons can blitz through graphene at velocities approaching the speed of light, far faster than they can travel through silicon and other semiconducting materials.

” … Graphene, therefore, has been touted as a promising successor to silicon, with the potential to enable faster, more efficient electronic and photonic devices.”

” … pristine graphene — a single, perfectly flat, ultrathin sheet of carbon atoms, precisely aligned and linked together like chickenwire — is extremely difficult.”

” … which can derail an electron’s bullet-train journey, significantly limiting graphene’s electrical performance.”

From an electron’s point of view, graphene must be a hair-raising thrill ride. For years, scientists have observed that electrons can blitz through graphene at velocities approaching the speed of light, far faster than they can travel through silicon and other semiconducting materials.

Graphene, therefore, has been touted as a promising successor to silicon, with the potential to enable faster, more efficient electronic and photonic devices.

But manufacturing pristine graphene — a single, perfectly flat, ultrathin sheet of carbon atoms, precisely aligned and linked together like chickenwire — is extremely difficult. Conventional fabrication processes often generate wrinkles, which can derail an electron’s bullet-train journey, significantly limiting graphene’s electrical performance.

Now engineers at MIT have found a way to make graphene with fewer wrinkles, and to iron out the wrinkles that do appear. After fabricating and then flattening out the graphene, the researchers tested its electrical conductivity. They found each wafer exhibited uniform performance, meaning that electrons flowed freely across each wafer, at similar speeds, even across previously wrinkled regions.

In a paper published today in the Proceedings of the National Academy of Sciences, the researchers report that their techniques successfully produce wafer-scale, “single-domain” graphene — single layers of graphene that are uniform in both atomic arrangement and electronic performance.

“For graphene to play as a main semiconductor material for industry, it has to be single-domain, so that if you make millions of devices on it, the performance of the devices is the same in any location,” says Jeehwan Kim, the Class of 1947 Career Development Assistant Professor in the departments of Mechanical Engineering and Materials Science and Engineering at MIT. “Now we can really produce single-domain graphene at wafer scale.”graphene wonder material images

Kim’s co-authors include Sanghoon Bae, Samuel Cruz, and Yunjo grapehene electronics imagesKim from MIT, along with researchers from IBM, the University of California at Los Angeles, and Kyungpook National University in South Korea.

A patchwork of wrinkles

The most common way to make graphene involves chemical vapor deposition, or CVD, a process in which carbon atoms are deposited onto a crystalline substrate such as copper foil. Once the copper foil is evenly coated with a single layer of carbon atoms, scientists submerge the entire thing in acid to etch away the copper. What remains is a single sheet of graphene, which researchers then pull out from the acid.

The CVD process can produce relatively large, macroscropic wrinkles in graphene, due to the roughness of the underlying copper itself and the process of pulling the graphene out from the acid. The alignment of carbon atoms is not uniform across the graphene, creating a “polycrystalline” state in which graphene resembles an uneven, patchwork terrain, preventing electrons from flowing at uniform rates.

In 2013, while working at IBM, Kim and his colleagues developed a method to fabricate wafers of single-crystalline graphene, in which the orientation of carbon atoms is exactly the same throughout a wafer.

Rather than using CVD, his team produced single-crystalline graphene from a silicon carbide wafer with an atomically smooth surface, albeit with tiny, step-like wrinkles on the order of several nanometers. They then used a thin sheet of nickel to peel off the topmost graphene from the silicon carbide wafer, in a process called layer-resolved graphene transfer.

Ironing charges

In their new paper, Kim and his colleagues discovered that the layer-resolved graphene transfer irons out the steps and tiny wrinkles in silicon carbide-fabricated graphene. Before transferring the layer of graphene onto a silicon wafer, the team oxidized the silicon, creating a layer of silicon dioxide that naturally exhibits electrostatic charges. When the researchers then deposited the graphene, the silicon dioxide effectively pulled graphene’s carbon atoms down onto the wafer, flattening out its steps and wrinkles.

