Tag Archives: US

Cellullose nanocrystals (CNC) and better concrete

Earlier this week in a March 30, 2015 post, I was bemoaning the dearth of applications for cellulose nanocrystals (CNC) with concomitant poor prospects for commercialization and problems for producers such as Canada’s CelluForce. Possibly this work at Purdue University (Indiana, US) will help address some of those issues (from a March 31, 2015 news item on Nanowerk),

Cellulose nanocrystals derived from industrial byproducts have been shown to increase the strength of concrete, representing a potential renewable additive to improve the ubiquitous construction material.

The cellulose nanocrystals (CNCs) could be refined from byproducts generated in the paper, bioenergy, agriculture and pulp industries. They are extracted from structures called cellulose microfibrils, which help to give plants and trees their high strength, lightweight and resilience. Now, researchers at Purdue University have demonstrated that the cellulose nanocrystals can increase the tensile strength of concrete by 30 percent.

A March 31, 2015 Purdue University news release by Emil Venere, which originated the news item, further describes the research published in print as of February 2015 (Note: A link has been removed),

One factor limiting the strength and durability of today’s concrete is that not all of the cement particles are hydrated after being mixed, leaving pores and defects that hamper strength and durability.

“So, in essence, we are not using 100 percent of the cement,” Zavattieri [Pablo Zavattieri, an associate professor in the Lyles School of Civil Engineering] said.

However, the researchers have discovered that the cellulose nanocrystals increase the hydration of the concrete mixture, allowing more of it to cure and potentially altering the structure of concrete and strengthening it.  As a result, less concrete needs to be used.

The cellulose nanocrystals are about 3 to 20 nanometers wide by 50-500 nanometers long – or about 1/1,000th the width of a grain of sand – making them too small to study with light microscopes and difficult to measure with laboratory instruments. They come from a variety of biological sources, primarily trees and plants.

The concrete was studied using several analytical and imaging techniques. Because chemical reactions in concrete hardening are exothermic, some of the tests measured the amount of heat released, indicating an increase in hydration of the concrete. The researchers also hypothesized the precise location of the nanocrystals in the cement matrix and learned how they interact with cement particles in both fresh and hardened concrete. The nanocrystals were shown to form little inlets for water to better penetrate the concrete.

The research dovetails with the goals of P3Nano, a public-private partnership supporting development and use of wood-based nanomaterial for a wide-range of commercial products.

“The idea is to support and help Purdue further advance the CNC-Cement technology for full-scale field trials and the potential for commercialization,” Zavattieri said.

The researchers have provided an image,

This transmission electron microscope image shows cellulose nanocrystals, tiny structures derived from renewable sources that might be used to create a new class of biomaterials with many potential applications. The structures have been shown to increase the strength of concrete. (Purdue Life Sciences Microscopy Center)

This transmission electron microscope image shows cellulose nanocrystals, tiny structures derived from renewable sources that might be used to create a new class of biomaterials with many potential applications. The structures have been shown to increase the strength of concrete. (Purdue Life Sciences Microscopy Center)

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

The influence of cellulose nanocrystal additions on the performance of cement paste by Yizheng Cao, Pablo Zavaterri, Jeff Youngblood, Robert Moon, and Jason Weiss. Cement and Concrete Composites, Volume 56, February 2015, Pages 73–83  DOI: 10.1016/j.cemconcomp.2014.11.008 Available online 18 November 2014

The paper is behind a paywall.

One final note, cellulose nanocrystals (CNC) may also be referred to nanocrystalline cellulose (NCC).

 

Entangling thousands of atoms

Quantum entanglement as an idea seems extraordinary to me like something from of the fevered imagination made possible only with certain kinds of hallucinogens. I suppose you could call theoretical physicists who’ve conceptualized entanglement a different breed as they don’t seem to need chemical assistance for their flights of fancy, which turn out to be reality. Researchers at MIT (Massachusetts Institute of Technology) and the University of Belgrade (Serbia) have entangled thousands of atoms with a single photon according to a March 26, 2015 news item on Nanotechnology Now,

Physicists from MIT and the University of Belgrade have developed a new technique that can successfully entangle 3,000 atoms using only a single photon. The results, published today in the journal Nature, represent the largest number of particles that have ever been mutually entangled experimentally.

The researchers say the technique provides a realistic method to generate large ensembles of entangled atoms, which are key components for realizing more-precise atomic clocks.

“You can make the argument that a single photon cannot possibly change the state of 3,000 atoms, but this one photon does — it builds up correlations that you didn’t have before,” says Vladan Vuletic, the Lester Wolfe Professor in MIT’s Department of Physics, and the paper’s senior author. “We have basically opened up a new class of entangled states we can make, but there are many more new classes to be explored.”

A March 26, 2015 MIT news release by Jennifer Chu (also on EurekAlert but dated March 25, 2015), which originated the news item, describes entanglement with particular attention to how it relates to atomic timekeeping,

Entanglement is a curious phenomenon: As the theory goes, two or more particles may be correlated in such a way that any change to one will simultaneously change the other, no matter how far apart they may be. For instance, if one atom in an entangled pair were somehow made to spin clockwise, the other atom would instantly be known to spin counterclockwise, even though the two may be physically separated by thousands of miles.

The phenomenon of entanglement, which physicist Albert Einstein once famously dismissed as “spooky action at a distance,” is described not by the laws of classical physics, but by quantum mechanics, which explains the interactions of particles at the nanoscale. At such minuscule scales, particles such as atoms are known to behave differently from matter at the macroscale.

Scientists have been searching for ways to entangle not just pairs, but large numbers of atoms; such ensembles could be the basis for powerful quantum computers and more-precise atomic clocks. The latter is a motivation for Vuletic’s group.

Today’s best atomic clocks are based on the natural oscillations within a cloud of trapped atoms. As the atoms oscillate, they act as a pendulum, keeping steady time. A laser beam within the clock, directed through the cloud of atoms, can detect the atoms’ vibrations, which ultimately determine the length of a single second.

“Today’s clocks are really amazing,” Vuletic says. “They would be less than a minute off if they ran since the Big Bang — that’s the stability of the best clocks that exist today. We’re hoping to get even further.”

The accuracy of atomic clocks improves as more and more atoms oscillate in a cloud. Conventional atomic clocks’ precision is proportional to the square root of the number of atoms: For example, a clock with nine times more atoms would only be three times as accurate. If these same atoms were entangled, a clock’s precision could be directly proportional to the number of atoms — in this case, nine times as accurate. The larger the number of entangled particles, then, the better an atomic clock’s timekeeping.

It seems weak lasers make big entanglements possible (from the news release),

Scientists have so far been able to entangle large groups of atoms, although most attempts have only generated entanglement between pairs in a group. Only one team has successfully entangled 100 atoms — the largest mutual entanglement to date, and only a small fraction of the whole atomic ensemble.

Now Vuletic and his colleagues have successfully created a mutual entanglement among 3,000 atoms, virtually all the atoms in the ensemble, using very weak laser light — down to pulses containing a single photon. The weaker the light, the better, Vuletic says, as it is less likely to disrupt the cloud. “The system remains in a relatively clean quantum state,” he says.

The researchers first cooled a cloud of atoms, then trapped them in a laser trap, and sent a weak laser pulse through the cloud. They then set up a detector to look for a particular photon within the beam. Vuletic reasoned that if a photon has passed through the atom cloud without event, its polarization, or direction of oscillation, would remain the same. If, however, a photon has interacted with the atoms, its polarization rotates just slightly — a sign that it was affected by quantum “noise” in the ensemble of spinning atoms, with the noise being the difference in the number of atoms spinning clockwise and counterclockwise.

“Every now and then, we observe an outgoing photon whose electric field oscillates in a direction perpendicular to that of the incoming photons,” Vuletic says. “When we detect such a photon, we know that must have been caused by the atomic ensemble, and surprisingly enough, that detection generates a very strongly entangled state of the atoms.”

Vuletic and his colleagues are currently using the single-photon detection technique to build a state-of-the-art atomic clock that they hope will overcome what’s known as the “standard quantum limit” — a limit to how accurate measurements can be in quantum systems. Vuletic says the group’s current setup may be a step toward developing even more complex entangled states.

