Nanoparticle eats away plaque that causes heart attacks

Michigan State University and Stanford University scientists have invented a nanoparticle that eats away—from the inside out—portions of plaques that cause heart attacks. 

Atherosclerosis is a cardiac-based disease where plaque builds up inside the body’s arteries, the blood vessels responsible for carrying oxygen-rich blood to the heart and other organs of the body. Plaque is made up of white immune blood cells, known as macrophages, fat, cholesterol, calcium, and other substances found in the blood. As this plaque hardens it narrows the arteries, limiting the flow of oxygen-rich blood around the body. This, in turn, can lead to serious problems, including heart attack, stroke, or even death.

The team states their nanoparticle reduces and stabilizes plaque, providing a potential treatment for atherosclerosis, a leading cause of death in the United States. The study is published in the journal Nature Nanotechnology.

Macrophages are a type of white blood cell in our immune system, which engulf and digest cellular debris, foreign substances, microbes, cancer cells, and anything else that does not have the type of proteins specific to healthy body cells.

Once inside the macrophages of arterial plaques, the nanoparticle delivers a drug agent that can stimulate the cell to engulf and eat cellular debris, removing the diseased/dead cells. By reinvigorating the macrophages, plaque size is reduced.

Future clinical trials on the nanoparticle are expected to reduce the risk of most types of heart attacks, with minimal side effects due to the unprecedented selectivity of the nanodrug, according to Smith. His research is focused on intercepting the signaling of the receptors in macrophages and sending a message via small molecules using Nano-immunotherapeutic platforms. Previous studies have acted on the surface of the cells, but this new approach works intracellularly and has been effective in stimulating macrophages.

"We found we could stimulate the macrophages to selectively eat dead and dying cells – these inflammatory cells are precursor cells to atherosclerosis – that are part of the cause of heart attacks," Smith said. "We could deliver a small molecule inside the macrophages to tell them to begin eating again."

This approach also has applications beyond atherosclerosis, he added.

"We were able to marry a groundbreaking finding in atherosclerosis by our collaborators with the state-of-the-art selectivity and delivery capabilities of our advanced nanomaterial platform," explained Smith. "We demonstrated the nanomaterials were able to selectively seek out and deliver a message to the very cells needed. It gives a particular energy to our future work, which will include clinical translation of these nanomaterials using large animal models and human tissue tests. We believe it is better than previous methods."

Smith has filed a provisional patent and will begin marketing it later this year.

Thanks https://www.sciencenews.org/article/nanoparticles-beat-back-atherosclerosis https://phys.org/news/2020-01-nanoparticle-chomps-plaques-heart.html,https://www.nhlbi.nih.gov/news/2020/plaque-eating-nanoparticles-may-help-prevent-heart-attacks

SprayableTech is so flexible in its application lets you turn on your lights or change the TV channel with a touch

"Since SprayableTech is so flexible in its application, you can imagine using this type of system beyond walls and surfaces to power larger-scale entities like interactive smart cities and interactive architecture in public places. We view this as a tool that will allow humans to interact with and use their environment in newfound ways.”"

Cecile G. Tamura

For example, if you have a brown couch and want to use the couch itself as a remote for a television, you’d spray the conductive ink in a transparent color to embed it with connected sensors. A microcontroller is then attached to the interface and to the board that runs the code for sensing the visual output.

This way you can swipe your hand over the arm of the couch to change the channel, turn up the volume, or do whatever you’d like. 

https://finance.yahoo.com

Graphene can hear your brain whisper

The body of knowledge about the human brain is keeps growing, but many questions remain unanswered. Researchers have been using electrode arrays to record the brain's electrical activity for decades, mapping activity in different brain regions to understand what it looks like when everything is working, and what is happening when it is not. Until now, however, these arrays have only been able to detect activity over a certain frequency threshold. A new technology developed by the Graphene Flagship overcomes this technical limitation, unlocking the wealth of information found below 0.1 Hz, while paving the way for future brain-computer interfaces.

The new device was developed thanks to a collaboration between three Graphene Flagship Partners (IMB-CNM, ICN2 and ICFO) and adapted for brain recordings together with biomedical experts at IDIBAPS. This new technology moves away from electrodes and uses an innovative transistor-based architecture that amplifies the brain's signals in situ before transmitting them to a receiver. The use of graphene to build this new architecture means the resulting implant can support many more recording sites than a standard electrode array. It is slim and flexible enough to be used over large areas of the cortex without being rejected or interfering with normal brain function. The result is an unprecedented mapping of the low frequency brain activity known to carry crucial information about different events, such as the onset and progression of epileptic seizures and strokes.
For neurologists this means they finally have access to some clues that our brains only whisper. This ground-breaking technology could change the way we record and view electrical activity from the brain. Future applications will give unprecedented insights into where and how seizures begin and end, enabling new approaches to the diagnosis and treatment of epilepsy.

"Beyond epilepsy, this precise mapping and interaction with the brain has other exciting applications," explains José Antonio Garrido, one of the leaders of the study working at Graphene Flagship Partner ICN2. "In contrast to the common standard passive electrodes, our active graphene-based transistor technology will boost the implementation of novel multiplexing strategies that can increase dramatically the number of recording sites in the brain, leading the development of a new generation of brain-computer interfaces." Taking advantage of 'multiplexing', this graphene-enabled technology can also be adapted by some of the same researchers to restore speech and communication. ICN2 has secured this technology through a patent that protects the use of graphene-based transistors to measure low-frequency neural signals.


