Water turns ice-like at room temperature

The peculiar property of turning ice-like at room temperatures occurs with water at the nanscale according to an Aug. 29, 2016 news item on phys.org,

New research by scientists at The University of Akron (UA) [Ohio, US] shows that a nanometer-thin layer of water between two charged surfaces exhibits ice-like tendencies that allow it to withstand pressures of hundreds of atmospheres. The discovery could lead to better ways to minimize friction in a variety of settings.

An Aug. 29, 2016 University of Akron news release on EurekAlert, which originated the news item, elaborates on the theme,

Why water between two surfaces does not always simply squeeze out when placed under severe pressure had never been fully understood. The UA researchers discovered that naturally-occurring charges between two surfaces under intense pressure traps the water, and gives it ice-like qualities. It is this ice-like layer of water–occurring at room temperature–that then lessens the friction between the two surfaces.

“For the first time we have a basic understanding of what happens to water under these conditions and why it keeps two surfaces apart,” says Professor Ali Dhinojwala. “We had suspected something was happening at the molecular level, and now we have proof.”

“This discovery could lead to improved designs where low friction surfaces are critically important, such as in biomedical knee implants,” says UA graduate student Nishad Dhopatkar.

Graduate student Adrian Defante, who was also part of the research team, says “the newfound properties of water might contribute to the development of more effective antimicrobial coatings, as a thin layer of water could prevent bacterial adhesion.”

Dhinojwala adds that the research conversely offers insight into how water might be kept away from two surfaces, which could lead to better adhesives in watery environments.

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

Ice-like water supports hydration forces and eases sliding friction by Nishad Dhopatkar, Adrian P. Defante, and Ali Dhinojwala. Science Advances  26 Aug 2016: Vol. 2, no. 8, e1600763 DOI: 10.1126/sciadv.1600763 Published 03 August 2016

This paper is open access.

Here’s an image the researchers are using to illustrate their work

Caption: Researchers at The University of Akron have discovered that a thin layer of water (blue molecules ) between two charged surfaces composed of surfactants (green molecules) --becomes ice-like, lessening the friction between the two surfaces. Credit: The University of Akron

Caption: Researchers at The University of Akron have discovered that a thin layer of water (blue molecules ) between two charged surfaces composed of surfactants (green molecules) –becomes ice-like, lessening the friction between the two surfaces. Credit: The University of Akron

All about Atomic Force Microscopy (AFM) with Gerd Binnig and Christoph Gerber

Gerd Binnig, Christoph Gerber, and Calvin Quate invented the atomic force microscope in the 1980s and an Aug. 16, 2016 news item on Nanotechnology Now announces a discussion with two of the inventors, Binnig and Gerber (Note: Links have been removed),

The inventors of one of the most versatile tools in modern science – the atomic force microscope, or AFM – tell their story in an interview published online this week. The AFM was invented in the mid 1980s by Gerd Binnig, Christoph Gerber and Calvin Quate, three physicists who are sharing the 2016 Kavli Prize in Nanoscience.

Binnig and Gerber discuss their inspiration for the device, how they solved problems through sport, and why their invention continues to propel science at the nanoscale.

This charming Aug. 20, 2016 discussion for the Kavli Foundation focuses on more than the AFM although it is the main topic,

Our roundtable panelists were:

GERD BINNIG –is a physicist and Nobel Laureate for his invention (with Heinrich Rohrer and Christoph Gerber) of the scanning tunneling microscope while at IBM Zurich. He began development of the atomic force microscope in 1986 to overcome the limitations of his previous invention.
CHRISTOPH GERBER –is a physicist and director for scientific communication at the Swiss Nanoscience Institute at the University of Basel. While at IBM, Gerber worked closely with Binnig on bringing both the scanning tunneling microscope and atomic force microscope to fruition.

Calvin Quate was unable to participate in the roundtable. The transcript has been amended and edited by the laureates

THE KAVLI FOUNDATION [TKF]: You filed your first patent for the atomic force microscope (AFM) nearly 30 years ago. How has it changed the way we look at the world since then?

GERD BINNIG: It was like the first time people looked through an optical microscope and saw bacteria. That completely changed how we look at the world. Suddenly, we understood what was really going on in nature, and we used that knowledge to learn how diseases spread. The AFM is the next step. It lets us look at the molecules that make life possible in those bacteria – and everywhere else – and see things we could not see before. It teaches us how to make changes to surfaces or molecules that we attempted blindly in the past. And it has been used in so many different scientific studies, from looking at polymers and chemical reactions to modifying surfaces at the atomic level.

CHRISTOPH GERBER: As Gerd explained, seeing is believing, and now we can do that onthe atomic scale. AFM has turned into the most powerful and most versatile toolkit that we have for doing nanoscience. And it keeps evolving. In just the past few years, researchers have learned to pick up a molecule on the tip of an AFM, which we can think of as the needle on a record player, and reveal chemical bonds while imaging molecules on surfaces. Nobody thought that ever would be possible.

TKF: Has this changed how researchers think about the ways nanoscale interactions affect the things they study?

BINNIG: Very much so. Before AFM, people who wanted to model very small structures –molecules, cell walls, semiconductors – had to make indirect measurements of them. But those structures can be complex and disordered, and indirect measurements do not always capture that, so the models they came up with were often wrong. But now, we can look at those structures and adapt our models to match what we observe. We as scientists always have to connect our theories to reality. Atomic force microscopy lets us do this.

