Nano News: February 2015

European Food Safety Authority publishes risk assessment of nanotechnologies in food and feed

In accordance with European Food Safety Authority (EFSA)’s strategy for cooperation and networking with Member States, a Network for Risk Assessment of Nanotechnologies in Food and Feed was established in 2010. The overall goals of this Network are to facilitate harmonisation of assessment practices and methodologies; to enhance exchange of information and data between EFSA and MS; and to achieve synergies in risk assessment activities. The Annual reports of the Network inform the public and the EFSA Advisory Forum about its specific activities and achievements. During 2014, the Network followed-up on its priority areas and contributed to the making of inventory lists of applications of Nanomaterials already present in the food/feed chain ("Annual report of the EFSA Scientific Network of Risk Assessment of Nanotechnologies in Food and Feed for 2014"; pdf). During its meeting in 2014, the Network dedicated most of its discussions on relevant research results for possible toxic effects following the oral route of exposure. The Network exchanged views on the technical aspects and implications of the definition for Nanomaterial. The network also shared its views on the ongoing and upcoming risk assessments of EFSA on applications comprising implicitly or explicitly nanoforms. The Network updated its list with national research and contact details of national laboratories that can analyse nanomaterials in complex matrices. Summary Developing networking and stronger co-operation with the Member States and strengthening EFSA’s relationship with its institutional partners (EU and international) and stakeholders are among the key recommendations formulated by EFSA’s Management Board. In accordance with EFSA’s strategy for co-operation and networking with Member States, the Scientific Network for Risk Assessment of Nanotechnologies in Food and Feed (hereafter referred to as ‘Nano Network’) was launched. The Nano Network had its inaugural meeting in February 2011 and following this, one meeting per year is scheduled. The overall goals of the Nano Network are to provide a forum for dialogue among participants; build mutual understanding of risk assessment principles; enhance knowledge on and confidence in the scientific assessments carried out in EU; and to provide increased transparency in the current process among Member States and EFSA on nanotechnology. All this with the aim to raise the level of harmonisation of the risk assessments developed in the EU on nanotechnology. The Network is composed of representatives from 21 Member States and Norway.In addition, observers to this Network represent the Former Yugoslav Republic of Macedonia, Turkey and Montenegro. There is also representation from the European Commission (DGSANTE and JRC), from the EFSA Scientific Committee and the relevant Units/Panels. During 2014, the Network followed-up on its priority areas and contributed to the making of inventory lists of applications of Nanomaterials already present in the food/feed chain. At its 2014 meeting the Network focussed again on updates of research results from toxicological studies relevant for the oral route of exposure. Member States representatives presented relevant studies. The type of nanomaterials that are now occurring in the food/feed chain are mainly Titaniumdioxide (TiO2) and Synthetic Amorphous Silica (SAS). The evidence bases for oral toxicity and for conducting comprehensive risk assessments of these two materials is building up, but more research remains needed. Challenges to draw firm risk assessment conclusions reside in (1) the intake estimation (2) the possible worst-case absorption and the dose-dependence of absorption (3) the potential irrelevance of high dose oral toxicity studies for risk assessment (4) the extrapolation of kinetic data from rat to man (5) the nanoparticle determination in tissues, and (6) the many differences between the types of nanoforms of one nanomaterial (e.g. in kinetics and toxicity). Some differences in behaviour of different nanoforms have been observed, but there is no clear overview. A new issue of concern is that absorption is not linear with dose: high dose studies are often used for tox testing for estimation of safe dose, while the high dose may result in aggregation, agglomeration, gelation and as a consequence dose-dependent absorption. Challenges also remain to exist regarding the technical aspects for considering a material as a nanomaterial (NM) for the regulatory purpose of food labelling. The NanoDefine project (FP7) is expected to deliver by 2017 an implementable test-scheme for regulatory purposes to distinguish nano from non-nano. The Network agreed that regardless the current challenges and regardless the % of nanoforms in the bulk material (particle size% or mass%), EFSA should assess the nano-fraction, no matter how small. Food law, as being implemented by the EFSA Panels is covering nanomaterials. Nanomaterials are addressed mainly by cross-referring to the Guidance on the risk assessment of the application of nanoscience and nanotechnologies in the food and feed chain (EFSA Scientific Committee, 2011; pdf). The Network also updated its list with contact details of national laboratories that have equipment and know-how for analysing certain nanomaterials in complex matrices.

European Food Safety Authority publishes risk assessment of nanotechnologies in food and feed

Ordered nanostructures from benzene could pave the way for novel nanotechnology applications

A way to link benzene rings together in a highly ordered three-dimensional helical structure using a straightforward polymerization procedure has been discovered by researchers from RIKEN Center for Sustainable Resource Science and the University of Tokyo ("Aryne Polymerization Enabling Straightforward Synthesis of Elusive Poly(ortho-arylene)s"). “We expect our achievement to open up new areas of nanocarbon and materials science,” says Koichiro Mikami from the research team.

Figure 1: Aryne (Ar) is reacted using a copper catalyst (Cu(I)) to assemble an ordered helical structure. (Image: K. Mikami, RIKEN Center for Sustainable Resource Science) Benzene (C6H6) is the simplest of the wide range of ‘aromatic’ compounds, which have rings of carbon atoms surrounded by ‘delocalized’ electrons that circulate around the molecules. A long-standing challenge for chemists has been the development of a straightforward way to link rings of benzene together in a regular manner such that the carbon atoms are bonded directly to their neighbors in adjacent rings to form a structured material. Masanobu Uchiyama from RIKEN and the University of Tokyo and his colleagues Mikami and Yoshihide Mizukoshi developed their linking procedure starting with the molecule aryne, which is very similar to benzene but has a triple bond between two adjacent carbon atoms in the ring (Fig. 1). After investigating many different combinations of chemicals and solvents, the researchers found a procedure involving copper ions that reliably links the rings together at the ortho position by a self-propagating polymerization reaction. The product, called poly(ortho-phenylene), is the simplest member of wide range of possible poly(ortho-arylene)s that could carry a selection of different atoms or chemical groups in place of one or more of the hydrogen atoms on the benzene-derived rings. The researchers found that their poly(ortho-phenylene) molecules have a regular and highly ordered three-dimensional structure consisting of stacked six-carbon rings. Such highly ordered materials are precisely the kinds of chemical building blocks that might be put to good use as components for nanotechnology. Having made this crucial breakthrough, the researchers’ next steps will be to explore the size and variety of structures that can be assembled by their technique. The team has so far managed to link approximately 100 rings together, but plans to extend this further and to control chain lengths and physical characteristics. “We are exploring the electrical, photodynamic and thermal properties of these poly(ortho-phenylene)s toward creating novel electronic devices and liquid crystals,” explains Mikami. In addition to providing scaffolding structures, nanocompounds become most interesting when they can respond to light, electric fields or the presence of other chemicals in precise and useful ways. Mikami says the team is also looking at forming chemical cross-links between individual helical chains, extending the fabrication possibilities to another dimension.

New research signals big future for quantum radar

A prototype quantum radar that has the potential to detect objects which are invisible to conventional systems has been developed by an international research team led by a quantum information scientist at the University of York. The new breed of radar is a hybrid system that uses quantum correlation between microwave and optical beams to detect objects of low reflectivity such as cancer cells or aircraft with a stealth capability. Because the quantum radar operates at much lower energies than conventional systems, it has the long-term potential for a range of applications in biomedicine including non-invasive NMR scans.

The research team led by Dr Stefano Pirandola, of the University's Department of Computer Science and the York Centre for Quantum Technologies, found that a special converter - a double-cavity device that couples the microwave beam to an optical beam using a nano-mechanical oscillator - was the key to the new system. The device can either generate microwave-optical entanglement (during the signal emission) or convert a microwave into an optical beam (during the collection of the reflection beams from the object). The research is published in ("Microwave Quantum Illumination"). A conventional radar antenna emits a microwave to scan a region of space. Any target object would reflect the signal to the source but objects of low reflectivity immersed in regions with high background noise are difficult to spot using classical radar systems. In contrast, quantum radars operate more effectively and exploit quantum entanglement to enhance their sensitivity to detect small signal reflections from very noisy regions. Dr Pirandola said that while quantum radars were some way off, they would have superior performance especially at the low-photon regime. "Such a non-invasive property is particularly important for short-range biomedical applications. In the long-term, the scheme could be operated at short distances to detect the presence of defects in biological samples or human tissues in a completely non-invasive fashion, thanks to the use of a low number of quantum-correlated photons. "Our method could be used to develop non-invasive NMR spectroscopy of fragile proteins and nucleic acids. In medicine, these techniques could potentially be applied to magnetic resonance imaging, with the aim of reducing the radiation dose absorbed by patients."

Optical features embedded in marine shells may help develop responsive, transparent displays (w/video)

The blue-rayed limpet is a tiny mollusk that lives in kelp beds along the coasts of Norway, Iceland, the United Kingdom, Portugal, and the Canary Islands. These diminutive organisms — as small as a fingernail — might escape notice entirely, if not for a very conspicuous feature: bright blue dotted lines that run in parallel along the length of their translucent shells. Depending on the angle at which light hits, a limpet’s shell can flash brilliantly even in murky water. Now scientists at MIT and Harvard University have identified two optical structures within the limpet’s shell that give its blue-striped appearance. The structures are configured to reflect blue light while absorbing all other wavelengths of incoming light. The researchers speculate that such patterning may have evolved to protect the limpet, as the blue lines resemble the color displays on the shells of more poisonous soft-bodied snails.

