Tag Archives: MIT

Fusing graphene flakes for 3D graphene structures that are 10x as strong as steel

A Jan. 6, 2017 news item on Nanowerk describes how geometry may have as much or more to do with the strength of 3D graphene structures than the graphene used to create them,

A team of researchers at MIT [Massachusetts Institute of Technology] has designed one of the strongest lightweight materials known, by compressing and fusing flakes of graphene, a two-dimensional form of carbon. The new material, a sponge-like configuration with a density of just 5 percent, can have a strength 10 times that of steel.

In its two-dimensional form, graphene is thought to be the strongest of all known materials. But researchers until now have had a hard time translating that two-dimensional strength into useful three-dimensional materials.

The new findings show that the crucial aspect of the new 3-D forms has more to do with their unusual geometrical configuration than with the material itself, which suggests that similar strong, lightweight materials could be made from a variety of materials by creating similar geometric features.

The findings are being reported today [Jan. 6, 2017\ in the journal Science Advances, in a paper by Markus Buehler, the head of MIT’s Department of Civil and Environmental Engineering (CEE) and the McAfee Professor of Engineering; Zhao Qin, a CEE research scientist; Gang Seob Jung, a graduate student; and Min Jeong Kang MEng ’16, a recent graduate.

A Jan. 6, 2017 MIT news release (also on EurekAlert), which originated the news item, describes the research in more detail,

Other groups had suggested the possibility of such lightweight structures, but lab experiments so far had failed to match predictions, with some results exhibiting several orders of magnitude less strength than expected. The MIT team decided to solve the mystery by analyzing the material’s behavior down to the level of individual atoms within the structure. They were able to produce a mathematical framework that very closely matches experimental observations.

Two-dimensional materials — basically flat sheets that are just one atom in thickness but can be indefinitely large in the other dimensions — have exceptional strength as well as unique electrical properties. But because of their extraordinary thinness, “they are not very useful for making 3-D materials that could be used in vehicles, buildings, or devices,” Buehler says. “What we’ve done is to realize the wish of translating these 2-D materials into three-dimensional structures.”

The team was able to compress small flakes of graphene using a combination of heat and pressure. This process produced a strong, stable structure whose form resembles that of some corals and microscopic creatures called diatoms. These shapes, which have an enormous surface area in proportion to their volume, proved to be remarkably strong. “Once we created these 3-D structures, we wanted to see what’s the limit — what’s the strongest possible material we can produce,” says Qin. To do that, they created a variety of 3-D models and then subjected them to various tests. In computational simulations, which mimic the loading conditions in the tensile and compression tests performed in a tensile loading machine, “one of our samples has 5 percent the density of steel, but 10 times the strength,” Qin says.

Buehler says that what happens to their 3-D graphene material, which is composed of curved surfaces under deformation, resembles what would happen with sheets of paper. Paper has little strength along its length and width, and can be easily crumpled up. But when made into certain shapes, for example rolled into a tube, suddenly the strength along the length of the tube is much greater and can support substantial weight. Similarly, the geometric arrangement of the graphene flakes after treatment naturally forms a very strong configuration.

The new configurations have been made in the lab using a high-resolution, multimaterial 3-D printer. They were mechanically tested for their tensile and compressive properties, and their mechanical response under loading was simulated using the team’s theoretical models. The results from the experiments and simulations matched accurately.

The new, more accurate results, based on atomistic computational modeling by the MIT team, ruled out a possibility proposed previously by other teams: that it might be possible to make 3-D graphene structures so lightweight that they would actually be lighter than air, and could be used as a durable replacement for helium in balloons. The current work shows, however, that at such low densities, the material would not have sufficient strength and would collapse from the surrounding air pressure.

But many other possible applications of the material could eventually be feasible, the researchers say, for uses that require a combination of extreme strength and light weight. “You could either use the real graphene material or use the geometry we discovered with other materials, like polymers or metals,” Buehler says, to gain similar advantages of strength combined with advantages in cost, processing methods, or other material properties (such as transparency or electrical conductivity).

“You can replace the material itself with anything,” Buehler says. “The geometry is the dominant factor. It’s something that has the potential to transfer to many things.”

The unusual geometric shapes that graphene naturally forms under heat and pressure look something like a Nerf ball — round, but full of holes. These shapes, known as gyroids, are so complex that “actually making them using conventional manufacturing methods is probably impossible,” Buehler says. The team used 3-D-printed models of the structure, enlarged to thousands of times their natural size, for testing purposes.

For actual synthesis, the researchers say, one possibility is to use the polymer or metal particles as templates, coat them with graphene by chemical vapor deposit before heat and pressure treatments, and then chemically or physically remove the polymer or metal phases to leave 3-D graphene in the gyroid form. For this, the computational model given in the current study provides a guideline to evaluate the mechanical quality of the synthesis output.

The same geometry could even be applied to large-scale structural materials, they suggest. For example, concrete for a structure such a bridge might be made with this porous geometry, providing comparable strength with a fraction of the weight. This approach would have the additional benefit of providing good insulation because of the large amount of enclosed airspace within it.

Because the shape is riddled with very tiny pore spaces, the material might also find application in some filtration systems, for either water or chemical processing. The mathematical descriptions derived by this group could facilitate the development of a variety of applications, the researchers say.

“This is an inspiring study on the mechanics of 3-D graphene assembly,” says Huajian Gao, a professor of engineering at Brown University, who was not involved in this work. “The combination of computational modeling with 3-D-printing-based experiments used in this paper is a powerful new approach in engineering research. It is impressive to see the scaling laws initially derived from nanoscale simulations resurface in macroscale experiments under the help of 3-D printing,” he says.

This work, Gao says, “shows a promising direction of bringing the strength of 2-D materials and the power of material architecture design together.”

There’s a video describing the work,

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

The mechanics and design of a lightweight three-dimensional graphene assembly by Zhao Qin, Gang Seob Jung, Min Jeong Kang, and Markus J. Buehler. Science Advances  06 Jan 2017: Vol. 3, no. 1, e1601536 DOI: 10.1126/sciadv.1601536  04 January 2017

This paper appears to be open access.

Water that freezes solid at over 100 degrees Celsius

The ‘magical property’ of water that freezes at temperatures higher than 100 degrees Celsius occurs at the nanoscale according to this Nov. 28, 2016 news item on Nanowerk,

It’s a well-known fact that water, at sea level, starts to boil at a temperature of 212 degrees Fahrenheit, or 100 degrees Celsius. And scientists have long observed that when water is confined in very small spaces, its boiling and freezing points can change a bit, usually dropping by around 10 C or so.

