Wednesday, November 30, 2011

Printed back and top gated carbon nanotube based electronics with OLED displays

Since the invention of liquid crystal displays in the mid-1960s, display electronics have undergone rapid transformation. Recently developed organic light-emitting diodes (OLEDs) have shown several advantages over LCDs, including their light weight, flexibility, wide viewing angles, improved brightness, high power efficiency and quick response.

OLED-based displays are now used in cell phones, digital cameras and other portable devices. But developing a lower-cost method for mass-producing such displays has been complicated by the difficulties of incorporating thin-film transistors that use amorphous silicon and polysilicon into the production process.

Now, researchers from Aneeve Nanotechnologies, a startup company at UCLA's on-campus technology incubator at the California NanoSystems Institute (CNSI), have used low-cost ink-jet printing to fabricate the first circuits composed of fully printed back-gated and top-gated carbon nanotube–based electronics for use with OLED displays. The research was published this month in the journal Nano Letters.

The startup includes collaborators from the departments of materials science and electrical engineering at the UCLA Henry Samueli School of Engineering and Applied Science and the department of electrical engineering at the University of Southern California.

In this innovative study, the team made carbon nanotube thin-film transistors with high mobility and a high on–off ratio, completely based on ink-jet printing. They demonstrated the first fully printed single-pixel OLED control circuits, and their fully printed thin-film circuits showed significant performance advantages over traditional organic-based printed electronics.

Ink-jet-printed circuit Ink-jet-printed circuit (Photo courtesy of UCLA CNSI)

Ink-jet-printed circuit (Photo courtesy of UCLA CNSI)
"This is the first practical demonstration of carbon nanotube–based printed circuits for display backplane applications," said Kos Galatsis, an associate adjunct professor of materials science at UCLA Engineering and a co-founder of Aneeve. "We have demonstrated carbon nanotubes' viable candidacy as a competing technology alongside amorphous silicon and metal-oxide semiconductor solution as a low-cost and scalable backplane option."

This distinct process utilizes an ink-jet printing method that eliminates the need for expensive vacuum equipment and lends itself to scalable manufacturing and roll-to-roll printing. The team solved many material integration problems, developed new cleaning processes and created new methods for negotiating nano-based ink solutions.

For active-matrix OLED applications, the printed carbon nanotube transistors will be fully integrated with OLED arrays, the researchers said. The encapsulation technology developed for OLEDs will also keep the carbon nanotube transistors well protected, as the organics in OLEDs are very sensitive to oxygen and moisture.

The technology incubator at the CNSI was established two years ago to nurture early-stage research and to help speed the commercial translation of technologies developed at UCLA. Aneeve Nanotechnologies LLC has been conducting proof-of-concept work at the tech incubator with the mission of developing superior, low-cost, high-performance electronics using nanotechnology solutions that bridge the gap between emerging and traditional platforms.


The California NanoSystems Institute is an integrated research facility located at UCLA and UC Santa Barbara. Its mission is to foster interdisciplinary collaborations in nanoscience and nanotechnology; to train a new generation of scientists, educators and technology leaders; to generate partnerships with industry; and to contribute to the economic development and the social well-being of California, the United States and the world. The CNSI was established in 2000 with $100 million from the state of California. The total amount of research funding in nanoscience and nanotechnology awarded to CNSI members has risen to over $900 million. UCLA CNSI members are drawn from UCLA's College of Letters and Science, the David Geffen School of Medicine, the School of Dentistry, the School of Public Health and the Henry Samueli School of Engineering and Applied Science. They are engaged in measuring, modifying and manipulating atoms and molecules — the building blocks of our world. Their work is carried out in an integrated laboratory environment. This dynamic research setting has enhanced understanding of phenomena at the nanoscale and promises to produce important discoveries in health, energy, the environment and information technology.

Contact: Jennifer Marcus 310-267-4839 University of California - Los Angeles

Tuesday, November 29, 2011

Graphene-based chemical sensors, thermoelectric devices and metamaterials

Graphene lights up with new possibilities. Rice researchers' two-step technique makes graphene suitable for organic chemistry

The future brightened for organic chemistry when researchers at Rice University found a highly controllable way to attach organic molecules to pristine graphene, making the miracle material suitable for a range of new applications.

The Rice lab of chemist James Tour, building upon a set of previous finds in the manipulation of graphene, discovered a two-step method that turned what was a single-atom-thick sheet of carbon into a superlattice for use in organic chemistry. The work could lead to advances in graphene-based chemical sensors, thermoelectric devices and metamaterials.

The work appeared this week in the online journal Nature Communications.

Graphene alone is inert to many organic reactions and, as a semimetal, has no band gap; this limits its usefulness in electronics. But the project led by the Tour Lab's Zhengzong Sun and Rice graduate Cary Pint, now a researcher at Intel, demonstrated that graphene, the strongest material there is because of the robust nature of carbon-carbon bonds, can be made suitable for novel types of chemistry.

Until now there was no way to attach molecules to the basal plane of a sheet of graphene, said Tour, Rice's T.T. and W.F. Chao Chair in Chemistry as well as a professor of mechanical engineering and materials science and of computer science. "They would mostly go to the edges, not the interior," he said. "But with this two-step technique, we can hydrogenate graphene to make a particular pattern and then attach molecules to where those hydrogens were.

Graphene-based chemical sensors, thermoelectric devices and metamaterials

Making a superlattice with patterns of hydrogenated graphene is the first step in making the material suitable for organic chemistry. The process was developed in the Rice University lab of chemist James Tour. (Credit Tour Lab/Rice University)

Graphene-based chemical sensors, thermoelectric devices and metamaterials

Researchers at Rice printed Owls, the university's mascot, in hydrogen atoms on a graphene substrate, turning it into a graphane superlattice suitable for organic chemistry. As proof, they "lit up" the Owls by coating them with a fluorophore and viewing them through fluorescence quenching microscopy. Graphene quenches fluorescence, but the molecules shine brightly when attached to the superlattice. (Credit Zhengzong Sun/Rice University)

"This is useful to make, for example, chemical sensors in which you want peptides, DNA nucleotides or saccharides projected upward in discrete places along a device. The reactivity at those sites is very fast relative to placing molecules just at the edges. Now we get to choose where they go."

The first step in the process involved creating a lithographic pattern to induce the attachment of hydrogen atoms to specific domains of graphene's honeycomb matrix; this restructure turned it into a two-dimensional, semiconducting superlattice called graphane. The hydrogen atoms were generated by a hot filament using an approach developed by Robert Hauge, a distinguished faculty fellow in chemistry at Rice and co-author of the paper.

The lab showed its ability to dot graphene with finely wrought graphane islands when it dropped microscopic text and an image of Rice's classic Owl mascot, about three times the width of a human hair, onto a tiny sheet and then spin-coated it with a fluorophore. Graphene naturally quenches fluorescent molecules, but graphane does not, so the Owl literally lit up when viewed with a new technique called fluorescence quenching microscopy (FQM).

FQM allowed the researchers to see patterns with a resolution as small as one micron, the limit of conventional lithography available to them. Finer patterning is possible with the right equipment, they reasoned.

In the next step, the lab exposed the material to diazonium salts that spontaneously attacked the islands' carbon-hydrogen bonds. The salts had the interesting effect of eliminating the hydrogen atoms, leaving a structure of carbon-carbon sp3 bonds that are more amenable to further functionalization with other organics.

"What we do with this paper is go from the graphene-graphane superlattice to a hybrid, a more complicated superlattice," said Sun, who recently earned his doctorate at Rice. "We want to make functional changes to materials where we can control the position, the bond types, the functional groups and the concentrations.

"In the future -- and it might be years -- you should be able to make a device with one kind of functional growth in one area and another functional growth in another area. They will work differently but still be part of one compact, cheap device," he said. "In the beginning, there was very little organic chemistry you could do with graphene. Now we can do almost all of it. This opens up a lot of possibilities."

The paper's co-authors are graduate students Daniela Marcano, Gedeng Ruan and Zheng Yan, former graduate student Jun Yao, postdoctoral researcher Yu Zhu and visiting student Chenguang Zhang, all of Rice.

The work was supported by the Air Force Office of Scientific Research, Sandia National Laboratory, the Nanoscale Science and Engineering Initiative of the National Science Foundation and the Office of Naval Research MURI graphene program.