Scientists at MIT and Harvard University have identified two optical structures within the blue-rayed limpet’s shell that give its blue-striped appearance. (Image: Courtesy of the researchers) The findings, reported this week in the journal ("A highly conspicuous mineralized composite photonic architecture in the translucent shell of the blue-rayed limpet"), represent the first evidence of an organism using mineralized structural components to produce optical displays. While birds, butterflies, and beetles can display brilliant blues, among other colors, they do so with organic structures, such as feathers, scales, and plates. The limpet, by contrast, produces its blue stripes through an interplay of inorganic, mineral structures, arranged in such a way as to reflect only blue light. The researchers say such natural optical structures may serve as a design guide for engineering color-selective, controllable, transparent displays that require no internal light source and could be incorporated into windows and glasses. “Let’s imagine a window surface in a car where you obviously want to see the outside world as you’re driving, but where you also can overlay the real world with an augmented reality that could involve projecting a map and other useful information on the world that exists on the other side of the windshield,” says co-author Mathias Kolle, an assistant professor of mechanical engineering at MIT. “We believe that the limpet’s approach to displaying color patterns in a translucent shell could serve as a starting point for developing such displays.” Optical structures and photonic materials Kolle, whose research is focused on engineering bioinspired, optical materials — including color-changing, deformable fibers — started looking into the optical features of the limpet when his brother Stefan, a marine biologist now working at Harvard, brought Kolle a few of the organisms in a small container. Stefan Kolle was struck by the mollusk’s brilliant patterning, and recruited his brother, along with several others, to delve deeper into the limpet shell’s optical properties. To do this, the team of researchers — which also included Ling Li and Christine Ortiz at MIT and James Weaver and Joanna Aizenberg at Harvard — performed a detailed structural and optical analysis of the limpet shells. They observed that the blue stripes first appear in juveniles, resembling dashed lines. The stripes grow more continuous as a limpet matures, and their shade varies from individual to individual, ranging from deep blue to turquoise. The researchers scanned the surface of a limpet’s shell using scanning electron microscopy, and found no structural differences in areas with and without the stripes — an observation that led them to think that perhaps the stripes arose from features embedded deeper in the shell. To get a picture of what lay beneath, the researchers used a combination of high-resolution 2-D and 3-D structural analysis to reveal the 3-D nanoarchitecture of the photonic structures embedded in the limpets’ translucent shells. What they found was revealing: In the regions with blue stripes, the shells’ top and bottom layers were relatively uniform, with dense stacks of calcium carbonate platelets and thin organic layers, similar to the shell structure of other mollusks. However, about 30 microns beneath the shell surface the researchers noted a stark difference. In these regions, the researchers found that the regular plates of calcium carbonate morphed into two distinct structural features: a multilayered structure with regular spacing between calcium carbonate layers resembling a zigzag pattern, and beneath this, a layer of randomly dispersed, spherical particles. The researchers measured the dimensions of the zigzagging plates, and found the spacing between them was much wider than the more uniform plates running through the shell’s unstriped sections. They then examined the potential optical roles of both the multilayer zigzagging structure and the spherical particles.

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Kolle and his colleagues used optical microscopy, spectroscopy, and diffraction microscopy to quantify the blue stripe’s light-reflection properties. They then measured the zigzagging structures and their angle with respect to the shell surface, and determined that this structure is optimized to reflect blue and green light. The researchers also determined that the disordered arrangement of spherical particles beneath the zigzag structures serves to absorb transmitted light that otherwise could de-saturate the reflected blue color. From these results, Kolle and his team deduced that the zigzag pattern acts as a filter, reflecting only blue light. As the rest of the incoming light passes through the shell, the underlying particles absorb this light — an effect that makes a shell’s stripes appear even more brilliantly blue. A natural balancing act The team then sought to tackle a follow-up question: What purpose do the blue stripes serve? The limpets live either concealed at the base of kelp plants, or further up in the fronds, where they are visually exposed. Those at the base grow a thicker shell with almost no stripes, while their blue-striped counterparts live higher on the plant. Limpets generally don’t have well-developed eyes, so the researchers reasoned that the blue stripes must not serve as a communication tool, attracting one organism to another. Rather, they think that the limpet’s stripes may be a defensive mechanism: The mollusk sits largely exposed on a frond, so a plausible defense against predators may be to appear either invisible or unappetizing. The researchers determined that the latter is more likely the case, as the limpet’s blue stripes resemble the patterning of poisonous marine snails that also happen to inhabit similar kelp beds. Kolle says the group’s work has revealed an interesting insight into the limpet’s optical properties, which may be exploited to engineer advanced transparent optical displays. The limpet, he points out, has evolved a microstructure in its shell to satisfy an optical purpose without overly compromising the shell’s mechanical integrity. Materials scientists and engineers could take inspiration from this natural balancing act. “It’s all about multifunctional materials in nature: Every organism — no matter if it has a shell, or skin, or feathers — interacts in various ways with the environment, and the materials with which it interfaces to the outside world frequently have to fulfill multiple functions simultaneously”, Kolle says. “[Engineers] are more and more focusing on not only optimizing just one single property in a material or device, like a brighter screen or higher pixel density, but rather on satisfying several … design and performance criteria simultaneously. We can gain inspiration and insight from nature.” Peter Vukusic, an associate professor of physics at the University of Exeter in the United Kingdom, says the researchers “have done an exquisite job” in uncovering the optical mechanism behind the limpet’s conspicuous appearance. “By using multiple and complementary analysis techniques they have elucidated, in glorious detail, the many structural and physiological factors that have given rise to the optical signature of this highly evolved system,” says Vukusic, who was not involved in the study. “The animal’s complex morphology is highly interesting for photonics scientists and technologists interested in manipulating light and creating specialized appearances.”

2D-NANOLATTICES nanoelectronics project makes important step with silicene

A European research project has made an important step towards the further miniaturisation of nanoelectronics, using a highly-promising new material called silicene. Its goal: to make devices of the future vastly more powerful and energy efficient. Silicene, a new semiconducting material combining properties of silicon and graphene, is one of the most promising candidates for manufacturing even tinier electronic circuitry for future smart devices. ‘Electronics are currently embedded in many layers of silicon atoms. If they can be manufactured in a single layer, they can be shrunk down to much smaller sizes and we can cut down on power leakage, at the same time making devices more powerful and energy efficient,’ explained Dr Athanasios Dimoulas, coordinator of the EU’s 2D-NANOLATTICES project.

2D-Nanolattices Graphene is an interesting substance in that it occurs in a single layer of atoms, but does not have the ‘energy gap’ needed to be a semiconductor material. Silicene, a 2D form of silicon, brings its semiconductor properties into the world of 2D materials. The problem with silicene, however, is it is modified in contact with other substances such as metals. Electronics that are 100 times smaller Condensing electronics into a single layer of silicene and retaining electronic performance has proved a difficult task for researchers – until now that is. The 2D-NANOLATTICES project has achieved a significant innovation worldwide by making a Field Effect Transistor (FET) out of the material to operate at room temperature. FETs are a key switching component in electronic circuitry. Embedding it into just one layer of silicon atoms (in silicene structure), then transferring the layer, grown on a silver substrate, to one made of a more neutral substance, silicon dioxide, is a considerable success. ‘Tests showed that performance of silicene is very, very good on the non-metal substrate,’ enthused Dr Dimoulas, of Demokritos, Greece’s National Center for Scientific Research. ‘The fact that we have this one transistor made of just one single layer of material like silicon has not been done before and this is really something that can be described as a breakthrough. On the basis of this achievement, it could be possible to make transistors up to 100 times smaller in the vertical direction,’ Dr Dimoulas added. Seeing the potential Now that the transistor has been shrunk vertically into just one 2D layer of atoms, the dimensions can be shrunk laterally, too, meaning the same area on a chip could accommodate up to 25 times more electronics, Dr Dimoulas calculated. Additionally, the use of a single, narrow channel to conduct electrical current reduces power leakages, a problem that has been worrying the semiconductor industry for some time: how to go even smaller without devices overheating in the form of power leakage. This is good news for chip manufacturers, as the race to produce the next wave of communications technologies hots up with the advent of 5G mobile networks. 2D NANOLATTICES, which received EUR 1.63 million of funding from FP7 (through the Future and Emerging Technologies scheme), took place from 1 June 2011 till 31 August 2014 and consisted of six partners, in four EU countries.

Moving molecules write letters

High performance materials for gas storage, thermal insulators or nanomachines need a thorough understanding of the behavior of the material down to the molecular level. Thermodynamics, which have been developed two hundred years ago to increase the efficiency of steam engines, typically observes and averages over a large number of molecules. Now a team of scientists has developed a methodology, to investigate the equilibrium thermodynamics of single molecules. On the search for high performance materials for applications such as gas storage, thermal insulators or dynamic nanosystems it is essential to understand the thermal behavior of matter down to the molecular level. Classical thermodynamics average over time and over a large number of molecules. Within a three dimensional space single molecules can adopt an almost infinite number of states, making the assessment of individual species nearly impossible. Now researchers from Technische Universität München (TUM) and Linköping University (LIU) have developed a methodology, which allows to explore equilibrium thermodynamics of single molecules with atomic resolution at appreciable temperatures. The breakthrough study ("Visualization and thermodynamic encoding of single-molecule partition function projections") is based on two pillars: a technology which allows to cage molecules within two-dimensional nanopores and extensive computational modelling.