Kim says this ironing method would not work on CVD-fabricated graphene, as the wrinkles generated through CVD are much larger, on the order of several microns.

“The CVD process creates wrinkles that are too high to be ironed out,” Kim notes. “For silicon carbide graphene, the wrinkles are just a few nanometers high, short enough to be flattened out.”

To test whether the flattened, single-crystalline graphene wafers were single-domain, the researchers fabricated tiny transistors on multiple sites on each wafer, including across previously wrinkled regions.

“We measured electron mobility throughout the wafers, and their performance was comparable,” Kim says. “What’s more, this mobility in ironed graphene is two times faster. So now we really have single-domain graphene, and its electrical quality is much higher [than graphene-attached silicon carbide].”

Kim says that while there are still challenges to adapting graphene for use in electronics, the group’s results give researchers a blueprint for how to reliably manufacture pristine, single-domain, wrinkle-free graphene at wafer scale.

“If you want to make any electronic device using graphene, you need to work with single-domain graphene,” Kim says. “There’s still a long way to go to make an operational transistor out of graphene. But we can now show the community guidelines for how you can make single-crystalline, single-domain graphene.”

MIT: New ‘Rubbery Nanowire” Fibers are Stretching the boundaries of neural implants ~ Hope for Spinal Cord Injuries


MIT-Stretch-Fiber-1_0Researchers have developed a rubber-like fiber, shown here, that can flex and stretch while simultaneously delivering both optical impulses, for optoelectronic stimulation, and electrical connections, for stimulation and monitoring. Image: Chi (Alice) Lu and Seongjun Park

Rubbery, multifunctional fibers could be used to study spinal cord neurons and potentially restore function.

Implantable fibers have been an enormous boon to brain research, allowing scientists to stimulate specific targets in the brain and monitor electrical responses. But similar studies in the nerves of the spinal cord, which might ultimately lead to treatments to alleviate spinal cord injuries, have been more difficult to carry out.

That’s because the spine flexes and stretches as the body moves, and the relatively stiff, brittle fibers used today could damage the delicate spinal cord tissue.

Now, researchers have developed a rubber-like fiber that can flex and stretch while simultaneously delivering both optical impulses, for optoelectronic stimulation, and electrical connections, for stimulation and monitoring. The new fibers are described in a paper in the journal Science Advances, by MIT graduate students Chi (Alice) Lu and Seongjun Park, Professor Polina Anikeeva, and eight others at MIT, the University of Washington, and Oxford University.

“I wanted to create a multimodal interface with mechanical properties compatible with tissues, for neural stimulation and recording,” as a tool for better understanding spinal cord functions, says Lu. But it was essential for the device to be stretchable, because “the spinal cord is not only bending but also stretching during movement.” The obvious choice would be some kind of elastomer, a rubber-like compound, but most of these materials are not adaptable to the process of fiber drawing, which turns a relatively large bundle of materials into a thread that can be narrower than a hair.

The spinal cord “undergoes stretches of about 12 percent during normal movement,” says Anikeeva, who is the Class of 1942 Career Development Professor in the Department of Materials Science and Engineering. “You don’t even need to get into a ‘downward dog’ [yoga position] to have such changes.” So finding a material that can match that degree of stretchiness could potentially make a big difference to research. “The goal was to mimic the stretchiness and softness and flexibility of the spinal cord,” she says. “You can match the stretchiness with a rubber. But drawing rubber is difficult — most of them just melt,” she says.

“Eventually, we’d like to be able to use something like this to combat spinal cord injury. But first, we have to have biocompatibility and to be able to withstand the stresses in the spinal cord without causing any damage,” she says.

 

 

 

 

 

 

 

 

 

The fibers are not only stretchable but also very flexible. “They’re so floppy, you could use them to do sutures, and do light delivery at the same time,” professor Polina Anikeeva says. (Video: Chi (Alice) Lu and Seongjun Park)

The team combined a newly developed transparent elastomer, which could act as a waveguide for optical signals, and a coating formed of a mesh of silver nanowires, producing a conductive layer for the electrical signals. To process the transparent elastomer, the material was embedded in a polymer cladding that enabled it to be drawn into a fiber that proved to be highly stretchable as well as flexible, Lu says. The cladding is dissolved away after the drawing process.