“This particular state can improve atomic clocks by a factor of two,” Vuletic says. “We’re striving toward making even more complicated states that can go further.”

This research was supported in part by the National Science Foundation, the Defense Advanced Research Projects Agency, and the Air Force Office of Scientific Research.

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

Entanglement with negative Wigner function of almost 3,000 atoms heralded by one photon by Robert McConnell, Hao Zhang, Jiazhong Hu, Senka Ćuk & Vladan Vuletić. Nature 519 439–442 (26 March 2015) doi:10.1038/nature14293 Published online 25 March 2015

This article is behind a paywall but there is a free preview via ReadCube Access.

This image illustrates the entanglement of a large number of atoms. The atoms, shown in purple, are shown mutually entangled with one another. Image: Christine Daniloff/MIT and Jose-Luis Olivares/MIT

This image illustrates the entanglement of a large number of atoms. The atoms, shown in purple, are shown mutually entangled with one another.
Image: Christine Daniloff/MIT and Jose-Luis Olivares/MIT

Frogs: monitoring them, finding new species, and research about the golden ones in Panama

I have three frog-oriented items and while they’re not strictly speaking in my usual range of topics, given this blog’s name and the fact I haven’t posted a frog piece in quite a while, it seems this is a good moment to address that lack.

Monitoring frogs and amphibians at Trent University (Ontario, Canada)

From a March 23, 2015 Trent University news release,

With the decline of amphibian populations around the world, a team of researchers led by Trent University’s Dr. Dennis Murray will seek to establish environmental DNA (eDNA) monitoring of amphibian occupancy and aquatic ecosystem risk assessment with the help of a significant grant of over $596,000 from the Natural Sciences and Engineering Research Council of Canada (NSERC).

Awarded to Professor Murray, a Canada research chair in integrative wildlife conservation, bioinformatics, and ecological modelling and professor at Trent University along with colleagues Dr. Craig Brunetti of the Biology department, and Dr. Chris Kyle of the Forensic Science program, and partners at Laurentian University, University of Toronto, McGill University, Ontario Ministry of Natural Resources and Forestry and Environment Canada, the grant will support the development of tools that will promote a cleaner aquatic environment.

The project will use amphibian DNA found in natural breeding habitats to determine the presence and abundance of amphibians as well as their pathogens. This new technology capitalizes on Trent University’s expertise and infrastructure in the areas of wildlife DNA and water quality.

“We’re honoured to have received the grant to help us drive the project forward,” said Prof. Murray. “Our plan is to place Canada, and Trent, in a leadership position with respect to aquatic wildlife monitoring and amphibian conservation.”

Amphibian populations are declining worldwide, yet in Canada, amphibian numbers are not monitored closely, meaning changes in their distribution or abundance may be unnoticeable. Amphibian monitoring in Canada is conducted by citizen scientists who record frog breeding calls when visiting bodies of water during the spring. However, the lack of formalized amphibian surveys leaves Canada in a vulnerable position regarding the status of its diverse amphibian community.

Prof. Murray believes that the protocols developed from this project could revolutionize how amphibian populations are monitored in Canada and in turn lead to new insights regarding the population trends for several amphibian species across the country.

Here’s more about NSERC and Trent University from the news release,

About NSERC

NSERC is a federal agency that helps make Canada a country of discoverers and innovators. The agency supports almost 30,000 post-secondary students and postdoctoral fellows in their advanced studies. NSERC promotes discovery by funding approximately 12,000 professors every year and fosters innovation by encouraging over 2,400 Canadian companies to participate and invest in post-secondary research projects.

The NSERC Strategic Project Grants aim to increase research and training in areas that could strongly influence Canada’s economy, society or environment in the next 10 years in four target areas: environmental science and technologies; information and communications technologies; manufacturing; and natural resources and energy.

About Trent University

One of Canada’s top universities, Trent University was founded on the ideal of interactive learning that’s personal, purposeful and transformative. Consistently recognized nationally for leadership in teaching, research and student satisfaction, Trent attracts excellent students from across the country and around the world. Here, undergraduate and graduate students connect and collaborate with faculty, staff and their peers through diverse communities that span residential colleges, classrooms, disciplines, hands-on research, co-curricular and community-based activities. Across all disciplines, Trent brings critical, integrative thinking to life every day. As the University celebrates its 50th anniversary in 2014/15, Trent’s unique approach to personal development through supportive, collaborative community engagement is in more demand than ever. Students lead the way by co-creating experiences rooted in dialogue, diverse perspectives and collaboration. In a learning environment that builds life-long passion for inclusion, leadership and social change, Trent’s students, alumni, faculty and staff are engaged global citizens who are catalysts in developing sustainable solutions to complex issues. Trent’s Peterborough campus boasts award-winning architecture in a breathtaking natural setting on the banks of the Otonabee River, just 90 minutes from downtown Toronto, while Trent University Durham delivers a distinct mix of programming in the GTA.

Trent University’s expertise in water quality could be traced to its proximity to Canada’s Experimental Lakes Area (ELA), a much beleaguered research environment due to federal political imperatives. You can read more about the area and the politics in this Wikipedia entry. BTW, I am delighted to learn that it still exists under the auspices of the International Institute for Sustainable Development (IISD),

Taking this post into nanotechnology territory while mentioning the ELA, Trent University published a Dec. 8, 2014 news release about research into silver nanoparticles,

For several years, Trent University’s Dr. Chris Metcalfe and Dr. Maggie Xenopoulos have dedicated countless hours to the study of aquatic contaminants and the threat they pose to our environment.

Now, through the efforts of the International Institute for Sustainable Development (IISD), their research is reaching a wider audience thanks to a new video (Note: A link has been removed).

The video is one of a five-part series being released by the IISD that looks into environmental issues in Canada. The video entitled “Distilling Science at the Experimental Lakes Area: Nanosilver” and featuring Professors Metcalfe and Xenopoulos profiles their research around nanomaterials at the Experimental Lakes Area.

Prof. Xenopolous’ involvement in the project falls in line with other environmental issues she has tackled. In the past, her research has examined how human activities – including climate change, eutrophication and land use – affect ecosystem structure and function in lakes and rivers. She has also taken an interest in how land use affects the material exported and processed in aquatic ecosystems.

Prof. Metcalfe’s ongoing research on the fate and distribution of pharmaceutical and personal care products in the environment has generated considerable attention both nationally and internationally.

Together, their research into nanomaterials is getting some attention. Nanomaterials are submicroscopic particles whose physical and chemical properties make them useful for a variety of everyday applications. They can be found in certain pieces of clothing, home appliances, paint, and kitchenware. Initial laboratory research conducted at Trent University showed that nanosilver could strongly affect aquatic organisms at the bottom of the food chain, such as bacteria, algae and zooplankton.

To further examine these effects in a real ecosystem, a team of researchers from Trent University, Fisheries and Oceans Canada and Environment Canada has been conducting studies at undisclosed lakes in northwestern Ontario. The Lake Ecosystem Nanosilver (LENS) project has been monitoring changes in the lakes’ ecosystem that occur after the addition of nanosilver.

“In our particular case, we will be able to study and understand the effects of only nanosilver because that is the only variable that is going to change,” says Prof. Xenopoulos. “It’s really the only place in the world where we can do that.”

The knowledge gained from the study will help policy-makers make decisions about whether nanomaterials can be a threat to aquatic ecosystems and whether regulatory action is required to control their release into the environment.

You can find the 13 mins. video here: https://www.youtube.com/watch?v=_nJai_B4YH0#action=share

Shapeshifting frogs, a new species in Ecuador

Caption: This image shows skin texture variation in one individual frog (Pristimantis mutabilis) from Reserva Las Gralarias. Note how skin texture shifts from highly tubercular to almost smooth; also note the relative size of the tubercles on the eyelid, lower lip, dorsum and limbs. Credit: Zoological Journal of the Linnean Society

Caption: This image shows skin texture variation in one individual frog (Pristimantis mutabilis) from Reserva Las Gralarias. Note how skin texture shifts from highly tubercular to almost smooth; also note the relative size of the tubercles on the eyelid, lower lip, dorsum and limbs.
Credit: Zoological Journal of the Linnean Society

Here’s more about the shapeshifting and how the scientists figured out what the frogs were doing (from a March 23, 2015 Case Western Research University news release on EurekAlert; Note: A link has been removed),

A frog in Ecuador’s western Andean cloud forest changes skin texture in minutes, appearing to mimic the texture it sits on.