The nanopore restricts the the freedom of movement of the adsorbed single molecule. (Image: C.-A. Palma / TUM) At the Chair of Molecular Nanoscience and Chemical Physics of Interfaces at TU München, led by Prof. Dr. Johannes V. Barth, PD Dr. Florian Klappenberger developed the method to produce high-quality metal-organic networks on a silver surface. The network forms nanopores which restrict the freedom of movement of adsorbed single molecules in two-dimensions. Using scanning tunneling microscopy the researchers were able to track their motions at different temperatures with sub-nanometer resolution. Parallel to the experiments, the researchers worked with sophisticated computer models to describe the temperature dependence of the dynamics of these single trapped molecules. “We have applied state-of-the-art supercomputer calculations to understand the interactions and energy landscape determining the motion of the molecules”, says Jonas Björk of Linköping University. Comparing experimental and modeled data the scientists unraveled that under certain conditions the integral theory approaches a simple projection of the molecular positions in space. This approach is central to statistical mechanics, but has never before been challenged to reproduce an experiment, due to the practically infinite molecular positions and energies one needed to consider without the nanoscale confinement.

The thermal movements of a single molecule trapped in a modified nanopore writes the letters L, I and U by simply adjusting the temperature. (Image: C.-A. Palma / TUM) “It was extremely exciting to employ two-dimensional networks as a confinement strategy to reduce the available conformational space of a single molecule, like a chaperone does with a protein”, says Dr. Carlos-Andres Palma, the lead author of the study. “In analogy to biology, such form of confinement technology has the potential to establish sensors, nanomachines and possibly logics controlled by and made of molecular distributions.” Applying their knowledge of characteristic equilibrium configurations, the researchers carefully modulated the nanopore, thus making a single molecule write letters of the alphabet such as L, I and U, just by fine-tuning the temperature.

nANO meets water VI: Nanotechnik für die Wasser-Praxis

Am 19. Februar 2015 hieß es wieder "nANO meets water" bei Fraunhofer UMSICHT. Gut 100 Fachleute aus Industrie und Wirtschaft kamen nach Oberhausen, um sich beim Thema Innovationen und Risiken von Nanomaterialien für die Wassertechnik auf den neuesten Stand zu bringen. Auch das Brennpunktthema "Mikroplastik" fand bei allen Beteiligten großen Anklang. Bereits zum sechsten Mal traf sich bei Fraunhofer UMSICHT die Fachwelt der Nano- und Wasserbranche unter dem Motto "nANO meets water". Grund für die Initiatorin der Veranstaltungsreihe, Dr. Ilka Gehrke, in die mit ca. 100 Teilnehmern sehr gut besuchte Veranstaltung mit einem Resümee der vergangenen sechs Jahre "nANO meets water" zu starten: Welche Nanomaterialien für die Wassertechnik gibt es? Wo liegt das Anwendungspotenzial? Wo werden sie bereits eingesetzt? Nach dem einleitenden Vortrag, in dem Dr. Michael Gross auf Nanopartikel hinwies, die in der Natur vorkommen, berichtete anschließend Dr. Albert Schnieders von der Firma CNM Technologies aus der Praxis. Er stellte eine Nanofolie vor, die bisher vorrangig für die Gasseparation eingesetzt wird, jedoch auch im Wasserbereich Verwendung finden kann. presentation

Gut 100 Fachleute aus Industrie und Wirtschaft bei "nANO meets water VI" Fraunhofer UMSICHT hat zusammen mit weiteren Projektpartnern diverse Nanokomposit-Filter entwickelt, mit denen zum einen photokatalytisch Spurenstoffe aus dem Wasser eliminiert werden können. Des Weiteren gibt es Varianten, die vom Helmholtz-Zentrum Dresden-Rossendorf mit selektiven Proteinschichten (protein layer) versehen werden und Wertstoffe wie Seltenerdmetalle und Platingruppenelemente aus Abwasser gewinnen können. Das KIT in Karlsruhe beschäftigt sich mit Nanofiltrationsmembranen und Nano-Biomembranen zur Spurenstoffelimination, wie Prof. Andrea Iris Schäfer, zu berichten wusste. Nanomaterialien bieten viele Anwendungsmöglichkeiten in der Wassertechnik. Sie stehen aber in Konkurrenz zu relativ preiswerten und etablierten Materialien wie Aktivkohle oder üblichen Membranverfahren. "Es müsste mehr Werbung dafür gemacht werden, dass Nanotechnik viele Vorteile wie große Oberflächen, hohe Flexibilität u.v.m. aufbietet, die eigentlich noch zu wenig genutzt werden", war die einhellige Meinung der Fachleute. Nanomaterial in der Umwelt Mit eventuellen Problemen in Zusammenhang mit Nanotechnik beschäftigten sich die folgenden drei Vorträge. Dr. Ralf Kägi, EAWAG, und Dr. Fadri Gottschalk, ETSS Gottschalk & Co., waren extra aus der Schweiz angereist, um über die Toxizität und Ausbreitungswege von Nanopartikeln zu referieren. Sie bestätigten, dass eingesetzte Silber-Nanopartikel komplett sulfidisiert werden. Sie gehen somit in einen Zustand über, in dem von den Partikeln keine Gefährdung für Mensch und Umwelt ausgeht. Allerdings kann es laut Dr. Kägi zu einer Wiederfreisetzung durch beispielsweise die Verbrennung von Klärschlamm kommen. Ihr Wissenschaftskollege Jonas Baumann von der Universität Bremen untersuchte Eisennanopartikel, die erfolgreich zur Bodensanierung eingesetzt werden und ihre potenzielle Wirkung auf Kleinstorganismen wie beispielsweise Wasserflöhe. Ein Problem, die Ausbreitungspfade von Nanopartikeln in der aquatischen Umwelt zu verfolgen, liegt beispielsweise in der nicht ausreichenden Datengrundlage. "Es sind noch nicht einmal genaue Zahlen zu den Produktionsmengen bekannt", beklagte Dr. Gottschalk. Brennpunktthema: Mikroplastik Große Erwartungen hatten die Beteiligten bereits im Vorfeld an das Brennpunktthema "Mikroplastik". Die drei Vorträge lieferten einen guten Überblick über den Stand der wissenschaftlichen Arbeiten – zunächst gab es eine Zusammenfassung der vorhandenen Fakten von Ralf Bertling, Fraunhofer UMSICHT, dann folgte die Sicht der Behörden durch Maren Heß vom Landesamt für Natur, Umwelt und Verbraucherschutz (LANUV) sowie der Blickwinkel der Wissenschaft durch Prof. Christian Laforsch von der Universität Bayreuth, der die Forschung auf diesem Gebiet in Bayern und Baden-Württemberg leitet. Fraunhofer UMSICHT hingegen wird in NRW aktiv: In Kooperation mit dem Institut für Energie- und Umwelttechnik e.V. (IUTA) in Duisburg, dem Wupperverband und in enger Abstimmung mit dem LANUV sollen wissenschaftlich Untersuchungen in Kläranlagen in NRW Aufschluss über die Problematik des dort vorhandenen Mikroplastiks bringen. Die einhellige Auffassung ist, dass sich zwar nachweislich sehr viel Plastik und Mikroplastik sowohl in den Meeren und Ozeanen wie auch in Flüssen befindet. Es gibt aber trotz 19 vorliegender Studien immer noch zu wenig verlässliche und vergleichbare Analysen, auf denen eine weitergehende Strategie aufgebaut werden kann. Dies soll kurz- bis mittelfristig durch bessere Kooperation verbessert werden. Einen großen Teil dazu trägt Fraunhofer UMSICHT mit der gerade entstehenden Internetplattform "Initiative Mikroplastik" bei. Hier werden Forschungsergebnisse und sonstige Informationen veröffentlicht, sodass eine gute Vernetzung vereinfacht wird. Es wird die gesamte Wertschöpfungskette betrachtet: Vermeidung, Substitution, Eintrags- und Abbauwege sowie Entsorgung – sowohl in Binnengewässern als auch in den Meeren. Blick nach oben Den Abschluss von "nANO meets water" bildete ein Vortrag von Prof. Johannes Feitzinger mit dem Titel "Woher kommt das Wasser im Universum und wie kommt es auf die Erde?". Der Physiker und Astronom der Ruhr-Universität Bochum beschrieb anschaulich und auch visuell sehr eindrucksvoll den Weg des Wassers aus dem Universum auf die Erde, begleitet von spektakulären Ein- und Ausblicken in den Weltraum.