TKF: When you started thinking about the AFM, biology was one of the fields you had inmind. Yet even you must have been surprised at how it has revolutionized biology.

GERBER: Yes. AFM’s capabilities keep evolving, and researchers are always finding new ways to use it. For example, in recent years, researchers have made tremendous progress in taking AFM measurements in real time. It’s like watching a movie. They can now see biological interactions, such as how molecules degrade or how antimicrobials attack bacterial membranes as they occur – something nobody could have foreseen 20 years ago. It took 15 years to get there, but we can now see biology in action and compare that to our theories.

BINNIG: Exactly. In biology, the biggest and most important question is always whether a molecule will bind to another molecule, change it, and by changing it cause something important to happen. This is all about forces, and researchers can use AFM to bring two molecules or even two cells close together, or pull them apart, and measure those forces directly. We can learn how big those forces are and under what conditions they occur. We’re actually looking into the heart of biology when we do that.

GERBER: And atomic force microscopy can tell us about many different types of forces that determine the outcome of chemical reactions at the nanoscale. These range from chemical, mechanical and electrostatic through, most recently, to the very weak interactions between molecules.

BINNIG: A great example of this is how Hermann Gaub, a professor of biophysics at Ludwig Maximilians University of Munich, used AFM to unfold proteins. He actually attached one end of a protein to a surface and the other end to an AFM tip. When he pulled the tip up, the protein straightened out and he could create a fingerprint of the unfolding forces that he could compare with his model.

TKF: What about applications you could not have foreseen?

BINNIG: I could not have foreseen that we can image molecules with such a high resolution. It’s unbelievable. We can see the bonds between molecules. We can watch them change during a chemical reaction, and sometimes there are surprises. Some researchers have observed an intermediate state in a chemical reaction that should not have lasted long enough to see. So they have had to rethink their theories to take into account why this intermediate state lasted so long. That’s what happens when we can observe such high-resolution details.

GERBER: Another example is high-speed AFM, which biologists use to see the cellular machinery in action. No other technique can do that. It works by tapping a very, very thin cantilever up and down, taking one quick measurement after another.

BINNIG: It is amazing how many people use the AFM in so many different fields. We first thought, well, maybe biology or semiconductor research. But it was picked up everywhere, from studying friction to cosmetics.

GERBER: I recently looked it up, and AFM was mentioned in 353,000 peer-reviewed papers. Our original article was published in Physical Review Letters, the top journal in the field in which all the important theoretical work is published. Ours is the only experimental paper on its list of most-cited papers.

TKF: Amazing. And yet AFM was actually a follow-up to another technology you worked on, the scanning tunneling microscope, or STM. It was probably the first instrument to achieve nanoscale resolution without using electrons or other high-energy beams that can damage what you are observing, right?


TKF: And where did that idea come from?

BINNIG: We were trying to solve a problem. IBM was working on a new type of semiconductor chip, and the insulator, which keeps the electric current from escaping the semiconductor, was leaking. But no one knew why. So Heinrich Rohrer, who was working at IBM Zurich, hired me. I looked to all the available instruments, and none of them could study materials on such a fine scale to find out.

So the two of us thought, well, okay, we’ll invent something. We thought we could take advantage of something called quantum tunneling. Quantum tunneling is when an electron tunnels through a conducting material and come out the other side. We developed STM to map the surface of the material by measuring where electrons emerged on the other side. Only later did we realize that we could move our probe from one spot to cover the entire surface.

TKF: Dr. Gerber, you quickly became part of the STM team. What convinced you to join?

GERBER: I felt this was such a crazy idea, and I’m always very fond of this sort of thing. I thought this was fantastic.

BINNIG: I can confirm this. Christoph always likes crazy things. That runs through his life.

GERBER: Actually, the development of STM was kind of an undercover project at the beginning, because Gerd and Heinrich were involved in other projects. I worked for a year or so on my own. When we started overcoming problems and we could see features on the surface of a material that were one-tenth of a nanometer, then it really took off.

I leave you to discover the discussion in its entirety: Aug. 20, 2016 discussion.

Synthite and its new ‘nano’ line of intensely coloured natural extracts

Synthite Industries, an Indian firm, has just announced a new line of intensely coloured natural extracts  using a nanotechnology process. There’s a little more detail in an Aug. 25, 2016 news article by Robin Wyers for foodingredientsfirst.com,

Indian extracts company Synthite has introduced a new line of colors derived from a nanotechnology process that offers a much brighter and better hue and therefore requires far lower dosages in use. Vextrano is the result of incessant research and scientific deliberations with an aim to give key characteristics to spices and spice derived products at an elemental level. The purpose of the exercise is multi-faceted with a view to develop an array of novel products that can achieve customized applications in food, beverage, cosmetics and pharmaceutical industries.

