Tag Archives: Germany

When an atom more or less makes a big difference

As scientists continue exploring the nanoscale, it seems that finding the number of atoms in your particle makes a difference is no longer so surprising. From a Jan. 28, 2016 news item on ScienceDaily,

Combining experimental investigations and theoretical simulations, researchers have explained why platinum nanoclusters of a specific size range facilitate the hydrogenation reaction used to produce ethane from ethylene. The research offers new insights into the role of cluster shapes in catalyzing reactions at the nanoscale, and could help materials scientists optimize nanocatalysts for a broad class of other reactions.

A Jan. 28, 2016 Georgia Institute of Technology (Georgia Tech) news release (*also on EurekAlert*), which originated the news item, expands on the theme,

At the macro-scale, the conversion of ethylene has long been considered among the reactions insensitive to the structure of the catalyst used. However, by examining reactions catalyzed by platinum clusters containing between 9 and 15 atoms, researchers in Germany and the United States found that at the nanoscale, that’s no longer true. The shape of nanoscale clusters, they found, can dramatically affect reaction efficiency.

While the study investigated only platinum nanoclusters and the ethylene reaction, the fundamental principles may apply to other catalysts and reactions, demonstrating how materials at the very smallest size scales can provide different properties than the same material in bulk quantities. …

“We have re-examined the validity of a very fundamental concept on a very fundamental reaction,” said Uzi Landman, a Regents’ Professor and F.E. Callaway Chair in the School of Physics at the Georgia Institute of Technology. “We found that in the ultra-small catalyst range, on the order of a nanometer in size, old concepts don’t hold. New types of reactivity can occur because of changes in one or two atoms of a cluster at the nanoscale.”

The widely-used conversion process actually involves two separate reactions: (1) dissociation of H2 molecules into single hydrogen atoms, and (2) their addition to the ethylene, which involves conversion of a double bond into a single bond. In addition to producing ethane, the reaction can also take an alternative route that leads to the production of ethylidyne, which poisons the catalyst and prevents further reaction.

The project began with Professor Ueli Heiz and researchers in his group at the Technical University of Munich experimentally examining reaction rates for clusters containing 9, 10, 11, 12 or 13 platinum atoms that had been placed atop a magnesium oxide substrate. The 9-atom nanoclusters failed to produce a significant reaction, while larger clusters catalyzed the ethylene hydrogenation reaction with increasingly better efficiency. The best reaction occurred with 13-atom clusters.

Bokwon Yoon, a research scientist in Georgia Tech’s Center for Computational Materials Science, and Landman, the center’s director, then used large-scale first-principles quantum mechanical simulations to understand how the size of the clusters – and their shape – affected the reactivity. Using their simulations, they discovered that the 9-atom cluster resembled a symmetrical “hut,” while the larger clusters had bulges that served to concentrate electrical charges from the substrate.

“That one atom changes the whole activity of the catalyst,” Landman said. “We found that the extra atom operates like a lightning rod. The distribution of the excess charge from the substrate helps facilitate the reaction. Platinum 9 has a compact shape that doesn’t facilitate the reaction, but adding just one atom changes everything.”

Here’s an illustration featuring the difference between a 9 atom cluster and a 10 atom cluster,

A single atom makes a difference in the catalytic properties of platinum nanoclusters. Shown are platinum 9 (top) and platinum 10 (bottom). (Credit: Uzi Landman, Georgia Tech)

A single atom makes a difference in the catalytic properties of platinum nanoclusters. Shown are platinum 9 (top) and platinum 10 (bottom). (Credit: Uzi Landman, Georgia Tech)

The news release explains why the larger clusters function as catalysts,

Nanoclusters with 13 atoms provided the maximum reactivity because the additional atoms shift the structure in a phenomena Landman calls “fluxionality.” This structural adjustment has also been noted in earlier work of these two research groups, in studies of clusters of gold [emphasis mine] which are used in other catalytic reactions.