"This work is a prime example of how a flexible, graphene-based transistor array technology can offer capabilities beyond what is achievable today, and open up tremendous possibilities for reading at unexplored frequencies of neurological activity" noted by Kostas Kostarelos, leader of the Health, Medicine and Sensors Division of the Graphene Flagship.

Andrea C. Ferrari, Science and Technology Officer of the Graphene Flagship, and Chair of its Management Panel added that "graphene and related materials have major opportunities for biomedical applications. The Graphene Flagship recognized this by funding a dedicated Work Package. The results of this study are a clear demonstration that graphene can bring unprecedented progress to the study of Brain processes."
This new technology will be one of the Graphene Pavilion's main attractions at the upcoming Mobile World Congress in Barcelona (25-28 February 2019). The exhibition will showcase the latest innovations on graphene and related materials made possible by the Graphene Flagship, one of the biggest research initiatives ever funded by the European Commission. Beyond applications in health and medical devices, the pavilion will be populated with new prototypes of graphene-enabled technologies for mobile and data communications, wearables, and the internet of things.

High-resolution mapping of infraslow cortical brain activity enabled by graphene microtransistors
Eduard Masvidal-Codina, Xavi Illa, Miguel Dasilva, Andrea Bonaccini Calia, Tanja Dragojević, Ernesto E. Vidal-Rosas, Elisabet Prats-Alfonso, Javier Martínez-Aguilar, Jose M. De la Cruz, Ramon Garcia-Cortadella, Philippe Godignon, Gemma Rius, Alessandra Camassa, Elena Del Corro, Jessica Bousquet, Clement Hébert, Turgut Durduran, Rosa Villa, Maria V. Sanchez-Vives, Jose A. Garrido & Anton Guimerà-Brunet
https://www.nanotechnologyworld.org/…/Graphene-can-hear-you…

Scientists Discover Atomic-resolution Details of Brain Signaling

Scientists have revealed never-before-seen details of how our brain sends rapid-fire messages between its cells. They mapped the 3-D atomic structure of a two-part protein complex that controls the release of signaling chemicals, called neurotransmitters, from brain cells.
Understanding how cells release those signals in less than one-thousandth of a second could help launch a new wave of research on drugs for treating brain disorders.

 
The experiments, at the Linac Coherent Light Source (LCLS) X-ray laser at the Department of Energy’s SLAC National Accelerator Laboratory, build upon decades of previous research at Stanford University, Stanford School of Medicine and SLAC. Researchers reported their latest findings today in the journal Nature.

“This is a very important, exciting advance that may open up possibilities for targeting new drugs to control neurotransmitter release. Many mental disorders, including depression, schizophrenia and anxiety, affect neurotransmitter systems,” said Axel Brunger, the study’s principal investigator. He is a professor at Stanford School of Medicine and SLAC and a Howard Hughes Medical Institute investigator.

“Both parts of this protein complex are essential,” Brunger said, “but until now it was unclear how its two pieces fit and work together.”
Unraveling the Combined Secrets of Two Proteins

The two protein parts are known as neuronal SNAREs and synaptotagmin-1.

Earlier X-ray studies, including experiments at SLAC’s Stanford Synchrotron Radiation Lightsource (SSRL) nearly two decades ago, shed light on the structure of the SNARE complex, a helical protein bundle found in yeasts and mammals. SNAREs play a key role in the brain’s chemical signaling by joining, or “fusing,” little packets of neurotransmitters to the outer edges of neurons, where they are released and then dock with chemical receptors in another neuron to trigger a response.

A ‘Smoking Gun’ for Neurotransmitter Release

In this latest research, the scientists found that when the SNAREs and synaptotagmin-1 join up, they act as an amplifier for a slight increase in calcium concentration, triggering a gunshot-like release of neurotransmitters from one neuron to another. They also learned that the proteins join together before they arrive at a neuron’s membrane, which helps to explain how they trigger brain signaling so rapidly.

“The neuron is not building the ‘gun’ as it sits there on the membrane – it’s already there,” Brunger said.

The team speculates that several of the joined protein complexes may group together and simultaneously interact with the same vesicle to efficiently trigger neurotransmitter release, an exciting area for further studies.

“The structure of the SNARE-synaptotagmin-1 complex is a milestone that the field has awaited for a long time, and it sets the framework for a better understanding of the system,” said James Rothman, a professor at Yale University who discovered the SNARE proteins and shared the 2013 Nobel Prize in Physiology or Medicine.

Thomas C. Südhof, a professor at the Stanford School of Medicine and Howard Hughes Medical Institute investigator who shared that 2013 Nobel Prize with Rothman, discovered synaptotagmin-1 and showed that it plays an important role as a calcium sensor and calcium-dependent trigger for neurotransmitter release.

“The new structure has identified unanticipated interfaces between synaptotagmin-1 and the neuronal SNARE complex that change how we think about their interaction by revealing, in atomic detail, exactly where they bind together,” Südhof said. “This is a new concept that goes much beyond previous general models of how synaptotagmin-1 functions.”

Using Crystals, Robotics and X-rays to Advance Neuroscience

To study the joined protein structure, researchers in Brunger’s laboratory at the Stanford School of Medicine found a way to grow crystals of the complex. They used a robotic system developed at SSRL to study the crystals at SLAC’s LCLS, an X-ray laser that is one of the brightest sources of X-rays on the planet. SSRL and LCLS are DOE Office of Science User Facilities.