Ashish Sharma (…) at Synthite briefly explained the concept to FoodIngredientsFirst: “This is a new product range which we commercialized in the market two months ago. We have bought a new plant for the production of these products. We are deriving this range from natural sources. For red colors we are using chili or paprika. For yellow, turmeric, and for green colors we are using black pepper [piperin]. …

“The key thing,” he notes, “is that when we are reducing the size of the particles to a very small level [to a particle level of 180-200 mesh], the dispersion of the light in any solvent is very good. That’s why you get the hue of the color much better.” In scientific terms, the process of maximizing the various active ingredients in a spice by reducing the size and inter molecular porosity to a feasible and ideal extent, without altering its molecular structure, leads to reduced energy consumption, waste generation and time required to achieve the end result in an application.

Sharma stresses that there are no regulatory issues around the use of this new line.  …

Synthite is just starting to roll the product out into market. …

So far, however, the product is only being sold in India, but it will be exported too, with the next promotion occurring at Fi South America, which is currently taking place in Sao Paolo, Brazil.

Vextrano is positioned as a vision for the future based on value addition to the bio-ingredients from spices. Synthite’s range includes: turmeric, spinach, piperine, marigold, paprika, black pepper, annatto and lutein.

Synthite Industries has a Wikipedia entry (Synthite Industrial Chemicals); Note: Links have been removed),

Synthite Industries Ltd (Synthite) is an Indian oleoresin extraction firm, supplying ingredients to the major food, fragrance and flavour houses. The company is based in Kochi. In 2008, it had 30% of the world’s market share,.[1][2]

The company was established in 1972 with 20 employees. It was founded by C.V. Jacob, who started the company after working in civil construction for two decades. Initially it produced industrial chemicals before shifting to oleoresins.[3] The oleoresin business was initially based on research by the Central Food Technological Research Institute in Mysore. However, the technology developed was not yet mature, and it took several years of additional research and development by Synthite to make the technology viable. It took another four years before they convinced food producers that they could produce quality products on time.[2]

By 2008, it has grown to 450 crore and 1200 employees, with a 2012 goal of 1,000 crore.[1] The company achieved this goal, with a total of 2,000 employees. The company only began selling directly to consumers in its native India in 2014.[4] Some of its major clients include Nestle, Bacardi and Pepsi.[4] The company is currently run by the founder’s son, Viju Jacob.[5]

The company produces oleoresin spices, essential oils, food colors, and sprayed products. It also has products that are organic and fair-trade. The company also has investments in realty and hospitality.[1]

You can find Synthite here but I haven’t found anything about Vextrano on that site. However, there is a LinkedIn account for Vextrano here.

Improving the quality of sight in artificial retinas

Researchers at France’s Centre national de la recherche scientifique (CNRS) and elsewhere have taken a step forward to improving sight derived from artificial retinas according to an Aug. 25, 2016 news item on Nanowerk (Note: A link has been removed),

A major therapeutic challenge, the retinal prostheses that have been under development during the past ten years can enable some blind subjects to perceive light signals, but the image thus restored is still far from being clear. By comparing in rodents the activity of the visual cortex generated artificially by implants against that produced by “natural sight”, scientists from CNRS, CEA [Commissariat à l’énergie atomique et aux énergies alternatives is the French Alternative Energies and Atomic Energy Commission], INSERM [Institut national de la santé et de la recherche médicale is the French National Institute of Health and Medical Research], AP-HM [Assistance Publique – Hôpitaux de Marseille] and Aix-Marseille Université identified two factors that limit the resolution of prostheses.

Based on these findings, they were able to improve the precision of prosthetic activation. These multidisciplinary efforts, published on 23 August 2016 in eLife (“Probing the functional impact of sub-retinal prosthesis”), thus open the way towards further advances in retinal prostheses that will enhance the quality of life of implanted patients.

An Aug. 24, 2015 CNRS press release, which originated the news item, expands on the theme,

A retinal prosthesis comprises three elements: a camera (inserted in the patient’s spectacles), an electronic microcircuit (which transforms data from the camera into an electrical signal) and a matrix of microscopic electrodes (implanted in the eye in contact with the retina). This prosthesis replaces the photoreceptor cells of the retina: like them, it converts visual information into electrical signals which are then transmitted to the brain via the optic nerve. It can treat blindness caused by a degeneration of retinal photoreceptors, on condition that the optical nerve has remained functional1. Equipped with these implants, patients who were totally blind can recover visual perceptions in the form of light spots, or phosphenes.  Unfortunately, at present, the light signals perceived are not clear enough to recognize faces, read or move about independently.

To understand the resolution limits of the image generated by the prosthesis, and to find ways of optimizing the system, the scientists carried out a large-scale experiment on rodents.  By combining their skills in ophthalmology and the physiology of vision, they compared the response of the visual system of rodents to both natural visual stimuli and those generated by the prosthesis.

Their work showed that the prosthesis activated the visual cortex of the rodent in the correct position and at ranges comparable to those obtained under natural conditions.  However, the extent of the activation was much too great, and its shape was much too elongated.  This deformation was due to two separate phenomena observed at the level of the electrode matrix. Firstly, the scientists observed excessive electrical diffusion: the thin layer of liquid situated between the electrode and the retina passively diffused the electrical stimulus to neighboring nerve cells. And secondly, they detected the unwanted activation of retinal fibers situated close to the cells targeted for stimulation.

Armed with these findings, the scientists were able to improve the properties of the interface between the prosthesis and retina, with the help of specialists in interface physics.  Together, they were able to generate less diffuse currents and significantly improve artificial activation, and hence the performance of the prosthesis.