After the entire fabrication process, what’s left is the transparent fiber with electrically conductive, stretchy nanowire coatings. “It’s really just a piece of rubber, but conductive,” Anikeeva says. The fiber can stretch by at least 20 to 30 percent without affecting its properties, she says.

The fibers are not only stretchable but also very flexible. “They’re so floppy, you could use them to do sutures and deliver light  at the same time,” she says.

“We’re the first to develop something that enables simultaneous electrical recording and optical stimulation in the spinal cords of freely moving mice,” Lu says. “So we hope our work opens up new avenues for neuroscience research.” Scientists doing research on spinal cord injuries or disease usually must use larger animals in their studies, because the larger nerve fibers can withstand the more rigid wires used for stimulus and recording. While mice are generally much easier to study and available in many genetically modified strains, there was previously no technology that allowed them to be used for this type of research, she says.

“There are many different types of cells in the spinal cord, and we don’t know how the different types respond to recovery, or lack of recovery, after an injury,” she says. These new fibers, the researchers hope, could help to fill in some of those blanks.

The team included Alexander Derry, Chong Hou, Siyuan Rao, Jeewoo Kang, and professor Yoel Fink at MIT; Tom Richner and professor Chet Mortiz at the University of Washington; and Imogen Brown at Oxford University. The research was supported by the National Science Foundation, the National Institute of Neurological Disorders and Stroke, the U.S. Army Research Laboratory, and the U.S. Army Research Office through the Institute for Soldier Nanotechnologies at MIT.

MIT: Making Smaller Microchip Patterns – Toward Faster More Powerful Computers


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Self-assembly technique could lead to long-awaited, simple method for making smaller microchip patterns.

For the last few decades, microchip manufacturers have been on a quest to find ways to make the patterns of wires and components in their microchips ever smaller, in order to fit more of them onto a single chip and thus continue the relentless progress toward faster and more powerful computers. That progress has become more difficult recently, as manufacturing processes bump up against fundamental limits involving, for example, the wavelengths of the light used to create the patterns.

Now, a team of researchers at MIT and in Chicago has found an approach that could break through some of those limits and make it possible to produce some of the narrowest wires yet, using a process with the potential to be economically viable for mass manufacturing with standard types of equipment.

The new findings are reported this week in the journal Nature Nanotechnology, in a paper by postdoc Do Han Kim, graduate student Priya Moni, and Professor Karen Gleason, all at MIT, and by postdoc Hyo Seon Suh, Professor Paul Nealey, and three others at the University of Chicago and Argonne National Laboratory. While there are other methods that can achieve such fine lines, the team says, none of them are cost-effective for large-scale manufacturing.

The new approach includes a technique in which polymer thin films are formed on a surface, first by heating precursurs so they vaporize, and then by allowing them to condense and polymerize on a cooler surface, much as water condenses on the outside of a cold drinking glass on a hot day.

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These scanning electron microscope images show the sequence of fabrication of fine lines by the team’s new method. First, an array of lines is produced by a conventional electron beam process (top). The addition of a block copolymer material and a topcoat result in a quadrupling of the number of lines (center). Then the topcoat is etched away, leaving the new pattern of fine lines exposed (bottom). Courtesy of the researchers

“People always want smaller and smaller patterns, but achieving that has been getting more and more expensive,” says Gleason, who is MIT’s associate provost as well as the Alexander and I. Michael Kasser (1960) Professor of Chemical Engineering. Today’s methods for producing features smaller than about 22 nanometers (billionths of a meter) across generally require either extreme ultraviolet light with very expensive optics or building up an image line by line, by scanning a beam of electrons or ions across the chip surface — a very slow process and therefore expensive to implement at large scale.