The researchers combined and analyzed hundreds of X-ray images from about 150 protein crystals to reveal the atomic-scale details of the joined structure.

SSRL’s Aina Cohen, who oversaw the development of the highly automated platform used for the neuroscience experiment, said, “This experiment was the first to use this robotic platform at LCLS to determine a previously unsolved structure of a large, challenging multi-protein complex.” The study was also supported by X-ray experiments at SSRL and at Argonne National Laboratory’s Advanced Photon Source.

“This is a good example of how advanced tools, instruments and X-ray methods are providing us new insights into what are truly complex mechanisms,” Cohen said.

Brunger said future studies will explore other protein interactions relevant to neurotransmitter release. “What we studied is only a subset,” he said. “There are many other factors interacting with this system and we want to know what these look like. This by no means is the end of the story.”

In addition to researchers at SLAC, Stanford University and the Stanford School of Medicine, other contributing scientists were from Lawrence Berkeley National Laboratory. The research was supported by the Howard Hughes Medical Institute; the National Institutes of Health (NIH); the DOE Office of Science; and the SSRL Structural Molecular Biology Program, which is also supported by the DOE Office of Science and the NIH’s National Institute of General Medical Sciences.
https://www.nanotechnologyworld.org/…/Scientists-Discover-A…

Nanosized Materials Help Electronics Compute Like Real Brains

Small size and new material go into devices that mimic speed and efficiency of neurons

Although processors have gotten smaller and faster over time, few computers can compete with the speed and computing power of the human brain. And none comes close to the organ’s energy efficiency. So some engineers want to develop electronics that mimic how the brain computes to build more powerful and efficient devices.

A team at IBM Research, Zurich, now reports that nanosized devices made from phase-change materials can mimic how neurons fire to perform certain calculations (Nat. Nanotechnol. 2016, DOI:10.1038/nnano.2016.70).

This report “shows quite concretely that we can make simple but effective hardware mimics of neurons, which could be made really small and therefore have low operating powers,” says C. David Wright, an electrical engineer at the University of Exeter who wrote a commentary accompanying the new article.

The IBM team’s device imitates how an individual neuron integrates incoming signals from other neurons to determine when it should fire. These input signals change the electrical potential across the neuron’s membrane—some increase it, others decrease it. Once that potential passes a certain threshold, the neuron fires.

Previously, engineers have mimicked this process using combinations of capacitors and silicon transistors, which can be complex and difficult to scale down, Wright explains in his commentary.

In the new work, IBM’s Evangelos Eleftheriou and colleagues demonstrate a potentially simpler system that uses a phase-change material to play the part of a neuron’s membrane potential. The doped chalcogenide Ge2Sb2Te5, which has been tested in conventional memory devices, can exist in two phases: a glassy amorphous state and a crystalline one. Electrical pulses slowly convert the material from amorphous to crystalline, which, in turn, changes its conductance. At a certain level of phase change, the material’s conductance suddenly jumps, and the device fires like a neuron.

The IBM team tested a mushroom-shaped device consisting of a 100-nm-thick layer of the chalcogenide sandwiched between two electrodes. In one demonstration, they used the neuronlike device to detect correlations in 1,000 streams of binary data. Such a calculation could spot trends in social media chatter or even in stock market transactions, Wright says.

He also points out that the devices fire faster than actual neurons, on a nanosecond timescale compared with a millisecond one. The neuron mimics, Wright says, are another step toward hardware that can process information as the brain does but at speeds orders of magnitudes faster than the organ. “That could do some remarkable things.”

http://www.ooyuz.com/geturl?aid=11669372

http://www.scientificamerican.com/…/nanosized-materials-he…/

http://cen.acs.org/…/Phase-change-material-help-electronics…
Cecile G. Tamura

New nanodevice to improve cancer treatment monitoring

The gold nanonparticules on the surface of this receiving tab modify the colour of light detected by the instrument. The captured colour perfectly reflects the exact concentration of the medication in the blood sample. Credit: University of Montreal
In less than a minute, a miniature device developed at the University of Montreal can measure a patient's blood for methotrexate, a commonly used but potentially toxic cancer drug. Just as accurate and ten times less expensive than equipment currently used in hospitals, this nanoscale device has an optical system that can rapidly gauge the optimal dose of methotrexate a patient needs, while minimizing the drug's adverse effects. The research was led by Jean-François Masson and Joelle Pelletier of the university's Department of Chemistry.
Methotrexate has been used for many years to treat certain cancers, among other diseases, because of its ability to block the enzyme dihydrofolate reductase (DHFR). This enzyme is active in the synthesis of DNA precursors and thus promotes the proliferation of cancer cells. "While effective, methotrexate is also highly toxic and can damage the healthy cells of patients, hence the importance of closely monitoring the drug's concentration in the serum of treated individuals to adjust the dosage," Masson explained.
Until now, monitoring has been done in hospitals with a device using fluorescent bioassays to measure light polarization produced by a drug sample. "The operation of the current device is based on a cumbersome, expensive platform that requires experienced personnel because of the many samples that need to be manipulated," Masson said.

Six years ago, Joelle Pelletier, a specialist of the DHFR enzyme, and Jean-François Masson, an expert in biomedical instrument design, investigated how to simplify the measurement of methotrexate concentration in patients.