But now, a team at MIT [Massachusetts Institute of Technology] has found a completely unexpected set of changes: Inside the tiniest of spaces — in carbon nanotubes whose inner dimensions are not much bigger than a few water molecules — water can freeze solid even at high temperatures that would normally set it boiling.

A Nov. 28, 2016 MIT news release (also on EurekAlert), which originated the news item, expands on the theme,

The discovery illustrates how even very familiar materials can drastically change their behavior when trapped inside structures measured in nanometers, or billionths of a meter. And the finding might lead to new applications — such as, essentially, ice-filled wires — that take advantage of the unique electrical and thermal properties of ice while remaining stable at room temperature.

“If you confine a fluid to a nanocavity, you can actually distort its phase behavior,” Strano says, referring to how and when the substance changes between solid, liquid, and gas phases. Such effects were expected, but the enormous magnitude of the change, and its direction (raising rather than lowering the freezing point), were a complete surprise: In one of the team’s tests, the water solidified at a temperature of 105 C or more. (The exact temperature is hard to determine, but 105 C was considered the minimum value in this test; the actual temperature could have been as high as 151 C.)

“The effect is much greater than anyone had anticipated,” Strano says.

It turns out that the way water’s behavior changes inside the tiny carbon nanotubes — structures the shape of a soda straw, made entirely of carbon atoms but only a few nanometers in diameter — depends crucially on the exact diameter of the tubes. “These are really the smallest pipes you could think of,” Strano says. In the experiments, the nanotubes were left open at both ends, with reservoirs of water at each opening.

Even the difference between nanotubes 1.05 nanometers and 1.06 nanometers across made a difference of tens of degrees in the apparent freezing point, the researchers found. Such extreme differences were completely unexpected. “All bets are off when you get really small,” Strano says. “It’s really an unexplored space.”

In earlier efforts to understand how water and other fluids would behave when confined to such small spaces, “there were some simulations that showed really contradictory results,” he says. Part of the reason for that is many teams weren’t able to measure the exact sizes of their carbon nanotubes so precisely, not realizing that such small differences could produce such different outcomes.

In fact, it’s surprising that water even enters into these tiny tubes in the first place, Strano says: Carbon nanotubes are thought to be hydrophobic, or water-repelling, so water molecules should have a hard time getting inside. The fact that they do gain entry remains a bit of a mystery, he says.

Strano and his team used highly sensitive imaging systems, using a technique called vibrational spectroscopy, that could track the movement of water inside the nanotubes, thus making its behavior subject to detailed measurement for the first time.

The team can detect not only the presence of water in the tube, but also its phase, he says: “We can tell if it’s vapor or liquid, and we can tell if it’s in a stiff phase.” While the water definitely goes into a solid phase, the team avoids calling it “ice” because that term implies a certain kind of crystalline structure, which they haven’t yet been able to show conclusively exists in these confined spaces. “It’s not necessarily ice, but it’s an ice-like phase,” Strano says.

Because this solid water doesn’t melt until well above the normal boiling point of water, it should remain perfectly stable indefinitely under room-temperature conditions. That makes it potentially a useful material for a variety of possible applications, he says. For example, it should be possible to make “ice wires” that would be among the best carriers known for protons, because water conducts protons at least 10 times more readily than typical conductive materials. “This gives us very stable water wires, at room temperature,” he says.

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

Observation of extreme phase transition temperatures of water confined inside isolated carbon nanotubes by Kumar Varoon Agrawal, Steven Shimizu, Lee W. Drahushuk, Daniel Kilcoyne, & Michael S. Strano. Nature Nanotechnology (2016)  doi:10.1038/nnano.2016.254 Published online 28 November 2016

This paper is behind a paywall.

Montreal Neuro creates a new paradigm for technology transfer?

It’s one heck of a Christmas present. Canadian businessmen Larry Tannenbaum and his wife Judy have given the Montreal Neurological Institute (Montreal Neuro), which is affiliated with McGill University, a $20M donation. From a Dec. 16, 2016 McGill University news release,

The Prime Minister of Canada, Justin Trudeau, was present today at the Montreal Neurological Institute and Hospital (MNI) for the announcement of an important donation of $20 million by the Larry and Judy Tanenbaum family. This transformative gift will help to establish the Tanenbaum Open Science Institute, a bold initiative that will facilitate the sharing of neuroscience findings worldwide to accelerate the discovery of leading edge therapeutics to treat patients suffering from neurological diseases.

‟Today, we take an important step forward in opening up new horizons in neuroscience research and discovery,” said Mr. Larry Tanenbaum. ‟Our digital world provides for unprecedented opportunities to leverage advances in technology to the benefit of science.  That is what we are celebrating here today: the transformation of research, the removal of barriers, the breaking of silos and, most of all, the courage of researchers to put patients and progress ahead of all other considerations.”

Neuroscience has reached a new frontier, and advances in technology now allow scientists to better understand the brain and all its complexities in ways that were previously deemed impossible. The sharing of research findings amongst scientists is critical, not only due to the sheer scale of data involved, but also because diseases of the brain and the nervous system are amongst the most compelling unmet medical needs of our time.

Neurological diseases, mental illnesses, addictions, and brain and spinal cord injuries directly impact 1 in 3 Canadians, representing approximately 11 million people across the country.

“As internationally-recognized leaders in the field of brain research, we are uniquely placed to deliver on this ambitious initiative and reinforce our reputation as an institution that drives innovation, discovery and advanced patient care,” said Dr. Guy Rouleau, Director of the Montreal Neurological Institute and Hospital and Chair of McGill University’s Department of Neurology and Neurosurgery. “Part of the Tanenbaum family’s donation will be used to incentivize other Canadian researchers and institutions to adopt an Open Science model, thus strengthening the network of like-minded institutes working in this field.”

What they don’t mention in the news release is that they will not be pursuing any patents (for five years according to one of the people in the video but I can’t find text to substantiate that time limit*; there are no time limits noted elsewhere) on their work. For this detail and others, you have to listen to the video they’ve created,

The CBC (Canadian Broadcasting Corporation) news online Dec. 16, 2016 posting (with files from Sarah Leavitt and Justin Hayward) adds a few personal details about Tannenbaum,

“Our goal is simple: to accelerate brain research and discovery to relieve suffering,” said Tanenbaum.

Tanenbaum, a Canadian businessman and chairman of Maple Leaf Sports and Entertainment, said many of his loved ones suffered from neurological disorders.

“I lost my mother to Alzheimer’s, my father to a stroke, three dear friends to brain cancer, and a brilliant friend and scientist to clinical depression,” said Tanenbaum.

He hopes the institute will serve as the template for science research across the world, a thought that Trudeau echoed.