Read the abstract at 11/29/2011 Mike Williams 713-348-6728

Sunday, November 27, 2011

New class of sensors and micromechanical devices controlled by magnetism

Led by a group at the University of Maryland (UMd), a multi-institution team of researchers has combined modern materials research and an age-old metallurgy technique to produce an alloy that could be the basis for a new class of sensors and micromechanical devices controlled by magnetism.* The alloy, a combination of cobalt and iron, is notable, among other things, for not using rare-earth elements to achieve its properties. Materials scientists at the National Institute of Standards and Technology (NIST) contributed precision measurements of the alloy's structure and mechanical properties to the project.

The alloy exhibits a phenomenon called "giant magnetostriction," an amplified change in dimensions when placed in a sufficiently strong magnetic field. The effect is analogous to the more familiar piezoelectric effect that causes certain materials, like quartz, to compress under an electric field. They can be used in a variety of ways, including as sensitive magnetic field detectors and tiny actuators for micromechanical devices. The latter is particularly interesting to engineers because, unlike piezoelectrics, magnetostrictive elements require no wires and can be controlled by an external magnetic field source.

To find the best mixture of metals and processing, the team used a combinatorial screening technique, fabricating hundreds of tiny test cantilevers -- tiny, 10-millimeter-long, silicon beams looking like diving boards -- and coating them with a thin film of alloy, gradually varying the ratio of cobalt to iron across the array of cantilevers. They also used two different heat treatments, including, critically, one in which the alloy was heated to an annealing temperature and then suddenly quenched in water.

annealed cobalt iron alloy

Caption: This is a transmission electron microscope image taken at NIST of an annealed cobalt iron alloy. The high magnetostriction seen in this alloy is due to the two-phase iron-rich (shaded blue) and cobalt-rich (shaded red) structure and the nanoscale segregation. Credit: Bendersky/NIST. Usage Restrictions: None
Quenching is a classic metallurgy technique to freeze a material's microstructure in a state that it normally only has when heated. In this case, measurements at NIST and the Stanford Synchrotron Radiation Lightsource (SSRL) showed that the best-performing alloy had a delicate hetereogenous, nanoscale structure in which cobalt-rich crystals were embedded throughout a different, iron-rich crystal structure. Magnetostriction was determined by measuring the amount by which the alloy bent the tiny silicon cantilever in a magnetic field, combined with delicate measurements at NIST to determine the stiffness of the cantilever.

The best annealed alloy showed a sizeable magnetostriction effect in magnetic fields as low as about 0.01 Tesla. (The earth's magnetic field generally ranges around roughly 0.000 045 T, and a typical ferrite refrigerator magnet might be about 0.7 T.)

The results, says team leader Ichiro Takeuchi of UMd, are lower than, but comparable to, the values for the best known magnetostrictive material, a rare-earth alloy called Tb-Dy-Fe** -- but with the advantage that the new alloy doesn't use the sometimes difficult to acquire rare earths. "Freezing in the heterogeneity by quenching is an old method in metallurgy, but our approach may be unique in thin films," he observes. "That's the beauty -- a nice, simple technique but you can get these large effects."

The quenched alloy might offer both size and processing advantages over more common piezoelectric microdevices, says NIST materials scientist Will Osborn. "Magnetorestriction devices are less developed than piezoelectrics, but they're becoming more interesting because the scale at which you can operate is smaller," he says. "Piezoelectrics are usually oxides, brittle and often lead-based, all of which is hard on manufacturing processes. These alloys are metal and much more compatible with the current generation of integrated device manufacturing. They're a good next-generation material for microelectromechanical machines."

The effort also involved researchers from the Russian Institute of Metal Physics, Urals Branch of the Academy of Science; Oregon State University and Rowan University. Funding sources included the Office of Naval Research and the National Science Foundation. SSRL is part of the SLAC National Accelerator Laboratory, operated under the auspices of the U.S. Department of Energy.

* D. Hunter, W. Osborn, K. Wang, N. Kazantseva, J. Hattrick-Simpers, R. Suchoski, R. Takahashi, M.L. Young, A. Mehta, L.A. Bendersky, S.E. Lofland, M. Wuttig and I. Takeuchi. Giant magnetostriction in annealed Co1-xFex thin-films. Nature Communications. Nov. 1, 2011. DOI: 10.1038/ncomms1529

** Terbium-dysprosium-iron.

Contact: Michael Baum 301-975-2763 National Institute of Standards and Technology (NIST)

Saturday, November 26, 2011

Integrating piezoelectric material into a silicon microelectromechanical system (MEMS) VIDEO

A team of university researchers, aided by scientists at the National Institute of Standards and Technology (NIST), have succeeded in integrating a new, highly efficient piezoelectric material into a silicon microelectromechanical system (MEMS).* This development could lead to significant advances in sensing, imaging and energy harvesting.

A piezoelectric material, such as quartz, expands slightly when fed electricity and, conversely, generates an electric charge when squeezed. Quartz watches take advantage of this property to keep time: electricity from the watch's battery causes a piece of quartz to expand and contract inside a small chamber at a specific frequency that circuitry in the watch translates into time.

Piezoelectric materials are also in sensors in sonar and ultrasound systems, which use the same principle in reverse to translate sound waves into images of, among other things, fetuses in utero and fish under the water.

Although conventional piezoelectric materials work fairly well for many applications, researchers have long sought to find or invent new ones that expand more and more forcefully and produce stronger electrical signals. More reactive materials would make for better sensors and could enable new technologies such as "energy harvesting," which would transform the energy of walking and other mechanical motions into electrical power.

Enter a material named PMN-PT.**

Caption: Animation of PMN-PT microcantilever. Credit: NIST. Usage Restrictions: None.
A large team led by scientists from the University of Wisconsin-Madison developed a way to incorporate PMN-PT into tiny, diving-board like cantilevers on a silicon base, a typical material for MEMS construction, and demonstrated that PMN-PT could deliver two to four times more movement with stronger force -- while using only 3 volts -- than most rival materials studied to date. It also generates a similarly strong electric charge when compressed, which is good news for those in the sensing and energy harvesting businesses.

To confirm that the experimental observations were due to the piezoelectric's performance, NIST researcher Vladimir Aksyuk developed engineering models of the cantilevers to estimate how much they would bend and at what voltage.

Aksyuk also made other performance measures in comparison to silicon systems that achieve similar effects using electrostatic attraction.

"Silicon is good for these systems, but it is passive and can only move if heated or using electrostatics, which requires high voltage or large dissipated power," says Aksyuk. "Our work shows definitively that the addition of PMN-PT to MEMS designed for sensing or as energy harvesters will provide a tremendous boost to their sensitivity and efficiency. A much bigger 'bend for your buck,' I guess you could say."

Other participants included researchers from Penn State University; the University of California, Berkeley; the University of Michigan; Cornell University; and Argonne National Laboratory.

* S.H. Baek, J.Park, D.M. Kim, V.A. Aksyuk, R.R. Das, S.D. Bu, D.A. Felker, J. Lettieri, V. Vaithyanathan, S.S.N. Bharadwaja, N. Bassiri-Gharb, Y.B. Chen, H.P. Sun, C.M. Folkman, H.W. Jang, D.J. Kreft, S.K. Streiffer, R. Ramesh, X.Q. Pan, S. Trolier-McKinstry, D.G. Schlom, M.S. Rzchowski, R.H. Blick and C.B. Eom. Giant piezoelectricity on Si for hyperactive MEMS. Science. Published Nov. 18, 2011. Vol. 334 no. 6058 pp. 958-961. DOI: 10.1126/science.1207186.

** A crystalline alloy of lead, magnesium niobate and lead titanate.

Contact: Mark Esser 301-975-8735 National Institute of Standards and Technology (NIST)

Thursday, November 24, 2011

Nanoparticle crystalline copper hexacyanoferrate electrode batteries make power storage on the energy grid feasible

Nanoparticle electrode for batteries could make large-scale power storage on the energy grid feasible, say Stanford researchers

Stanford researchers have used nanoparticles of a copper compound to develop a high-power battery electrode that is so inexpensive to make, so efficient and so durable that it could be used to build batteries big enough for economical large-scale energy storage on the electrical grid – something researchers have sought for years.

The sun doesn't always shine and the breeze doesn't always blow and therein lie perhaps the biggest hurdles to making wind and solar power usable on a grand scale. If only there were an efficient, durable, high-power, rechargeable battery we could use to store large quantities of excess power generated on windy or sunny days until we needed it. And as long as we're fantasizing, let's imagine the battery is cheap to build, too.

Now Stanford researchers have developed part of that dream battery, a new electrode that employs crystalline nanoparticles of a copper compound.