Originally discovered by a Case Western Reserve University PhD student and her husband, a projects manager at Cleveland Metroparks’ Natural Resources Division, the amphibian is believed to be the first known to have this shape-shifting capability.

But the new species, called Pristimantis mutabilis, or mutable rainfrog, has company. Colleagues working with the couple recently found that a known relative of the frog shares the same texture-changing quality–but it was never reported before.

The frogs are found at Reserva Las Gralarias, a nature reserve originally created to protect endangered birds in the Parish of Mindo, in north-central Ecuador.

The researchers, Katherine and Tim Krynak, and colleagues from Universidad Indoamérica and Tropical Herping (Ecuador) co-authored a manuscript describing the new animal and skin texture plasticity in the Zoological Journal of the Linnean Society this week. They believe their findings have broad implications for how species are and have been identified. The process may now require photographs and longer observations in the field to ensure the one species is not mistakenly perceived as two because at least two species of rain frogs can change their appearance.

Katherine Krynak believes the ability to change skin texture to reflect its surroundings may enable P. mutabilis to help camouflage itself from birds and other predators.

The Krynaks originally spotted the small, spiny frog, nearly the width of a marble, sitting on a moss-covered leaf about a yard off the ground on a misty July night in 2009. The Krynaks had never seen this animal before, though Tim had surveyed animals on annual trips to Las Gralarias since 2001, and Katherine since 2005.

They captured the little frog and tucked it into a cup with a lid before resuming their nightly search for wildlife. They nicknamed it “punk rocker” because of the thorn-like spines covering its body.

The next day, Katherine Krynak pulled the frog from the cup and set it on a smooth white sheet of plastic for Tim to photograph. It wasn’t “punk “–it was smooth-skinned. They assumed that, much to her dismay, she must have picked up the wrong frog.

“I then put the frog back in the cup and added some moss,” she said. “The spines came back… we simply couldn’t believe our eyes, our frog changed skin texture!

“I put the frog back on the smooth white background. Its skin became smooth.”

“The spines and coloration help them blend into mossy habitats, making it hard for us to see them,” she said. “But whether the texture really helps them elude predators still needs to be tested.”

During the next three years, a team of fellow biologists studied the frogs. They found the animals shift skin texture in a little more than three minutes.

Juan M. Guayasamin, from Universidad Tecnológica Indoamérica, Ecuador, the manuscript’s first author, performed morphological and genetic analyses showing that P. mutabilis was a unique and undescribed species. Carl R. Hutter, from the University of Kansas, studied the frog’s calls, finding three songs the species uses, which differentiate them from relatives. The fifth author of the paper, Jamie Culebras, assisted with fieldwork and was able to locate a second population of the species. Culebras is a member of Tropical Herping, an organization committed to discovering, and studying reptiles and amphibians.

Guayasamin and Hutter discovered that Prismantis sobetes, a relative with similar markings but about twice the size of P. mutabilis, has the same trait when they placed a spiny specimen on a sheet and watched its skin turn smooth. P. sobetes is the only relative that has been tested so far.

Because the appearance of animals has long been one of the keys to identifying them as a certain species, the researchers believe their find challenges the system, particularly for species identified by one or just a few preserved specimens. With those, there was and is no way to know if the appearance is changeable.

The Krynaks, who helped form Las Gralarias Foundation to support the conservation efforts of the reserve, plan to return to continue surveying for mutable rain frogs and to work with fellow researchers to further document their behaviors, lifecycle and texture shifting, and estimate their population, all in effort to improve our knowledge and subsequent ability to conserve this paradigm shifting species.

Further, they hope to discern whether more relatives have the ability to shift skin texture and if that trait comes from a common ancestor. If P. mutabilis and P. sobetes are the only species within this branch of Pristimantis frogs to have this capability, they hope to learn whether they retained it from an ancestor while relatives did not, or whether the trait evolved independently in each species.

Golden frog of Panama and its skin microbiome

Caption: Researchers studied microbial communities on the skin of Panamanian golden frogs to learn more about amphibian disease resistance. Panamanian golden frogs live only in captivity. Continued studies may help restore them back to the wild. Credit: B. Gratwicke/Smithsonian Conservation Biology Institute

Caption: Researchers studied microbial communities on the skin of Panamanian golden frogs to learn more about amphibian disease resistance. Panamanian golden frogs live only in captivity. Continued studies may help restore them back to the wild.
Credit: B. Gratwicke/Smithsonian Conservation Biology Institute

Among many of the pressures on frog populations, there’s a lethal fungus which has affected some 200 species of frogs. A March 23, 2015 news item on ScienceDaily describes some recent research into the bacterial communities present on frog skin,

A team of scientists including Virginia Tech researchers is one step closer to understanding how bacteria on a frog’s skin affects its likelihood of contracting disease.

A frog-killing fungus known as Batrachochytrium dendrobatidis, or Bd, has already led to the decline of more than 200 amphibian species including the now extinct-in-the-wild Panamanian golden frog.

In a recent study, the research team attempted to apply beneficial bacteria found on the skin of various Bd-resistant wild Panamanian frog species to Panamanian golden frogs in captivity, to see if this would stimulate a defense against the disease.

A March 23, 2015 Virginia Tech University news release on EurekAlert, which originated the news item, provides a twist and a turn in the story (Note: Links have been removed),

They found that while the treatment with beneficial bacteria was not successful due to its inability to stick to the skin, there were some frogs that survived exposure to the fungus.

These survivors actually had unique bacterial communities on their skin before the experiments started.

The next step is to explore these new bacterial communities.

“We were disappointed that the treatment didn’t work, but glad to have discovered new information about the relationship between these symbiotic microbial communities and amphibian disease resistance,” said Lisa Belden, an associate professor of biological sciences in the College of Science, a Fralin Life Science Institute affiliate, and a faculty member with the new Global Change Center at Virginia Tech. “Every bit of information gets us closer to getting these frogs back into nature.”

Studying the microbial communities of Panamanian golden frogs was the dissertation focus of Belden’s former graduate student Matthew Becker, who graduated with a Ph.D. in biological sciences from Virginia Tech in 2014 and is now a fellow at the Smithsonian Conservation Biology Institute.

“Anything that can help us predict resistance to this disease is very useful because the ultimate goal of this research is to establish healthy populations of golden frogs in their native habitat,” Becker told Smithsonian Science News. “I think identifying alternative probiotic treatment methods that optimize dosages and exposure times will be key for moving forward with the use of probiotics to mitigate chytridiomycosis.”

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

Composition of symbiotic bacteria predicts survival in Panamanian golden frogs infected with a lethal fungus by Matthew H. Becker , Jenifer B. Walke , Shawna Cikanek , Anna E. Savage , Nichole Mattheus , Celina N. Santiago , Kevin P. C. Minbiole , Reid N. Harris , Lisa K. Belden , Brian Gratwicke. April 2015 Volume: 282 Issue: 1805 DOI: 10.1098/rspb.2014.2881 Published 18 March 2015

This is an open access paper.

For anyone curious about the article in the Smithsonian mentioned in the news release, you can find it here.

 

Spinal cords, brains, implants, and remote control

I have two items about implants and brains and an item about being able to exert remote control of the brain, all of which hint at a cyborg future for at least a few of us.

e-Dura, the spinal column, and the brain

The first item concerns some research, at the École Polytechnique de Lausanne (EPFL) which features flexible electronics. From a March 24, 2015 article by Ben Schiller for Fast Company (Note: Links have been removed),

Researchers at the Swiss Federal Institute of Technology, in Lausanne, have developed the e-Dura—a tiny skinlike device that attaches directly to damaged spinal cords. By sending out small electrical pulses, it stimulates the cord as if it were receiving signals from the brain, thus allowing movement.

“The purpose of the neuro-prosthesis is to excite the neurons that are on the spinal cord below the site of the injury and activate them, just like if they were receiving information from the brain,” says Stéphanie Lacour, a professor at the institute.