Graphene shows potential as novel anti-cancer therapeutic strategy

University of Manchester scientists have used graphene to target and neutralise cancer stem cells while not harming other cells. This new development opens up the possibility of preventing or treating a broad range of cancers, using a non-toxic material. Writing in the journal ("Graphene oxide selectively targets cancer stem cells, across multiple tumor types: Implications for non-toxic cancer treatment, via “differentiation-based nano-therapy”"), the team of researchers led by Professor Michael Lisanti and Dr Aravind Vijayaraghavan has shown that graphene oxide, a modified form of graphene, acts as an anti-cancer agent that selectively targets cancer stem cells (CSCs). In combination with existing treatments, this could eventually lead to tumour shrinkage as well as preventing the spread of cancer and its recurrence after treatment. However, more pre-clinical studies and extensive clinical trials will be necessary to move this forward into the clinic to ensure patient benefit. Professor Lisanti, the Director of the Manchester Centre for Cellular Metabolism within the University's Institute of Cancer Sciences, explained: "Cancer stem cells possess the ability to give rise to many different tumour cell types. They are responsible for the spread of cancer within the body - known as metastasis- which is responsible for 90% of cancer deaths. "They also play a crucial role in the recurrence of tumours after treatment. This is because conventional radiation and chemotherapies only kill the 'bulk' cancer cells, but do not generally affect the CSCs." Dr Vijayaraghavan added: "Graphene oxide is stable in water and has shown potential in biomedical applications. It can readily enter or attach to the surface of cells, making it a candidate for targeted drug delivery. In this work, surprisingly, it's the graphene oxide itself that has been shown to be an effective anti-cancer drug. "Cancer stem cells differentiate to form a small mass of cells known as a tumour-sphere. We saw that the graphene oxide flakes prevented CSCs from forming these, and instead forced them to differentiate into non-cancer stem-cells. "Naturally, any new discovery such as this needs to undergo extensive study and trials before emerging as a therapeutic. We hope that these exciting results in laboratory cell cultures can translate into an equally effective real-life option for cancer therapy." The team prepared a variety of graphene oxide formulations for testing against six different cancer types - breast, pancreatic, lung, brain, ovarian and prostate. The flakes inhibited the formation of tumour sphere formation in all six types, suggesting that graphene oxide can be effective across all, or at least a large number of different cancers, by blocking processes which take place at the surface of the cells. The researchers suggest that, used in combination with conventional cancer treatments, this may deliver a better overall clinical outcome. Dr Federica Sotgia, one of the co-authors of the study concluded: "These findings show that graphene oxide could possibly be applied as a lavage or rinse during surgery to clear CSCs or as a drug targeted at CSCs. "Our results also show that graphene oxide is not toxic to healthy cells, which suggests that this treatment is likely to have fewer side-effects if used as an anti-cancer therapy." Graphene has the potential to revolutionise a vast number of applications, lighter, stronger composites to flexible, bendable electronics. Graphene oxide can be used to create membranes that can coat surfaces to prevent corrosion, or filter clean water in real time. Demonstrating the remarkable properties of graphene won a University team of researchers the Nobel Prize for Physics in 2010.

New nanowire structure absorbs light efficiently

Researchers at Aalto University have developed a new method to implement different types of nanowires side-by-side into a single array on a single substrate. The new technique makes it possible to use different semiconductor materials for the different types of nanowires. 'We have succeeded in combining nanowires grown by the VLS (vapor-liquid-solid) and SAE (selective-area epitaxy) techniques onto the same platform. The difference compared with studies conducted previously on the same topic is that in the dual-type array the different materials do not grow in the same nanowire, but rather as separate wires on the same substrate', says Docent Teppo Huhtio. The research results were published in the journal on 5 February 2015 ("Fabrication of Dual-Type Nanowire Arrays on a Single Substrate").

Electronmicrograph - An electron micrograph of the dual-type nanowire array. Several applications The new fabrication process has many phases. First, gold nanoparticles are spread on a substrate. Next, the substrate is coated with silicon oxide, into which small holes are then patterned using electron beam lithography. In the first step of growth, (SAE), nanowires grow from where the holes are located, after which the silicon oxide is removed. In the second phase different types of nanowires are grown with the help of the gold nanoparticles (VLS). The researchers used metalorganic vapor phase epitaxy reactor in which the starting materials decompose at a high temperature, forming semiconductor compounds on the substrate. 'In this way we managed to combine two growth methods into the same process', says doctoral candidate Joona-Pekko Kakko. 'We noticed in optical reflection measurements that light couples better to this kind of combination structure. For instance, a solar cell has less reflection and better absorption of light', Huhtio adds.

Nanowire structure - Initially the substrate is prepared by depositing Au nanoparticles on it and covering it with a hole-patterned oxide. The first nanowires grow from these holes and after the oxide is removed, the other type of nanowires are grown via the deposited nanoparticles. The resulting dual-type array is presented on the electron micrograph on the right. In addition to solar cells and LEDs, the researchers also see good applications in thermoelectric generators. Further processing for component applications has already begun. Nanowires are being intensely researched, because semiconductor components that are currently in use need to be made smaller and more cost-effective. The nanowires made out of semiconductor materials are typically 1-10 micrometres in length, with diameters of 5-100 nanometres.

Fakir-like graphene

Graphene is a one atom thick sheet of carbon atoms, arranged in a periodic hexagonal lattice. It is famous not only for its remarkable electronic properties, but also for its exceptional mechanical strength and flexibility. To exploit these two last properties, researchers at Université Paris-Sud have draped a graphene sheet over square lattices of nanometer-sized pillars etched from silicon oxide (, "Strain Superlattices and Macroscale Suspension of Graphene Induced by Corrugated Substrates"). The pillars are either cones or cylinders, with a diameter of a the few tens of nanometer. They are produced by reactive ion etching of silicon oxide, through an electron-beam designed mask of aluminum nanocylinders. The large-area graphene sheet is produced by decomposition at high temperature of a methane/hydrogen mixture, on a copper substrate that acts as a catalyst. The graphene sheet is then transferred onto the pillar array using a polymer film.

Transferred graphene on nanopillars. (a) Schematic view of graphene membrane deposited onto SiO2 nanopillar array. (b) Atomic force micrograph of graphene deposited on SiO2 nanopillars. (c) Schematics of graphene (in black) transferred onto nanopillars array (in blue). For dense array (a < a*), fully suspended graphene over large areas are observed. At low array density (a > a*), graphene conforms with the substrate and forms highly symmetric ripples. (d) and (e): Series of SEM micrographs showing the behavior of transferred graphene membrane for 270 nm height silicon pillars. (d) the pillar pitch a is respectively equal to 2.3 and 0.25 µm. Scale bars lengths are 2 µm. Scanning electron microscopy and atomic force microscopy are used to detect the different ways in which the graphene sheet rests on the pillars, whose separation in the arrays varies between 0.3 microns and 4 microns. The scientists found a characteristic pillar separation (characteristic lattice constant a*) of the order of one micrometer. For smaller pillar lattice constants (a < a*), the graphene lays flat, fakir-like, resting on the tips of the pillars. For less dense pillar arrays (a > a*), the graphene hugs the substrate and pillars tightly, without tearing. A high stress thus occurs at each pillar tip, leading to a deformation of the graphene hexagons that was detected by Raman spectroscopy. Stress is also released via the formation of folds that are oriented parallel to pillar lattice directions. The density of folds results from competing energies, the elastic deformation energy of graphene, and the attractive interaction between graphene and substrate (stemming from the energetics of the transfer process onto the irregular, sharp substrate: electrostatics, van der Waals, capillary, etc…). In this work a variety of nanostructures has been created that can modify the electronic properties of graphene, either by periodic modulation of the electrostatic potential, or by periodic mechanical stress that can generate an effective magnetic structure. Both electronic transport and magnetisation measurements of these structures are underway to reveal the consequences of such mesoscopically stressed graphene.

New projects support research in 'valleytronics'

Two new three-year research projects are supporting the role of the Stanford Institute for Materials and Energy Sciences (SIMES) as a leading center for studying exotic new materials that could enable future innovative electronic and photonic applications. SIMES is a joint institute of Stanford University and the Department of Energy's SLAC National Accelerator Laboratory. “These awards are very important for SIMES,” said Tom Devereaux, a professor at SLAC and director of SIMES. “We have been establishing leadership in scientific areas that make SLAC unique. The awards significantly strengthen our core efforts in ultrafast science and quantum materials.” The two complementary projects will explore several theoretical and experimental aspects of an emerging area called “valleytronics.” In valleytronics, electrons move through the lattice of a two-dimensional semiconductor as a wave with two energy valleys whose characteristics can be used to encode information. Prime valleytronic materials are chalcogenides (pronounced cal-CAW-gin-eyeds), materials composed of a heavy metal atom and one or more atoms of oxygen, sulfur, selenium or tellurium. Many chalcogenides naturally form atom-scale layers that, under the right circumstances, result in special properties of interest to the SIMES researchers. “For example,” said SIMES researcher Yi Cui, “shining certain types of light onto some chalcogenides can control their electrons’ movements in ways that produce properties favorable for their use in efficient photodetectors, low-energy computer logic and data storage chips or quantum computers.” The SIMES researchers will perform theoretical calculations, make new nanomaterials and perform experiments in SLAC’s laboratories and DOE Office of Science User Facilities, including the Stanford Synchrotron Radiation Lightsource and the Linac Coherent Light Source. Their ultimate goal is to learn how to tune the materials to optimize their electronic properties. “SIMES and SLAC provide a wonderful combination of expertise in material synthesis, advanced characterization capabilities and theory, bringing together the key ingredients to make progress in this exciting new field,” remarked Stanford/SLAC Professor and SLAC Chemical Sciences Division Director Tony Heinz. One project, titled “Induction and Dynamics of New States of Matter in Two-Dimensional Materials,” is led by Devereaux, with co-investigators Zhi-Xun Shen, Aaron Lindenberg and Tony Heinz. It has received funding under the DOE’s "Scientific Discovery through Ultrafast Materials and Chemical Sciences" program. SLAC was the only DOE national lab chosen as a sole principal investigator in this program. The second project, “Chalcogenide Nanomaterials,” is led by SIMES researcher Yi Cui with co-investigators Harold Hwang, Shoucheng Zhang, Jun-Sik Lee and Hongtao Yuan. After the project's success with last year’s seed funding, the DOE has established a core program at SLAC in this novel area.