This lengthy study, because of the range of parameters covered (to study the different positions, types and intensities of signals) and the surgical problems encountered (in inserting the implant and recording the images generated in the animal’s brain) has nevertheless opened the way towards making promising improvements to retinal prostheses for humans.

This work was carried out by scientists from the Institut de Neurosciences de la Timone (CNRS/AMU) and AP-HM, in collaboration with CEA-Leti and the Institut de la Vision (CNRS/Inserm/UPMC).

Artificial retinas

© F. Chavane & S. Roux.

Activation (colored circles at the level of the visual cortex) of the visual system by prosthetic stimulation (in the middle, in red, the insert shows an image of an implanted prosthesis) is greater and more elongated than the activation achieved under natural stimulation (on the left, in yellow). Using a protocol to adapt stimulation (on the right, in green), the size and shape of the activation can be controlled and are more similar to natural visual activation (yellow).

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

Probing the functional impact of sub-retinal prosthesis by Sébastien Roux, Frédéric Matonti, Florent Dupont, Louis Hoffart, Sylvain Takerkart, Serge Picaud, Pascale Pham, and Frédéric Chavane. eLife 2016;5:e12687 DOI: http://dx.doi.org/10.7554/eLife.12687 Published August 23, 2016

This paper appears to be open access.

Nanoavalanches in glass

An Aug. 24, 2016 news item on Nanowerk takes a rather roundabout way to describe some new findings about glass (Note: A link has been removed),

The main purpose of McLaren’s exchange study in Marburg was to learn more about a complex process involving transformations in glass that occur under intense electrical and thermal conditions. New understanding of these mechanisms could lead the way to more energy-efficient glass manufacturing, and even glass supercapacitors that leapfrog the performance of batteries now used for electric cars and solar energy.

“This technology is relevant to companies seeking the next wave of portable, reliable energy,” said Himanshu Jain, McLaren’s advisor and the T. L. Diamond Distinguished Chair in Materials Science and Engineering at Lehigh and director of its International Materials Institute for New Functionality in Glass. “A breakthrough in the use of glass for power storage could unleash a torrent of innovation in the transportation and energy sectors, and even support efforts to curb global warming.”

As part of his doctoral research, McLaren discovered that applying a direct current field across glass reduced its melting temperature. In their experiments, they placed a block of glass between a cathode and anode, and then exerted steady pressure on the glass while gradually heating it. McLaren and Jain, together with colleagues at the University of Colorado, published their discovery in Applied Physics Letters (“Electric field-induced softening of alkali silicate glasses”).

The implications for the finding were intriguing. In addition to making glass formulation viable at lower temperatures and reducing energy needs, designers using electrical current in glass manufacturing would have a tool to make precise manipulations not possible with heat alone.

“You could make a mask for the glass, for example, and apply an electrical field on a micron scale,” said Jain. “This would allow you to deform the glass with high precision, and soften it in a far more selective way than you could with heat, which gets distributed throughout the glass.”

Though McLaren and Jain had isolated the phenomenon and determined how to dial up the variables for optimal results, they did not yet fully understand the mechanisms behind it. McLaren and Jain had been following the work of Dr. Bernard Roling at the University of Marburg, who had discovered some remarkable characteristics of glass using electro-thermal poling, a technique that employs both temperature manipulation and electrical current to create a charge in normally inert glass. The process imparts useful optical and even bioactive qualities to glass.

Roling invited McLaren to spend a semester at Marburg to analyze the behavior of glass under electro-thermal poling, to see if it would reveal more about the fundamental science underlying what McLaren and Jain had observed in their Lehigh lab.

An Aug. 22, 2016 Lehigh University news release by Chris Quirk, which originated the news item, describes the latest work,

McLaren’s work in Marburg revealed a two-step process in which a thin sliver of the glass nearest the anode, called a depletion layer, becomes much more resistant to electrical current than the rest of the glass as alkali ions in the glass migrate away. This is followed by a catastrophic change in the layer, known as dielectric breakdown, which dramatically increases its conductivity. McLaren likens the process of dielectric breakdown to a high-speed avalanche, and uses spectroscopic analysis with electro-thermal poling as a way to see what is happening in slow motion.

“The results in Germany gave us a very good model for what is going on in the electric field-induced softening that we did here. It told us about the start conditions for where dielectric breakdown can begin,” said McLaren.

“Charlie’s work in Marburg has helped us see the kinetics of the process,” Jain said. “We could see it happening abruptly in our experiments here at Lehigh, but we now have a way to separate out what occurs specifically with the depletion layer.”

“The Marburg trip was incredibly useful professionally and enlightening personally,” said McLaren. “Scientifically, it’s always good to see your work from another vantage point, and see how other research groups interpret data or perform experiments. The group in Marburg was extremely hard-working, which I loved, and they were very supportive of each other. If someone submitted a paper, the whole group would have a barbecue to celebrate, and they always gave each other feedback on their work. Sometimes it was brutally honest––they didn’t hold back––but they were things you needed to hear.”

“Working in Marburg also showed me how to interact with a completely different group of people. “You see differences in your own culture best when you have the chance to see other cultures close up. It’s always a fresh perspective.”