“Dynamic fluxionality is the ability of the cluster to distort its structure to accommodate the reactants to actually enhance reactivity,” he explained. “Only very small aggregates of metal can show such behavior, which mimics a biochemical enzyme.”

The simulations showed that catalyst poisoning also varies with cluster size – and temperature. The 10-atom clusters can be poisoned at room temperature, while the 13-atom clusters are poisoned only at higher temperatures, helping to account for their improved reactivity.

“Small really is different,” said Landman. “Once you get into this size regime, the old rules of structure sensitivity and structure insensitivity must be assessed for their continued validity. It’s not a question anymore of surface-to-volume ratio because everything is on the surface in these very small clusters.”

While the project examined only one reaction and one type of catalyst, the principles governing nanoscale catalysis – and the importance of re-examining traditional expectations – likely apply to a broad range of reactions catalyzed by nanoclusters at the smallest size scale. Such nanocatalysts are becoming more attractive as a means of conserving supplies of costly platinum.

“It’s a much richer world at the nanoscale than at the macroscopic scale,” added Landman. “These are very important messages for materials scientists and chemists who wish to design catalysts for new purposes, because the capabilities can be very different.”

Along with the experimental surface characterization and reactivity measurements, the first-principles theoretical simulations provide a unique practical means for examining these structural and electronic issues because the clusters are too small to be seen with sufficient resolution using most electron microscopy techniques or traditional crystallography.

“We have looked at how the number of atoms dictates the geometrical structure of the cluster catalysts on the surface and how this geometrical structure is associated with electronic properties that bring about chemical bonding characteristics that enhance the reactions,” Landman added.

I highlighted the news release’s reference to gold nanoclusters as I have noted the number issue in two April 14, 2015 postings, neither of which featured Georgia Tech, Gold atoms: sometimes they’re a metal and sometimes they’re a molecule and Nature’s patterns reflected in gold nanoparticles.

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

Structure sensitivity in the nonscalable regime explored via catalysed ethylene hydrogenation on supported platinum nanoclusters by Andrew S. Crampton, Marian D. Rötzer, Claron J. Ridge, Florian F. Schweinberger, Ueli Heiz, Bokwon Yoon, & Uzi Landman.  Nature Communications 7, Article number: 10389  doi:10.1038/ncomms10389 Published 28 January 2016

This paper is open access.

*’also on EurekAlert’ added Jan. 29, 2016.

Nano-fireworks

Fig. 1: Nano-fireworks in an argon nanoparticle are ignited by a moderately intense and invisible XUV laser pulse. A subsequent visible laser pulse heats the nanoparticle very efficiently, resulting in its explosion. Electrons and ions move in different directions and send out fluorescence light in various colors. Without the XUV pulse the nanoparticle would remain intact. Courtesy: Max Born Institute in Berlin (Germany)

Fig. 1: Nano-fireworks in an argon nanoparticle are ignited by a moderately intense and invisible XUV laser pulse. A subsequent visible laser pulse heats the nanoparticle very efficiently, resulting in its explosion. Electrons and ions move in different directions and send out fluorescence light in various colors. Without the XUV pulse the nanoparticle would remain intact. Courtesy: Max Born Institute in Berlin [Germany]

You can see why these have been called nano-fireworks by the researchers. Here’s more from a Jan. 23, 2016 news item on Nanowerk,

A team of researchers from the Max Born Institute in Berlin and the University of Rostock demonstrated a new way to turn initially transparent nanoparticles suddenly into strong absorbers for intense laser light and let them explode.

Intense laser pulses can transform transparent material into a plasma that captures energy of the incoming light very efficiently. Scientists from Berlin and Rostock discovered a trick to start and control this process in a way that is so efficient that it could advance methods in nanofabrication and medicine. The light-matter encounter was studied by a team of physicists from the Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy (MBI) in Berlin and from the Institute of Physics of the University of Rostock [Germany].