Nanotechnology quick test for Ebola

When diagnosing a case of Ebola, time is of the essence. However, existing diagnostic tests take at least a day or two to yield results, preventing health care workers from quickly determining whether a patient needs immediate treatment and isolation. A new test from MIT researchers could change that: The device, a simple paper strip similar to a pregnancy test, can rapidly diagnose Ebola, as well as other viral hemorrhagic fevers such as yellow fever and dengue fever. “As we saw with the recent Ebola outbreak, sometimes people present with symptoms and it’s not clear what they have,” says Kimberly Hamad-Schifferli, a visiting scientist in MIT’s Department of Mechanical Engineering and a member of the technical staff at MIT’s Lincoln Laboratory. “We wanted to come up with a rapid diagnostic that could differentiate between different diseases.”

A new paper diagnostic device can detect Ebola as well as other viral hemorrhagic fevers in about 10 minutes. The device (pictured here) has silver nanoparticles of different colors that indicate different diseases. On the left is the unused device, opened to reveal the contents inside. On the right, the device has been used for diagnosis; the colored bands show positive tests. (Photo courtesy of Jose Gomez-Marquez, Helena de Puig, and Chun-Wan Yen) Hamad-Schifferli and Lee Gehrke, the Hermann L.F. von Helmholtz Professor in MIT’s Institute for Medical Engineering and Science (IMES), are the senior authors of a paper describing the new device in the journal ("Multicolored silver nanoparticles for multiplexed disease diagnostics: distinguishing dengue, yellow fever, and Ebola viruses"). The paper’s lead author is IMES postdoc Chun-Wan Yen, and other authors are graduate student Helena de Puig, IMES postdoc Justina Tam, IMES instructor Jose Gomez-Marquez, and visiting scientist Irene Bosch. Color-coded test Currently, the only way to diagnose Ebola is to send patient blood samples to a lab that can perform advanced techniques such as polymerase chain reaction (PCR), which can detect genetic material from the Ebola virus. This is very accurate but time-consuming, and some areas of Africa where Ebola and other fevers are endemic have limited access to this kind of technology. The new device relies on lateral flow technology, which is used in pregnancy tests and has recently been exploited for diagnosing strep throat and other bacterial infections. Until now, however, no one has applied a multiplexing approach, using multicolored nanoparticles, to simultaneously screen for multiple pathogens. “For many hemorrhagic fever viruses, like West Nile and dengue and Ebola, and a lot of other ones in developing countries, like Argentine hemorrhagic fever and the Hantavirus diseases, there are just no rapid diagnostics at all,” says Gehrke, who began working with Hamad-Schifferli four years ago to develop the new device. Unlike most existing paper diagnostics, which test for only one disease, the new MIT strips are color-coded so they can be used to distinguish among several diseases. To achieve that, the researchers used triangular nanoparticles, made of silver, that can take on different colors depending on their size. The researchers created red, orange, and green nanoparticles and linked them to antibodies that recognize Ebola, dengue fever, and yellow fever. As a patient’s blood serum flows along the strip, any viral proteins that match the antibodies painted on the stripes will get caught, and those nanoparticles will become visible. This can be seen by the naked eye; for those who are colorblind, a cellphone camera could be used to distinguish the colors. “When we run a patient sample through the strip, if you see an orange band you know they have yellow fever, if it shows up as a red band you know they have Ebola, and if it shows up green then we know that they have dengue,” Hamad-Schifferli says. This process takes about 10 minutes, allowing health care workers to rapidly perform triage and determine if patients should be isolated, helping to prevent the disease from spreading further. Warren Chan, an associate professor at the University of Toronto Institute of Biomaterials and Biomedical Engineering, says he is impressed with the device because it not only offers faster diagnosis, but also requires smaller patient blood samples, as just one test strip can detect multiple diseases. “It’s a step up from what everyone else is doing,” says Chan, who was not involved in the research. “They’re targeting diseases that are really relevant to what’s going on in the world at this point, and have shown that they can detect them simultaneously.” Faster triage The researchers envision their new device as a complement to existing diagnostic technologies, such as PCR. “If you’re in a situation in the field with no power and no special technologies, if you want to know if a patient has Ebola, this test can tell you very quickly that you might not want to put that patient in a waiting room with other people who might not be infected,” says Gehrke, who is also a professor of microbiology and immunology at Harvard Medical School. “That initial triage can be very important from a public health standpoint, and there could be a follow-up test later with PCR or something to confirm.” The researchers hope to obtain Food and Drug Administration approval to begin using the device in areas where the Ebola outbreak is still ongoing. In order to do that, they are now testing the device in the lab with engineered viral proteins, as well as serum samples from infected animals. This type of device could also be customized to detect other viral hemorrhagic fevers or other infectious diseases, by linking the silver nanoparticles to different antibodies. “Thankfully the Ebola outbreak is dying off, which is a good thing,” Gehrke says. “But what we’re thinking about is what’s coming next. There will undoubtedly be other viral outbreaks. It might be Sudan virus, it might be another hemorrhagic fever. What we’re trying to do is develop the antibodies needed to be ready for the next outbreak that’s going to happen.”

Uncovering the personality of wonder ultrathin materials

A micron-scale optical microgram showing a characteristically triangular molybdenum disulphide ultrathin film grown in York. Following the discovery of graphene, an ultra-thin wonder material made of a carbon sheet of only one atom thickness, a number of other ultra-thin membranes have become the focus of study by nanotechnologists. These ultra-thin materials can be used not only to study physics in ‘flat land’ but also can be used as building blocks to produce ultra-thin or artificially stacked and flexible electronic devices.

Using sophisticated high-resolution electron microscopy, the researchers, who included scientists from Zhejiang University in Hangzhou, Beijing University, Reming University and Chinese Academy of Science in Beijing, China and King Abdullah University of Science and Technology in Saudi Arabia, have scanned these two-dimensional sheets for defects with resolution down to the atomic scale.

They have discovered that atomically thin molybdenum disulfide (MoS2) sheets have different ‘personalities’ or dominant defects depending how they are produced. If the atomically thin sheet is cleaved from minerals or grown by chemical reaction, then the dominant defects are loss of sulphur atoms from the crystalline structure. On the other hand, if the atomically thin sheet is grown by direct evaporation of bulk MoS2, then the dominant defect is the so-called anti-site type with molybdenum atoms replacing sulphur atoms in the crystal.

Unlikely pairs

In the rational world of science, everything can be explained by cause and effect. Sometimes when the cause is known, the ensuing effects can be predicted. But more often scientists try to measure something that “should be there”, or else they discover new phenomena that have no apparent reason or cause. Indeed, most scientific research arises from these two starting points, working from opposite directions to connect cause with effect. Prof. Moty Heiblum of the Condensed Matter Physics Department and his research group recently conducted an experiment ("Robust Electron Pairing in the Integer Quantum Hall Effect Regime") looking for an effect that “should be there” and ended up with an unexplained phenomenon. Working in the Braun Center for Submicron Research, the group was experimenting with a phenomenon known as the quantum Hall effect. In this system, electrons flow in a two-dimensional plane and are exposed to a strong magnetic field perpendicular to the plane. The electrons, which “prefer” to run in straight lines, get pulled from their original paths by the magnetic field and end up traveling around the edges of the plane. But what Heiblum and his group observed in the electron flow seemed to belong to a different type of system: superconductivity. Electrons, which all carry negative charges, normally repel one another. However, under very special conditions, in some materials and at extremely low temperatures, electrons can actually “hook up” to form pairs called Cooper pairs. Cooper pairs can move through a material with no resistance whatsoever, and this state is thus known as superconductivity.

An electron interferometer: Pairing of electrons takes place in the path denoted by the broken red line. So it came as a great surprise to discover electrons pairing up under certain conditions in their quantum Hall system – forming pairs that were remarkably similar to Cooper pairs. This is, indeed, the first time that this phenomenon has been observed outside of superconductivity, and the scientists are still not quite sure what to make of it. Once the electrons are pulled from their path by the magnetic field and forced to flow near the edges of the quantum Hall system, they travel in “parallel lanes” at varying distances from the edge. The scientists are now wondering if the close proximity of electrons moving in those parallel lanes could somehow cause electrons to “feel” one another more strongly and, consequently, interact in a different manner than the ubiquitous repulsion. The phenomenon was observed at the exit to the system. Electrons leaving the outer lane were measured; the surprise came when the exiting charges were found to be twice that of a normal, single electron. In other words, the current was carried by paired electrons, similar to that of Cooper pairs that flow so freely in the superconducting state. Although this phenomenon was completely unexpected and is still not understood, the question asked by the prophet Amos, with his insistence on rational cause and effect, resonates with the scientists: Why do these pairs of electrons “walk together,” apparently in total “agreement”? What causes the electrons in this system to form pairs? Or conversely, what is the effect of electron pairing on the functioning of the system? The Weizmann Institute scientists are already conducting new experiments to help sort out the riddle of the quantum Hall electron pairs.