In laboratory tests, the electrode survived 40,000 cycles of charging and discharging, after which it could still be charged to more than 80 percent of its original charge capacity. For comparison, the average lithium ion battery can handle about 400 charge/discharge cycles before it deteriorates too much to be of practical use.

"At a rate of several cycles per day, this electrode would have a good 30 years of useful life on the electrical grid," said Colin Wessells, a graduate student in materials science and engineering who is the lead author of a paper describing the research, published this week in Nature Communications.

Wind Farm

The research offers a promising solution to the problem of sharp drop-offs in the output of wind and solar systems with minor changes in weather conditions. Charles Cook / Creative Commons
"That is a breakthrough performance – a battery that will keep running for tens of thousands of cycles and never fail," said Yi Cui, an associate professor of materials science and engineering, who is Wessell's adviser and a coauthor of the paper.

The electrode's durability derives from the atomic structure of the crystalline copper hexacyanoferrate used to make it. The crystals have an open framework that allows ions – electrically charged particles whose movements en masse either charge or discharge a battery – to easily go in and out without damaging the electrode. Most batteries fail because of accumulated damage to an electrode's crystal structure.

Because the ions can move so freely, the electrode's cycle of charging and discharging is extremely fast, which is important because the power you get out of a battery is proportional to how fast you can discharge the electrode.

To maximize the benefit of the open structure, the researchers needed to use the right size ions. Too big and the ions would tend to get stuck and could damage the crystal structure when they moved in and out of the electrode. Too small and they might end up sticking to one side of the open spaces between atoms, instead of easily passing through. The right-sized ion turned out to be hydrated potassium, a much better fit compared with other hydrated ions such as sodium and lithium.

"It fits perfectly – really, really nicely," said Cui. "Potassium will just zoom in and zoom out, so you can have an extremely high-power battery."

The speed of the electrode is further enhanced because the particles of electrode material that Wessell synthesized are tiny even by nanoparticle standards – a mere 100 atoms across.

Those modest dimensions mean the ions don't have to travel very far into the electrode to react with active sites in a particle to charge the electrode to its maximum capacity, or to get back out during discharge.

A lot of recent research on batteries, including other work done by Cui's research group, has focused on lithium ion batteries, which have a high energy density – meaning they hold a lot of charge for their size. That makes them great for portable electronics such as laptop computers.

But energy density really doesn't matter as much when you're talking about storage on the power grid. You could have a battery as big as a house since it doesn't need to be portable. Cost is a greater concern.

Some of the components in lithium ion batteries are expensive and no one knows for certain that making the batteries on a scale for use in the power grid will ever be economical.

"We decided we needed to develop a 'new chemistry' if we were going to make low-cost batteries and battery electrodes for the power grid," Wessells said.

The researchers chose to use a water-based electrolyte, which Wessells described as "basically free compared to the cost of an organic electrolyte" such as is used in lithium ion batteries. They made the battery electric materials from readily available precursors such as iron, copper, carbon and nitrogen – all of which are extremely inexpensive compared with lithium.

The sole significant limitation to the new electrode is that its chemical properties cause it to be usable only as a high voltage electrode. But every battery needs two electrodes – a high voltage cathode and a low voltage anode – in order to create the voltage difference that produces electricity. The researchers need to find another material to use for the anode before they can build an actual battery.

But Cui said they have already been investigating various materials for an anode and have some promising candidates.

Even though they haven't constructed a full battery yet, the performance of the new electrode is so superior to any other existing battery electrode that Robert Huggins, an emeritus professor of materials science and engineering who worked on the project, said the electrode "leads to a promising electrochemical solution to the extremely important problem of the large number of sharp drop-offs in the output of wind and solar systems" that result from events as simple and commonplace as a cloud passing over a solar farm.

Cui and Wessells noted that other electrode materials have been developed that show tremendous promise in laboratory testing but would be difficult to produce commercially. That should not be a problem with their electrode.

Wessells has been able to readily synthesize the electrode material in gram quantities in the lab. He said the process should easily be scaled up to commercial levels of production.

"We put chemicals in a flask and you get this electrode material. You can do that on any scale," he said.

"There are no technical challenges to producing this on a big-enough scale to actually build a real battery."

Huggins is a coauthor of the Nature Communications paper. Funding for the research was provided by the U.S. Department of Energy and the King Abdullah University of Science and Technology.

Contact: Louis Bergeron 650-725-1944 Stanford University

Media Contact: Yi Cui, Department of Materials Science and Engineering: (650) 723-4613,

Wednesday, November 23, 2011

Ion beams extract a cross-section of compressed gold nanofilm create enclosed nano channels

PROVIDENCE, R.I. -- Wrinkles and folds are ubiquitous. They occur in furrowed brows, planetary topology, the surface of the human brain, even the bottom of a gecko's foot. In many cases, they are nature's ingenious way of packing more surface area into a limited space. Scientists, mimicking nature, have long sought to manipulate surfaces to create wrinkles and folds to make smaller, more flexible electronic devices, fluid-carrying nanochannels or even printable cell phones and computers.

But to attain those technology-bending feats, scientists must fully understand the profile and performance of wrinkles and folds at the nanoscale, dimensions 1/50,000th the thickness of a human hair. In a series of observations and experiments, engineers at Brown University and in Korea have discovered unusual properties in wrinkles and folds at the nanoscale. The researchers report that wrinkles created on super-thin films have hidden long waves that lengthen even when the film is compressed. The team also discovered that when folds are formed in such films, closed nanochannels appear below the surface, like thousands of super-tiny pipes.

"Wrinkles are everywhere in science," said Kyung-Suk Kim, professor of engineering at Brown and corresponding author of the paper published in the journal Proceedings of the Royal Society A. "But they hold certain secrets. With this study, we have found mathematically how the wrinkle spacings of a thin sheet are determined on a largely deformed soft substrate and how the wrinkles evolve into regular folds."

Wrinkles are made when a thin stiff sheet is buckled on a soft foundation or in a soft surrounding. They are precursors of regular folds: When the sheet is compressed enough, the wrinkles are so closely spaced that they form folds. The folds are interesting to manufacturers, because they can fit a large surface area of a sheet in a finite space.


Caption: Researchers at Brown University and in Korea used focused ion beams to extract a cross-section of compressed gold nanofilm. When tips of regular, neighboring folds touched, nanopipes were created beneath the surface.

Credit: Kyung-Suk Kim lab, Brown University. Usage Restrictions: None.
Kim and his team laid gold nanogranular film sheets ranging from 20 to 80 nanometers thick on a rubbery substrate commonly used in the microelectronics industry. The researchers compressed the film, creating wrinkles and examined their properties. As in previous studies, they saw primary wrinkles with short periodicities, the distance between individual wrinkles' peaks or valleys. But Kim and his colleagues discovered a second type of wrinkle, with a much longer periodicity than the primary wrinkles — like a hidden long wave. As the researchers compressed the gold nanogranular film, the primary wrinkles' periodicity decreased, as expected. But the periodicity between the hidden long waves, which the group labeled secondary wrinkles, lengthened.

"We thought that was strange," Kim said.

It got even stranger when the group formed folds in the gold nanogranular sheets.

On the surface, everything appeared normal. The folds were created as the peaks of neighboring wrinkles got so close that they touched. But the research team calculated that those folds, if elongated, did not match the length of the film before it had been compressed. A piece of the original film surface was not accounted for, "as if it had been buried," Kim said.

Indeed, it had been, as nano-size closed channels. Previous researchers, using atomic force microscopy that scans the film's surface, had been unable to see the buried channels. Kim's group turned to focused ion beams to extract a cross-section of the film. There, below the surface, were rows of closed channels, about 50 to a few 100 nanometers in diameter. "They were hidden," Kim said. "We were the first ones to cut (the film) and see that there are channels underneath."

The enclosed nano channels are important because they could be used to funnel liquids, from drugs on patches to treat diseases or infections, to clean water and energy harvesting, like a microscopic hydraulic pump. ###

Contributing authors include Jeong-Yun Sun and Kyu Hwan Oh from Seoul National University; Myoung-Woon Moon from the Korea Institute of Science and Technology; and Shuman Xia, a researcher at Brown and now at the Georgia Institute of Technology. The National Science Foundation, the Korea Institute of Science and Technology, the Ministry of Knowledge Economy of Korea, and the Ministry of Education, Science, and Technology of Korea supported the research.

Contact: Richard Lewis 401-863-3766 Brown University

Tuesday, November 22, 2011

Streaming of real-time information across your field of vision is a step closer to reality

The streaming of real-time information across your field of vision is a step closer to reality with the development of a prototype contact lens that could potentially provide the wearer with hands-free information updates.