“This vision around open science, recognizing the role that Canada can and should play, the leadership that Canadians can have in this initiative is truly, truly exciting,” said Trudeau.

The Neurological Institute says the pharmaceutical industry is supportive of the open science concept because it will provide crucial base research that can later be used to develop drugs to fight an array of neurological conditions.

Jack Stilgoe in a Dec. 16, 2016 posting on the Guardian blogs explains what this donation could mean (Note: Links have been removed),

With the help of Tanenbaum’s gift of 20 million Canadian dollars (£12million) the ‘Neuro’, the Montreal Neurological Institute and Hospital, is setting up an experiment in experimentation, an Open Science Initiative with the express purpose of finding out the best way to realise the potential of scientific research.

Governments in science-rich countries are increasingly concerned that they do not appear to reaping the economic returns they feel they deserve from investments in scientific research. Their favoured response has been to try to bridge what they see as a ‘valley of death’ between basic scientific research and industrial applications. This has meant more funding for ‘translational research’ and the flowering of technology transfer offices within universities.

… There are some success stories, particularly in the life sciences. Patents from the work of Richard Axel at Columbia University at one point brought the university almost $100 million per year. The University of Florida received more than $150 million for inventing Gatorade in the 1960s. The stakes are high in the current battle between Berkely and MIT/Harvard over who owns the rights to the CRISPR/Cas9 system that has revolutionised genetic engineering and could be worth billions.

Policymakers imagine a world in which universities pay for themselves just as a pharmaceutical research lab does. However, for critics of technology transfer, such stories blind us to the reality of university’s entrepreneurial abilities.

For most universities, evidence of their money-making prowess is, to put it charitably, mixed. A recent Bloomberg report shows how quickly university patent incomes plunge once we look beyond the megastars. In 2014, just 15 US universities earned 70% of all patent royalties. British science policy researchers Paul Nightingale and Alex Coad conclude that ‘Roughly 9/10 US universities lose money on their technology transfer offices… MIT makes more money from selling T-shirts than it does from licensing’. A report from the Brookings institute concluded that the model of technology transfer ‘is unprofitable for most universities and sometimes even risks alienating the private sector’. In the UK, the situation is even worse. Businesses who have dealings with universities report that their technology transfer offices are often unrealistic in negotiations. In many cases, academics are, like a small child who refuses to let others play with a brand new football, unable to make the most of their gifts. And areas of science outside the life sciences are harder to patent than medicines, sports drinks and genetic engineering techniques. Trying too hard to force science towards the market may be, to use the phrase of science policy professor Keith Pavitt, like pushing a piece of string.

Science policy is slowly waking up to the realisation that the value of science may lie in people and places rather than papers and patents. It’s an idea that the Neuro, with the help of Tanenbaum’s gift, is going to test. By sharing data and giving away intellectual property, the initiative aims to attract new private partners to the institute and build Montreal as a hub for knowledge and innovation. The hypothesis is that this will be more lucrative than hoarding patents.

This experiment is not wishful thinking. It will be scientifically measured. It is the job of Richard Gold, a McGill University law professor, to see whether it works. He told me that his first task is ‘to figure out what to counts… There’s going to be a gap between what we would like to measure and what we can measure’. However, he sees an open-mindedness among his colleagues that is unusual. Some are evangelists for open science; some are sceptics. But they share a curiosity about new approaches and a recognition of a problem in neuroscience: ‘We haven’t come up with a new drug for Parkinson’s in 30 years. We don’t even understand the biological basis for many of these diseases. So whatever we’re doing at the moment doesn’t work’. …

Montreal Neuro made news on the ‘open science’ front in January 2016 when it formally announced its research would be freely available and that researchers would not be pursuing patents (see my January 22, 2016 posting).

I recommend reading Stilgoe’s posting in its entirety and for those who don’t know or have forgotten, Prime Minister’s Trudeau’s family has some experience with mental illness. His mother has been very open about her travails. This makes his presence at the announcement perhaps a bit more meaningful than the usual political presence at a major funding announcement.

*The five-year time limit is confirmed in a Feb. 17, 2017 McGill University news release about their presentations at the AAAS (American Association for the Advancement of Science) 2017 annual meeting) on EurekAlert,

umpstarting Neurological Research through Open Science – MNI & McGill University

Friday, February 17, 2017, 1:30-2:30 PM/ Room 208

Neurological research is advancing too slowly according to Dr. Guy Rouleau, director of the Montreal Neurological Institute (MNI) of McGill University. To speed up discovery, MNI has become the first ever Open Science academic institution in the world. In a five-year experiment, MNI is opening its books and making itself transparent to an international group of social scientists, policymakers, industrial partners, and members of civil society. They hope, by doing so, to accelerate research and the discovery of new treatments for patients with neurological diseases, and to encourage other leading institutions around the world to consider a similar model. A team led by McGill Faculty of Law’s Professor Richard Gold will monitor and evaluate how well the MNI Open Science experiment works and provide the scientific and policy worlds with insight into 21st century university-industry partnerships. At this workshop, Rouleau and Gold will discuss the benefits and challenges of this open-science initiative.

Morphing airplane wing

Long a science fiction trope, ‘morphing’, in this case, an airplane wing, is closer to reality with this work from the Massachusetts Institute of Technology (MIT). From a Nov. 3, 2016 MIT news release (also on EurekAlert),

When the Wright brothers accomplished their first powered flight more than a century ago, they controlled the motion of their Flyer 1 aircraft using wires and pulleys that bent and twisted the wood-and-canvas wings. This system was quite different than the separate, hinged flaps and ailerons that have performed those functions on most aircraft ever since. But now, thanks to some high-tech wizardry developed by engineers at MIT and NASA, some aircraft may be returning to their roots, with a new kind of bendable, “morphing” wing.

The new wing architecture, which could greatly simplify the manufacturing process and reduce fuel consumption by improving the wing’s aerodynamics, as well as improving its agility, is based on a system of tiny, lightweight subunits that could be assembled by a team of small specialized robots, and ultimately could be used to build the entire airframe. The wing would be covered by a “skin” made of overlapping pieces that might resemble scales or feathers.

The new concept is described in the journal Soft Robotics, in a paper by Neil Gershenfeld, director of MIT’s Center for Bits and Atoms (CBA); Benjamin Jenett, a CBA graduate student; Kenneth Cheung PhD ’12, a CBA alumnus and NASA research scientist; and four others.