Gold nanoparticles on the surface of the receptacle change the colour of the light detected by the instrument. The detected colour reflects the exact concentration of the drug in the blood sample. In the course of their research, they developed and manufactured a miniaturized device that works by surface plasmon resonance. Roughly, it measures the concentration of serum (or blood) methotrexate through gold nanoparticles on the surface of a receptacle. In "competing" with methotrexate to block the enzyme, the gold nanoparticles change the colour of the light detected by the instrument. And the colour of the light detected reflects the exact concentration of the drug in the blood sample.

As preicse yet 10 times less expensive than current hospital equipment, this little device contains an optical system that enables it to rapidly identify the dose of methotrexate that a cancer requires, minimising the drugs undesirable side effects. Credit: University of Montreal
The accuracy of the measurements taken by the new device were compared with those produced by equipment used at the Maisonneuve-Rosemont Hospital in Montreal. "Testing was conclusive: not only were the measurements as accurate, but our device took less than 60 seconds to produce results, compared to 30 minutes for current devices," Masson said. Moreover, the comparative tests were performed by laboratory technicians who were not experienced with surface plasmon resonance and did not encounter major difficulties in operating the new equipment or obtaining the same conclusive results as Masson and his research team.
In addition to producing results in real time, the device designed by Masson is small and portable and requires little manipulation of samples. "In the near future, we can foresee the device in doctors' offices or even at the bedside, where patients would receive individualized and optimal doses while minimizing the risk of complications," Masson said. Another benefit, and a considerable one: "While traditional equipment requires an investment of around $100,000, the new mobile device would likely cost ten times less, around $10,000."

Two Americans, a German win 2014 Nobel prize for chemistry (super-resolved fluorescence microscopy)

Two US and one German scientist win Nobels for opening a window into the nanoworld with their development of ‘super-resolved fluorescence microscopy’

Eric Betzig, of Howard Hughes Medical Institute, and William E Moerner, of Stanford University, in the US and Stefan W Hell, of the Max Planck Institute in Göttingen, Germany, won for circumventing limitations on optical microscopy.

The Nobel assembly, which awards the prize, said: “For a long time optical microscopy was held back by a presumed limitation: that it would never obtain a better resolution than half the wavelength of light. Helped by fluorescent molecules, the Nobel laureates in chemistry 2014 ingeniously circumvented this limitation. Their groundbreaking work has brought optical microscopy into the nanodimension.”

Nanostructured metal-oxide catalyst efficiently converts carbon dioxide to methanol

Nano structured metal-oxide catalyst efficiently converts carbon dioxide to methanol, a key commodity for chemicals and fuels

Scientists at the U.S. Department of Energy's (DOE) Brookhaven National Laboratory have discovered a new catalytic system for converting carbon dioxide (CO2) to methanol-a key commodity used to create a wide range of industrial chemicals and fuels. With significantly higher activity than other catalysts now in use, the new system could make it easier to get normally unreactive CO2 to participate in these reactions.


"Developing an effective catalyst for synthesizing methanol from CO2 could greatly expand the use of this abundant gas as an economical feedstock," said Brookhaven chemist Jose Rodriguez, who led the research. It's even possible to imagine a future in which such catalysts help mitigate the accumulation of this greenhouse gas, by capturing CO2 emitted from methanol-powered combustion engines and fuel cells, and recycling it to synthesize new fuel.
That future, of course, will be determined by a variety of factors, including economics. "Our basic research studies are focused on the science-the discovery of how such catalysts work, and the use of this knowledge to improve their activity and selectivity," Rodriguez emphasized.
The research team, which included scientists from Brookhaven, the University of Seville in Spain, and Central University of Venezuela, describes their results in the August 1, 2014, issue of the journal Science.

New tools for discovery

Because CO2 is normally such a reluctant participant in chemical reactions, interacting weakly with most catalysts, it's also rather difficult to study. These studies required the use of newly developed in-situ (or on-site, meaning under reaction conditions) imaging and chemical "fingerprinting" techniques. These techniques allowed the scientists to peer into the dynamic evolution of a variety of catalysts as they operated in real time. The scientists also used computational modeling at the University of Seville and the Barcelona Supercomputing Center to provide a molecular description of the methanol synthesis mechanism.

The team was particularly interested in exploring a catalyst composed of copper and ceria (cerium-oxide) nanoparticles, sometimes also mixed with titania. The scientists' previous studies with such metal-oxide nanoparticle catalysts have demonstrated their exceptional reactivity in a variety of reactions. In those studies, the interfaces of the two types of nanoparticles turned out to be critical to the reactivity of the catalysts, with highly reactive sites forming at regions where the two phases meet.

To explore the reactivity of such dual particle catalytic systems in converting CO2 to methanol, the scientists used spectroscopic techniques to investigate the interaction of CO2 with plain copper, plain cerium-oxide, and cerium-oxide/copper surfaces at a range of reaction temperatures and pressures. Chemical fingerprinting was combined with computational modeling to reveal the most probable progression of intermediates as the reaction from CO2 to methanol proceeded.

These studies revealed that the metal component of the catalysts alone could not carry out all the chemical steps necessary for the production of methanol. The most effective binding and activation of CO2 occurred at the interfaces between metal and oxide nanoparticles in the cerium-oxide/copper catalytic system.
"The key active sites for the chemical transformations involved atoms from the metal [copper] and oxide [ceria or ceria/titania] phases," said Jesus Graciani, a chemist from the University of Seville and first author on the paper. The resulting catalyst converts CO2 to methanol more than a thousand times faster than plain copper particles, and almost 90 times faster than a common copper/zinc-oxide catalyst currently in industrial use.