Here are links and citations for both the papers mentioned. The first link is for the most recent paper and second link is for the earlier work,

Depletion Layer Formation in Alkali Silicate Glasses by
Electro-Thermal Poling by C. McLaren, M. Balabajew, M. Gellert, B. Roling, and H. Jain. Journal of The Electrochemical Society, 163 (9) H809-H817 (2016) H809 DOI: 10.1149/2.0881609jes Published July 19, 2016

Electric field-induced softening of alkali silicate glasses by C. McLaren, W. Heffner, R. Tessarollo, R. Raj, and H. Jain. Appl. Phys. Lett. 107, 184101 (2015); http://dx.doi.org/10.1063/1.4934945 Published online 03 November 2015

The most recent paper (first link) appears to be open access; the earlier paper (second link) is behind a paywall.

Nanotubes tunnel between neurons in Parkinson’s disease

An Aug. 22, 2016 news item on ScienceDaily describes how scientists from the Institut Pasteur (France) have developed insight into one of the processes in Parkinson’s disease,

Scientists have demonstrated the role of lysosomal vesicles in transporting alpha-synuclein aggregates, responsible for Parkinson’s and other neurodegenerative diseases, between neurons. These proteins move from one neuron to the next in lysosomal vesicles which travel along the ‘tunneling nanotubes’ between cells.

An Aug. 22, 2016 Institut Pasteur press release (also on EurekAlert), expands on the theme,

Synucleinopathies, a group of neurodegenerative diseases including Parkinson’s disease, are characterized by the pathological deposition of aggregates of the misfolded α-synuclein protein into inclusions throughout the central and peripheral nervous system. Intercellular propagation (from one neuron to the next) of α-synuclein aggregates contributes to the progression of the neuropathology, but little was known about the mechanism by which spread occurs.

In this study, scientists from the Membrane Traffic and Pathogenesis Unit, directed by Chiara Zurzolo at the Institut Pasteur, used fluorescence microscopy to demonstrate that pathogenic α-synuclein fibrils travel between neurons in culture, inside lysosomal vesicles through tunneling nanotubes (TNTs), a new mechanism of intercellular communication.

After being transferred via TNTs, α-synuclein fibrils are able to recruit and induce aggregation of the soluble α-synuclein protein in the cytosol of cells receiving the fibrils, thus explaining the propagation of the disease. The scientists propose that cells overloaded with α-synuclein aggregates in lysosomes dispose of this material by hijacking TNT-mediated intercellular trafficking. However, this results in the disease being spread to naive neurons.

This study demonstrates that TNTs play a significant part in the intercellular transfer of α-synuclein fibrils and reveals the specific role of lysosomes in this process. This represents a major breakthrough in understanding the mechanisms underlying the progression of synucleinopathies.

These compelling findings, together with previous reports from the same team, point to the general role of TNTs in the propagation of prion-like proteins in neurodegenerative diseases and identify TNTs as a new therapeutic target to combat the progression of these incurable diseases.

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

Tunneling nanotubes spread fibrillar α‐synuclein by intercellular trafficking of lysosomes by Saïda Abounit, Luc Bousset, Frida Loria, Seng Zhu, Fabrice de Chaumont, Laura Pieri, Jean-Christophe Olivo-Marin, Ronald Melki, Chiara Zurzolo. The EMBO Journal (2016) e201593411 DOI 10.15252/embj.201593411 Published online 22.08.2016

This paper is behind a paywall.

Making magnetic rust behave like gold and the nanoscale

Researchers at the University of Georgia (US) have found a way to combine gold nanoparticles with magnetic rust nanoparticles for a hybrid structure that behaves with the properties of both types of nanoparticles. From a Sept. 15, 2016 news item on ScienceDaily,

Researchers from the University of Georgia are giving new meaning to the phrase “turning rust into gold”—and making the use of gold in research settings and industrial applications far more affordable.

The research is akin to a type of modern-day alchemy, said Simona Hunyadi Murph, adjunct professor in the UGA Franklin College of Arts and Sciences department of physics and astronomy. Researchers combine small amounts of gold nanoparticles with magnetic rust nanoparticles to create a hybrid nanostructure that retains both the properties of gold and rust.

A Sept. 15, 2016 University of Georgia news release by Jessica Luton, which originated the news item, expands on the theme,

“Medieval alchemists tried to create gold from other metals,” she said. “That’s kind of what we did with our research. It’s not real alchemy, in the medieval sense, but it is a sort of 21st century version.”

Gold has long been a valuable resource for industry, medicine, dentistry, computers, electronics and aerospace, among others, due to unique physical and chemical properties that make it inert and resistant to oxidation. But because of its high cost and limited supply, large scale projects using gold can be prohibitive. At the nanoscale, however, using a very small amount of gold is far more affordable.

In the new study published this summer in the Journal of Physical Chemistry C, the researchers used solution chemistry to reduce gold ions into a metallic gold structure using sodium citrate. In this process, if other ingredients-rust in this case-are present in the reaction pot during the transformation process, the metallic gold structures nucleate and grow on these “ingredients,” otherwise known as supports.

“We are really excited to share our new discoveries. When researchers are looking at gold as a potential material for research, we talk about how expensive gold is. For the first time ever, we’ve been able to create a new class of cheaper, highly efficient, nontoxic, magnetically reusable hybrid nanomaterials that contain a far more abundant material-rust-than the typical noble metal gold,” said Murph, who is also a principal scientist in the National Security Directorate at the Savannah River National Laboratory in Aiken, South Carolina.