A January 8, 2015 (?) EPFL press release provides more information about the research,

EPFL scientists have managed to get rats walking on their own again using a combination of electrical and chemical stimulation. But applying this method to humans would require multifunctional implants that could be installed for long periods of time on the spinal cord without causing any tissue damage. This is precisely what the teams of professors Stéphanie Lacour and Grégoire Courtine have developed. Their e-Dura implant is designed specifically for implantation on the surface of the brain or spinal cord. The small device closely imitates the mechanical properties of living tissue, and can simultaneously deliver electric impulses and pharmacological substances. The risks of rejection and/or damage to the spinal cord have been drastically reduced. An article about the implant will appear in early January [2015] in Science Magazine.

So-called “surface implants” have reached a roadblock; they cannot be applied long term to the spinal cord or brain, beneath the nervous system’s protective envelope, otherwise known as the “dura mater,” because when nerve tissues move or stretch, they rub against these rigid devices. After a while, this repeated friction causes inflammation, scar tissue buildup, and rejection.

Here’s what the implant looks like,

Courtesy: EPFL

Courtesy: EPFL

The press release describes how the implant is placed (Note: A link has been removed),

Flexible and stretchy, the implant developed at EPFL is placed beneath the dura mater, directly onto the spinal cord. Its elasticity and its potential for deformation are almost identical to the living tissue surrounding it. This reduces friction and inflammation to a minimum. When implanted into rats, the e-Dura prototype caused neither damage nor rejection, even after two months. More rigid traditional implants would have caused significant nerve tissue damage during this period of time.

The researchers tested the device prototype by applying their rehabilitation protocol — which combines electrical and chemical stimulation – to paralyzed rats. Not only did the implant prove its biocompatibility, but it also did its job perfectly, allowing the rats to regain the ability to walk on their own again after a few weeks of training.

“Our e-Dura implant can remain for a long period of time on the spinal cord or the cortex, precisely because it has the same mechanical properties as the dura mater itself. This opens up new therapeutic possibilities for patients suffering from neurological trauma or disorders, particularly individuals who have become paralyzed following spinal cord injury,” explains Lacour, co-author of the paper, and holder of EPFL’s Bertarelli Chair in Neuroprosthetic Technology.

The press release goes on to describe the engineering achievements,

Developing the e-Dura implant was quite a feat of engineering. As flexible and stretchable as living tissue, it nonetheless includes electronic elements that stimulate the spinal cord at the point of injury. The silicon substrate is covered with cracked gold electric conducting tracks that can be pulled and stretched. The electrodes are made of an innovative composite of silicon and platinum microbeads. They can be deformed in any direction, while still ensuring optimal electrical conductivity. Finally, a fluidic microchannel enables the delivery of pharmacological substances – neurotransmitters in this case – that will reanimate the nerve cells beneath the injured tissue.

The implant can also be used to monitor electrical impulses from the brain in real time. When they did this, the scientists were able to extract with precision the animal’s motor intention before it was translated into movement.

“It’s the first neuronal surface implant designed from the start for long-term application. In order to build it, we had to combine expertise from a considerable number of areas,” explains Courtine, co-author and holder of EPFL’s IRP Chair in Spinal Cord Repair. “These include materials science, electronics, neuroscience, medicine, and algorithm programming. I don’t think there are many places in the world where one finds the level of interdisciplinary cooperation that exists in our Center for Neuroprosthetics.”

For the time being, the e-Dura implant has been primarily tested in cases of spinal cord injury in paralyzed rats. But the potential for applying these surface implants is huge – for example in epilepsy, Parkinson’s disease and pain management. The scientists are planning to move towards clinical trials in humans, and to develop their prototype in preparation for commercialization.

EPFL has provided a video of researcher Stéphanie Lacour describing e-Dura and expressing hopes for its commercialization,

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

Electronic dura mater for long-term multimodal neural interfaces by Ivan R. Minev, Pavel Musienko, Arthur Hirsch, Quentin Barraud, Nikolaus Wenger, Eduardo Martin Moraud, Jérôme Gandar, Marco Capogrosso, Tomislav Milekovic, Léonie Asboth, Rafael Fajardo Torres, Nicolas Vachicouras, Qihan Liu, Natalia Pavlova, Simone Duis, Alexandre Larmagnac, Janos Vörös, Silvestro Micera, Zhigang Suo, Grégoire Courtine, Stéphanie P. Lacour. Science 9 January 2015: Vol. 347 no. 6218 pp. 159-163 DOI: 10.1126/science.1260318

This paper is behind a paywall.

Carbon nanotube fibres could connect to the brain

Researchers at Rice University (Texas, US) are excited about the possibilities that carbon nanotube fibres offer in the field of implantable electronics for the brain. From a March 25, 2015 news item on Nanowerk,

Carbon nanotube fibers invented at Rice University may provide the best way to communicate directly with the brain.

The fibers have proven superior to metal electrodes for deep brain stimulation and to read signals from a neuronal network. Because they provide a two-way connection, they show promise for treating patients with neurological disorders while monitoring the real-time response of neural circuits in areas that control movement, mood and bodily functions.

New experiments at Rice demonstrated the biocompatible fibers are ideal candidates for small, safe electrodes that interact with the brain’s neuronal system, according to the researchers. They could replace much larger electrodes currently used in devices for deep brain stimulation therapies in Parkinson’s disease patients.

They may also advance technologies to restore sensory or motor functions and brain-machine interfaces as well as deep brain stimulation therapies for other neurological disorders, including dystonia and depression, the researchers wrote.

A March 25, 2015 Rice University news release (also on EurekAlert*), which originated the news item, provides more details,

The fibers created by the Rice lab of chemist and chemical engineer Matteo Pasquali consist of bundles of long nanotubes originally intended for aerospace applications where strength, weight and conductivity are paramount.

The individual nanotubes measure only a few nanometers across, but when millions are bundled in a process called wet spinning, they become thread-like fibers about a quarter the width of a human hair.

“We developed these fibers as high-strength, high-conductivity materials,” Pasquali said. “Yet, once we had them in our hand, we realized that they had an unexpected property: They are really soft, much like a thread of silk. Their unique combination of strength, conductivity and softness makes them ideal for interfacing with the electrical function of the human body.”

The simultaneous arrival in 2012 of Caleb Kemere, a Rice assistant professor who brought expertise in animal models of Parkinson’s disease, and lead author Flavia Vitale, a research scientist in Pasquali’s lab with degrees in chemical and biomedical engineering, prompted the investigation.

“The brain is basically the consistency of pudding and doesn’t interact well with stiff metal electrodes,” Kemere said. “The dream is to have electrodes with the same consistency, and that’s why we’re really excited about these flexible carbon nanotube fibers and their long-term biocompatibility.”

Weeks-long tests on cells and then in rats with Parkinson’s symptoms proved the fibers are stable and as efficient as commercial platinum electrodes at only a fraction of the size. The soft fibers caused little inflammation, which helped maintain strong electrical connections to neurons by preventing the body’s defenses from scarring and encapsulating the site of the injury.

The highly conductive carbon nanotube fibers also show much more favorable impedance – the quality of the electrical connection — than state-of-the-art metal electrodes, making for better contact at lower voltages over long periods, Kemere said.

The working end of the fiber is the exposed tip, which is about the width of a neuron. The rest is encased with a three-micron layer of a flexible, biocompatible polymer with excellent insulating properties.

The challenge is in placing the tips. “That’s really just a matter of having a brain atlas, and during the experiment adjusting the electrodes very delicately and putting them into the right place,” said Kemere, whose lab studies ways to connect signal-processing systems and the brain’s memory and cognitive centers.

Doctors who implant deep brain stimulation devices start with a recording probe able to “listen” to neurons that emit characteristic signals depending on their functions, Kemere said. Once a surgeon finds the right spot, the probe is removed and the stimulating electrode gently inserted. Rice carbon nanotube fibers that send and receive signals would simplify implantation, Vitale said.

The fibers could lead to self-regulating therapeutic devices for Parkinson’s and other patients. Current devices include an implant that sends electrical signals to the brain to calm the tremors that afflict Parkinson’s patients.