This study illustrates the substantial benefits that can be obtained by properly tuning the properties of a metal-oxide interface in catalysts for methanol synthesis.

How Nanotechnology Could Reengineer Us

Thanks http://www.keithley.com

New 2D nano-material

A two-dimensional nano-material may be converted to nano-transistors used in high-speed electronics. The researchers say this may be the foundation of a new electronics revolution. Image: Image: Dr Daniel J White, Science FX A new 2D nano-material that encourages the free flow of electrons may be the foundation for a new electronics revolution. The material – made up of layers of crystal known as molybdenum oxides – has unique properties that encourage the free flow of electrons at ultra-high speeds. In a paper published in the January 2013 issue of Advanced Materials, the researchers explain how they adapted a revolutionary material known as graphene to create a new conductive nano-material. Graphene was created in 2004 by scientists in the UK and won its inventors a Nobel Prize in 2010. While graphene supports high-speed electrons, its physical properties prevent it from being used for high-speed electronics. The CSIRO's Dr Serge Zhuiykov said the new nano-material comprised layered sheets – similar to graphite layers that make up a pencil's core. "Within these layers, electrons can zip through at high speeds with minimal scattering," Dr Zhuiykov said. "The importance of our breakthrough is how quickly and fluently electrons – which conduct electricity – can flow through the new material." RMIT's Professor Kourosh Kalantar-Zadeh said the researchers were able to remove "roadblocks" that could obstruct the electrons, an essential step for developing high-speed electronics. "Instead of scattering when they hit roadblocks, as they would in conventional materials, they can simply pass through this new material and get through the structure faster," Professor Kalantar-Zadeh said. "Quite simply, if electrons can pass through a structure quicker, we can build smaller devices and transfer data at much higher speeds. "While more work needs to be done before we can develop actual gadgets using this new 2D nano-material, this breakthrough lays the foundation for a new electronics revolution, and we look forward to exploring its potential." In the paper titled 'Enhanced Charge Carrier Mobility in Two-Dimensional High Dielectric Molybdenum Oxide,' the researchers describe how they used a process known as "exfoliation" to create layers of the material ~11 nm thick. The material was manipulated to convert into a semiconductor, and nanoscale transistors were then created using molybdenum oxide. The result was electron mobility values of >1,100 cm2/Vs – exceeding the current industry standard for low dimensional silicon. The work, with RMIT doctoral researcher Sivacarendran Balendhran as the lead author, was supported by the CSIRO Sensors and Sensor Networks Transformational Capability Platform and the CSIRO Materials Science and Engineering Division. It was also a result of collaboration between researchers from Monash University, the University of California – Los Angeles (UCLA), CSIRO, Massachusetts Institute of Technology (MIT) and RMIT. Editor's Note: Original news release can be found here.

Nano-data storage a step closer

AGENCY FOR SCIENCE, TECHNOLOGY AND RESEARCH

Share on print The research found that an ultra-smooth surface is the key factor for 'self assembly' - a cheap, high-volume, high-density patterning technique. Image: Henrik5000/iStockphoto Imagine being able to store thousands of songs and high-resolution images on data devices no bigger than a fingernail. Researchers from A*STAR's Institute of Materials Research and Engineering (IMRE) and the National University of Singapore (NUS) have discovered that an ultra-smooth surface is the key factor for 'self-assembly' - a cheap, high-volume, high-density patterning technique. This allows manufacturers to use the method on a variety of different surfaces. This discovery paves the way for the development of next generation data storage devices, with capacities of up to 10 Terabits per square inch, which could lead to significantly greater storage on much smaller data devices. The 'self-assembly' technique is one of the simplest and cheapest high-volume methods for creating uniform, densely-packed nanostructures that could potentially help store data. Self-assembly is one of the leading candidates for large scale nanofabrication at very high pattern densities. One of its most obvious applications will be in the field of bit patterned media, or the hard disk industry.  It is widely used in research and is gaining acceptance in industry as a practical lithographic tool for sub-100 nm, low-cost, large area patterning. However, attempts to employ self-assembly on different surface types, such as magnetic media used for data storage, have shown varying and erratic results to date. This phenomenon has continued to puzzle industry researchers and scientists globally. Researchers from A*STAR's IMRE and NUS have now solved this mystery and identified that the smoother the surface, the more efficient the self-assembly of nanostructures will be. This breakthrough allows the method to be used on more surfaces and reduce the number of defects in an industrial setting. The more densely packed the structures are in a given area, the higher the amount of data that can be stored.           "A height close to 10 atoms, or 10 angstroms in technical terms, is all it takes to make or break self-assembly," explained Dr MSM Saifullah, one of the key researchers from A*STARís IMRE who made the discovery. This is based on a root mean squared surface roughness of 5 angstrom.  The team discovered that this was the limit of surface roughness allowed for the successful self-assembly of dots, which could eventually be used in making high-density data storage. ìIf we want large scale, large area nanopatterning using very affordable self-assembly, the surface needs to be extremely smooth so that we can achieve efficient, successful self-assembly and with lower incidences of defects." The discovery was recently published in Scientific Reports, an open access journal fromNature.  Editor's Note: Original news release can be found here.