The new process uses a novel integration of three existing methods. First, a pattern of lines is produced on the chip surface using well-established lithographic techniques, in which an electron beam is used to “write” the pattern on the chip.

Then, a layer of material known as a block copolymer — a mix of two different polymer materials that naturally segregate themselves into alternating layers or other predictable patterns — is formed by spin coating a solution. The block copolymers are made up of chain-like molecules, each consisting of two different polymer materials connected end-to-end.

“One half is friendly with oil, the other half is friendly with water,” Kim explains. “But because they are completely bonded, they’re kind of stuck with each other.” The dimensions of the two blocks predetermine the sizes of periodic layers or other patterns they will assemble themselves into when they are deposited.

Finally, a top, protective polymer layer is deposited on top of the others using initiated chemical vapor deposition (iCVD). This top coat, it turns out, is a key to the process: It constrains the way the block copolymers self-assemble, forcing them to form into vertical layers rather than horizontal ones, like a layer cake on its side.

The underlying lithographic pattern guides the positioning of these layers, but the natural tendencies of the copolymers cause their width to be much smaller than that of the base lines. The result is that there are now four (or more, depending on the chemistry) lines, each of them a fourth as wide, in place of each original one. The combination of the lithographed layer and topcoat “controls both the orientation and the alignment” of the resulting finer lines, explains Moni.

Because the top polymer layer can additionally be patterned, the system can be used to build up any kind of complex patterning, as needed for the interconnections of a microchip.

Most microchip manufacturing facilities use the existing lithographic method, and the CVD process itself is a well-understood additional step that could be added relatively easily. Thus, implementing the new method could be much more straightforward than other proposed methods of making finer lines. With the new method, Gleason says, “you wouldn’t need to change all those machines. And everything that’s involved are well-known materials.”

“Being able to create sub-10-nanometer features with polymers is major progress in the area of nanofabrication,” says Joerg Lahann, a professor of chemical engineering at the University of Michigan, who was not involved in this work. “The quality and robustness of this process will open an entirely new area of applications, from nanopatterning to nanotribology.”

Lahann adds, “This work is an ingenious extension of previous research by these researchers. The fact that they can demonstrate arbitrary structures highlights the quality and versatility of this novel technology.”

The team also included Shisheng Xiong at the University of Chicago and Argonne National Laboratory, and Leonidas Ocola and Nestor Zaluzec at Argonne. The work was supported by the National Science Foundation and the U.S. Army Research Office, through MIT’s Institute for Soldier Nanotechnologies.

MIT: New kind of supercapacitor made without carbon


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To demonstrate the supercapacitor’s ability to store power, the researchers modified an off-the-shelf hand-crank flashlight (the red parts at each side) by cutting it in half and installing a small supercapacitor in the center, in a conventional button battery case, seen at top. When the crank is turned to provide power to the flashlight, the light continues to glow long after the cranking stops, thanks to the stored energy. Photo: Melanie Gonick

Energy storage device could deliver more power than current versions of this technology.

Energy storage devices called supercapacitors have become a hot area of research, in part because they can be charged rapidly and deliver intense bursts of power. However, all supercapacitors currently use components made of carbon, which require high temperatures and harsh chemicals to produce.

Now researchers at MIT and elsewhere have for the first time developed a supercapacitor that uses no conductive carbon at all, and that could potentially produce more power than existing versions of this technology.

The team’s findings are being reported in the journal Nature Materials, in a paper by Mircea Dincă, an MIT associate professor of chemistry; Yang Shao-Horn, the W.M. Keck Professor of Energy; and four others.

“We’ve found an entirely new class of materials for supercapacitors,” Dincă says.

Dincă and his team have been exploring for years a class of materials called metal-organic frameworks, or MOFs, which are extremely porous, sponge-like structures. These materials have an extraordinarily large surface area for their size, much greater than the carbon materials do. That is an essential characteristic for supercapacitors, whose performance depends on their surface area. But MOFs have a major drawback for such applications: They are not very electrically conductive, which is also an essential property for a material used in a capacitor.