“But our technology enables the ability to record while stimulating,” Vitale said. “Current electrodes can only stimulate tissue. They’re too big to detect any spiking activity, so basically the clinical devices send continuous pulses regardless of the response of the brain.”

Kemere foresees a closed-loop system that can read neuronal signals and adapt stimulation therapy in real time. He anticipates building a device with many electrodes that can be addressed individually to gain fine control over stimulation and monitoring from a small, implantable device.

“Interestingly, conductivity is not the most important electrical property of the nanotube fibers,” Pasquali said. “These fibers are intrinsically porous and extremely stable, which are both great advantages over metal electrodes for sensing electrochemical signals and maintaining performance over long periods of time.”

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

Neural Stimulation and Recording with Bidirectional, Soft Carbon Nanotube Fiber Microelectrodes by Flavia Vitale, Samantha R. Summerson, Behnaam Aazhang, Caleb Kemere, and Matteo Pasquali. ACS Nano, Just Accepted Manuscript DOI: 10.1021/acsnano.5b01060 Publication Date (Web): March 24, 2015

Copyright © 2015 American Chemical Society

The paper is open access provided you register on the website.

Remote control for stimulation of the brain

Mo Costandi, neuroscientist and freelance science writer, has written a March 24, 2015 post for the Guardian science blog network focusing on neuronal remote control,

Two teams of scientists have developed new ways of stimulating neurons with nanoparticles, allowing them to activate brain cells remotely using light or magnetic fields. The new methods are quicker and far less invasive than other hi-tech methods available, so could be more suitable for potential new treatments for human diseases.

Researchers have various methods for manipulating brain cell activity, arguably the most powerful being optogenetics, which enables them to switch specific brain cells on or off with unprecedented precision, and simultaneously record their behaviour, using pulses of light.

This is very useful for probing neural circuits and behaviour, but involves first creating genetically engineered mice with light-sensitive neurons, and then inserting the optical fibres that deliver light into the brain, so there are major technical and ethical barriers to its use in humans.

Nanomedicine could get around this. Francisco Bezanilla of the University of Chicago and his colleagues knew that gold nanoparticles can absorb light and convert it into heat, and several years ago they discovered that infrared light can make neurons fire nervous impulses by heating up their cell membranes.

Polina Anikeeva’s team at the Massachusetts Institute of Technology adopted a slightly different approach, using spherical iron oxide particles that give off heat when exposed to an alternating magnetic field.

Although still in the experimental stages, research like this may eventually allow for wireless and minimally invasive deep brain stimulation of the human brain. Bezanilla’s group aim to apply their method to develop treatments for macular degeneration and other conditions that kill off light-sensitive cells in the retina. This would involve injecting nanoparticles into the eye so that they bind to other retinal cells, allowing natural light to excite them into firing impulses to the optic nerve.

Costandi’s article is intended for an audience that either understands the science or can deal with the uncertainty of not understanding absolutely everything. Provided you fall into either of those categories, the article is well written and it provides links and citations to the papers for both research teams being featured.

Taken together, the research at EPFL, Rice University, University of Chicago, and Massachusetts Institute of Technology provides a clue as to how much money and intellectual power is being directed at the brain.

* EurekAlert link added on March 26, 2015.

New molecular ruler could help with developing antibiotics

Researchers at the University of Utah have developed a molecular ruler which could help to determine the length at which a nanoscale needle is effective. From a March 17, 2015 news item on Azonano,

When a salmonella bacterium attacks a cell, it uses a nanoscopic needle to inject it with proteins to aid the infection. If the needle is too short, the cell won’t be infected. Too long, and the needle breaks. Now, University of Utah biologists report how a disposable molecular ruler or tape measure determines the length of the bacterial needle so it is just right.

The findings have potential long-term applications for developing new antibiotics against salmonella and certain other disease-causing bacteria, for designing bacteria that could inject cancer cells with chemotherapy drugs, and for helping people how to design machines at the nanoscopic or molecular scale.

A March 16, 2015 University of Utah news release, which originated the news item, provides some insight from the researchers,

“If you look at important pathogens – the bubonic plague bacterium, salmonella, shigella and plant pathogens like fire blight – they all use hypodermic-like needles to inject proteins that facilitate disease processes,” Hughes [University of Utah biology professor Kelly Hughes] says.

“Our work says that there is one mechanism – the molecular ruler – to explain how the lengths are controlled for needles in gram-negative bacteria and for hooks on flagella [the U-joints in propellers bacteria use to move] in all bacteria,” he adds.

In their study, Wee [University of Utah doctoral student Daniel Wee] and Hughes found that as a bacterial needle or “injectisome” grows, a molecular ruler – really, more like a gooey tape measure – is secreted from within the needle’s base. It oozes up through the tube-like needle, and when the bottom end of the ruler reaches the bottom end of the needle, the needle stops growing and begins to inject proteins into the target cell to help the infection process.

The biologists say the [US] National Institutes of Health-funded study refutes other theories for how salmonella and some other disease bacteria determine needle lengths.

The news release also explains how this finding could be made useful,

“What we understand from bacteria can help us build nanomachines and nanobots,” Hughes says, noting that bacterial flagella – the nanoscopic motor-and-propeller system they use to swim to dinner or to targets – are “the most sophisticated nanomachines in the universe.”

In one example, Swiss scientists are using the design of bacterial flagella as the basis for a nanobot that will be put inside the eye to do nanoscale surgery, he adds.

In addition to flagella, a number of disease-causing bacteria also have injectisomes, which also are built of proteins, as are most structures in living organisms.

“In the case of the needle, you have a structure that extends from the surface of the bacterium like a hypodermic,” Hughes says. “These needles are fragile. If one is too long, it will break off and be useless. If you make it too short, then it can’t get past the surface proteins on cells it needs to invade.”

By understanding how bacteria determine the length for their needles, it someday may be possible to engineer bacteria to inject chemotherapy drugs right into cancer cells.

“People would like to design bacteria that can get to cancer cells and inject poisons into just those cells and kill them, and not harm the rest of us,” Hughes says.

And by understanding how certain disease-causing bacteria build their injectisomes, new antibiotics might be developed in a decade or so to target and destroy the needles and thus deter bacterial infections. The rulers that help build flagella also might be attacked by drugs to prevent bacteria from reaching target cells, “so you can kill two birds with one stone by hitting the two machines at the same time,” Hughes says.

He says that approach might work against injectisome-equipped bacteria such as salmonella species that cause typhoid fever and food poisoning; shigella species that cause dysentery; the bubonic plague bacterium Yersinia pestis; disease-causing E. coli; sexually transmitted Chlamydia trachomatis; many plant pathogens; and Pseudomonas aeruginosa, which often infects burn patients and the lungs of cystic fibrosis patients.

Not usually my kind of thing, I find this quite fascinating (from the news release),

Bacteria secrete a molecular ruler to measure needle length

Bacterial injectisomes are incredibly small, measuring only 20 to 100 nanometers long. A nanometer is one billionth of a meter, and a meter is about 39 inches long. The width of a typical human hair often is given as 100 microns, so the maximum length of a bacterial needle, 100 nanometers, is one-thousandth of the width of a human hair.

Gram-negative, disease-causing bacteria “are very closely related species, so how do they subtly control the various needle lengths to be perfect?” Hughes asks. “In one case it might be 40 nanometers versus 55 nanometers. These are small sizes. So to do this, the bacteria developed molecular rulers to differentiate needles of different lengths.”

(Gram-negative bacteria are those with membranes lining both the inside and outside of their cell wall, while gram-positive bacteria have only an inner membrane.)

Like any cell, a bacterium is encased in a cell wall. So bacteria developed all kinds of secretions to make contact with and infect other cells: flagellar propellers to swim to food or target cells, docking structures to help bacteria stick to targets, and injectisomes to inject infection-promoting proteins into targets.

When a bacterium builds a needle, it first builds a base. “A series of proteins form a doughnut, and inside the doughnut hole, the actual secretion machine gets constructed,” Hughes says. “It’s the same for the flagella as it is for these needles.”

Next, proteins start assembling to form the needle or injectisome.