Chromium-centered cycloparaphenylene rings as new tools for making functionalized nanocarbons

Professor Kenichiro Itami, Yasutomo Segawa and Natsumi Kubota of the JST-ERATO Itami Molecular Nanocarbon Project and the Institute of Transformative Bio-Molecules (ITbM), Nagoya University have synthesized novel cycloparaphenylene (CPP) chromium complexes and demonstrated their utility in obtaining monofunctionalized CPPs, which could become useful precursors for making carbon nanotubes with unprecedented structures. CPPs consist of a chain of benzene rings and are the shortest segment of carbon nanotubes. Since their first synthesis and isolation in 2008, CPPs have attracted wide attention in the fields of materials science and supramolecular chemistry. Applying the basic concepts of chromium arene chemistry, Itami and his coworkers have performed the first selective installation of a functional group on CPP, which has previously been difficult due to multiple reactive arene sites on the CPP ring. By being able to selectively install and tune the functional groups on CPPs, it is envisaged that carbon nanotubes with new properties can be constructed by this method.

One-pot selective monofunctionalization of CPP via a chromium complex. The study, published online on January 12, 2015 in the ("η6-Cycloparaphenylene Transition Metal Complexes: Synthesis, Structure, Photophysical Properties, and Application to the Selective Monofunctionalization of Cycloparaphenylenes"), illustrates the first synthesis, isolation and analysis of a CPP chromium complex, which enables a one-pot access to monofunctionalized CPPs. This outcome is believed to be a significant advance in the fields of both CPP chemistry and organometallic chemistry. Arenes are known to coordinate to transition metals and the corresponding metal complexes exhibit different reactivities relative to the free arene. CPPs, which consist of a chain of arenes, also reacted with chromium carbonyl to successfully generate the first chromium complex of CPP. Interestingly, the main product was a CPP with one chromium moiety complexed to one arene on the outer side of the ring, as confirmed by 1H NMR (nuclear magnetic resonance) spectroscopy, high-resolution mass spectrometry and X-ray crystallography. “Chromium arene chemistry is a well-established area and we decided to apply this organometallic method to synthesize the first CPP chromium complex,” says Itami, the Director of the JST-ERATO project and the Institute of Transformative Bio-Molecules. “As CPPs have a number of arene rings, we initially expected that chromium would form a complex with each arene ring,” says Segawa, a group leader of the JST-ERATO project. “However, we were surprised to see that CPP reacted with chromium in a 1:1 ratio in all the conditions that we tried. Simulation of the molecular structure suggested that the first equivalent of chromium complexed to CPP lowers its reactivity, thus preventing the reaction with a second chromium moiety.”

Obtaining substituted CPPs – traditional method and one-pot sequence (this work). (click on image to enlarge) Upon finding that a monometallic CPP complex could be obtained, Itami’s team explored the possibility of obtaining monofunctionalized CPPs from this complex. Itami and Segawa describe the steps in achieving this. “This was not an easy task as chromium arene complexes are usually air and light sensitive, and CPP chromium complexes were no exception. But Natsumi worked persistently to obtain a pure crystal of the first CPP chromium complex,” says Itami. “We then performed the subsequent reactions in one-pot, to synthesize monofunctionalized CPPs after addition of base/electrophiles and removal of the metal from the CPP chromium complex,” says Segawa. Selective monofunctionalizations of CPPs i.e. installation of one functional group at a single position on the arene ring, are difficult to achieve as all carbon-hydrogen bonds on the arene rings are chemically equivalent. Direct functionalization of metal-free CPPs usually leads to multiple substitutions on the arene rings in an uncontrolled manner. Despite CPPs being desirable components for carbon nanotubes, there has been no efficient method to obtain directly functionalized CPPs up to now. “We were pleased to see that a functional group could be selectively installed on one arene ring via chromium coordination of CPPs,” says Segawa. “As electrophiles, we utilized silyl, boryl and ester groups, which act as handles that can be easily transformed to other useful functionalities,” he continues. Itami says, “We hope that this new approach evolves to become a valuable method to construct carbon nanotubes with unique structures and properties.”

EPSRC unveils world-leading SuperSTEM microscope that sees single atoms

A new super powerful electron microscope that can pinpoint the position of single atoms, and will help scientists push boundaries even further, in fields such as advanced materials, healthcare and power generation, has been unveiled yesterday, Thursday February 19th, by the Engineering and Physical Sciences Research Council (EPSRC). The £3.7 million Nion Hermes Scanning Transmission Electron Microscope, one of only three in the world, will be sited at the EPSRC SuperSTEM facility at the Daresbury laboratory complex near Warrington, which is part of the Science and Technology Facilities Council (STFC).

SuperSTEM3, one of only three monochromated Nion electron microscopes in existence, boasts the world's highest energy resolution at a mere 10meV, along with the highest spatial resolution for a microscope operating in this energy range (0.1nm at 60kV, 0.8nm at 100kV). The microscope not only allows imaging of unprecedented resolution of objects a million times smaller than a human hair, but also analysis of materials. This means that researchers will not only be able to clearly identify the atoms, but observe the strength of the bonds between them. This will improve understanding of their electronic properties when in bulk and how they may perform when used. Minister for Universities, Science and Cities, Greg Clark, said: “The UK is a world leader in the development and application of STEM (Scanning Transmission Electron Microscope) techniques, and this new super-powerful microscope will ensure we remain world-class. “From developing new materials for space travel to creating a better, cheaper treatment for anaemia, this new super-powerful microscope lets UK scientists examine how materials behave at a level a million times smaller than a human hair. This exciting research will help lead to breakthroughs that will benefit not only our health but the environment too.” Professor Philip Nelson, EPSRC’s Chief Executive said: “This EPSRC investment in state-of-the-art equipment is an investment in UK science and engineering. It will give scientists access to a tool that can delve into the heart of materials, discoveries made using this microscope will aid research and lead to innovations that benefit society and our economy. The EPSRC SuperSTEM facility at Daresbury has already delivered us new knowledge and applications and this new equipment will continue that pedigree.” SuperSTEM Consortium SuperSTEM is supported by a network of collaborating Universities: Leeds, Glasgow, Liverpool, Manchester and Oxford and a Steering Committee. These provide extensive supporting expertise in the application of analytical electron microscopy to a broad variety of samples ranging from advanced materials to geological and even biological materials. The consortium also provides access to complementary electron microscopy and sample preparation techniques for the benefit of user project.

Acquiring nanotechnology advancements to march ahead of the race

OMICS Group invites researchers, academicians, scientists, Institutions, corporate entities, associations and students from across the world to attend the Nanotechnology Congress & Expo from 11-13 August 2015, at Frankfurt, Germany with a theme “Exploring and Acquiring the Advances in Nanotechnology”. Nanoscience and nanotechnology involves the study and application of nanoscale particles across all the other science fields, such as chemistry, biology, physics, materials science, and engineering. Today’s scientists and engineers are finding variety of ways to deliberately use Nanomaterials to take advantage of their enhanced properties such as higher strength, lighter weight, increased control of light spectrum, and greater chemical reactivity than their larger-scale counterparts. The innovation and emerging nanotechnologies have significantly reshaped the manufacturing, biotechnology, environmental and pharmaceutical markets. Nanoporous, nanotubes, nanocomposites,Nanotoxicology and nanoclays are all covered within BCC Research reports. In-depth market analysis of these technologies as well as trends, forecasts and profiles of major players prove how valuable the growth of nanotechnology has become. Efficiency of nanotechnology has led to great discoveries in prescription drug products, photonics and has had a great environmental impact in the water treatment and decreasing the amount of pollutants that deplete the environment. Nanotech-2015 offers an international platform for presenting research about marketing, exchanging ideas about it and thus, contributes to the dissemination of knowledge in marketing for the benefit of both the academia and business. It covers a broad area of physics- Nanophysics, Material Science, Smart Materials and others. It will help to gain knowledge about the recent advancements and it is of course a good opportunity to discuss various aspects of Nanotechnology Frankfurt is hosting this conference as it is the largest city in the German state of Hessen and the fifth-largest city in Germany. Frankfurt is the largest financial centre in continental Europe and ranks among the world's leading financial centers. It is home to the European Central Bank, Deutsche Bundesbank, Frankfurt Stock Exchange and several large commercial banks. The European Central Bank is the central bank of the eurozone, consisting of 18 EU member states that have adopted theeuro (€) as their common currency and sole legal tender. Major Nanotechnology Associations around the Europe including German Association of Nanotechnology, Brazilian Nanotechnology National Laboratory, International Council on Nanotechnology (ICON) , and Nano Science and Technology Institute (NSTI) have been focusing on Nanotechnolgoy research. Presence of top rated academic institutions like University of Oxford, University of Cambridge, Imperial College London, and Queens marry university also encourages the organizing committee to vote for Frankfurt as a conference venue. Nanotechnology-2015 offers an exciting opportunity to showcase the new technology, the new products of your company, and/or the service your industry may offer to a broad international audience. It covers a lot of topics and it will be a nice platform to showcase their recent researches on Nanotechnology, Material Science and other interesting topics. The organizing committee is gearing up for an exciting and informative conference program including plenary lectures, symposia, workshops on a variety of topics, poster presentations and various programs for participants from all over the world. We invite you to join us at the Nanotechnology-2015, where you will be sure to have a meaningful experience with scholars from around the world. All members of the Nanotechnology-2015 organizing committee look forward to meeting you in Frankfurt, Germany

Free-standing monolayers made from protein-bound gold nanoparticles

Free-standing nanoparticle films are of great interest for technical applications, such as the development of nanoelectronic devices. In the journal ("Free-Standing Gold-Nanoparticle Monolayer Film Fabricated by Protein Self-Assembly of α-Synuclein"), Korean scientists have introduced very flexible and stable monolayers of gold nanoparticles made by a self-assembly process based on protein aggregation. The films were used to coat wafers up to 10 cm in diameter. Free-standing monolayers made from protein-bound gold nanoparticles