In a study published today, 22 November, in IOP Publishing’s Journal of Micromechanics and Microengineering, researchers constructed a computerised contact lens and demonstrated its safety by testing it on live eyes. There were no signs of adverse side effects.

At the moment, the contact lens device contains only a single pixel but the researchers see this as a “proof-of-concept” for producing lenses with multiple pixels which, in their hundreds, could be used to display short emails and text messages right before your eyes.

The device could overlay computer-generated visual information on to the real world and be of use in gaming devices and navigation systems. It could also be linked to biosensors in the user’s body to provide up-to-date information on glucose or lactate levels.

The contact lens, created by researchers at the University of Washington and Aalto University, Finland, consisted of an antenna to harvest power sent out by an external source, as well as an integrated circuit to store this energy and transfer it to a transparent sapphire chip containing a single< blue LED. One major problem the researchers had to overcome was the fact that the human eye, with its minimum focal distance of several centimetres, cannot resolve objects on a contact lens. Any information projected on to the lens would probably appear blurry.

prototype contact lensTo combat this, the researchers incorporated a set of Fresnel lenses into the device; these are much thinner and flatter than conventional bulky lenses, and were used here to focus the projected image on to the retina.

After testing the contact lens in free space, it was fitted to the eye of a rabbit, under the strict guidelines for animal use in the laboratory, to evaluate the effect of wearing the contact lens on the cornea and the body in general. In addition to visualising techniques, a fluorescent dye was added to the eye of the rabbit to test for any abrasion or thermal burning.

After demonstrating the operation and safety of the contact, the researchers state that significant improvements are necessary to produce fully functional, remotely powered, high-resolution displays. For instance, the device could be wirelessly powered in free space from approximately one metre away, but this was reduced to about two centimetres when placed on the rabbit’s eye.

Co-author of the study, Professor Babak Parviz, said “We need to improve the antenna design and the associated matching network and optimize the transmission frequency to achieve an overall improvement in the range of wireless power transmission.

“Our next goal, however, is to incorporate some predetermined text in the contact lens.”

Contact: Michael Bishop 44-011-793-01032 Institute of Physics

Sunday, November 20, 2011

University model discovers adaptable decision-making in bacteria communities

Smart swarms of bacteria inspire robotics researchers. Tel Aviv University model discovers adaptable decision-making in bacteria communities.

Much to humans' chagrin, bacteria have superior survival skills. Their decision-making processes and collective behaviors allow them to thrive and even spread efficiently in difficult environments.

Now researchers at Tel Aviv University have developed a computational model that better explains how bacteria move in a swarm — and this model can be applied to man-made technologies, including computers, artificial intelligence, and robotics. Ph.D. student Adi Shklarsh — with her supervisor Prof. Eshel Ben-Jacob of TAU's Sackler School of Physics and Astronomy, Gil Ariel from Bar Ilan University and Elad Schneidman from the Weizmann Institute of Science — has discovered how bacteria collectively gather information about their environment and find an optimal path to growth, even in the most complex terrains.

Studying the principles of bacteria navigation will allow researchers to design a new generation of smart robots that can form intelligent swarms, aid in the development of medical micro-robots used to diagnose or distribute medications in the body, or "de-code" systems used in social networks and throughout the Internet to gather information on consumer behaviors. The research was recently published in PLoS Computational Biology.

A dash of bacterial self-confidence

Bacteria aren't the only organisms that travel in swarms, says Shklarsh. Fish, bees, and birds also exhibit collective navigation. But as simple organisms with less sophisticated receptors, bacteria are not as well-equipped to deal with large amounts of information or "noise" in the complex environments they navigate, such as human tissue. The assumption has been, she says, that bacteria would be at a disadvantage compared to other swarming organisms.

Credit: American Friends of Tel Aviv University (AFTAU) Usage Restrictions: None. Caption: Simulated interacting agents collectively navigate towards a target. Credit: American Friends of Tel Aviv University (AFTAU) Usage Restrictions: None

But in a surprising discovery, the researchers found that computationally, bacteria actually have superior survival tactics, finding "food" and avoiding harm more easily than swarms such as amoeba or fish. Their secret? A liberal amount of self-confidence.

Many animal swarms, Shklarsh explains, can be harmed by "erroneous positive feedback," a common side effect of navigating complex terrains. This occurs when a subgroup of the swarm, based on wrong information, leads the entire group in the wrong direction. But bacteria communicate differently, through molecular, chemical and mechanical means, and can avoid this pitfall.

Based on confidence in their own information and decisions, "bacteria can adjust their interactions with their peers," Prof. Ben-Jacob says. "When an individual bacterium finds a more beneficial path, it pays less attention to the signals from the other cells. But at other times, upon encountering challenging paths, the individual cell will increase its interaction with the other cells and learn from its peers. Since each of the cells adopts the same strategy, the group as a whole is able to find an optimal trajectory in an extremely complex terrain."

Benefitting from short-term memory

In the computer model developed by the TAU researchers, bacteria decreased their peers' influence while navigating in a beneficial direction, but listened to each other when they sensed they were failing. This is not only a superior way to operate, but a simple one as well. Such a model shows how a swarm can perform optimally with only simple computational abilities and short term memory, says Shklarsh, It's also a principle that can be used to design new and more efficient technologies.

Robots are often required to navigate complex environments, such as terrains in space, deep in the sea, or the online world, and communicate their findings among themselves. Currently, this is based on complex algorithms and data structures that use a great deal of computer resources. Understanding the secrets of bacteria swarms, Shklarsh concludes, can provide crucial hints towards the design of new generation robots that are programmed to perform adjustable interactions without taking up a great amount of data or memory.


American Friends of Tel Aviv University ( supports Israel's leading, most comprehensive and most sought-after center of higher learning. Independently ranked 94th among the world's top universities for the impact of its research, TAU's innovations and discoveries are cited more often by the global scientific community than all but 10 other universities.

Internationally recognized for the scope and groundbreaking nature of its research and scholarship, Tel Aviv University consistently produces work with profound implications for the future.

Contact: George Hunka 212-742-9070 American Friends of Tel Aviv University

Saturday, November 19, 2011

Nanoparticles of cerium oxide diesel fuel additive can travel from the lungs to the liver

HUNTINGTON, W.Va. - Recent studies conducted at Marshall University have demonstrated that nanoparticles of cerium oxide—common diesel fuel additives used to increase the fuel efficiency of automobile engines—can travel from the lungs to the liver and that this process is associated with liver damage.

The data in the study by Dr. Eric R. Blough and his colleagues at Marshall’s Center for Diagnostic Nanosystems indicate there is a dose-dependent increase in the concentration of cerium in the liver of animals that had been exposed to the nanoparticles, which are only about 1/40,000 times as large as the width of a human hair. These increases in cerium were associated with elevations of liver enzymes in the blood and histological evidence consistent with liver damage. The research was published in the October 13 issue of the peer-reviewed research journal International Journal of Nanomedicine.

Cerium oxide is widely used as a polishing agent for glass mirrors, television tubes and ophthalmic lenses. Cerium oxide nanoparticles are used in the automobile industry to increase fuel efficiency and reduce particulate emissions. Some studies have found that cerium oxide nanoparticles may also be capable of acting as antioxidants, leading researchers to suggest these particles may also be useful for the treatment of cardiovascular disease, neurodegenerative disease and radiation-induced tissue damage.

Blough, the center’s director and an associate professor in the university’s Department of Biological Sciences, said, “Given the ever-increasing use of nanomaterials in industry and in the products we buy, it is becoming increasingly important to understand if these substances may be harmful. To our knowledge, this is the first report to evaluate if inhaled cerium oxide nanoparticles exhibit toxic effects in the liver.”


Dr. Eric R. Blough
Dr. Siva K. Nalabotu, the study’s lead author and a Ph.D. student in Blough’s lab, said, “The potential effects of nanomaterials on the environment and cellular function is not yet well understood. Interest in nanotoxicity is rapidly growing.

“Our studies show that cerium oxide nanoparticles are capable of entering the liver from lungs through the circulation, where they show dose-dependent toxic effects on the liver. Our next step is to determine the mechanism of the toxicity.”

The research was supported with funding from the U.S. Department of Energy, grant DE-PS02-09ER09-01.

Associate Professor. Suite 311 Science Bldg. 1 John Marshall Drive. Marshall University. Huntington, WV 25755. 304-696-2708 (Office). 304-696-7136 (Fax).