The new study demonstrated that in salmonella, the ruler or tape measure is secreted slowly through the channel of the growing needle. Once amino acids at the bottom end of the ruler pass through the base of the needle, they tell the bacterium that the needle is long enough and to stop growing. They also tell the needle to injecting virulence proteins into the target cell, and the molecular ruler is ejected, Wee says.

Here’s an image of what the injectisome looks like,

On the left is an electron microscope image of an injectisome, the nanoscopic needle that salmonella and certain other bacteria use to inject proteins into target cells as part of the infection process. The illustration at center depicts the exterior of the needle and its base. The cross-section at right shows the string-like molecular ruler that determines the length of salmonella’s bacteria needle, according to a new University of Utah study by doctoral student Daniel Wee and biology professor Kelly Hughes. Credit: Daniel Wee, University of Utah

On the left is an electron microscope image of an injectisome, the nanoscopic needle that salmonella and certain other bacteria use to inject proteins into target cells as part of the infection process. The illustration at center depicts the exterior of the needle and its base. The cross-section at right shows the string-like molecular ruler that determines the length of salmonella’s bacteria needle, according to a new University of Utah study by doctoral student Daniel Wee and biology professor Kelly Hughes. Credit: Daniel Wee, University of Utah

The news release also offers some specific details about the research,

How the study was performed

The new study used the Typhimurium strain of Salmonella enterica, which causes food poisoning. The researchers proved the molecular ruler determines needle length in salmonella by inserting amino acids from the plague bacterium’s molecular ruler genes into genes for salmonella’s molecular ruler, making rulers with seven different lengths.

Genetically engineered salmonella with seven ruler lengths were grown in a flask, their needles isolated, and the needle lengths measured under an electron microscope.

Wee found the ruler lengths correlated precisely with the lengths of the resulting needles or injectisomes, with each amino acid added to the ruler gene making the resulting needle 0.2 nanometers longer.

Previous studies found the molecular ruler determines the length of the hook or U-joint that helps turn flagella or propellers in many bacteria. Research also found the molecular ruler determines the length of both the flagellar hook and the needle in plague bacteria. But some researchers argued salmonella needle’s length was determined by some other mechanism:

– One theory holds that a molecular measuring cup in the needle’s base sends a cupful of needle components to assemble the needle, and the length of the needle is determined by the size of the cup. The new study disproved that by genetically removing the cup and showing that the injectisomes or needles still grew to correct lengths.

– Another theory says that as needle components assemble outside the needle’s base, a rod-shaped structure assembles inside the base to link the base and needle, and that when the rod is complete, needle assembly stops, thus determining needle length. But the Utah study found the rod and needle components are not made simultaneously, but compete with each other, so as more rod parts are made, fewer needle parts are made, giving an illusion that rod completion controls needle length.

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

Molecular ruler determines needle length for the Salmonella Spi-1 injectisome by Daniel H. Wee and Kelly T. Hughes. Published online before print March 16, 2015, doi: 10.1073/pnas.1423492112 PNAS March 16, 2015

This paper is behind a paywall.

 

Dancing droplets—a mystery solved

I love simple yet profound discoveries like the one described in a March 12, 2015 news item on Nanowerk (Note: A link has been removed),

 A puzzling observation, pursued through hundreds of experiments, has led Stanford researchers to a simple yet profound discovery: under certain circumstances, droplets of fluid will move like performers in a dance choreographed by molecular physics.

“These droplets sense one another. They move and interact, almost like living cells,” said Manu Prakash, an assistant professor of bioengineering and senior author of an article published in Nature (“Vapour-mediated sensing and motility in two-component droplets”).

A March 11, 2015 Stanford University news release by Tom Abate, which originated the news item, describes possible applications and the genesis of this research,

The unexpected findings may prove useful in semiconductor manufacturing and self-cleaning solar panels, but what truly excites Prakash is that the discovery resulted from years of persistent effort to satisfy a scientific curiosity.

The research began in 2009 when Nate Cira, then an undergraduate at the University of Wisconsin, was doing an unrelated experiment. In the course of that experiment Cira deposited several droplets of food coloring onto a sterilized glass slide and was astonished when they began to move.

Here’s a video of the researchers discussing their work and their findings (Video by Kurt Hickman),

The news release elaborates,

Together they spent three years performing increasingly refined experiments to learn how these tiny droplets of food coloring sense one another and move. In living cells these processes of sensing and motility are known as chemotaxis.

“We’ve discovered how droplets can exhibit behaviors akin to artificial chemotaxis,” Prakash said.

As the Nature article explains, the critical fact was that food coloring is a two-component fluid. In such fluids, two different chemical compounds coexist while retaining separate molecular identities

The droplets in this experiment consisted of two molecular compounds found naturally in food coloring: water and propylene glycol.

The researchers discovered how the dynamic interactions of these two molecular components enabled inanimate droplets to mimic some of the behaviors of living cells.

Surface tension and evaporation

Essentially, the droplets danced because of a delicate balance between surface tension and evaporation.

Evaporation is easily understood. On the surface of any liquid, some molecules convert to a gaseous state and float away.

Surface tension is what causes liquids to bead up. It arises from how tightly the molecules in a liquid bind together.

Water evaporates more quickly than propylene glycol. Water also has a higher surface tension.  These differences create a tornado-like flow inside the droplets, which not only allows them to move but also allows a single droplet to sense its neighbors.

To understand the molecular forces involved, imagine shrinking down to size and diving inside a droplet.

There, water and propylene glycol molecules try to remain evenly distributed but differences in evaporation and surface tension create turmoil within the droplet.

On the curved dome of each droplet, water molecules become gaseous and float away faster than their evaporation-averse propylene glycol neighbors.

This evaporation happens more readily on the thin lower edges of the domed droplet, leaving excess of propylene glycol there. Meanwhile, the peak of the dome has a higher concentration of water.

The water at the top exerts its higher surface tension to pull the droplet tight so it doesn’t flatten out. This tugging causes a tumbling molecular motion inside the droplet. Thus surface tension gets the droplet ready to roll.

Evaporation determines the direction of that motion. Each droplet sends aloft gaseous molecules of water like a radially emanating signal announcing the exact location of any given droplet. The droplets converge where the signal is strongest.

So evaporation provided the sensing mechanism and surface tension the pull to move droplets together in what seemed to the eye to be a careful dance.

Rule for two-component fluids

The researchers experimented with varied proportions of water and propylene glycol. Droplets that were 1 percent propylene glycol (PG) to 99 percent water exhibited much the same behavior as droplets that were two-thirds PG to just one-third water.

Based on these experiments the paper describes a “universal rule” to identify any two-component fluids that will demonstrate sensing and motility.

Adding colors to the mixtures made it easier to tell how the droplets of different concentrations behaved and created some visually striking results.

In one experiment, a droplet with more propylene glycol seems to chase a droplet with more water. In actuality, the droplet with more water exerts a higher surface tension tug, pulling the propylene droplet along.

In another experiment, researchers showed how physically separated droplets could align themselves using ever-so-slight signals of evaporation.

In a third experiment they used Sharpie pens to draw black lines on glass slides. The lines changed the surface of the slide and created a series of catch basins. The researchers filled each basin with fluids of different concentrations to create a self-sorting mechanism. Droplets bounced from reservoir to reservoir until they sensed the fluid that matched their concentration and merged with that pool.

What started as a curiosity-driven project may also have many practical implications.

The deep physical understanding of two component fluids allows the researchers to predict which fluids and surfaces will show these unusual effects. The effect is present on a large number of common surfaces and can be replicated with a number of chemical compounds.

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

Vapour-mediated sensing and motility in two-component droplets by N. J. Cira, A. Benusiglio, & M. Prakash. Nature  (2015) doi:10.1038/nature14272 Published online 11 March 2015

This paper is behind a paywall.