Researchers have been trying for many years to achieve a reliable way of deforming wings as a substitute for the conventional, separate, moving surfaces, but all those efforts “have had little practical impact,” Gershenfeld says. The biggest problem was that most of these attempts relied on deforming the wing through the use of mechanical control structures within the wing, but these structures tended to be so heavy that they canceled out any efficiency advantages produced by the smoother aerodynamic surfaces. They also added complexity and reliability issues.

By contrast, Gershenfeld says, “We make the whole wing the mechanism. It’s not something we put into the wing.” In the team’s new approach, the whole shape of the wing can be changed, and twisted uniformly along its length, by activating two small motors that apply a twisting pressure to each wingtip.

Like building with blocks

The basic principle behind the new concept is the use of an array of tiny, lightweight structural pieces, which Gershenfeld calls “digital materials,” that can be assembled into a virtually infinite variety of shapes, much like assembling a structure from Lego blocks. The assembly, performed by hand for this initial experiment, could be done by simple miniature robots that would crawl along or inside the structure as it took shape. The team has already developed prototypes of such robots.

The individual pieces are strong and stiff, but the exact choice of the dimensions and materials used for the pieces, and the geometry of how they are assembled, allow for a precise tuning of the flexibility of the final shape. For the initial test structure, the goal was to allow the wing to twist in a precise way that would substitute for the motion of separate structural pieces (such as the small ailerons at the trailing edges of conventional wings), while providing a single, smooth aerodynamic surface.

Building up a large and complex structure from an array of small, identical building blocks, which have an exceptional combination of strength, light weight, and flexibility, greatly simplifies the manufacturing process, Gershenfeld explains. While the construction of light composite wings for today’s aircraft requires large, specialized equipment for layering and hardening the material, the new modular structures could be rapidly manufactured in mass quantities and then assembled robotically in place.

Gershenfeld and his team have been pursuing this approach to building complex structures for years, with many potential applications for robotic devices of various kinds. For example, this method could lead to robotic arms and legs whose shapes could bend continuously along their entire length, rather than just having a fixed number of joints.

This research, says Cheung, “presents a general strategy for increasing the performance of highly compliant — that is, ‘soft’ — robots and mechanisms,” by replacing conventional flexible materials with new cellular materials “that are much lower weight, more tunable, and can be made to dissipate energy at much lower rates” while having equivalent stiffness.

Saving fuel, cutting emissions

While exploring possible applications of this nascent technology, Gershenfeld and his team consulted with NASA engineers and others seeking ways to improve the efficiency of aircraft manufacturing and flight. They learned that “the idea that you could continuously deform a wing shape to do pure lift and roll has been a holy grail in the field, for both efficiency and agility,” he says. Given the importance of fuel costs in both the economics of the airline industry and that sector’s contribution to greenhouse gas emissions, even small improvements in fuel efficiency could have a significant impact.

Wind-tunnel tests of this structure showed that it at least matches the aerodynamic properties of a conventional wing, at about one-tenth the weight.

The “skin” of the wing also enhances the structure’s performance. It’s made from overlapping strips of flexible material, layered somewhat like feathers or fish scales, allowing for the pieces to move across each other as the wing flexes, while still providing a smooth outer surface.

The modular structure also provides greater ease of both assembly and disassembly: One of this system’s big advantages, in principle, Gershenfeld says, is that when it’s no longer needed, the whole structure can be taken apart into its component parts, which can then be reassembled into something completely different. Similarly, repairs could be made by simply replacing an area of damaged subunits.

“An inspection robot could just find where the broken part is and replace it, and keep the aircraft 100 percent healthy at all times,” says Jenett.

Following up on the successful wind tunnel tests, the team is now extending the work to tests of a flyable unpiloted aircraft, and initial tests have shown great promise, Jenett says. “The first tests were done by a certified test pilot, and he found it so responsive that he decided to do some aerobatics.”

Some of the first uses of the technology may be to make small, robotic aircraft — “super-efficient long-range drones,” Gershenfeld says, that could be used in developing countries as a way of delivering medicines to remote areas.

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

Digital Morphing Wing: Active Wing Shaping Concept Using Composite Lattice-Based Cellular Structures by Benjamin Jenett, Sam Calisch, Daniel Cellucci, Nick Cramer, Neil Gershenfeld, Sean Swei, and Kenneth C. Cheung. Soft Robotics. October 2016, ahead of print. doi:10.1089/soro.2016.0032. Published online: Oct. 26, 2016

This paper is open access.

Spinach and plant nanobionics

Who knew that spinach leaves could be turned into electronic devices? The answer is: engineers at the Massachusetts Institute of Technology, according to an Oct. 31, 2016 news item on phys.org,

Spinach is no longer just a superfood: By embedding leaves with carbon nanotubes, MIT engineers have transformed spinach plants into sensors that can detect explosives and wirelessly relay that information to a handheld device similar to a smartphone.

This is one of the first demonstrations of engineering electronic systems into plants, an approach that the researchers call “plant nanobionics.”

An Oct. 31, 2016 MIT news release (also on EurekAlert), which originated the news item, describes the research further (Note: Links have been removed),

“The goal of plant nanobionics is to introduce nanoparticles into the plant to give it non-native functions,” says Michael Strano, the Carbon P. Dubbs Professor of Chemical Engineering at MIT and the leader of the research team.

In this case, the plants were designed to detect chemical compounds known as nitroaromatics, which are often used in landmines and other explosives. When one of these chemicals is present in the groundwater sampled naturally by the plant, carbon nanotubes embedded in the plant leaves emit a fluorescent signal that can be read with an infrared camera. The camera can be attached to a small computer similar to a smartphone, which then sends an email to the user.

“This is a novel demonstration of how we have overcome the plant/human communication barrier,” says Strano, who believes plant power could also be harnessed to warn of pollutants and environmental conditions such as drought.

Strano is the senior author of a paper describing the nanobionic plants in the Oct. 31 [2016] issue of Nature Materials. The paper’s lead authors are Min Hao Wong, an MIT graduate student who has started a company called Plantea to further develop this technology, and Juan Pablo Giraldo, a former MIT postdoc who is now an assistant professor at the University of California at Riverside.

Environmental monitoring

Two years ago, in the first demonstration of plant nanobionics, Strano and former MIT postdoc Juan Pablo Giraldo used nanoparticles to enhance plants’ photosynthesis ability and to turn them into sensors for nitric oxide, a pollutant produced by combustion.

Plants are ideally suited for monitoring the environment because they already take in a lot of information from their surroundings, Strano says.

“Plants are very good analytical chemists,” he says. “They have an extensive root network in the soil, are constantly sampling groundwater, and have a way to self-power the transport of that water up into the leaves.”