When materials are broken down in size to reach nanometer scale dimensions-1-100 nanometers, which is approximately 100,000 times smaller than the diameter of human hair-these substances can take on new properties. For example, bulk gold does not display catalytic properties; however, at the nanoscale, gold is an efficient catalyst, accelerating chemical change for many reactions including oxidation, hydrogen production or reduction of aromatic nitro compounds.

Gold nanoparticles of different sizes and shapes display different colors when impinged by light because they absorb and scatter light at specific wavelengths, known as plasmonic resonances. These plasmonic resonances are of particular interest for biological applications. If someone shines light on the gold nanoparticles, the absorbed light can be converted to heat in the surrounding media, and if bacteria or cancerous cells are in the vicinity of such gold nanoparticles, they can be destroyed by using light of appropriate wavelength. This phenomenon is known as photothermal therapy.

By replacing some of the nano-gold with magnetic nano-rust, researchers show that the hybrid gold and rust nanostructures are able to photothermally heat the surrounding media as efficiently as pure gold nanoparticles, even with a significantly smaller concentration of gold.

“In a way, we’ve done a little better than alchemy,” said George Larsen, co-investigator and postdoctoral researcher in the Group for Innovation and Advancements in Nano-Technology Sciences at the Savannah River National Laboratory, “because these new hybrid nanoparticles not only behave better than gold in some cases, but also have magnetic functionality.”

Murph and her team looked at three different shapes of hybrid nanoparticles in this research-spheres, rings and tubes.

“A differently shaped nanoparticle means that the atoms are arranged differently-into cubes, hexagons or triangles, for example,” she said. “A different atom arrangement means different packing densities, spacing between atoms, defects, surface area and surface energies. Different shapes lead to an increased atom area that is exposed to catalyze a chemical reaction. Scientifically speaking, different shape means different crystallographic facets and surface energy that could lead to higher catalytic activity and different catalytic products.

“The results of our research showed that the ring- and tube-shaped hybrid nanoparticles proved to be better catalytic materials than the sphere-shaped nanoparticles because of the way the atoms are arranged in the structure at this nanoscale. More importantly, the hybrid nanoparticles of gold and rust are better catalysts than gold nanoparticles alone, even with a significantly smaller amount of gold.

When these different shaped hybrid nanoparticles were exposed to light of specific wavelength, the spheres heated the solution up to slightly higher temperatures than the ring- or tube-shaped nanoparticles.

“This could have a variety of biological applications such as tracking, drug delivery or imaging inside the body,” Murph said. “If you feed these gold nanoparticles to bacteria and shine the light on them, you could destroy these by just using light.”

The hybrid structures could also be used for new application [sic], such as sensing, hyperthermia treatment, environmental cleaning and protection medical imaging applications including magnetic resonance imaging contrast agents, product detection and manipulation.

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

Multifunctional Hybrid Fe2O3-Au Nanoparticles for Efficient Plasmonic Heating by Simona E. Hunyadi Murph, George K. Larsen, Robert J. Lascola. Journal of Visualized Experiments, 2016; (108) DOI: 10.3791/53598

This paper/video appears to be open access.

Doing math in a test tube using analog DNA

Basically, scientists at Duke University (US) have created an analog computer at the nanoscale, which can perform basic arithmetic. From an Aug. 23, 2016 news item on ScienceDaily,

Often described as the blueprint of life, DNA contains the instructions for making every living thing from a human to a house fly.

But in recent decades, some researchers have been putting the letters of the genetic code to a different use: making tiny nanoscale computers.

In a new study, a Duke University team led by professor John Reif created strands of synthetic DNA that, when mixed together in a test tube in the right concentrations, form an analog circuit that can add, subtract and multiply as they form and break bonds.

Rather than voltage, DNA circuits use the concentrations of specific DNA strands as signals.

An Aug. 23, 2016 Duke University news release (also on EurekAlert), which originated the news item, describes how most DNA-based circuits operate and what makes the one from Duke different,

Other teams have designed DNA-based circuits that can solve problems ranging from calculating square roots to playing tic-tac-toe. But most DNA circuits are digital, where information is encoded as a sequence of zeroes and ones.

Instead, the new Duke device performs calculations in an analog fashion by measuring the varying concentrations of specific DNA molecules directly, without requiring special circuitry to convert them to zeroes and ones first.

Unlike the silicon-based circuits used in most modern day electronics, commercial applications of DNA circuits are still a long way off, Reif said.

For one, the test tube calculations are slow. It can take hours to get an answer.

“We can do some limited computing, but we can’t even begin to think of competing with modern-day PCs or other conventional computing devices,” Reif said.

But DNA circuits can be far tinier than those made of silicon. And unlike electronic circuits, DNA circuits work in wet environments, which might make them useful for computing inside the bloodstream or the soupy, cramped quarters of the cell.

The technology takes advantage of DNA’s natural ability to zip and unzip to perform computations. Just like Velcro and magnets have complementary hooks or poles, the nucleotide bases of DNA pair up and bind in a predictable way.

The researchers first create short pieces of synthetic DNA, some single-stranded and some double-stranded with single-stranded ends, and mix them in a test tube.