For more information, contact Blough at or (304) 696-2708.

TEXT CREDIT: Marshall University. Contact: Ginny Painter, Communications Director, Marshall University Research Corporation, 304.746.1964


Friday, November 18, 2011

Microfabrication piezoelectric material equals near-nanoscale electromechanical devices

Microfabrication breakthrough could set piezoelectric material applications in motion

MADISON – Integrating a complex, single-crystal material with "giant" piezoelectric properties onto silicon, University of Wisconsin-Madison engineers and physicists can fabricate low-voltage, near-nanoscale electromechanical devices that could lead to improvements in high-resolution 3-D imaging, signal processing, communications, energy harvesting, sensing, and actuators for nanopositioning devices, among others.

Led by Chang-Beom Eom, a UW-Madison professor of materials science and engineering and physics, the multi-institutional team published its results in the Nov. 18, issue of the journal Science. (Eom and his students also are co-authors on another paper, "Domain dynamics during ferroelectric switching," published in the same issue.)

Piezoelectric materials use mechanical motion to generate an electrical signal, such as the light that flashes in some children's shoe heels when they stomp their feet. Conversely, piezoelectrics also can use an electrical signal to generate mechanical motion—for example, piezoelectric materials are used to generate high-frequency acoustic waves for ultrasound imaging.

Eom studies the advanced piezoelectric material lead magnesium niobate-lead titanate, or PMN-PT. Such materials exhibit a "giant" piezoelectric response that can deliver much greater mechanical displacement with the same amount of electric field as traditional piezoelectric materials. They also can act as both actuators and sensors. For example, they use electricity to deliver an ultrasound wave that penetrates deeply into the body and returns data capable of displaying a high-quality 3-D image.

Chang-Beom Eom
Chang-Beom Eom
Currently, a major limitation of these advanced materials is that to incorporate them into very small-scale devices, researchers start with a bulk material and grind, cut and polish it to the size they desire. It's an imprecise, error-prone process that's intrinsically ill-suited for nanoelectromechanical systems (NEMS) or microelectromechanical systems (MEMS).

Until now, the complexity of PMN-PT has thwarted researchers' efforts to develop simple, reproducable microscale fabrication techniques.

Applying microscale fabrication techniques such as those used in computer electronics, Eom's team has overcome that barrier. He and his colleagues worked from the ground up to integrate PMN-PT seamlessly onto silicon. Because of potential chemical reactions among the components, they layered materials and carefully planned the locations of individual atoms. "You have to lay down the right element first," says Eom.

Onto a silicon "platform," his team adds a very thin layer of strontium titanate, which acts as a template and mimics the structure of silicon. Next comes a layer of strontium ruthenate, an electrode Eom developed some years ago, and finally, the single-crystal piezoelectric material PMN-PT.

The researchers have characterized the material's piezoelectric response, which correlates with theoretical predictions. "The properties of the single crystal we integrated on silicon are as good as the bulk single crystal," says Eom.

His team calls devices fabricated from this giant piezoelectric material "hyper-active MEMS" for their potential to offer researchers a high level of active control. Using the material, his team also developed a process for fabricating piezoelectric MEMS. Applied in signal processing, communications, medical imaging and nanopositioning actuators, hyper-active MEMS devices could reduce power consumption and increase actuator speed and sensor sensitivity. Additionally, through a process called energy harvesting, hyper-active MEMS devices could convert energy from sources such as mechanical vibrations into electricity that powers other small devices—for example, for wireless communication.

The National Science Foundation is funding the research via a four-year, $1.35 million NIRT grant. At UW-Madison, team members include Lynn H. Matthias Professor in Electrical and Computer Engineering Professor Robert Blick and Physics Professor Mark Rzchowski. Other collaborators include people at the National Institute of Standards and Technology, Pennsylvania State University, the University of Michigan, Argonne National Laboratory, the University of California at Berkeley, and Cornell University.


Contact: Chang-Beom Eom 608-263-6305 University of Wisconsin-Madison

Wednesday, November 16, 2011

Loading gold nanorods into cells could lead to new cancer treatment to cook tumors from the inside VIDEO

heating elements to cook tumors from the inside. The research appears online this week in the chemical journal Angewandte Chemie International Edition.

"The breast cancer cells that we studied were so laden with gold nanorods that their masses increased by an average of about 13 percent," said study leader Eugene Zubarev, associate professor of chemistry at Rice. "Remarkably, the cells continued to function normally, even with all of this gold inside them."

Though the ultimate goal is to kill cancer, Zubarev said the strategy is to deliver nontoxic particles that become deadly only when they are activated by a laser. The nanorods, which are about the size of a small virus, can harvest and convert otherwise harmless light into heat. But because each nanorod radiates miniscule heat, many are needed to kill a cell.

"Ideally, you'd like to use a low-power laser to minimize the risks to healthy tissue, and the more particles you can load inside the cell, the lower you can set the power level and irradiation time," said Zubarev, an investigator at Rice's BioScience Research Collaborative (BRC).

Unfortunately, scientists who study gold nanorods have found it difficult to load large numbers of particles into living cells. For starters, nanorods are pure gold, which means they won't dissolve in solution unless they are combined with some kind of polymer or surfactant. The most commonly used of these is cetyltrimethylammonium bromide, or CTAB, a soapy chemical often used in hair conditioner.

Leonid Vigderman (left) and Eugene Zubarev

Rice University's Leonid Vigderman (left) and Eugene Zubarev have found a way to load more than 2 million tiny gold particles called nanorods into a single cancer cell. CREDIT: Jeff Fitlow/Rice University
CTAB is a key ingredient in the production of nanorods, so scientists have often relied upon it to make nanorods soluble in water. CTAB does this job by coating the surface of the nanorods in much the same way that soap envelopes and dissolves droplets of grease in dishwater. CTAB-encased nanorods also have a positive charge on their surfaces, which encourages cells to ingest them. Unfortunately, CTAB is also toxic, which makes it problematic for biomedical applications.

In the new research, Zubarev, Rice graduate student Leonid Vigderman and former graduate student Pramit Manna, now at Applied Materials Inc., describe a method to completely replace CTAB with a closely related molecule called MTAB that has two additional atoms attached at one end.

The additional atoms -- one sulfur and one hydrogen -- allow MTAB to form a permanent chemical bond with gold nanorods. In contrast, CTAB binds more weakly to nanorods and has a tendency to leak into surrounding media from time to time, which is believed to be the underlying cause of CTAB-encased nanorod toxicity.

It took Zubarev, Vigderman and Manna several years to identify the optimal strategy to synthesize MTAB and substitute it for CTAB on the surface of the nanorods. In addition, they developed a purification process that can completely remove all traces of CTAB from a solution of nanorods.

### The research was funded by the National Science Foundation.

Rice's BRC is an innovative space where scientists and educators from Rice and other institutions in the Texas Medical Center work together to perform leading research that benefits human medicine and health.

Contact: David Ruth 713-348-6327 Rice University

Tuesday, November 15, 2011

Nanoscale light-emitting diode could transform computer data transmission at the chip level

A team at Stanford's School of Engineering has demonstrated an ultrafast nanoscale light emitting diode (LED) that is orders of magnitude lower in power consumption than today's laser-based systems and able to transmit data at 10 billion bits per second. The researchers say it is a major step forward in providing a practical ultrafast, low-power light sources for on-chip computer data transmission.

Stanford's Jelena Vuckovic, an associate professor of electrical engineering and the study's senior author, and first author Gary Shambat, a doctoral candidate in electrical engineering, announced their device in paper to be published November 15 in the journal Nature Communications.

Vuckovic had earlier this year produced a nanoscale laser that was similarly efficient and fast, but that device operated only at temperatures below 150 Kelvin, about 190 degrees below zero Fahrenheit, making them impractical for commercial use. The new device operates at room temperature and could, therefore, represent an important step toward next-generation computer processors.

"Low-power, electrically controlled light sources are vital for next generation optical systems to meet the growing energy demands of the computer industry," said Vuckovic. "This moves us in that direction significantly."

Single-Mode Light

Single-Mode LED Nanophotonic Data Device Schematic

Caption: This illustration shows how a single nanophotonic single-mode LED is constructed.

Credit: Gary Shambat, Stanford School of Engineering. Usage Restrictions: None.

Jelena Vuckovic lab team

Caption: Members of the Vuckovic team in the lab from left to right: Arka Majumdar, Tomas Sarmiento, Jan Petykiewicz, Jelena Vuckovic, and Gary Shambat (holding the chip carrier).