The success of this new strategy relies on a small protein called α-synuclein, which is responsible for regulation of dopamine release in the brain, among other things. Incorrectly folded forms of this protein, which aggregate into poorly soluble fibril structures, seem to be involved in the development of neurodegenerative diseases such as Parkinson’s. As devastating as this misfolding protein is to the brain, it has shown itself to be quite useful in the production of extensive films made of gold nanoparticles. To produce these new films, scientists working with Seung R. Paik (Seoul National University) first coat gold nanoparticles with α-synuclein. They then adsorb the proteins onto a polycarbonate surface that has been cleaned by treatment with oxygen plasma. The proteins bind to this surface particularly well and eventually build up to form a densely packed monolayer of gold nanoparticles that is held together through unspecific interactions between the proteins. In the final step, the polycarbonate support is dissolved away with chloroform. At the same time, this solvent also triggers the misfolding of the proteins, which allows them to aggregate tightly and specifically, giving the free-standing monolayers necessary stability – even after they are dried. In contrast to previously described methods, this technique can produce films with dimensions reaching the millimeter and centimeter range, such as a 4 inch wafer. The color of the transparent films depends on the size of the gold particles used: 10 nm particle films are bright pink, 20 nm particle films are purple, and those made from 30 nm particles are dark blue. The films are so flexible that they can be crumpled up and then smoothed out again in a liquid. They can also encase round objects, such as silica spheres, without tearing. The researchers were additionally able to use lithographically prepared surfaces to make films with patterns of holes. Sequential adsorption on the support also allowed them to make films with a color pattern made from nanoparticles of two different sizes. The scientists hope to be able to add a variety of functionalities to their films, by using magnetic nanoparticles or quantum dots, for example. Potential areas of application include electronic components, ultrathin displays, and biocompatible sensors for the in vivo observation of organs and tissues. They expect these films to be used for not only controlling cellular activity like cancer treatment, but also cell-to-machine interface in the areas of neuroscience and robotics.

New nanogel for drug delivery

Scientists are interested in using gels to deliver drugs because they can be molded into specific shapes and designed to release their payload over a specified time period. However, current versions aren’t always practical because must be implanted surgically. To help overcome that obstacle, MIT chemical engineers have designed a new type of self-healing hydrogel that could be injected through a syringe. Such gels, which can carry one or two drugs at a time, could be useful for treating cancer, macular degeneration, or heart disease, among other diseases, the researchers say.

hydrogels made of nanoparticles interacting with long polymer chains

These scanning electron microscopy images, taken at different magnifications, show the structure of new hydrogels made of nanoparticles interacting with long polymer chains. (Image courtesy of the researchers) The new gel consists of a mesh network made of two components: nanoparticles made of polymers entwined within strands of another polymer, such as cellulose. “Now you have a gel that can change shape when you apply stress to it, and then, importantly, it can re-heal when you relax those forces. That allows you to squeeze it through a syringe or a needle and get it into the body without surgery,” says Mark Tibbitt, a postdoc at MIT’s Koch Institute for Integrative Cancer Research and one of the lead authors of a paper describing the gel in s on Feb. 19. Koch Institute postdoc Eric Appel is also a lead author of the paper, and the paper’s senior author is Robert Langer, the David H. Koch Institute Professor at MIT. Other authors are postdoc Matthew Webber, undergraduate Bradley Mattix, and postdoc Omid Veiseh. Heal thyself Scientists have previously constructed hydrogels for biomedical uses by forming irreversible chemical linkages between polymers. These gels, used to make soft contact lenses, among other applications, are tough and sturdy, but once they are formed their shape cannot easily be altered. The MIT team set out to create a gel that could survive strong mechanical forces, known as shear forces, and then reform itself. Other researchers have created such gels by engineering proteins that self-assemble into hydrogels, but this approach requires complex biochemical processes. The MIT team wanted to design something simpler. “We’re working with really simple materials,” Tibbitt says. “They don’t require any advanced chemical functionalization.” The MIT approach relies on a combination of two readily available components. One is a type of nanoparticle formed of PEG-PLA copolymers, first developed in Langer’s lab decades ago and now commonly used to package and deliver drugs. To form a hydrogel, the researchers mixed these particles with a polymer — in this case, cellulose. Each polymer chain forms weak bonds with many nanoparticles, producing a loosely woven lattice of polymers and nanoparticles. Because each attachment point is fairly weak, the bonds break apart under mechanical stress, such as when injected through a syringe. When the shear forces are over, the polymers and nanoparticles form new attachments with different partners, healing the gel. Using two components to form the gel also gives the researchers the opportunity to deliver two different drugs at the same time. PEG-PLA nanoparticles have an inner core that is ideally suited to carry hydrophobic small-molecule drugs, which include many chemotherapy drugs. Meanwhile, the polymers, which exist in a watery solution, can carry hydrophilic molecules such as proteins, including antibodies and growth factors. Long-term drug delivery In this study, the researchers showed that the gels survived injection under the skin of mice and successfully released two drugs, one hydrophobic and one hydrophilic, over several days. This type of gel offers an important advantage over injecting a liquid solution of drug-delivery nanoparticles: While a solution will immediately disperse throughout the body, the gel stays in place after injection, allowing the drug to be targeted to a specific tissue. Furthermore, the properties of each gel component can be tuned so the drugs they carry are released at different rates, allowing them to be tailored for different uses. The researchers are now looking into using the gel to deliver anti-angiogenesis drugs to treat macular degeneration. Currently, patients receive these drugs, which cut off the growth of blood vessels that interfere with sight, as an injection into the eye once a month. The MIT team envisions that the new gel could be programmed to deliver these drugs over several months, reducing the frequency of injections. Another potential application for the gels is delivering drugs, such as growth factors, that could help repair damaged heart tissue after a heart attack. The researchers are also pursuing the possibility of using this gel to deliver cancer drugs to kill tumor cells that get left behind after surgery. In that case, the gel would be loaded with a chemical that lures cancer cells toward the gel, as well as a chemotherapy drug that would kill them. This could help eliminate the residual cancer cells that often form new tumors following surgery. “Removing the tumor leaves behind a cavity that you could fill with our material, which would provide some therapeutic benefit over the long term in recruiting and killing those cells,” Appel says. “We can tailor the materials to provide us with the drug-release profile that makes it the most effective at actually recruiting the cells.”

Microfluidic diamond sensor

Measuring faint magnetic fields is a trillion-dollar business. Gigabytes of data, stored and quickly retrieved from chips the size of a coin, are at the heart of consumer electronics. Even higher data densities can be achieved by enhancing magnetic detection sensitivity---perhaps down to nano-tesla levels. Greater magnetic sensitivity is also useful in many scientific areas, such as the identification of biomolecules such as DNA or viruses. This research must often take place in a warm, wet environment, where clean conditions or low temperatures are not possible. JQI scientists address this concern by developing a diamond sensor that operates in a fluid environment. The sensor makes magnetic maps (with a 17 micro-tesla sensitivity) of small particles (a stand-in for actual bio-molecules) with a spatial resolution of about 50 nm. This is probably the most sensitive magnetic measurement conducted at room temperature in microfluidics. The results of the new experiment conducted by JQI scientist Edo Waks (a professor at the University of Maryland) and his associates appear in the journal ("Scanning Localized Magnetic Fields in a Microfluidic Device with a Single Nitrogen Vacancy Center") .

A diamond nanocrystal (white object to the right of center) is used to map the magnetic field around a particle (red object at center). The particle floats in a shallow bath of ionic liquid. The particle can be moved about (dotted line) with great precision by making the liquid flow using voltages applied to electrodes (4 shiny rods). Inset: the NV center at the heart of the diamond nano-crystal reacts to a combination of incoming green laser light, radio-frequency waves (magenta), and the magnetism of the nearby micro-particle. If all these fields have just the right values the NV center will emit red light. The observed light provides a measure of the micro-particle’s magnetic field. (Image: Kelley/JQI) Diamond NV centers At the heart of the sensor is a tiny diamond nano-crystal. This diamond, when brought close to a magnetic particle while simultaneously being bathed in laser light and a subtle microwave signal, will fluoresce in a manner proportional to the strength of the particle’s own magnetic field. Thus light from the diamond is used to map magnetism. How does the diamond work and how is the particle maneuvered near enough to the diamond to be scanned? The diamond nanocrystal is made in the same process by which synthetic diamonds are formed, in a process called chemical vapor deposition. Some of the diamonds have tiny imperfections, including occasionally nitrogen atoms substituting for carbon atoms. Sometimes a carbon atom is missing altogether from the otherwise tightly-coordinated diamond solid structure. In those cases where the nitrogen (N) and the vacancy (V) are next to each other, an interesting optical effect can occur. The NV combination acts as a sort of artificial atom called an NV color center. If prompted by the right kind of green laser, the NV center will shine. That is, if will absorb green laser light and emit red light, one photon at a time. The NV emission rate can be altered in the presence of magnetic fields at the microscopic level. For this to happen, though, the internal energy levels of the NV center has to be just right, and this comes about when the center is exposed to signals from the radio-frequency source (shown at the edge of the figure) and the fields emitted by the nearby magnetic particle itself. The particle floats in a shallow lake of de-ionized- water based solution in a setup called a microfluidic chip. The diamond is attached firmly to the bottom of this lake. The particle moves, and is steered around the chip when electrodes positioned in the channels coax ions in the liquid into forming gentle currents. Like a ship sailing to Europe with the help of the Gulf Stream, the particle rides these currents with sub-micron control. The particle can even be maneuvered in the vertical direction by an external magnetic coil (not shown in the drawing). “We plan to use multiple diamonds in order to do complex vectorial magnetic analysis.,” says graduact student Kangmook Lim, the lead author on the publication. “We will also use floating diamonds instead of stationary, which would be very useful for scanning nano- magnetism of biological samples.”