Nanomaterial to store ‘future fuel’

THE UNIVERSITY OF NEW SOUTH WALES

Share on print Hydrogen, considered a major fuel of the future, could be used to power buildings, portable electronics and vehicles. Image: davidf/iStockphoto For the first time, engineers at the University of New South Wales have demonstrated that hydrogen can be released and reabsorbed from a promising storage material, overcoming a major hurdle to its use as an alternative fuel source.   Researchers from the Materials Energy Research Laboratory in nanoscale (MERLin) at UNSW have synthesised nanoparticles of a commonly overlooked chemical compound called sodium borohydride and encased these inside nickel shells.   Their unique "core-shell" nanostructure has demonstrated remarkable hydrogen storage properties, including the release of energy at much lower temperatures than previously observed.    “No one has ever tried to synthesise these particles at the nanoscale because they thought it was too difficult, and couldn’t be done. We’re the first to do so, and demonstrate that energy in the form of hydrogen can be stored with sodium borohydride at practical temperatures and pressures,” says Dr Kondo-Francois Aguey-Zinsou from the School of Chemical Engineering at UNSW.   Considered a major a fuel of the future, hydrogen could be used to power buildings, portable electronics and vehicles – but this application hinges on practical storage technology.   Lightweight compounds known as borohydrides (including lithium and sodium compounds) are known to be effective storage materials but it was believed that once the energy was released it could not be reabsorbed – a critical limitation. This perceived “irreversibility” means there has been little focus on sodium borohydride.   However, the result, published last week in the journal ACS Nano, demonstrates for the first time that reversibility is indeed possible using a borohydride material by itself and could herald significant advances in the design of novel hydrogen storage materials.   “By controlling the size and architecture of these structures we can tune theirproperties and make them reversible – this means they can release and reabsorb hydrogen,” says Aguey-Zinsou, lead author on the paper. “We now have a way to tap into all these borohydride materials, which are particularly exciting for application on vehicles because of their highhydrogen storage capacity.”   The researchers observed remarkable improvements in the thermodynamic and kinetic properties of their material. This means the chemical reactions needed to absorb and release hydrogen occurred faster than previously studied materials, and at significantly reduced temperatures – making possible application far more practical.   In its bulk form, sodium borohydride requires temperatures above 550 degrees Celsius just to release hydrogen. Even on the nano-scale the improvements were minimal. However, with their core-shell nanostructure, the researchers saw initial energy release happening at just 50 °C, and significant release at 350 °C.   “The new materials that could be generated by this exciting strategy could provide practical solutions to meet many of the energy targets set by the US Department of Energy,” says Aguey-Zinsou. “The key thing here is that we’ve opened the doorway.” Editor's Note: Original news release can be found here.

Nano tritium battery

The NanoTritium can travel into enemy territory, plunge to the bottom of the ocean and even settle into the human heart. And it keeps going, even through extreme temperatures and vibration, for 20 years or more. Just the size of an adult’s thumb, NanoTritium is a different kind of battery — and now it’s available commercially. Homestead-based City Labs, the small high-tech company that created NanoTritium, is a radioactive isotope of hydrogen containing two neutrons and one proton, its atom is unstable and decays into helium. This decay is accompanied by release of energy in the form of electrons, which can then be used to power devices. The element being mildly radioactive does not affect health of the user. The electrons released during thIS procedure are capable of powering the battery but are not radioactive enough to escape the battery and harm user

When installing micro-electronic devices in locations that are expensive or hard to reach, or just downright dangerous, you don't want to have to keep returning to swap out a battery cell. Canada's City Labs has announced the commercial launch of its NanoTritium betavoltaic power source. This thumb-sized battery draws on the energy released from its radioactive element to provide continuous nanoWatt power for over 20 years.

Contrary to the celluloid claims of Dr Octavius (in the movie Spiderman 2), there's quite a bit more than 25 pounds (11 kg) of tritium (a radioactive isotope of hydrogen) in the world today. Although occurring naturally in the upper atmosphere, it's also produced commercially in nuclear reactors and used in such self-luminescent products as aircraft dials, gauges, luminous paints, exit signs in buildings and wristwatches. It's also considered a relatively benign betavoltaic, providing a continuous flow of low-powered electrons for a good many years.

According to the Environmental Protection Agency, tritium has a half-life of 12.3 years and the Model P100a NanoTritium betavoltaic power source from Toronto's City Labs is claimed to be capable of providing juice to low-power micro-electronic and sensor applications for over 20 years. It's described as robust and hermetically sealed, and the tritium is incorporated in solid form.

Independent testing undertaken by Lockheed Martin during an industry-wide survey also found the technology to be resistant to broad temperature extremes (-50° C to 150° C/-58° F to 302° F), as well as extreme vibration and altitude.

Examples of possible applications for the technology offered by City Labs include environmental pressure/temperature sensors, intelligence sensors, medical implants, trickle charging lithium batteries, semi-passive and active RFID tags, deep space probes, silicon clocks, SRAM memory backup, deep-sea oil well electronics, and lower power processors.

The company reports that it has just been granted a Product Regulatory General License to manufacture, sell, and distribute its NanoTritium battery, making its P100a the first betavoltaic power source to be made available to customers who don't have a radiation license, haven't obtained regulatory approval or undergone special training.

The company's Denset Serralta confirmed that its betavoltaic power source is available now (with a 6 to 8 week lead time) and told us that "price ranges are in the US$1,000s, future price ranges will drop from that or will increase in power output."

City Labs (which is backed by Alienware's co-founder Alex Aguila, currently located within the NASA-sponsored Carrie Meek Business Center in Homestead, Florida and includes betavoltaic pioneer Larry Olsen as Director of Research) says that higher power batteries are currently under development, which could provide tens of microwatts over the long haul as well as short bursts of milliwatt power.