Credit: Michal Bajcsy, Stanford School of Engineering. Usage Restrictions: None.
The LED in question is a "single-mode LED," a special type of diode that emits light more or less at a single wavelength, very similar to a laser.

"Traditionally, engineers have thought only lasers can communicate at high data rates and ultralow power," said Shambat. "Our nanophotonic, single-mode LED can perform all the same tasks as lasers, but at much lower power."

Nanophotonics is key to the technology. In the heart of their device, the engineers have inserted little islands of the material indium arsenide, which, when pulsed with electricity, produce light. These islands are surrounded by photonic crystal – an array of tiny holes etched in a semiconductor. The photonic crystal serves as a mirror that bounces the light toward the center of the device, confining it inside the LED and forcing it to resonate at a single frequency.

"In other words, the light becomes single-mode," said Shambat.

"Without these nanophotonic ingredients – the 'quantum dots' and the photonic crystal – it is impossible to make an LED efficient, single-mode and fast all at the same time," said Vuckovic.

Engineering Ingenuity

The new device includes a bit of engineering ingenuity, too. Existing devices are actually two devices, a laser coupled with an external modulator. Both devices require electricity. Vuckovic's diode combines light emission and modulation functions into one device that drastically reduces energy consumption.

On average, the new LED device transmits data at 0.25 femto-Joules per bit of data. By comparison, today's typical 'low' power laser device requires about 500 femto-Joules to transmit a single bit. Some technologies consume as much as one pico-Joule per bit.

"Our device is 2000 to 4000 times more energy efficient than best devices in use today" said Vuckovic.

Stanford Professor James Harris, former PhD student Bryan Ellis, and doctoral candidates Arka Majumdar, Jan Petykiewicz and Tomas Sarmiento also contributed to this research.


This article was written by Andrew Myers, the associate director of communications at the Stanford School of Engineering.

Contact: Andrew Myers 650-736-2241 Stanford School of Engineering

Sunday, November 13, 2011

Performance of nanotube sheets suggests possible applications photo-deflectors & switchable invisibility cloaks VIDEO

Performance of nanotube sheets suggests possible applications photo-deflectors & switchable invisibility cloaks VIDEO

"Mirage effect from thermally modulated transparent carbon nanotube sheet" Aliev A et al 2011 Nanotechnology 22 435704

The single-beam mirage effect, also known as photothermal deflection, is studied using a free-standing, highly aligned carbon nanotube aerogel sheet as the heat source. The extremely low thermal capacitance and high heat transfer ability of these transparent forest-drawn carbon nanotube sheets enables high frequency modulation of sheet temperature over an enormous temperature range, thereby providing a sharp, rapidly changing gradient of refractive index in the surrounding liquid or gas.

The advantages of temperature modulation using carbon nanotube sheets are multiple: in inert gases the temperature can reach > 2500 K; the obtained frequency range for photothermal modulation is ~ 100 kHz in gases and over 100 Hz in high refractive index liquids; and the heat source is transparent for optical and acoustical waves. Unlike for conventional heat sources for photothermal deflection, the intensity and phase of the thermally modulated beam component linearly depends upon the beam-to-sheet separation over a wide range of distances. This aspect enables convenient measurements of accurate values for thermal diffusivity and the temperature dependence of refractive index for both liquids and gases. The remarkable performance of nanotube sheets suggests possible applications as photo-deflectors and for switchable invisibility cloaks, and provides useful insights into their use as thermoacoustic projectors and sonar. Visibility cloaking is demonstrated in a liquid. FULL Abstract

The paper in PDF format is available to download here - Mirage effect from thermally modulated transparent carbon nanotube sheet

VIDEO CREDIT: InstituteofPhysics

Saturday, November 12, 2011

A floating weed that clogs waterways inspired a high-tech waterproof coating

COLUMBUS, Ohio – A floating weed that clogs waterways around the world has at least one redeeming feature: It’s inspired a high-tech waterproof coating intended for boats and submarines.

The Brazilian fern Salvinia molesta has proliferated around the Americas and Australia in part because its surface is dotted with oddly shaped hairs that trap air, reduce friction, and help the plant stay afloat.

In the November 1 issue of the Journal of Colloid and Interface Science, Ohio State University engineers describe how they recreated the texture, which resembles a carpet of tiny eggbeater-shaped fibers. The plastic coating they created in the laboratory is soft and plush, like a microscopic shag carpet.

In nature, air pockets trapped at the base of Salvinia’s hairs reduce friction in the water and help the plant float, while a sticky region at the tips of the eggbeaters clings lightly to the water, providing stability.

It’s the combination of slippery and sticky surfaces that makes the texture so special, said Bharat Bhushan, Ohio Eminent Scholar and the Howard D. Winbigler Professor of mechanical engineering at Ohio State.

“The Salvinia leaf is an amazing hybrid structure. The sides of the hairs are hydrophobic – in nature, they’re covered with wax – which prevents water from touching the leaves and traps air beneath the eggbeater shape at the top. The trapped air gives the plant buoyancy,” he said.

Bharat Bhushan

While the plant is a nuisance to ships today, it could ultimately provide a benefit if a commercial coating based on its texture became available. "With this study, we’ve gotten deep insight into a very simple concept [how the Salvinia leaf works]. That’s where the fun is,” Bhushan said.
“But the tops of the hairs are hydrophilic. They stick to the water just a tiny bit, which keeps the plant stable on the water surface.”

In tests, the coating performed just as the Salvinia hairs do in nature. The bases of the hairs were slippery, while the tips of the hairs were sticky. Water droplets did not penetrate between the hairs, but instead clung to the tops of the eggbeater structures – even when the coating sample was turned on its side to a 90-degree vertical.

With commercial development, the coating could reduce drag and boost buoyancy and stability on boats and submarines, Bhushan said.

Bhushan and master’s student Jams Hunt compared the stickiness of their plastic coating to the stickiness of the natural Salvinia leaf using an atomic force microscope. The two surfaces performed nearly identically, with the plastic coating generating an adhesive force of 201 nanoNewtons (billionths of a Newton) and the leaf generating 207 nanoNewtons.

That’s a very tiny force compared to familiar adhesives such as transparent tape or even masking tape. But the adhesion is similar to that of another natural surface studied by Bhushan and other researchers: gecko feet.

“I’ve studied the gecko feet, which are sticky, and the lotus leaf, which is slippery,” Bhushan said. “Salvinia combines aspects of both.”

Bhushan develops biomimetic structures – artificial structures created in the lab to mimic structures found in nature. The gecko feet inspired him to investigate a repositionable, “smart” adhesive, and the lotus leaf inspired the notion of glass that repels water and dirt.

He came to study Salvinia through a colleague in the university’s Biological Sciences Greenhouse, who provided samples of the plant for the study.

Salvinia molesta, also known as giant salvinia, is native to Brazil, and is a popular plant for home aquariums and decorative ponds around the world. It needs no dirt, but lives solely in the water – even moving water such as rivers and lakes.

At some point, the hearty plant escaped from people’s homes into the wild. Now it has proliferated into commercial waterways in North America, South America, and Australia, where it has become an invasive species.

While the plant is a nuisance to ships today, it could ultimately provide a benefit if a commercial coating based on its texture became available. Bhushan has no plans to commercialize it himself, though.

“With this study, we’ve gotten deep insight into a very simple concept [how the Salvinia leaf works]. That’s where the fun is,” he said. “Besides, I’ve already moved on to studying shark skin.”

Contact: Bharat Bhushan, (614) 292-0651; Written by Pam Frost Gorder, (614) 292-9475;

Contact: Bharat Bhushan 614-292-0651 Ohio State University

Friday, November 11, 2011

The next generation of super-resolution Stimulated Emission Depletion microscopy

Leica Microsystems, the Max Planck Society and the German Cancer Research Center sign license agreement.

Leica Microsystems has signed an agreement with the Max Planck Society and the German Cancer Research Center (DKFZ) for the development of the next generation of super-resolution STED (Stimulated Emission Depletion) microscopy. This gives Leica Microsystems the license to develop the new technology, called gated STED, into a commercial product and put it on the market.

Stefan Hell, Director at the Max Planck Institute for Biophysical Chemistry, has taken his idea of STED microscopy a momentous step further with gated STED: The new technology significantly improves the resolution and contrast previously attained with CW-STED (Continuous-Wave Stimulated Emission Depletion) microscopy, while distinctly reducing laser intensity. This enhances photostability as well as live cell capability, substantially extending the range of possible applications. Also, gated STED technology will considerably increase the number of issues that can be addressed with STED fluorescence correlation spectroscopy (STED-FCS). The main application of gated STED technology will be the observation of molecule movements in the membrane of living cells.