“One of our long-term goals was to make these materials electrically conductive,” Dincă says, even though doing so “was thought to be extremely difficult, if not impossible.” But the material did exhibit another needed characteristic for such electrodes, which is that it conducts ions (atoms or molecules that carry a net electric charge) very well.

“All double-layer supercapacitors today are made from carbon,” Dincă says. “They use carbon nanotubes, graphene, activated carbon, all shapes and forms, but nothing else besides carbon. So this is the first noncarbon, electrical double-layer supercapacitor.”

One advantage of the material used in these experiments, technically known as Ni3(hexaiminotriphenylene)2, is that it can be made under much less harsh conditions than those needed for the carbon-based materials, which require very high temperatures above 800 degrees Celsius and strong reagent chemicals for pretreatment.

The team says supercapacitors, with their ability to store relatively large amounts of power, could play an important role in making renewable energy sources practical for widespread deployment. They could provide grid-scale storage that could help match usage times with generation times, for example, or be used in electric vehicles and other applications.

The new devices produced by the team, even without any optimization of their characteristics, already match or exceed the performance of existing carbon-based versions in key parameters, such as their ability to withstand large numbers of charge/discharge cycles. Tests showed they lost less than 10 percent of their performance after 10,000 cycles, which is comparable to existing commercial supercapacitors.

But that’s likely just the beginning, Dincă says. MOFs are a large class of materials whose characteristics can be tuned to a great extent by varying their chemical structure. Work on optimizing their molecular configurations to provide the most desirable attributes for this specific application is likely to lead to variations that could outperform any existing materials. “We have a new material to work with, and we haven’t optimized it at all,” he says. “It’s completely tunable, and that’s what’s exciting.”

While there has been much research on MOFs, most of it has been directed at uses that take advantage of the materials’ record porosity, such as for storage of gases. “Our lab’s discovery of highly electrically conductive MOFs opened up a whole new category of applications,” Dincă says. Besides the new supercapacitor uses, the conductive MOFs could be useful for making electrochromic windows, which can be darkened with the flip of a switch, and chemoresistive sensors, which could be useful for detecting trace amounts of chemicals for medical or security applications.

While the MOF material has advantages in the simplicity and potentially low cost of manufacturing, the materials used to make it are more expensive than conventional carbon-based materials, Dincă says. “Carbon is dirt cheap. It’s hard to find anything cheaper.” But even if the material ends up being more expensive, if its performance is significantly better than that of carbon-based materials, it could find useful applications, he says.

This discovery is “very significant, from both a scientific and applications point of view,” says Alexandru Vlad, a professor of chemistry at the Catholic University of Louvain in Belgium, who was not involved in this research. He adds that “the supercapacitor field was (but will not be anymore) dominated by activated carbons,” because of their very high surface area and conductivity. But now, “here is the breakthrough provided by Dinca et al.: They could design a MOF with high surface area and high electrical conductivity, and thus completely challenge the supercapacitor value chain! There is essentially no more need of carbons for this highly demanded technology.”

And a key advantage of that, he explains, is that “this work shows only the tip of the iceberg. With carbons we know pretty much everything, and the developments over the past years were modest and slow. But the MOF used by Dinca is one of the lowest-surface-area MOFs known, and some of these materials can reach up to three times more [surface area] than carbons. The capacity would then be astonishingly high, probably close to that of batteries, but with the power performance [the ability to deliver high power output] of supercapacitors.”

The research team included former MIT postdoc Dennis Sheberla (now a postdoc at Harvard University), MIT graduate student John Bachman, Joseph Elias PhD ’16, and Cheng-Jun Sun of Argonne National Laboratory. The work was supported by the U.S. Department of Energy through the Center for Excitonics, the Sloan Foundation, the Research Corporation for Science Advancement, 3M, and the National Science Foundation.