Carbon nanotube commercialization report from the US National Nanotechnology Initiative

Apparently a workshop on the topic commercializing carbon nanotubes was held in Washington, DC. in Sept. 2014. A March 12, 2015 news item on Nanowerk (originated by  March 12, 2015 US National Nanotechnology Initiative news release on EurekAlert) announces the outcome of that workshop (Note: Links have been removed),

The National Nanotechnology Initiative today published the proceedings of a technical interchange meeting on “Realizing the Promise of Carbon Nanotubes: Challenges, Opportunities, and the Pathway to Commercialization” (pdf), held at the National Aeronautics and Space Administration (NASA) Headquarters on September 15, 2014. This meeting brought together some of the Nation’s leading experts in carbon nanotube materials to identify, discuss, and report on technical barriers to the production of carbon nanotube (CNT)-based bulk and composite materials with properties that more closely match those of individual CNTs and to explore ways to overcome these barriers.

The outcomes of this meeting, as detailed in this report, will help inform the future directions of the NNI Nanotechnology Signature Initiative “Sustainable Nanomanufacturing: Creating the Industries of the Future”, which was launched in 2010 to accelerate the development of industrial-scale methods for manufacturing functional nanoscale systems.

The Technical Interchange Proceedings ‘Realizing the Promise of Carbon Nanotubes: Challenges, Opportunities, and the Pathway to Commercialization‘ (30 pp. PDF) describes areas for improvement in its executive summary,

A number of common themes and areas requiring focused attention were identified:

● Increased efforts devoted to manufacturing, quality control, and scale-up are needed. The development of a robust supply of CNT bulk materials with well-controlled properties would greatly enhance commercialization and spur use in a broad range of applications.
● Improvements are needed in the mechanical and electrical properties of CNT-based bulk materials (composites, sheets, and fibers) to approach the properties of individual CNTs. The development of bulk materials with properties nearing ideal CNT values would accelerate widespread adoption of these materials.
● More effective use of simulation and modeling is needed to provide insight into the fundamentals of the CNT growth process. Theoretical insight into the fundamentals of the growth process will inform the development of processes capable of producing high-quality material in quantity.
● Work is needed to help develop an understanding of the properties of bulk CNT-containing materials at longer length scales. Longer length scale understanding will enable the development of predictive models of structure–process–properties relationships and structural design technology tailored to take advantage of CNT properties.
● Standard materials and protocols are needed to guide the testing of CNT-based products for commercial applications. Advances in measurement methods are also required to characterize bulk CNT material properties and to understand the mechanism(s) of failure to help ensure material reliability.
● Life cycle assessments are needed for gauging commercial readiness. Life cycle assessments should include energy usage, performance lifetime, and degradation or disposal of CNT-based products.
● Collaboration to leverage resources and expertise is needed to advance commercialization of CNT-based products. Coordinated, focused efforts across academia, government laboratories, and industry to target grand challenges with support from public–private partnerships would accelerate efforts to provide solutions to overcome these technical barriers.

This meeting identified a number of the technical barriers that need to be overcome to make the promise of carbon nanotubes a reality. A more concerted effort is needed to focus R&D activities towards addressing these barriers and accelerating commercialization. The outcomes from this meeting will inform the future directions of the NNI Nanomanufacturing Signature Initiative and provide specific areas that warrant broader focus in the CNT research community. [p. vii print; p. 9 PDF]

This report, in its final section, explains the basis for the interest in and the hopes for carbon nanotubes,

Improving the electrical and mechanical properties of bulk carbon nanotube materials (yarns, fibers, wires, sheets, and composites) to more closely match those of individual carbon nanotubes will enable a revolution in materials that will have a broad impact on U.S. industries, global competitiveness, and the environment. Use of composites reinforced with high-strength carbon nanotube fibers in terrestrial and air transportation vehicles could enable a 25% reduction in their overall weight, reduce U.S. oil consumption by nearly 6 million barrels per day by 2035 [42], and reduce worldwide consumption of petroleum and other liquid fuels by 25%. This would result in the reduction of CO2 emissions by as much as 3.75 billion metric tons per year. Use of carbon nanotube-based data and power cables would lead to further reductions in vehicle weight, fuel consumption, and CO2 emissions. For example, replacement of the copper wiring in a Boeing 777 with CNT data and power cables that are 50% lighter would enable a 2,000-pound reduction in airplane weight. Use of carbon nanotube wiring in power distribution lines would reduce transmission losses by approximately 41 billion kilowatt hours annually [42], leading to significant savings in coal and gas consumption and reductions in the electric power industry’s carbon footprint.

The impact of developing these materials on U.S. global competitiveness is also significant. For example, global demand for carbon fibers is expected to grow from 46,000 metric tons per year in 2011 to more than 153,000 metric tons in 2020 due to the exponential growth in the use of composites in commercial aircraft, automobiles, aerospace, and wind energy [43]. Ultrahigh-strength CNT fibers would be highly attractive in each of these applications because they offer the advantage of reduced weight and improved performance over conventional carbon fibers. [p. 10 print; p. 20 PDF]

As these things go, this is a very short document, which makes it a fast read, and it has a reference list, something I always find useful.

My colleague, Dexter Johnson in a March 17, 2015 posting on his Nanoclast blog (on the IEEE [Institute for Electrical and Electronics Engineers] website) provides some background information before launching into an analysis of the report’s recommendations (Note: Links have been removed),

In the last half-a-decade we have witnessed once-beloved carbon nanotubes (CNTs) slowly being eclipsed by graphene as the “wonder material” of the nanomaterial universe.

This changing of the guard has occurred primarily within the research community, where the amount of papers being published about graphene seems to be steadily increasing. But in terms of commercial development, CNTs still have a leg up on graphene, finding increasing use in creating light but strong composites. Nonetheless, the commercial prospects for CNTs have been taking hits recently, with some producers scaling down capacity because of lack of demand.

With this as the backdrop, the National Nanotechnology Initiative (NNI), famous for its estimate back in 2001 that the market for nanotechnology will be worth $1 trillion by 2015,  has released a report based on a meeting held last September. …

I recommend reading Dexter’s analysis.

Two Irelands-US research initiative: UNITE

Happy St. Patrick’s Day on March 17, 2015! Researchers, building on an earlier collaborative effort (FOCUS), have announced a new US-Ireland initiative, from a March 9, 2015 news item on Nanowerk,

A three-year US-Ireland collaborative scientific project aims to reduce power consumption and increase battery life in mobile devices. Researchers will explore new semiconducting materials in the miniaturisation of transistors which are essential to all portable devices.

Leading researchers from the Republic of Ireland (Tyndall National Institute & Dublin City University), Northern Ireland (Queens University Belfast) and the US (University of Texas at Dallas) – each funded by their respective government agencies – are collaborating to develop ultra-efficient electronic materials through the UNITE project: Understanding the Nature of Interfaces in Two-Dimensional Electronic Devices.

A March 9, 2015 (?) Tyndall National Institute press release, which originated the news item, details the project, the researchers, and the hoped for applications,

UNITE will create and test the properties of atomically-thin, 2-dimensional layers of semiconductors called, Transition Metal Dichalcogenides or TMD’s for short. These layers are 100,000 times smaller than the smallest thing the human eye can see. The properties these materials have displayed to date suggest that they could facilitate extremely efficient power usage and high performance computing.

Tyndall’s lead researcher Dr. Paul Hurley explains that, “materials that we are currently reliant on, such as silicon, are soon expected to reach the limit of their performance. If we want to continue to increase performance, while maintaining or even reducing power consumption, it is important to explore these new TMD materials.”

The application of these materials in transistors could prolong the battery charge life of portable devices and phones, as well as having applications in larger more power intensive operations like data storage and server centres. This will have obvious environmental benefits through the reduction of electrical energy consumed by information and communication technologies as well as benefitting consumers.

UNITE builds on a previous highly successful US-Ireland collaborative project between these academic research partners called FOCUS. The success of this project played a role in demonstrating why funders should back the new project, including training for five graduate students in the USA and Ireland, as well as student exchanges between the Institutes, which will provide a broader scientific and cultural experience for the graduates involved.

The press release goes on to describe FOCUS, the researchers’ prior collaborative project,

UNITE builds on a previous highly successful US-Ireland collaborative project between these academic research partners called FOCUS. The success of this project played a role in demonstrating why funders should back the new project, including training for five graduate students in the USA and Ireland, as well as student exchanges between the Institutes, which will provide a broader scientific and cultural experience for the graduates involved.