Strano’s lab has previously developed carbon nanotubes that can be used as sensors to detect a wide range of molecules, including hydrogen peroxide, the explosive TNT, and the nerve gas sarin. When the target molecule binds to a polymer wrapped around the nanotube, it alters the tube’s fluorescence.

In the new study, the researchers embedded sensors for nitroaromatic compounds into the leaves of spinach plants. Using a technique called vascular infusion, which involves applying a solution of nanoparticles to the underside of the leaf, they placed the sensors into a leaf layer known as the mesophyll, which is where most photosynthesis takes place.

They also embedded carbon nanotubes that emit a constant fluorescent signal that serves as a reference. This allows the researchers to compare the two fluorescent signals, making it easier to determine if the explosive sensor has detected anything. If there are any explosive molecules in the groundwater, it takes about 10 minutes for the plant to draw them up into the leaves, where they encounter the detector.

To read the signal, the researchers shine a laser onto the leaf, prompting the nanotubes in the leaf to emit near-infrared fluorescent light. This can be detected with a small infrared camera connected to a Raspberry Pi, a $35 credit-card-sized computer similar to the computer inside a smartphone. The signal could also be detected with a smartphone by removing the infrared filter that most camera phones have, the researchers say.

“This setup could be replaced by a cell phone and the right kind of camera,” Strano says. “It’s just the infrared filter that would stop you from using your cell phone.”

Using this setup, the researchers can pick up a signal from about 1 meter away from the plant, and they are now working on increasing that distance.

Michael McAlpine, an associate professor of mechanical engineering at the University of Minnesota, says this approach holds great potential for engineering not only sensors but many other kinds of bionic plants that might receive radio signals or change color.

“When you have manmade materials infiltrated into a living organism, you can have plants do things that plants don’t ordinarily do,” says McAlpine, who was not involved in the research. “Once you start to think of living organisms like plants as biomaterials that can be combined with electronic materials, this is all possible.”

“A wealth of information”

In the 2014 plant nanobionics study, Strano’s lab worked with a common laboratory plant known as Arabidopsis thaliana. However, the researchers wanted to use common spinach plants for the latest study, to demonstrate the versatility of this technique. “You can apply these techniques with any living plant,” Strano says.

So far, the researchers have also engineered spinach plants that can detect dopamine, which influences plant root growth, and they are now working on additional sensors, including some that track the chemicals plants use to convey information within their own tissues.

“Plants are very environmentally responsive,” Strano says. “They know that there is going to be a drought long before we do. They can detect small changes in the properties of soil and water potential. If we tap into those chemical signaling pathways, there is a wealth of information to access.”

These sensors could also help botanists learn more about the inner workings of plants, monitor plant health, and maximize the yield of rare compounds synthesized by plants such as the Madagascar periwinkle, which produces drugs used to treat cancer.

“These sensors give real-time information from the plant. It is almost like having the plant talk to us about the environment they are in,” Wong says. “In the case of precision agriculture, having such information can directly affect yield and margins.”

Once getting over the excitement, questions spring to mind. How could this be implemented? Is somebody  going to plant a field of spinach and then embed the leaves so they can detect landmines? How will anyone know where to plant the spinach? And on a different track, is this spinach edible? I suspect that if spinach can be successfully used as a sensor, it might not be for explosives but for pollution as the researchers suggest.

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

Nitroaromatic detection and infrared communication from wild-type plants using plant nanobionics by Min Hao Wong, Juan P. Giraldo, Seon-Yeong Kwak, Volodymyr B. Koman, Rosalie Sinclair, Tedrick Thomas Salim Lew, Gili Bisker, Pingwei Liu, & Michael S. Strano. Nature Materials (2016) doi:10.1038/nmat4771 Published online 31 October 2016

This paper is behind a paywall.

The last posting here which featured Strano’s research is in an Aug. 25, 2015 piece about carbon nanotubes and medical sensors.

Stretchy optical materials for implants that could pulse light

An Oct. 17, 2016 Massachusetts Institute of Technology (MIT) news release (also on EurekAlert) by Emily Chu describes research that could lead to long-lasting implants offering preventive health strategies,

Researchers from MIT and Harvard Medical School have developed a biocompatible and highly stretchable optical fiber made from hydrogel — an elastic, rubbery material composed mostly of water. The fiber, which is as bendable as a rope of licorice, may one day be implanted in the body to deliver therapeutic pulses of light or light up at the first sign of disease. [emphasis mine]

The researchers say the fiber may serve as a long-lasting implant that would bend and twist with the body without breaking down. The team has published its results online in the journal Advanced Materials.

Using light to activate cells, and particularly neurons in the brain, is a highly active field known as optogenetics, in which researchers deliver short pulses of light to targeted tissues using needle-like fibers, through which they shine light from an LED source.

“But the brain is like a bowl of Jell-O, whereas these fibers are like glass — very rigid, which can possibly damage brain tissues,” says Xuanhe Zhao, the Robert N. Noyce Career Development Associate Professor in MIT’s Department of Mechanical Engineering. “If these fibers could match the flexibility and softness of the brain, they could provide long-term more effective stimulation and therapy.”

Getting to the core of it

Zhao’s group at MIT, including graduate students Xinyue Liu and Hyunwoo Yuk, specializes in tuning the mechanical properties of hydrogels. The researchers have devised multiple recipes for making tough yet pliable hydrogels out of various biopolymers. The team has also come up with ways to bond hydrogels with various surfaces such as metallic sensors and LEDs, to create stretchable electronics.

The researchers only thought to explore hydrogel’s use in optical fibers after conversations with the bio-optics group at Harvard Medical School, led by Associate Professor Seok-Hyun (Andy) Yun. Yun’s group had previously fabricated an optical fiber from hydrogel material that successfully transmitted light through the fiber. However, the material broke apart when bent or slightly stretched. Zhao’s hydrogels, in contrast, could stretch and bend like taffy. The two groups joined efforts and looked for ways to incorporate Zhao’s hydrogel into Yun’s optical fiber design.

Yun’s design consists of a core material encased in an outer cladding. To transmit the maximum amount of light through the core of the fiber, the core and the cladding should be made of materials with very different refractive indices, or degrees to which they can bend light.

“If these two things are too similar, whatever light source flows through the fiber will just fade away,” Yuk explains. “In optical fibers, people want to have a much higher refractive index in the core, versus cladding, so that when light goes through the core, it bounces off the interface of the cladding and stays within the core.”

Happily, they found that Zhao’s hydrogel material was highly transparent and possessed a refractive index that was ideal as a core material. But when they tried to coat the hydrogel with a cladding polymer solution, the two materials tended to peel apart when the fiber was stretched or bent.

To bond the two materials together, the researchers added conjugation chemicals to the cladding solution, which, when coated over the hydrogel core, generated chemical links between the outer surfaces of both materials.