The Entrepreneur with the $100 Million Plan to Link Brains to Computers


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Entrepreneur Bryan Johnson says he wanted to become very rich in order to do something great for humankind. Well …

Last year Johnson, founder of the online payments company Braintree, starting making news when he threw $100 million behind Kernel, a startup he founded to enhance human intelligence by developing brain implants capable of linking people’s thoughts to computers.

Johnson isn’t alone in believing that “neurotechnology” could be the next big thing. To many in Silicon Valley, the brain looks like an unconquered frontier whose importance dwarfs any achievement made in computing or the Web.

According to neuroscientists, several figures from the tech sector are currently scouring labs across the U.S. for technology that might fuse human and artificial intelligence. In addition to Johnson, Elon Musk has been teasing a project called “neural lace,” which he said at a 2016 conference will lead to “symbiosis with machines.” And Mark Zuckerberg declared in a 2015 Q&A that people will one day be able to share “full sensory and emotional experiences,” not just photos. Facebook has been hiring neuroscientists for an undisclosed project at Building 8, its secretive hardware division.

As these people see it, computing keeps achieving new heights, but our ability to interface with silicon is stuck in the keyboard era. Even when speaking to a computer program like Alexa or Siri, you can convey at most about 40 bits per second of information and only for short bursts. Compare that to data transfer records of a trillion bits per second along a fiber-optic cable.

“Ridiculously slow,” Musk complained.

But it turns out that connecting to the brain isn’t so easy. Six months after launching Kernel amid a media blitz, Johnson says he’s dropped his initial plans for a “memory implant,” switched scientific advisors, hired a new team, and decided to instead invest in developing a more general-purpose technology for recording and stimulating the brain using electrodes.

Johnson says the switch-up is part of trying something new. “If you look at the key contributing technologies of society, the ones with the most impact, like rockets, the Internet, biology—there was a transition point from academia to the private sector, and for the most part neuroscience hasn’t made that jump,” says Johnson. “The most critical element is timing, when is the right time to pursue this.”

Memory implants

After making a fortune selling Braintree to eBay for $800 million in 2013, Johnson, now 39, reportedly sought the advice of nearly 200 people on how to invest his new wealth. He settled on neurotechnology and, last August, he announced he’d create Kernel and build the first neural prosthetic for human intelligence enhancement.

But Johnson’s business plan was extremely vague; one scientist called it “metaphysical.” Kernel’s website was plastered with book-jacket-like endorsements from scientific celebrities including J. Craig Venter and Tim O’Reilly, extolling his “great” and “serious” commitment to understanding human intelligence, not to mention the impressive $100 million he later promised to invest in Kernel.

                                              

Bryan Johnson

The reality is that interfacing with the brain is tough: electronics irritate its tissue and stop working after a while, and no one will get brain surgery just in order to send an e-mail. What’s more, even if you can communicate with the brain, you might not know what it is saying.

“Billionaires entering the broader neurotechnology field are very optimistic and may overlook details of the problem, which is we are far away from meaningfully understanding the brain,” says Konrad Kording, a Northwestern University neuroscientist who has advised Johnson. “But neurotechnology allows you to work on the most interesting questions in the universe while potentially making money, and so that is exciting.”

Johnson’s persona is part buttoned-down Mormon missionary (he once was one), part hard-driving door-to-door credit-processing salesman (he was that too), but now, with his new wealth, he’s also taken on the mantle of a technology prophet. At a 2016 startup conference in Silicon Valley, he showed up with his hair unbrushed, wearing a T-shirt with holes in it, and gave a wide-ranging lecture on human tool use from prehistory into the present, arguing that now “our very existence is programmable” through biology and machine interfaces.

Kernel’s original technology was a memory prosthesis, developed by Theodore Berger of the University of Southern California, who until recently was also the company’s chief scientific officer. Berger’s technology (see “10 Breakthrough Technologies: Memory Implants”) is a way of recording memories of rats and monkeys, storing these patterns on a computer chip, and re-delivering them to the hippocampus. One version of the setup, Berger says, has been tested in a handful of human patients undergoing brain surgery for other reasons.