Perfect Nanotube Could Be Grown One Meter Long, 50,000 Times Thinner Than a Human Hair

Defects in nanotubes heal very quickly in a very small zone at or near the iron catalyst before they ever get into the tube wall, according to calculations by theoretical physicists at Rice University, Hong Kong Polytechnic University and Tsinghua University. (Credit: Courtesy of Feng Ding/Rice/Hong Kong Polytechnic)

Science Daily  — At the right temperature, with the right catalyst, there's no reason a perfect single-walled carbon nanotube 50,000 times thinner than a human hair can't be grown a meter long.

That calculation is one result of a study by collaborators at Rice, Hong Kong Polytechnic and Tsinghua universities who explored the self-healing mechanism that could make such extraordinary growth possible. That's important to scientists who see high-quality carbon nanotubes as critical to advanced materials and, if they can be woven into long cables, power distribution over the grid of the future.

The report published online by Physical Review Letters is by Rice theoretical physicist Boris Yakobson; Feng Ding, an adjunct assistant professor at Rice and an assistant professor at Hong Kong Polytechnic; lead author Qinghong Yuan, a postdoctoral researcher at Hong Kong Polytechnic; and Zhiping Xu, a professor of engineering mechanics at Tsinghua and former postdoctoral researcher at Rice.

They determined that iron is the best and quickest among common catalysts at healing topological defects -- rings with too many or too few atoms -- that inevitably bubble up during the formation of nanotubes and affect their valuable electronic and physical properties. The right combination of factors, primarily temperature, leads to kinetic healing in which carbon atoms gone astray are redirected to form the energetically favorable hexagons that make up nanotubes and their flat cousin, graphene. The team employed density functional theory to analyze the energies necessary for the transformation.

"It is surprising that the healing of all potential defects -- pentagons, heptagons and their pairs -- during carbon nanotube growth is quite easy," said Ding, who was a research scientist in Yakobson's Rice lab from 2005 to 2009. "Only less than one-10 billionth may survive an optimum condition of growth. The rate of defect healing is amazing. If we take hexagons as good guys and others as bad guys, there would be only one bad guy on Earth."

The energies associated with each carbon atom determine how it finds its place in the chicken-wire-like form of a nanotube, said Yakobson, Rice's Karl F. Hasselmann Chair in Engineering and a professor of materials science and mechanical engineering and of chemistry. But there has been a long debate among scientists over what actually happens at the interface between the catalyst and a growing tube.

"There have been two hypotheses," Yakobson said. "A popular one was that defects are being created quite frequently and get into the wall of the tube, but then later they anneal. There's some kind of fixing process. Another hypothesis is that they basically don't form at all, which sounds quite unreasonable.

"This was all just talk; there was no quantitative analysis. And that's where this work makes an important contribution. It evaluates quantitatively, based on state-of-the-art computations, specifically how fast this annealing can take place, depending on location," he said.

A nanotube grows in a furnace as carbon atoms are added, one by one, at the catalyst. It's like building the peak of a skyscraper first and adding bricks to the bottom. But because those bricks are being added at a furious rate -- millions in a matter of minutes -- mistakes can happen, altering the structure.

In theory, if one ring has five or seven atoms instead of six, it would skew the way all subsequent atoms in the chain orient themselves; an isolated pentagon would turn the nanotube into a cone, and a heptagon would turn it into a horn, Yakobson said.

But calculations also showed such isolated defects cannot exist in a nanotube wall; they would always appear in 5/7 pairs. That makes a quick fix easier: If one atom can be prompted to move from the heptagon to the pentagon, both rings come up sixes.

The researchers found that very transition happens best when carbon nanotubes are grown at temperatures around 930 kelvins (1,214 degrees Fahrenheit). That is the optimum for healing with an iron catalyst, which the researchers found has the lowest energy barrier and reaction energy among the three common catalysts considered, including nickel and cobalt.

Once a 5/7 forms at the interface between the catalyst and the growing nanotube, healing must happen very quickly. The further new atoms push the defect into the nanotube wall, the less likely it is to be healed, they determined; more than four atoms away from the catalyst, the defect is locked in.

Tight control of the conditions under which nanotubes grow can help them self-correct on the fly. Errors in atom placement are caught and fixed in a fraction of a millisecond, before they become part of the nanotube wall.

The researchers also determined through simulations that the slower the growth, the longer a perfect nanotube could be. A nanotube growing about 1 micrometer a second at 700 kelvins could potentially reach the meter milestone, they found.

The work at Rice University was initially supported by the National Science Foundation and at a later stage by an Office of Naval Research grant.

Engineers Perfecting Carbon Nanotubes for Highly Energy-Efficient Computing

An electron microscope image showing carbon nanotube transistors (CNTs) arranged in an integrated logic circuit. (Credit: Stanford University School of Engineering)                 Science Daily — Energy efficiency is the most significant challenge standing in the way of continued miniaturization of electronic systems, and miniaturization is the principal driver of the semiconductor industry. "As we approach the ultimate limits of Moore's Law, however, silicon will have to be replaced in order to miniaturize further," said Jeffrey Bokor, deputy director for science at the Molecular Foundry at the Lawrence Berkeley National Laboratory and Professor at UC-Berkeley.

Early promiseTo this end, carbon nanotubes (CNTs) are a significant departure from traditional silicon technologies and a very promising path to solving the challenge of energy efficiency. CNTs are cylindrical nanostructures of carbon with exceptional electrical, thermal and mechanical properties. Nanotube circuits could provide a ten-times improvement in energy efficiency over silicon.