“It clicks together the carboxyl groups in the cladding, and the amine groups in the core material, like molecular-level glue,” Yuk says.

Sensing strain

The researchers tested the optical fibers’ ability to propagate light by shining a laser through fibers of various lengths. Each fiber transmitted light without significant attenuation, or fading. They also found that fibers could be stretched over seven times their original length without breaking.

Now that they had developed a highly flexible and robust optical fiber, made from a hydrogel material that was also biocompatible, the researchers began to play with the fiber’s optical properties, to see if they could design a fiber that could sense when and where it was being stretched.

They first loaded a fiber with red, green, and blue organic dyes, placed at specific spots along the fiber’s length. Next, they shone a laser through the fiber and stretched, for instance, the red region. They measured the spectrum of light that made it all the way through the fiber, and noted the intensity of the red light. They reasoned that this intensity relates directly to the amount of light absorbed by the red dye, as a result of that region being stretched.

In other words, by measuring the amount of light at the far end of the fiber, the researchers can quantitatively determine where and by how much a fiber was stretched.

“When you stretch a certain portion of the fiber, the dimensions of that part of the fiber changes, along with the amount of light that region absorbs and scatters, so in this way, the fiber can serve as a sensor of strain,” Liu explains.

“This is like a multistrain sensor through a single fiber,” Yuk adds. “So it can be an implantable or wearable strain gauge.”

The researchers imagine that such stretchable, strain-sensing optical fibers could be implanted or fitted along the length of a patient’s arm or leg, to monitor for signs of improving mobility.

Zhao envisions the fibers may also serve as sensors, lighting up in response to signs of disease.

“We may be able to use optical fibers for long-term diagnostics, to optically monitor tumors or inflammation,” he says. “The applications can be impactful.”

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

Highly Stretchable, Strain Sensing Hydrogel Optical Fibers by Jingjing Guo, Xinyue Liu, Nan Jiang, Ali K. Yetisen, Hyunwoo Yuk, Changxi Yang, Ali Khademhosseini, Xuanhe Zhao, and Seok-Hyun Yun. Advanced Materials DOI: 10.1002/adma.201603160 Version of Record online: 7 OCT 2016

© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

This paper is behind a paywall.

Science innovation (nanomedicine) can be tough

Robert Langer is a well known researcher in the field of nanomedicine. Weirdly not included in a listing of prominent nanoscientists in a series by Slate.com writers (my Oct. 7, 2016 posting), it seems the English are making up for this oversight. Amy Fleming in an Oct. 17, 2016 article for the Guardian tells Langer’s story in the context of his recent award of the £1m Queen Elizabeth prize for engineering (Note: Links have been removed),

Robert Langer seems incredibly well adjusted for a man with transatlantic jetlag. And, for that matter, for someone who struggled for years to get his pioneering work in drug delivery accepted by the scientific establishment. As a young professor, his first nine research grant applications were turned down. Once, at a formal dinner in the early 80s, a senior colleague blew smoke in his eyes and told him to find another job.

And yet here he is, a good-natured nanotechnology trailblazer, swooping into the UK for duties associated with having won the £1m Queen Elizabeth prize for engineering. His work has improved the lives of 2 billion people and counting. He has collected awards from two US presidents, as well as the Queen. He has more than 1,000 patents on the go, and 30 companies have spun out from his vast lab at Massachusetts Institute of Technology (the largest biomedical lab in the world). At 68, he is still the future.

… the huge range of his research interests. There’s contraceptive microchip implants; a gel to repair damaged vocal cords; spinal cord repair tissue; an invisible “second skin” for conditions such as eczema (with the cosmetic side effect of rendering skin smooth and elastic); cutting-edge anti-frizz haircare; and what Langer calls “super-long-acting capsules or pills, that would last a week, a month, or even a year”. …

Fleming describes some of Langer’s innovations in more detail (Note: Links have been removed),

Commonly, when pharmaceuticals enter the body, they are coated in synthetic substances called polymers. These allow effective amounts of the drug to reach the body, slowly enough so as not to cause toxicity. Until Langer came along, this controlled method only worked for simpler, small-molecule drugs. Sophisticated large-molecule drugs, that can target diseases such as cancer, diabetes and mental illness, were too big to pass through polymers. “People wouldn’t think you could walk through a wall either,” he says. “But we built all these tortuous channels in what was the equivalent of the wall so somebody could get through, but they get through very slowly, like driving through London in rush hour.”

Langer also designed biologically tolerable polymer pellets – nanopellets, he calls them – that enable drugs to be implanted directly into cancer tumours. This enabled Langer and the cancer researcher Judah Folkman to isolate the first vascular inhibitors, which stop new blood vessels feeding tumours. “We thought it could be a new way of treating cancer,” Langer says, “and it’s become that. Drugs such as Avastin [bevacizumab] and Eylea [aflibercept] are based, in part, on our early research.” He also created new polymers that could dissolve like a bar of soap and release drugs in a very controlled way over months to years. And he and neurosurgeon Henry Brem developed implants (called gliadel wafers) that could be implanted in the brain to treat brain cancer. Trials in 1996 saw a 63% survival rate against just 19% in the control group.

If you have the time, it’s well worth reading Fleming’s article in its entirety.

Creative destruction for Canada’s fundamental science

After receiving an ‘invitation’ from the Canadian Science Policy Centre, I wrote an opinion piece, drawing on my submission for the public consultation on Canada’s fundamental science research. It seems the invitation was more of a ‘call’ for submissions and my piece did not end up being selected for inclusion on the website. So rather than waste the piece, here it is,

Creative destruction for Canada’s fundamental science

At a time when we are dealing with the consequences of our sins and virtues, fundamental science, at heart, an exercise in imagination, can seem a waste of precious time. Pollution and climate change (sins: ill-considered uses of technology) and food security and water requirements (virtues: efforts to improve health and save more lives) would seem to demand solutions not the flights of fancy associated with basic science. After all, what does the ‘big bang’ have to do with potable water?

It’s not an unfair question despite the impatience some might feel when answering it by citing a number of practical applications which are the result of all that ‘fanciful’ or ‘blue sky’ science. The beauty and importance of the question is that it will always be asked and can never be definitively answered, rendering it a near constant goad or insurance against complacency.

In many ways Canada’s review of fundamental science (deadline for comments was Sept. 30, 2016) is not just an examination of the current funding schemes but an opportunity to introduce more ‘goads’ or ‘anti-complacency’ measures into Canada’s fundamental science efforts for a kind of ‘creative destruction’.