But a mere six months after starting Kernel, Berger is no longer part of the company, and memory implants are no longer part of Kernel’s near-term plans. Johnson and Berger both confirmed the separation.

Berger’s vision, according to several people, was too complex, too speculative, and too far from becoming a medical reality, while Johnson hoped to see a return on his investment sometime soon. “They have a new direction, but we’re still talking,” says Berger. “The basic reason is it was going to take too long. It’s one thing to think about this and quite another to do it.”

Johnson says he concluded that Berger’s work “is really interesting, but not an entry point” into a commercially viable business.

Brain interface

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Read More: “Its’ All in Our Heads … “

By last November, Johnson was already exploring a pivot for his company, meeting with Christian Wentz, head of a small Cambridge startup, Kendall Research Systems, that sells equipment for recording in the neurons of mice and other animals. The company spun out of the laboratory of Edward Boyden, a professor at MIT who invents new ways of analyzing brain tissue.

In February, Johnson acquired Wentz’s company (for an undisclosed sum) and with it brought in a new team, including Wentz and Adam Marblestone, a noted theorist of both the limitations and possibilities of brain interfaces, who will become chief strategy officer. Both are former Boyden lab members, as are two other Kernel scientists, Caroline Moore-Kochlacs and Jake Bernstein.

Johnson says Kernel will now develop a “generalized human electrophysiology platform”—that is, a flexible way of measuring the electrical impulses from many neurons at once, and stimulating them, too. The eventual objective is to use such electronics to treat major diseases, like depression or Alzheimer’s. “It’s for clinical use,” he says. “We are a for-profit company.”

Wentz says as part of the acquisition he and Johnson agreed that much more R&D on brain interfaces will probably be needed. “We have a very sober view of what can and can’t be done,” Wentz says. “We are not naïve.” He calls Kernel’s effort a “15-year endeavor,” although he adds that “we want to do in that period what has been done in the last 100 years.”

With the pivot, Johnson is effectively jumping on an opportunity created by the Brain Initiative, an Obama-era project which plowed money into new schemes for recording neurons. That influx of cash has spurred the formation of several other startups, including Paradromics and Cortera, also developing novel hardware for collecting brain signals. As part of the government brain project, the defense R&D agency DARPA says it is close to announcing $60 million in contracts under a program to create a “high-fidelity” brain interface able to simultaneously record from one million neurons (the current record is about 200) and stimulate 100,000 at a time.

“It’s time for neuroscience to graduate from academia to a general neuroscience platform,” says Johnson. With such a technology “a whole range of new applications—a lot of white space—would open up.”

Johnson declined to describe the specifics of Kernel’s technological approach to connecting with the brain, as did Boyden and Wentz. However, the team members have been working on well-identified problems. Wentz has been involved with developing electronics for high-speed reading of data emitted by wireless implants. Already, the flow of information that can be collected from a mouse’s brain in real time outruns what a laptop computer can handle. The team also needs a way to interface with the human brain. Boyden’s lab has worked on several concepts to do so, including needle-shaped probes with tiny electrodes etched onto their surface. Another idea is to record neural activity by threading tiny optical fibers through the brain’s capillaries, an idea roughly similar to Musk’s neural lace.

More sophisticated means of reading and writing to the brain are seen as potential ways to treat psychiatric disorders. Under a concept that Boyden calls “brain coprocessors,” it may be possible to create closed-loop systems that detect certain brain signals—say, those associated with depression—and shock the brain to reverse them. Some surgeons and doctors funded by another DARPA program are in the early stages of determining whether serious mental conditions can be treated in this way (see “A Shocking Way to Fix the Brain”).

Boyden says Johnson’s $100 million makes a big difference to how he and his students view the entrepreneur’s goals. “A lot of neurotechnology has come and gone. But one thing is that it’s very expensive,” he says. “The inventing is expensive, the clinical work is expensive. It’s not easy. And here is someone putting money into the game.”