The new product of Leica Microsystems will be launched in the first half of the year 2012. Thanks to Leica Microsystems’ modular concept, the Leica TCS SP5 and Leica TCS STED CW confocal systems already on the market can be upgraded with gated STED.

Stimulated Emission Depletion microscopy

g-STED nanoscopy provides fundamentally improved spatial resolution over confocal microscopy in living cells. Here, the protein keratin is marked with the fluorescent protein Citrine in a living PtK2 cell. The insets show a magnified view of the marked areas, demonstrating the separation of features as small as 60 nm in the living cell. Fluorescence excitation at 485 nm, STED at 592 nm wavelength using a CW beam. Scale bars 1 μm.

© Max Planck Institute for Biophysical Chemistry

“We’re delighted to be able to continue the provenly successful cooperation with the Max Planck Society, its technology transfer organization Max Planck Innovation and the DKFZ with this trailblazing product development,” says Stefan Traeger, Vice President of Leica Microsystems’ Life Science Division. “The new gated STED microscope will enable us to further strengthen our technological lead in super-resolution microscopy especially for confocal systems."

Contact: Markus Berninger 49-892-909-1930 Max-Planck-Gesellschaft

Thursday, November 10, 2011

NASA produces material that absorbs more than 99% of ultraviolet, visible, infrared, and far-infrared light that hits it

NASA engineers have produced a material that absorbs on average more than 99 percent of the ultraviolet, visible, infrared, and far-infrared light that hits it -- a development that promises to open new frontiers in space technology.

The team of engineers at NASA's Goddard Space Flight Center in Greenbelt, Md., reported their findings recently at the SPIE Optics and Photonics conference, the largest interdisciplinary technical meeting in this discipline. The team has since reconfirmed the material's absorption capabilities in additional testing, said John Hagopian, who is leading the effort involving 10 Goddard technologists.

"The reflectance tests showed that our team had extended by 50 times the range of the material’s absorption capabilities. Though other researchers are reporting near-perfect absorption levels mainly in the ultraviolet and visible, our material is darn near perfect across multiple wavelength bands, from the ultraviolet to the far infrared," Hagopian said. "No one else has achieved this milestone yet."

carbon-nanotube coating

This close-up view (only about 0.03 inches wide) shows the internal structure of a carbon-nanotube coating that absorbs about 99 percent of the ultraviolet, visible, infrared, and far-infrared light that strikes it. A section of the coating, which was grown on smooth silicon, was purposely removed to show the tubes' vertical alignment. (Credit: Stephanie Getty, NASA Goddard)

The nanotech-based coating is a thin layer of multi-walled carbon nanotubes, tiny hollow tubes made of pure carbon about 10,000 times thinner than a strand of human hair. They are positioned vertically on various substrate materials much like a shag rug. The team has grown the nanotubes on silicon, silicon nitride, titanium, and stainless steel, materials commonly used in space-based scientific instruments. (To grow carbon nanotubes, Goddard technologist Stephanie Getty applies a catalyst layer of iron to an underlayer on silicon, titanium, and other materials. She then heats the material in an oven to about 1,382 degrees Fahrenheit. While heating, the material is bathed in carbon-containing feedstock gas.)

The tests indicate that the nanotube material is especially useful for a variety of spaceflight applications where observing in multiple wavelength bands is important to scientific discovery. One such application is stray-light suppression. The tiny gaps between the tubes collect and trap background light to prevent it from reflecting off surfaces and interfering with the light that scientists actually want to measure. Because only a small fraction of light reflects off the coating, the human eye and sensitive detectors see the material as black.

In particular, the team found that the material absorbs 99.5 percent of the light in the ultraviolet and visible, dipping to 98 percent in the longer or far-infrared bands. "The advantage over other materials is that our material is from 10 to 100 times more absorbent, depending on the specific wavelength band," Hagopian said.

"We were a little surprised by the results," said Goddard engineer Manuel Quijada, who co-authored the SPIE paper and carried out the reflectance tests. "We knew it was absorbent. We just didn't think it would be this absorbent from the ultraviolet to the far infrared."

hollow carbon nanotubes

This high-magnification image, taken with an electron microscope, shows an even closer view of the hollow carbon nanotubes. A coating made of this material is seen as black by the human eye and sensitive detectors because the tiny gaps between the tubes collect and trap light, preventing reflection. (Credit: Stephanie Getty, NASA Goddard)

If used in detectors and other instrument components, the technology would allow scientists to gather hard-to-obtain measurements of objects so distant in the universe that astronomers no longer can see them in visible light or those in high-contrast areas, including planets in orbit around other stars, Hagopian said. Earth scientists studying the oceans and atmosphere also would benefit. More than 90 percent of the light Earth-monitoring instruments gather comes from the atmosphere, overwhelming the faint signal they are trying to retrieve.

Currently, instrument developers apply black paint to baffles and other components to help prevent stray light from ricocheting off surfaces. However, black paints absorb only 90 percent of the light that strikes it. The effect of multiple bounces makes the coating’s overall advantage even larger, potentially resulting in hundreds of times less stray light.

In addition, black paints do not remain black when exposed to cryogenic temperatures. They take on a shiny, slightly silver quality, said Goddard scientist Ed Wollack, who is evaluating the carbon-nanotube material for use as a calibrator on far-infrared-sensing instruments that must operate in super-cold conditions to gather faint far-infrared signals emanating from objects in the very distant universe. If these instruments are not cold, thermal heat generated by the instrument and observatory, will swamp the faint infrared they are designed to collect.

Black materials also serve another important function on spacecraft instruments, particularly infrared-sensing instruments, added Goddard engineer Jim Tuttle. The blacker the material, the more heat it radiates away. In other words, super-black materials, like the carbon nanotube coating, can be used on devices that remove heat from instruments and radiate it away to deep space. This cools the instruments to lower temperatures, where they are more sensitive to faint signals.

To prevent the black paints from losing their absorption and radiative properties at long wavelengths, instrument developers currently use epoxies loaded with conductive metals to create a black coating. However, the mixture adds weight, always a concern for instrument developers. With the carbon-nanotube coating, however, the material is less dense and remains black without additives, and therefore is effective at absorbing light and removing heat. "This is a very promising material," Wollack said. "It's robust, lightweight, and extremely black. It is better than black paint by a long shot."

Goddard Release No. 11-070 Lori Keesey NASA's Goddard Space Flight Center, Greenbelt, Md. 301-258-0192 Ed Campion NASA's Goddard Space Flight Center, Greenbelt, Md. 301-286-0697

Tuesday, November 08, 2011

Re-programmable cell, biological cell-equivalent of a computer operating system

Re-programmable cell, biological cell-equivalent of a computer operating system and new life forms

Scientists at The University of Nottingham are leading an ambitious research project to develop an in vivo biological cell-equivalent of a computer operating system.

The success of the project to create a ‘re-programmable cell’ could revolutionise synthetic biology and would pave the way for scientists to create completely new and useful forms of life using a relatively hassle-free approach.

Professor Natalio Krasnogor of the University’s School of Computer Science, who leads the Interdisciplinary Computing and Complex Systems Research Group, said: “We are looking at creating a cell’s equivalent to a computer operating system in such a way that a given group of cells could be seamlessly re-programmed to perform any function without needing to modifying its hardware.”

“We are talking about a highly ambitious goal leading to a fundamental breakthrough that will, —ultimately, allow us to rapidly prototype, implement and deploy living entities that are completely new and do not appear in nature, adapting them so they perform new useful functions.”

The game-changing technology could substantially accelerate Synthetic Biology research and development, which has been linked to myriad applications — from the creation of new sources of food and environmental solutions to a host of new medical breakthroughs such as drugs tailored to individual patients and the growth of new organs for transplant patients.

Re-programmable cells

Easily 'Re-programmable cells' could be key in creation of new life forms

The multi-disciplinary project, funded with a leadership fellowship for Professor Krasnogor worth more than £1 million from the Engineering and Physical Sciences Research Council (EPSRC), involves computer scientists, biologists and chemists from Nottingham as well as academic colleagues at other universities in Scotland, the US, Spain and Israel.

The project — Towards a Biological Cell Operating System (AUdACiOuS) — is attempting to go beyond systems biology — the science behind understanding how living organisms work — to give scientists the power to create biological systems. The scientists will start the work by attempting to make e.coli bacteria much more easy to program.