Introduced by economist Joseph Schumpeter, the concept is derived from Karl Marx’s work but these days is associated with disruptive, painful, and regenerative innovation of all kinds and Canadian fundamental science needs more ‘creative destruction’. There’s at least one movement in this direction (found both in Canada and internationally) which takes us beyond uncomfortable, confrontative questions and occasional funding reviews—the integration of arts and humanities as an attempt at ‘creative destruction’ of the science endeavour.

At one point in the early 2000s, Canada developed a programme where the National Research Council could get joint funding with the Canada Council for the Arts for artists to work with their scientists. It was abandoned a few years later, as a failure. But, since then, several informal attempts at combining arts, sciences, and humanities have sprung up.

For example, Curiosity Collider (founded in 2015) hosts artists and scientists presenting their art/science pieces at various events in Vancouver. Beakerhead has mashed up science, engineering, arts, and entertainment in a festival founded and held in Calgary since 2013. Toronto’s ArtSci Salon hosts events and installations for local, national, and international collaborations of artists and scientists. And, getting back to Vancouver, Anecdotal Evidence is a science storytelling series which has been appearing sporadically since 2015.

There is a tendency to dismiss these types of collaboration as a form of science outreach designed to amuse or entertain but they can be much more than that. Illustrators have taught botanists a thing or two about plants. Markus Buehler at the Massachusetts Institute of Technology has used his understanding of music to explore material science (spider’s webs). Domenico Vicinanza has sonified data from space vehicle, Voyager 1, to produce a symphony, which is also a highly compressed means of communicating data.

C. P. Snow’s ‘The Two Cultures’ (lecture and book) covered much of the same territory in 1959 noting the idea that the arts and sciences (and humanities) can and should be linked in some fashion was not new. For centuries the sciences were referred to as Natural Philosophy (humanities), albeit only chemistry and physics were considered sciences, and many universities have or had faculties of arts and sciences or colleges of arts and science (e.g., the University of Saskatchewan still has such a college).

The current art/sci or sci-art movement can be seen as more than an attempt to resuscitate a ‘golden’ period from the past. It could be a means of embedding a continuous state of regeneration or ‘creative destruction’ for fundamental science in Canada.

Powering up your graphene implants so you don’t get fried in the process

A Sept. 23, 2016 news item on phys.org describes a way of making graphene-based medical implants safer,

In the future, our health may be monitored and maintained by tiny sensors and drug dispensers, deployed within the body and made from graphene—one of the strongest, lightest materials in the world. Graphene is composed of a single sheet of carbon atoms, linked together like razor-thin chicken wire, and its properties may be tuned in countless ways, making it a versatile material for tiny, next-generation implants.

But graphene is incredibly stiff, whereas biological tissue is soft. Because of this, any power applied to operate a graphene implant could precipitously heat up and fry surrounding cells.

Now, engineers from MIT [Massachusetts Institute of Technology] and Tsinghua University in Beijing have precisely simulated how electrical power may generate heat between a single layer of graphene and a simple cell membrane. While direct contact between the two layers inevitably overheats and kills the cell, the researchers found they could prevent this effect with a very thin, in-between layer of water.

A Sept. 23, 2016 MIT news release by Emily Chu, which originated the news item, provides more technical details,

By tuning the thickness of this intermediate water layer, the researchers could carefully control the amount of heat transferred between graphene and biological tissue. They also identified the critical power to apply to the graphene layer, without frying the cell membrane. …

Co-author Zhao Qin, a research scientist in MIT’s Department of Civil and Environmental Engineering (CEE), says the team’s simulations may help guide the development of graphene implants and their optimal power requirements.

“We’ve provided a lot of insight, like what’s the critical power we can accept that will not fry the cell,” Qin says. “But sometimes we might want to intentionally increase the temperature, because for some biomedical applications, we want to kill cells like cancer cells. This work can also be used as guidance [for those efforts.]”

Sandwich model

Typically, heat travels between two materials via vibrations in each material’s atoms. These atoms are always vibrating, at frequencies that depend on the properties of their materials. As a surface heats up, its atoms vibrate even more, causing collisions with other atoms and transferring heat in the process.

The researchers sought to accurately characterize the way heat travels, at the level of individual atoms, between graphene and biological tissue. To do this, they considered the simplest interface, comprising a small, 500-nanometer-square sheet of graphene and a simple cell membrane, separated by a thin layer of water.

“In the body, water is everywhere, and the outer surface of membranes will always like to interact with water, so you cannot totally remove it,” Qin says. “So we came up with a sandwich model for graphene, water, and membrane, that is a crystal clear system for seeing the thermal conductance between these two materials.”

Qin’s colleagues at Tsinghua University had previously developed a model to precisely simulate the interactions between atoms in graphene and water, using density functional theory — a computational modeling technique that considers the structure of an atom’s electrons in determining how that atom will interact with other atoms.

However, to apply this modeling technique to the group’s sandwich model, which comprised about half a million atoms, would have required an incredible amount of computational power. Instead, Qin and his colleagues used classical molecular dynamics — a mathematical technique based on a “force field” potential function, or a simplified version of the interactions between atoms — that enabled them to efficiently calculate interactions within larger atomic systems.

The researchers then built an atom-level sandwich model of graphene, water, and a cell membrane, based on the group’s simplified force field. They carried out molecular dynamics simulations in which they changed the amount of power applied to the graphene, as well as the thickness of the intermediate water layer, and observed the amount of heat that carried over from the graphene to the cell membrane.

Watery crystals

Because the stiffness of graphene and biological tissue is so different, Qin and his colleagues expected that heat would conduct rather poorly between the two materials, building up steeply in the graphene before flooding and overheating the cell membrane. However, the intermediate water layer helped dissipate this heat, easing its conduction and preventing a temperature spike in the cell membrane.

Looking more closely at the interactions within this interface, the researchers made a surprising discovery: Within the sandwich model, the water, pressed against graphene’s chicken-wire pattern, morphed into a similar crystal-like structure.

“Graphene’s lattice acts like a template to guide the water to form network structures,” Qin explains. “The water acts more like a solid material and makes the stiffness transition from graphene and membrane less abrupt. We think this helps heat to conduct from graphene to the membrane side.”

The group varied the thickness of the intermediate water layer in simulations, and found that a 1-nanometer-wide layer of water helped to dissipate heat very effectively. In terms of the power applied to the system, they calculated that about a megawatt of power per meter squared, applied in tiny, microsecond bursts, was the most power that could be applied to the interface without overheating the cell membrane.

Qin says going forward, implant designers can use the group’s model and simulations to determine the critical power requirements for graphene devices of different dimensions. As for how they might practically control the thickness of the intermediate water layer, he says graphene’s surface may be modified to attract a particular number of water molecules.