When the first rudimentary nanotube transistors were demonstrated in 1998, researchers imagined a new age of highly efficient, advanced computing electronics. That promise, however, is yet to be realized due to substantial material imperfections inherent to nanotubes that left engineers wondering whether CNTs would ever prove viable.

Over the last few years, a team of Stanford engineering professors, doctoral students, undergraduates, and high-school interns, led by Professors Subhasish Mitra and H.-S. Philip Wong, took on the challenge and has produced a series of breakthroughs that represent the most advanced computing and storage elements yet created using CNTs.

These high-quality, robust nanotube circuits are immune to the stubborn and crippling material flaws that have stumped researchers for over a decade, a difficult hurdle that has prevented the wider adoption of nanotube circuits in industry. The advance represents a major milestone toward Very-large Scale Integrated (VLSI) systems based on nanotubes.

"The first CNTs wowed the research community with their exceptional electrical, thermal and mechanical properties over a decade ago, but this recent work at Stanford has provided the first glimpse of their viability to complement silicon CMOS transistors," said Larry Pileggi, Tanoto Professor of Electrical and Computer Engineering at Carnegie Mellon University and director of the Focus Center Research Program Center for Circuit and System Solutions.

Major barriers

While there have been significant accomplishments in CNT circuits over the years, they have come mostly at the single-nanotube level. At least two major barriers remain before CNTs can be harnessed into technologies of practical impact: First, "perfect" alignment of nanotubes has proved all but impossible to achieve, introducing detrimental stray conducting paths and faulty functionality into the circuits; second, the presence of metallic CNTs (as opposed to more desirable semiconducting CNTs) in the circuits leads to short circuits, excessive power leakage and susceptibility to noise. No CNT synthesis technique has yet produced exclusively semiconducting nanotubes.

"Carbon nanotube transistors are attractive for many reasons as a basis for dense, energy efficient integrated circuits in the future. But, being borne out of chemistry, they come with unique challenges as we try to adapt them into microelectronics for the first time. Chief among them is variability in their placement and their electrical properties. The Stanford work, that looks at designing circuits taking into consideration such variability, is therefore an extremely important step in the right direction," Supratik Guha, Director of the Physical Sciences Department at the IBM Thomas J. Watson Research Center .

"This is very interesting and creative work. While there are many difficult challenges ahead, the work of Wong and Mitra makes good progress at solving some of these challenges," added Bokor.

Realizing that better processes alone will never overcome these imperfections, the Stanford engineers managed to circumvent the barriers using a unique imperfection-immune design paradigm to produce the first-ever full-wafer-scale digital logic structures that are unaffected by misaligned and mis-positioned CNTs. Additionally, they addressed the challenges of metallic CNTs with the invention of a technique to remove these undesirable elements from their circuits.

Striking features

The Stanford design approach has two striking features in that it sacrifices virtually none of CNTs' energy efficiency and it is also compatible with existing fabrication methods and infrastructure, pushing the technology a significant step toward commercialization.

"This transformative research is made all the more promising by the fact that it can co-exist with today's mainstream silicon technologies, and leverage today's manufacturing and system design infrastructure, providing the critical feature of economic viability," said Betsy Weitzman of the Focus Center Research Program at the Semiconductor Research Corporation

The engineers next demonstrated the possibilities of their techniques by creating the essential components of digital integrated systems: arithmetic circuits and sequential storage, as well as the first monolithic three-dimensional integrated circuits with extreme levels of integration.

The Stanford team's work was featured recently as an invited paper at the International Electron Devices Meeting (IEDM) as well as a "keynote paper" in the IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems.

"Many researchers assumed that the way to live with imperfections in CNT manufacturing was through expensive fault-tolerance techniques. Through clever insights, Mitra and Wong have shown otherwise. Their inexpensive and practical methods can significantly improve CNT circuit robustness, and go a long way toward making CNT circuits viable," said Sachin S. Sapatnekar, Editor-in-Chief, IEEE Transactions on CAD. "I anticipate high reader interest in the paper," Sapatnekar noted.

Nanocomposite Cavity Filler Reverses Decay, Killing Bacteria and Regenerating Tooth Structure

By Clay Dillow

Fighting Tooth Decay U.S. Navy

Dentists may soon be getting a potent new weapons with which to wage the global fight against cavities. The University of Maryland has developed a novel new nanocomposite material that can be used not only as filling for cavities, but that will also kill any remaining bacteria in the tooth and regenerate the actual structure lost to decay.

The nanocomposite is made up of silver nanoparticles and calcium phosphate nanoparticles, both of which are piped into the tooth as filler for a cavity. The silver nanoparticles along with a few other ingredients in the material kill off whatever bacteria is still lingering inside the tooth, paving the way for the calcium phosphate to regenerate tooth minerals. Over time, the tooth strengthens again.

But as IEEE Spectrum notes, the silver nanoparticles could prove to be problematic, and this is probably why this treatment is offered as a cavity filling rather than a toothpaste or mouthwash. Silver nanoparticles aren’t totally understood, and there have been some concerns voiced about the potential risks and perils associated with ingesting the stuff. The nanocomposite is currently undergoing both human and animal testing right now, hopefully with an eye toward clarifying and alleviating any health concerns. If the composite can pass muster, dentists everywhere can get down to the business of rolling back the clock on cavities.

[IEEE Spectrum]