When a single strand encounters a perfect match at the end of one of the partially double-stranded ones, it latches on and binds, displacing the previously bound strand and causing it to detach, like someone cutting in on a dancing couple.

The newly released strand can in turn pair up with other complementary DNA molecules downstream in the circuit, creating a domino effect.

The researchers solve math problems by measuring the concentrations of specific outgoing strands as the reaction reaches equilibrium.

To see how their circuit would perform over time as the reactions proceeded, Reif and Duke graduate student Tianqi Song used computer software to simulate the reactions over a range of input concentrations. They have also been testing the circuit experimentally in the lab.

Besides addition, subtraction and multiplication, the researchers are also designing more sophisticated analog DNA circuits that can do a wider range of calculations, such as logarithms and exponentials.

Conventional computers went digital decades ago. But for DNA computing, the analog approach has its advantages, the researchers say. For one, analog DNA circuits require fewer strands of DNA than digital ones, Song said.

Analog circuits are also better suited for sensing signals that don’t lend themselves to simple on-off, all-or-none values, such as vital signs and other physiological measurements involved in diagnosing and treating disease.

The hope is that, in the distant future, such devices could be programmed to sense whether particular blood chemicals lie inside or outside the range of values considered normal, and release a specific DNA or RNA — DNA’s chemical cousin — that has a drug-like effect.

Reif’s lab is also beginning to work on DNA-based devices that could detect molecular signatures of particular types of cancer cells, and release substances that spur the immune system to fight back.

“Even very simple DNA computing could still have huge impacts in medicine or science,” Reif said.

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

Analog Computation by DNA Strand Displacement Circuits by Tianqi Song, Sudhanshu Garg, Reem Mokhtar, Hieu Bui, and John Reif. ACS Synth. Biol., 2016, 5 (8), pp 898–912 DOI: 10.1021/acssynbio.6b00144 Publication Date (Web): July 01, 2016

Copyright © 2016 American Chemical Society

This paper is behind a paywall.

Creating quantum dots (artificial atoms) in graphene

An Aug. 22, 2016 news item on phys.org describes some recent work on artificial atoms and graphene from the Technical University of Vienna (Austria) and partners in Germany and the UK,

In a tiny quantum prison, electrons behave quite differently as compared to their counterparts in free space. They can only occupy discrete energy levels, much like the electrons in an atom – for this reason, such electron prisons are often called “artificial atoms”. Artificial atoms may also feature properties beyond those of conventional ones, with the potential for many applications for example in quantum computing. Such additional properties have now been shown for artificial atoms in the carbon material graphene. The results have been published in the journal Nano Letters, the project was a collaboration of scientists from TU Wien (Vienna, Austria), RWTH Aachen (Germany) and the University of Manchester (GB).

“Artificial atoms open up new, exciting possibilities, because we can directly tune their properties”, says Professor Joachim Burgdörfer (TU Wien, Vienna). In semiconductor materials such as gallium arsenide, trapping electrons in tiny confinements has already been shown to be possible. These structures are often referred to as “quantum dots”. Just like in an atom, where the electrons can only circle the nucleus on certain orbits, electrons in these quantum dots are forced into discrete quantum states.

Even more interesting possibilities are opened up by using graphene, a material consisting of a single layer of carbon atoms, which has attracted a lot of attention in the last few years. “In most materials, electrons may occupy two different quantum states at a given energy. The high symmetry of the graphene lattice allows for four different quantum states. This opens up new pathways for quantum information processing and storage” explains Florian Libisch from TU Wien. However, creating well-controlled artificial atoms in graphene turned out to be extremely challenging.

Florian Libisch, explaining the structure of graphene. Courtesy Technical University of Vienna

Florian Libisch, explaining the structure of graphene. Courtesy Technical University of Vienna

An Aug. 22, 2016 Technical University of Vienna press release (also on EurekAlert), which originated the news item, provides more detail,

There are different ways of creating artificial atoms: The simplest one is putting electrons into tiny flakes, cut out of a thin layer of the material. While this works for graphene, the symmetry of the material is broken by the edges of the flake which can never be perfectly smooth. Consequently, the special four-fold multiplicity of states in graphene is reduced to the conventional two-fold one.

Therefore, different ways had to be found: It is not necessary to use small graphene flakes to capture electrons. Using clever combinations of electrical and magnetic fields is a much better option. With the tip of a scanning tunnelling microscope, an electric field can be applied locally. That way, a tiny region is created within the graphene surface, in which low energy electrons can be trapped. At the same time, the electrons are forced into tiny circular orbits by applying a magnetic field. “If we would only use an electric field, quantum effects allow the electrons to quickly leave the trap” explains Libisch.

The artificial atoms were measured at the RWTH Aachen by Nils Freitag and Peter Nemes-Incze in the group of Professor Markus Morgenstern. Simulations and theoretical models were developed at TU Wien (Vienna) by Larisa Chizhova, Florian Libisch and Joachim Burgdörfer. The exceptionally clean graphene sample came from the team around Andre Geim and Kostya Novoselov from Manchester (GB) – these two researchers were awarded the Nobel Prize in 2010 for creating graphene sheets for the first time.