“I think graphene provides a very promising candidate for implantable devices,” Qin says. “Our calculations can provide knowledge for designing these devices in the future, for specific applications, like sensors, monitors, and other biomedical applications.”

This research was supported in part by the MIT International Science and Technology Initiative (MISTI): MIT-China Seed Fund, the National Natural Science Foundation of China, DARPA [US Defense Advanced Research Projects Agency], the Department of Defense (DoD) Office of Naval Research, the DoD Multidisciplinary Research Initiatives program, the MIT Energy Initiative, and the National Science Foundation.

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

Intercalated water layers promote thermal dissipation at bio–nano interfaces by Yanlei Wang, Zhao Qin, Markus J. Buehler, & Zhiping Xu. Nature Communications 7, Article number: 12854 doi:10.1038/ncomms12854 Published 23 September 2016

This paper is open access.

Unbreakable encrypted message with key that’s shorter than the message

A Sept. 5, 2016 University of Rochester (NY state, US) news release (also on EurekAlert), makes an intriguing announcement,

Researchers at the University of Rochester have moved beyond the theoretical in demonstrating that an unbreakable encrypted message can be sent with a key that’s far shorter than the message—the first time that has ever been done.

Until now, unbreakable encrypted messages were transmitted via a system envisioned by American mathematician Claude Shannon, considered the “father of information theory.” Shannon combined his knowledge of algebra and electrical circuitry to come up with a binary system of transmitting messages that are secure, under three conditions: the key is random, used only once, and is at least as long as the message itself.

The findings by Daniel Lum, a graduate student in physics, and John Howell, a professor of physics, have been published in the journal Physical Review A.

“Daniel’s research amounts to an important step forward, not just for encryption, but for the field of quantum data locking,” said Howell.

Quantum data locking is a method of encryption advanced by Seth Lloyd, a professor of quantum information at Massachusetts Institute of Technology, that uses photons—the smallest particles associated with light—to carry a message. Quantum data locking was thought to have limitations for securely encrypting messages, but Lloyd figured out how to make additional assumptions—namely those involving the boundary between light and matter—to make it a more secure method of sending data.  While a binary system allows for only an on or off position with each bit of information, photon waves can be altered in many more ways: the angle of tilt can be changed, the wavelength can be made longer or shorter, and the size of the amplitude can be modified. Since a photon has more variables—and there are fundamental uncertainties when it comes to quantum measurements—the quantum key for encrypting and deciphering a message can be shorter that the message itself.

Lloyd’s system remained theoretical until this year, when Lum and his team developed a device—a quantum enigma machine—that would put the theory into practice. The device takes its name from the encryption machine used by Germany during World War II, which employed a coding method that the British and Polish intelligence agencies were secretly able to crack.

Let’s assume that Alice wants to send an encrypted message to Bob. She uses the machine to generate photons that travel through free space and into a spatial light modulator (SLM) that alters the properties of the individual photons (e.g. amplitude, tilt) to properly encode the message into flat but tilted wavefronts that can be focused to unique points dictated by the tilt. But the SLM does one more thing: it distorts the shapes of the photons into random patterns, such that the wavefront is no longer flat which means it no longer has a well-defined focus. Alice and Bob both know the keys which identify the implemented scrambling operations, so Bob is able to use his own SLM to flatten the wavefront, re-focus the photons, and translate the altered properties into the distinct elements of the message.

Along with modifying the shape of the photons, Lum and the team made use of the uncertainty principle, which states that the more we know about one property of a particle, the less we know about another of its properties. Because of that, the researchers were able to securely lock in six bits of classical information using only one bit of an encryption key—an operation called data locking.

“While our device is not 100 percent secure, due to photon loss,” said Lum, “it does show that data locking in message encryption is far more than a theory.”

The ultimate goal of the quantum enigma machine is to prevent a third party—for example, someone named Eve—from intercepting and deciphering the message. A crucial principle of quantum theory is that the mere act of measuring a quantum system changes the system. As a result, Eve has only one shot at obtaining and translating the encrypted message—something that is virtually impossible, given the nearly limitless number of patterns that exist for each photon.

The paper by Lum and Howell was one of two papers published simultaneously on the same topic. The other paper, “Quantum data locking,” was from a team led by Chinese physicist Jian-Wei Pan.

“It’s highly unlikely that our free-space implementation will be useful through atmospheric conditions,” said Lum. “Instead, we have identified the use of optic fiber as a more practical route for data locking, a path Pan’s group actually started with. Regardless, the field is still in its infancy with a great deal more research needed.”

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

Quantum enigma machine: Experimentally demonstrating quantum data locking by Daniel J. Lum, John C. Howell, M. S. Allman, Thomas Gerrits, Varun B. Verma, Sae Woo Nam, Cosmo Lupo, and Seth Lloyd. Phys. Rev. A, Vol. 94, Iss. 2 — August 2016 DOI: http://dx.doi.org/10.1103/PhysRevA.94.022315

©2016 American Physical Society

This paper is behind a paywall.

There is an earlier open access version of the paper by the Chinese researchers on arXiv.org,

Experimental quantum data locking by Yang Liu, Zhu Cao, Cheng Wu, Daiji Fukuda, Lixing You, Jiaqiang Zhong, Takayuki Numata, Sijing Chen, Weijun Zhang, Sheng-Cai Shi, Chao-Yang Lu, Zhen Wang, Xiongfeng Ma, Jingyun Fan, Qiang Zhang, Jian-Wei Pan. arXiv.org > quant-ph > arXiv:1605.04030

The Chinese team’s later version of the paper is available here,

Experimental quantum data locking by Yang Liu, Zhu Cao, Cheng Wu, Daiji Fukuda, Lixing You, Jiaqiang Zhong, Takayuki Numata, Sijing Chen, Weijun Zhang, Sheng-Cai Shi, Chao-Yang Lu, Zhen Wang, Xiongfeng Ma, Jingyun Fan, Qiang Zhang, and Jian-Wei Pan. Phys. Rev. A, Vol. 94, Iss. 2 — August 2016 DOI: http://dx.doi.org/10.1103/PhysRevA.94.020301

©2016 American Physical Society

This version is behind a paywall.

Getting back to the folks at the University of Rochester, they have provided this image to illustrate their work,

The quantum enigma machine developed by researchers at the University of Rochester, MIT, and the National Institute of Standards and Technology. (Image by Daniel Lum/University of Rochester)

The quantum enigma machine developed by researchers at the University of Rochester, MIT, and the National Institute of Standards and Technology. (Image by Daniel Lum/University of Rochester)