Professor Krasnogor added: “This EPSRC Leadership Fellowship will allow me to transfer my expertise in Computer Science and informatics into the wet lab.

“Currently, each time we need a cell that will perform a certain new function we have to recreate it from scratch which is a long and laborious process. Most people think all we have to do to modify behaviour is to modify a cell’s DNA but it’s not as simple as that — we usually find we get the wrong behaviour and then we are back to square one. If we succeed with this AUdACiOuS project, in five years time, we will be programming bacterial cells in the computer and compiling and storing its program into these new cells so they can readily execute them.

“Like for a computer, we are trying to create a basic operating system for a biological cell.”

Among the most fundamental challenges facing the scientists will be developing new computer models that more accurately predict the behaviour of cells in the laboratory.

Scientists can already programme individual cells to complete certain tasks but scaling up to create a larger organism is trickier.

The creation of more sophisticated computer modelling programmes and a cell that could be re-programmed to fulfil any function without having to go back to the drawing board each time could largely remove the trial and error approach currently taken and allow synthetic biology research to take a significant leap forward.

The technology could be used in a whole range of applications where being able to modify the behaviour of organisms could be advantageous. In the long run, this includes the creation of new microorganisms that could help to clean the environment for example by capturing carbon from the burning of fossil fuel or removing contaminants, e.g. arsenic from water sources. Alternatively, the efficacy of medicine could be improved by tailoring it to specific patients to maximise the effect of the drugs and to reduce any harmful side effects.

The partners in the project are The University of Nottingham and The University of Edinburgh in the UK; Arizona State University, Massachusetts Institute of Technology, Michigan State University, New York University, University of California Santa Barbara, University of California, San Francisco in the US; Centro Nacional de Biotecnologia in Spain; and the Weizmann Institute of Science in Israel.

— Ends —

Notes to editors: The University of Nottingham, described by The Sunday Times University Guide 2011 as ‘the embodiment of the modern international university’, has award-winning campuses in the United Kingdom, China and Malaysia. It is ranked in the UK's Top 10 and the World's Top 75 universities by the Shanghai Jiao Tong (SJTU) and the QS World University Rankings. It was named ‘Europe’s greenest university’ in the UI GreenMetric World University Ranking, a league table of the world’s most environmentally-friendly higher education institutions, which ranked Nottingham second in the world overall.

The University is committed to providing a truly international education for its 40,000 students, producing world-leading research and benefiting the communities around its campuses in the UK and Asia. Impact: The Nottingham Campaign, its biggest ever fund-raising campaign, will deliver the University’s vision to change lives, tackle global issues and shape the future. For more details, visit:

More than 90 per cent of research at The University of Nottingham is of international quality, according to the most recent Research Assessment Exercise, with almost 60 per cent of all research defined as ‘world-leading’ or ‘internationally excellent’. Research Fortnight analysis of RAE 2008 ranked the University 7th in the UK by research power. The University’s vision is to be recognised around the world for its signature contributions, especially in global food security, energy & sustainability, and health.

More information is available from Professor Natalio Krasnogor on +44 (0)115 846 7592,; or Twitter — nkrasnogor

Emma Thorne - Media Relations Manager Email: Phone: +44 (0)115 951 5793 Location: King's Meadow Campus

The University of Nottingham University Park Nottingham, NG7 2RD telephone: +44 (0) 115 951 5765 email:

Monday, November 07, 2011

Thermal dip-pen nanolithography turns the tip of a scanning probe microscope into a tiny soldering iron

Researchers with the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab) have shed light on the role of temperature in controlling a fabrication technique for drawing chemical patterns as small as 20 nanometers. This technique could provide an inexpensive, fast route to growing and patterning a wide variety of materials on surfaces to build electrical circuits and chemical sensors, or study how pharmaceuticals bind to proteins and viruses.

One way of directly writing nanoscale structures onto a substrate is to use an atomic force microscope (AFM) tip as a pen to deposit ink molecules through molecular diffusion onto the surface. Unlike conventional nanofabrication techniques that are expensive, require specialized environments and usually work with only a few materials, this technique, called dip-pen nanolithography, can be used in almost any environment to write many different chemical compounds. A cousin of this technique — called thermal dip-pen nanolithography — extends this technique to solid materials by turning an AFM tip into a tiny soldering iron.

Dip-pen nanolithography can be used to pattern features as small as 20 nanometers, more than forty thousand times smaller than the width of a human hair. What’s more, the writing tip also performs as a surface profiler, allowing a freshly-writ surface to be imaged with nanoscale precision immediately after patterning.

“Tip-based manufacturing holds real promise for precise fabrication of nanoscale devices,” says Jim DeYoreo, interim director of Berkeley Lab’s Molecular Foundry, a DOE nanoscience research center. “However, a robust technology requires a scientific foundation built on an understanding of material transfer during this process. Our study is the first to provide this fundamental understanding of thermal dip-pen nanolithography.”


Thermal dip-pen nanolithography turns the tip of a scanning probe microscope into a tiny soldering iron that can be used to draw chemical patterns as small as 20 nanometers on surfaces. (Image courtesy of DeYoreo, et. al)

In this study, DeYoreo and coworkers systematically investigated the effect of temperature on feature size. Using their results, the team developed a new model to deconstruct how ink molecules travel from the writing tip to the substrate, assemble into an ordered layer and grow into a nanoscale feature.

“By carefully considering the role of temperature in thermal dip-pen nanolithography, we may be able to design and fabricate nanoscale patterns of materials ranging from small molecules to polymers with better control over feature sizes and shapes on a variety of substrates,” says Sungwook Chung, a staff scientist in Berkeley Lab’s Physical Biosciences Division, and Foundry user working with DeYoreo. “This technique helps overcome fundamental length scale limitations without the need for complex growth methods.”

DeYoreo and Chung collaborated with a research team from the University of Illinois at Urbana-Champaign that specializes in fabricating specialized tips for AFMs. Here, these collaborators developed a silicon-based AFM tip with a gradient of charge-carrying atoms sprinkled into the silicon such that a higher number reside at the base while fewer sit at the tip. This makes the tip heat up when electricity flows through it, much like the burner on an electric stove.

This ‘nanoheater’ can then be used to heat up inks applied to the tip, causing them to flow to the surface for fabricating microscale and nanoscale features. The group demonstrated this by drawing dots and lines of the organic molecule mercaptohexadecanoic acid on gold surfaces. The hotter the tip, the larger the feature size the team could draw.

“We are excited about this collaboration with Berkeley Lab, which combines their remarkable nanoscience capabilities with our technology to control temperature and heat flow on the nanometer scale,” says co-author William P. King, a University of Illinois professor of mechanical sciences and engineering. “Our ability to control the temperature within a nanometer-scale spot enabled this study of molecular-scale transport. By tuning the hotspot temperature, we can probe how molecules flow to a surface.”

“This thermal control over tip-to-surface transfer developed by Professor King’s group adds versatility by enabling on-the-fly variations in feature size and patterning of both liquid and solid materials,” DeYoreo adds.

Chung is the lead author and DeYoreo the corresponding author of a paper reporting this research in the journal Applied Physics Letters. The paper is titled “Temperature-dependence of ink transport during thermal dip-pen nanolithography.” Co-authoring the paper with Chung, DeYoreo and King were Jonathan Felts and Debin Wang.

This work at the Molecular Foundry was supported by DOE’s Office of Science and the Defense Advanced Research Projects Agency.

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The Molecular Foundry is one of five DOE Nanoscale Science Research Centers (NSRCs), national user facilities for interdisciplinary research at the nanoscale, supported by the DOE Office of Science. Together the NSRCs comprise a suite of complementary facilities that provide researchers with state-of-the-art capabilities to fabricate, process, characterize and model nanoscale materials, and constitute the largest infrastructure investment of the National Nanotechnology Initiative. The NSRCs are located at DOE’s Argonne, Brookhaven, Lawrence Berkeley, Oak Ridge and Sandia and Los Alamos National Laboratories. For more information about the DOE NSRCs, please visit

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Lawrence Berkeley National Laboratory addresses the world’s most urgent scientific challenges by advancing sustainable energy, protecting human health, creating new materials, and revealing the origin and fate of the universe. Founded in 1931, Berkeley Lab’s scientific expertise has been recognized with 13 Nobel prizes. The University of California manages Berkeley Lab for the U.S. Department of Energy’s Office of Science. For more, visit

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Contact: Aditi Risbud 510-486-4861 DOE/Lawrence Berkeley National Laboratory