The new artificial atoms now open up new possibilities for many quantum technological experiments: “Four localized electron states with the same energy allow for switching between different quantum states to store information”, says Joachim Burgdörfer. The electrons can preserve arbitrary superpositions for a long time, ideal properties for quantum computers. In addition, the new method has the big advantage of scalability: it should be possible to fit many such artificial atoms on a small chip in order to use them for quantum information applications.

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

Electrostatically Confined Monolayer Graphene Quantum Dots with Orbital and Valley Splittings by Nils M. Freitag, Larisa A. Chizhova, Peter Nemes-Incze, Colin R. Woods, Roman V. Gorbachev, Yang Cao, Andre K. Geim, Kostya S. Novoselov, Joachim Burgdörfer, Florian Libisch, and Markus Morgenstern. Nano Lett., Article ASAP DOI: 10.1021/acs.nanolett.6b02548 Publication Date (Web): July 28, 2016

Copyright © 2016 American Chemical Society

This paper is behind a paywall.

Dexter Johnson in an Aug. 23, 2016 post on his Nanoclast blog (on the IEEE [Institute of Electrical and Electronics Engineers] website) provides some additional insight into the world of quantum dots,

Quantum dots made from semiconductor materials, like silicon, are beginning to transform the display market. While it is their optoelectronic properties that are being leveraged in displays, the peculiar property of quantum dots that allows their electrons to be forced into discrete quantum states has long held out the promise of enabling quantum computing.

If you have time to read it, Dexter’s post features an email interview with Florian Libisch where they further discuss quantum dots and quantum computing.

Canada’s Ingenuity Lab receives a $1.7M grant to develop oil recovery system for oil spills

A Sept. 15, 2016 news item on Benzinga.com describes the reasons for the $1.7M grant for Alberta’s (Canada) Ingenuity Lab to develop an oil spill recovery system,

Since 2010’s tragic events, which saw BP’s Deepwater Horizon disaster desecrate the Gulf of Mexico, oil safety has been on the forefront of the environmental debate and media outrage. In line with the mounting concerns continuing to pique public attention, at the end of this month [Sept. 2016], Hollywood will release its own biopic of the event. As can be expected, more questions will be raised about what exactly went wrong, in addition to fresh criticism aimed at the entire industry.

One question that is likely to emerge is how do we prevent such a calamity from ever happening again? Fortunately, some of the brightest minds in science have been preparing for such an answer.

One team that has been focusing on this dilemma is Alberta-based, multi-disciplinary research initiative Ingenuity Lab. The institution has just secured $1.7m in project funding for developing a highly advanced system for recovering oil from oil spills. This injection of capital will enable Ingenuity Lab to conduct new research and develop commercial production processes for recovering heavy oil spills in marine environments. The technology is centred on cutting edge nanowire-based stimuli-responsive membranes and devices that are capable for recovering oil.

A Sept. 15, 2016 Ingenuity Lab news release on MarketWired, which originated the news item, provides more insight into the oil spill situation,

Oil is a common pollutant in our oceans; more than three million metric tonnes contaminate the sea each year. When crude oil is accidentally released into a body of water by an oil tanker, refinery, storage facility, underwater pipeline or offshore oil-drilling rig, it is an environmental emergency of the most urgent kind.

Depending on the location, oil spills can be highly hazardous, as well as environmentally destructive. Consequently, a timely clean up is absolutely crucial in order to protect the integrity of the water, the shoreline and the numerous creatures that depend on these habitats.

Due to increased scrutiny of the oil industry with regard to its unseemly environmental track record, attention must be focused on the development of new materials and technologies for removing organic contaminants from waterways. Simply put, existing methods are not sufficiently robust.

Fortuitously, however, nanotechnology has opened the door for the development of sophisticated new tools that use specifically designed materials with properties that are ideally suited to enable complex separations, including the separation of crude oil from water.

Ingenuity Lab’s project focuses on the efficient recovery of oil through the development of this novel technology using a variety of stimuli-responsive nanomaterials. When the time comes for scale up production for this technology, Ingenuity Lab will work closely with industry trendsetters, Tortech Nanofibers.

This project forms a strong element of the Oil Spill Response Science (OSRS), which is part of Canada’s world-class tanker safety system for Responsible Resource Development. Through this programme, the Canadian Government ensures that the country’s resource wealth can be safely developed and transported to market, thus creating new jobs and economic growth for all Canadians.

From a communications standpoint, the news release is well written and well strategized to underline the seriousness of the situation and to take advantage of renewed interest in the devastating (people’s lives were lost and environmental damage is still being assessed) 2010 BP oil spill in the Gulf of Mexico due to the upcoming movie titled, Deepwater Horizon. A little more information about the team (how many people, who’s leading the research, are there international and/or interprovincial collaborators?), plans for the research (have they already started? what work, if any, are they building on? what challenges are they facing?) and some technical details would have been welcome.

Regardless, it’s good to hear about this initiative and I wish them great success with it.

You can find our more about Ingenuity Lab here and Tortech Nanofibers here. Interestingly, Tortech is a joint venture between Israel’s Plasan Sasa and the UK’s Q-Flo. (Q-Flo is a spinoff from Cambridge University.) One more thing, Tortech Nanofibers produces materials made of carbon nanotubes (CNTs). Presumably Ingenuity’s “nanowire-based stimuli-responsive membranes” include carbon nanotubes.