A March 13, 2015 (?) Tyndall National Institute press release describes both an event to celebrate the success enjoyed by FOCUS and gives specifics about the achievements,

FOCUS, a US-Ireland collaborative project will be presented as a research success highlight to An Taoiseach Enda Kenny on St. Patrick’s Day along with industry and academic leaders, at a Science Foundation Ireland (SFI) event in Washington DC. The event is to celebrate the SFI St. Patrick’s Day Science Medal Award and is an important occasion on the St. Patrick’s Day schedule in the USA.

Funded under the US-Ireland R&D Partnership Programme, FOCUS (Future Oxides and Channel Materials for Ultimate Scaling) linked researchers in Tyndall National Institute (Dr Paul Hurley), Dublin City University (Prof. Greg Hughes), Queen’s University Belfast (Dr David McNeill) and the University of Texas at Dallas (Prof. Robert Wallace).

Billions of silicon-based transistors are crammed onto a single chip and used in billions of electronic devices around the world such as computers, laptops and mobile phones. The FOCUS project group investigated if it was possible to use alternative materials to silicon in the active channels of transistors to improve their energy efficiency and battery life.

The consortium explored using Germanium and Indium-Gallium-Arsenide in combination with high dielectric constant oxides as a viable alternative to silicon. Their research was able to improve the electronic properties of these alternative semiconductor/oxide interfaces to the level needed for practical device applications and the outcomes of their research have now moved to industry for practical application.

The key achievements from the project include:

  • Strong collaboration with Intel USA and Intel Ireland resulting in Paul Hurley receiving the Intel Outstanding Researcher Award in 2012
  • Presentation of the project findings at the annual Intel European Research and Innovation Conference
  • 3 Postdocs trained and 5 PhDs awarded in areas of strong interest to semiconductor manufacturers
  • 35 journal papers published
  • 2011 article on InGaAs surface treatment optimisation listed as one of the top 10 most cited articles in the Journal of Applied Physics in 2012
  • 10 invited presentations at key scientific conferences
  • University research partnership established between Tyndall National Institute and University of Texas at Dallas
  • Project highlighted in Irish press, The Times of India and The Irish Voice
  • Visit by the Consul General of Ireland to University of Texas at Dallas
  • Numerous students and staff exchanges between all partner institutions

Good luck to the UNITE project!

Nanomedicine living up to its promise?

Michael Berger has written a March 10, 2015 Nanowerk spotlight article reviewing nanomedicine’s  progress or lack thereof (Note: Links have been removed),

In early 2003, the European Science Foundation launched its Scientific Forward Look on Nanomedicine, a foresight study (report here ;pdf) and in 2004, the U.S. National Institute[s] of Health (NIH) published its Roadmap (now Common Fund) of the Nanomedicine Initiative. This program began in 2005 with a national network of eight Nanomedicine Development Centers. Now, in the second half of this 10-year program, the four centers best positioned to effectively apply their findings to translational studies were selected to continue receiving support.

A generally accepted definition of nanomedicine refers to highly specific medical intervention at the molecular scale for curing disease or repairing damaged tissues, such as bone, muscle, or nerve.

Much of Berger’s article is based on Subbu Venkatraman’s, Director of the NTU (Nanyang Technological University)-Northwestern Nanomedicine Institute in Singapore, paper, Has nanomedicine lived up to its promise?, 2014 Nanotechnology 25 372501 doi:10.1088/0957-4484/25/37/372501 (Note: Links have been removed),

… Historically, the approval of Doxil as the very first nanotherapeutic product in 1995 is generally regarded as the dawn of nanomedicine for human use. Since then, research activity in this area has been frenetic, with, for example, 2000 patents being generated in 2003, in addition to 1200 papers [2]. In the same time period, a total of 207 companies were involved in developing nanomedicinal products in diagnostics, imaging, drug delivery and implants. About 38 products loosely classified as nanomedicine products were in fact approved by 2004. Out of these, however, a number of products (five in all) were based on PEG-ylated proteins, which strictly speaking, are not so much nanomedicine products as molecular therapeutics. Nevertheless, the promise of nanomedicine was being translated into funding for small companies, and into clinical success, so that by 2013, the number of approved products had reached 54 in all, with another 150 in various stages of clinical trials [3]. The number of companies and institutions had risen to 241 (including research centres that were working on nanomedicine). A PubMed search on articles relating to nanomedicine shows 7400 hits over 10 years, of which 1874 were published in 2013 alone. Similarly, the US patent office database shows 409 patents (since 1976) that were granted in nanomedicine, with another 679 applications awaiting approval. So judging by research activity and funding the field of nanomedicine has been very fertile; however, when we use the yardstick of clinical success and paradigm shifts in treatment, the results appear more modest.

Both Berger’s spotlight article and Venkatraman’s review provide interesting reading and neither is especially long.

Think of your skin as a smartphone

A March 5, 2015 news item on Azonano highlights work on flexible, transparent electronics designed to adhere to your skin,

Someone wearing a smartwatch can look at a calendar or receive e-mails without having to reach further than their wrist. However, the interaction area offered by the watch face is both fixed and small, making it difficult to actually hit individual buttons with adequate precision. A method currently being developed by a team of computer scientists from Saarbrücken in collaboration with researchers from Carnegie Mellon University in the USA may provide a solution to this problem. They have developed touch-sensitive stickers made from flexible silicone and electrically conducting sensors that can be worn on the skin.

Here’s what the sticker looks like,

Caption: The stickers are skin-friendly and are attached to the skin with a biocompatible, medical-grade adhesive. Credit: Oliver Dietze

Caption: The stickers are skin-friendly and are attached to the skin with a biocompatible, medical-grade adhesive. Credit: Oliver Dietze Courtesy: Saarland University

A March 4, 2015 University of Saarland press release on EurekAlert, which originated the news item, expands on the theme on connecting technology to the body,

… The stickers can act as an input space that receives and executes commands and thus controls mobile devices. Depending on the type of skin sticker used, applying pressure to the sticker could, for example, answer an incoming call or adjust the volume of a music player. ‘The stickers allow us to enlarge the input space accessible to the user as they can be attached practically anywhere on the body,’ explains Martin Weigel, a PhD student in the team led by Jürgen Steimle at the Cluster of Excellence at Saarland University. The ‘iSkin’ approach enables the human body to become more closely connected to technology. [emphasis mine]

Users can also design their iSkin patches on a computer beforehand to suit their individual tastes. ‘A simple graphics program is all you need,’ says Weigel. One sticker, for instance, is based on musical notation, another is circular in shape like an LP. The silicone used to fabricate the sensor patches makes them flexible and stretchable. ‘This makes them easier to use in an everyday environment. The music player can simply be rolled up and put in a pocket,’ explains Jürgen Steimle, who heads the ‘Embodied Interaction Group’ in which Weigel is doing his research. ‘They are also skin-friendly, as they are attached to the skin with a biocompatible, medical-grade adhesive. Users can therefore decide where they want to position the sensor patch and how long they want to wear it.’

In addition to controlling music or phone calls, the iSkin technology could be used for many other applications. For example, a keyboard sticker could be used to type and send messages. Currently the sensor stickers are connected via cable to a computer system. According to Steimle, in-built microchips may in future allow the skin-worn sensor patches to communicate wirelessly with other mobile devices.

The publication about ‘iSkin’ won the ‘Best Paper Award’ at the SIGCHI conference, which ranks among the most important conferences within the research area of human computer interaction. The researchers will present their project at the SIGCHI conference in April [2015] in Seoul, Korea, and beforehand at the computer expo Cebit, which takes place from the 16th until the 20th of March [2015] in Hannover (hall 9, booth E13).

Hopefully, you’ll have a chance to catch researchers’ presentation at the SIGCHI or Cebit events.

That quote about enabling “the human body to become more closely connected to technology” reminds me of a tag (machine/flesh) I created to categorize research of this nature. I explained the idea being explored in a May 9, 2012 posting titled: Everything becomes part machine,

Machine/flesh. That’s what I’ve taken to calling this process of integrating machinery into our and, as I newly realized, other animals’ flesh.

I think my latest previous post on this topic was a Jan. 10, 2014 post titled: Chemistry of Cyborgs: review of the state of the art by German researchers.