Cheap nanostructured solar cells made with carbon quantum dots from shrimp shells

The materials chitin and chitosan found in the shells are abundant and significantly cheaper to produce than the expensive metals such as ruthenium, which is similar to platinum, that are currently used in making nanostructured solar-cells. shrimp

Currently the efficiency of solar cells made with these biomass-derived materials is low but if it can be improved they could be placed in everything from wearable chargers for tablets, phones and smartwatches, to semi-transparent films over window. Researchers, from QMUL’s School of Engineering and Materials Science, used a process known as hydrothermal carbonization to create the carbon quantum dots (CQDs) from the widely and cheaply available chemicals found in crustacean shells (, "Biomass-derived Carbon Quantom Dots Sensitizers for Solid-State Nanostructured Solar Cells"). They then coat standard zinc oxide nanorods with the CQDs to make the solar cells. Dr Joe Briscoe, one of the researchers on the project, said: “This could be a great new way to make these versatile, quick and easy to produce solar cells from readily available, sustainable materials. Once we’ve improved their efficiency they could be used anywhere that solar cells are used now, particularly to charge the kinds of devices people carry with them every day. Professor Magdalena Titirici, Professor of Sustainable Materials Technology at QMUL, said: “New techniques mean that we can produce exciting new materials from organic by-products that are already easily available. Sustainable materials can be both high-tech and low-cost.” “We’ve also used biomass, in that case algae, to make the kinds of supercapacitors that can be used to store power in consumer electronics, in defibrillators and for energy recovery in vehicles.”

Three-dimensional opto-electric integration

Three-dimensional (3D) integration of various materials on top of bulk silicon could be the best answer for cost-effectively marrying optical devices with electronics. A*STAR researchers have used this approach to create a photodetector system for optical communications on a silicon chip ("Three-dimensional (3D) monolithically integrated photodetector and WDM receiver based on bulk silicon wafer"). Lund

A germanium photodetector integrated on a silicon bulk wafer. (© Optical Society of America) As computers become increasingly powerful, there is a need to find elegant ways to combine electronics and high-speed optical interconnect technology to meet the growing demand for ever faster data processing and communication. “We believe that, in the future of on-chip and chip-to-chip communication, opto-electric integrated circuits on silicon will be a key technology to realize high-speed, low-power and low-cost chips,” explains Junfeng Song from the A*STAR Institute of Microelectronics. To date, most attempts to make hybrid electronic-optical silicon chips have relied on silicon-on-insulator (SOI) technology in which an insulating layer of silicon dioxide is formed on a silicon wafer. While this approach works well, it has the disadvantage of being very expensive — SOI wafers cost about ten times more than bulk silicon wafers. SOI wafers also suffer from poor thermal conductivity, making it difficult to dissipate heat from devices. The team instead decided to explore the use of conventional bulk silicon wafers, which are a natural platform for microelectronics, but then fabricate optical devices in layers integrated on top of the wafers, resulting in a 3D design. Song and co-workers demonstrated this concept by fabricating an integrated photodetector system. A germanium detector was built directly on top of a silicon wafer (see image) and fed with an optical waveguide and grating coupler formed in silicon nitride. The researchers tested the detector and found it was capable of handling data at speeds of 10 gigabits per second per wavelength channel. The team is confident that this can be pushed to much higher speeds. “In the current device, the three-decibel bandwidth is small but by employing an electronic amplifier we can already get 20 gigabits per second rather easily,” explains Song. “I don’t think that the data rate has any physical limit, so it should be possible to achieve 50 gigabits per second or higher.” According to Song, the next challenge is to make more sophisticated integrated systems featuring more optical devices and more electronics. Possibilities include adding optical modulators, variable optical attenuators, optical switches, electronic amplifiers and electronic drivers to the chip circuitry. Other plans are to experiment with using alternative materials on top of the silicon, such as aluminum nitride, which has electro-optic properties and could bring new functionality.

Extremely repellent surfaces

A computational technique to analyze how water vapor condenses on a surface patterned with an array of tiny pillars has been co-developed by an A*STAR researcher. Calculations carried out using this technique reveal that water droplets preferentially form either on top of the pillars or in the gaps between them, depending on factors such as the height and spacing of the pillars ("Numerical Study of Vapor Condensation on Patterned Hydrophobic Surfaces Using the String Method").

Superhydrophobic surfaces, which strongly repel water, are promising for many applications. Surfaces that strongly repel water, known as superhydrophobic surfaces, are important for many industrial applications as well as self-cleaning, defrosting and anti-icing surfaces. Scientists have discovered that inherently water repellent surfaces can be made much more water repellent by patterning them with micro- or nanoscale structures. On such surfaces, water droplets can either be suspended across neighboring protrusions or impaled between them. The transition between these two states has previously been explored experimentally and theoretically. Furthermore, the effect of microstructures on vapor condensation has been studied experimentally, but there have been few computational studies of how droplets initially form by condensation from vapor. Now, Weiqing Ren from the A*STAR Institute of High Performance Computing and Yunzhi Li of the National University of Singapore have systematically analyzed how micropillars on a hydrophobic surface affect the condensation of water vapor. To do this, they used a powerful computational technique known as the string method, which Ren developed in a previous study. Ren and Li used the technique to investigate the effect of parameters such as the height and spacing of the micropillars and the supersaturation and intrinsic wettability of the surface on the condensation process. They discovered that both the pathway and configuration of the initial nucleus from which droplets form — known as the critical nucleus — depends on the geometry of the surface patterns. In particular, the scientists found that for tall, closely spaced pillars on a surface with a low supersaturation and low wettability, the critical nucleus prefers the suspended state, whereas for the opposite case it prefers the impaled state. By generating a phase diagram, they could determine the critical values of the geometrical parameters at which the configuration of the critical nucleus changes from the suspended state to the impaled state. These results provide “insights into the effect of surface structure on condensation,” explains Ren, “and a quantitative basis for designing surfaces optimized to either inhibit or enhance condensation in engineered systems.” In the future, the researchers intend to study how fluid flow affects nucleation and the wetting transition on patterned surfaces.

Discovery of a factor that determines the photocatalytic activity of titanium dioxide

The research group consisting of Assistant Professor Kenichi Ozawa in the Graduate School of Science and Engineering at the Tokyo Institute of Technology, Associate Professor Iwao Matsuda and Research Associate Susumu Yamamoto in the Institute for Solid State Physics at the University of Tokyo, and Professor Hiroshi Sakama in the Faculty of Science and Technology at Sophia University, discovered through the in situ observation of the behavior of photoexcited carriers1) on the surface of a titanium dioxide (TiO2) crystal used as a photocatalyst2) that the carrier (electron and positive hole) lifetime3) on the crystal surface is an important factor to determine the catalytic activity ("Electron-Hole Recombination Time at TiO2 Single-crystal Surfaces: Influence of Surface Band Bending").

This shows how the surface carrier lifetime of anatase and rutile TiO2 is affected by the surface potential barrier. The graph above, where the line of anatase TiO2 is always higher than that of rutile TiO2, indicates that the carrier lifetime of the former is longer than that of the latter at the same magnitude of surface potential barrier. TiO2 has two crystalline forms with different atomic structures: rutile and anatase. Differences in the catalytic activity between the two types were not revealed except that anatase has higher catalytic activity than rutile. The present study discovered that it is because the carrier lifetime on the anatase crystal surface is more than 10 times longer than that on the rutile crystal surface and suggested that more efficient photocatalyst can be developed by controlling the surface carrier lifetime with the chemical treatment of the catalyst surface. Taking notice of the fact that TiO2 has semiconducting properties, the researchers succeeded for the first time in analyzing the dynamical behavior of the photoexcited carriers on the crystal surface by tracing changes in the surface photovoltage4), a phenomenon specific to semiconductor, on a nanosecond basis. The experiment was conducted by using the time-resolved photoemission spectroscopy equipment with ultraviolet laser and soft X-ray synchrotron radiation at the synchrotron radiation outstation beamline "BL07LSU" of the University of Tokyo at the large synchrotron radiation facility "Spring-8." Explanations of Technical Terms 1.Photoexcited carrier When a semiconductor is illuminated by light with energy higher than its band gap, valence-band electrons are excited into the conduction band, leaving holes in the valence band. These excited electrons and the holes (positive holes) in the valence band are collectively called as photoexcited carriers. 2.Photocatalyst It is a substance that promotes chemical reactions when exposed to light without undergoing any change in itself during the reactions. Some semiconductor materials with band gaps have photocatalytic properties. 3.Carrier lifetime It is defined as a period of time after photoexcited carriers are generated until they disappear. They disappear when electrons and positive holes are recombined. 4.Surface photovoltage Photoexcited carriers generated on the surface of a semiconductor with surface potential move along the electric field gradient of the potential, which disturbs the charge balance between the surface and inside of the crystal resulting in a voltage difference. This effect is called surface photovoltage.