A Jan. 19, 2016 MBI press release, which originated the news item, offers more detail,

The researchers studied the interaction of intense near-infrared (NIR) laser pulses with tiny, nanometer-sized particles that contain only a few thousand Argon atoms – so-called atomic nanoclusters. The visible NIR light pulse alone can only generate a plasma if its electromagnetic waves are so strong that they rip individual atoms apart into electrons and ions. The scientists could outsmart this so-called ignition threshold by illuminating the clusters with an additional weak extreme-ultraviolet (XUV) laser pulse that is invisible to the human eye and lasts only a few femtoseconds (a femtosecond is a millionth of a billionth of a second). With this trick the researchers could “switch on” the energy transfer from the near-infrared light to the particle at unexpectedly low NIR intensities and created nano-fireworks, during which electrons, ions and colourful fluorescence light are sent out from the clusters in different directions .. . …

The experiments were carried out at the Max Born Institute at a 12 meter long high-harmonic generation (HHG) beamline. “The observation that argon clusters were strongly ionized even at moderate NIR laser intensities was very surprising”, explains Dr. Bernd Schütte from MBI, who conceived and performed the experiments. “Even though the additional XUV laser pulse is weak, its presence is crucial: without the XUV ignition pulse, the nanoparticles remained unaffected and transparent for the NIR light … .” Theorists around Prof. Thomas Fennel from the University of Rostock modelled the light-matter processes with numerical simulations and uncovered the origin of the observed synergy of the two laser pulses. They found that only a few seed electrons created by the ionizing radiation of the XUV pulse are sufficient to start a process similar to a snow avalanche in the mountains. The seed electrons are heated in the NIR laser light and kick out even more electrons. “In this avalanching process, the number of free electrons in the nanoparticle increases exponentially”, explains Prof. Fennel. “Eventually, the nanoscale plasma in the particles can be heated so strongly that highly charged ions are created.”

The novel concept of starting ionization avalanching with XUV light makes it possible to spatially and temporally control the strong-field ionization of nanoparticles and solids. Using HHG pulses paves the way for monitoring and controlling the ionization of nanoparticles on attosecond time scales, which is incredibly fast. One attosecond compares to a second as one second to the age of the universe. Moreover, the ignition method is expected to be applicable also to dielectric solids. This makes the concept very interesting for applications, in which intense laser pulses are used for the fabrication of nanostructures. By applying XUV pulses, a smaller focus size and therefore a higher precision could be achieved. At the same time, the overall efficiency can be improved, as NIR pulses with a much lower intensity compared to current methods could be used. In this way, novel nanolithography and nanosurgery applications may become possible in the future.

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

Ionization Avalanching in Clusters Ignited by Extreme-Ultraviolet Driven Seed Electrons by Bernd Schütte, Mathias Arbeiter, Alexandre Mermillod-Blondin, Marc J. J. Vrakking, Arnaud Rouzée, and Thomas Fennel.
Phys. Rev. Lett. 116, 033001 – Published 19 January 2016 DOI:http://dx.doi.org/10.1103/PhysRevLett.116.033001

© 2016 American Physical Society

This paper is behind a paywall.

Weaving at the nanoscale

A Jan. 21, 2016 news item on ScienceDaily announces a brand new technique,

For the first time, scientists have been able to weave a material at molecular level. The research is led by University of California Berkeley, in cooperation with Stockholm University. …

A Jan. 21, 2016 Stockholm University press release, which originated the news item, provides more information,

Weaving is a well-known way of making fabric, but has until now never been used at the molecular level. Scientists have now been able to weave organic threads into a three-dimensional material, using copper as a template. The new material is a COF, covalent organic framework, and is named COF-505. The copper ions can be removed and added without changing the underlying structure, and at the same time the elasticity can be reversibly changed.

– It almost looks like a molecular version of the Vikings chain-armour. The material is very flexible, says Peter Oleynikov, researcher at the Department of Materials and Environmental Chemistry at Stockholm University.

COF’s are like MOF’s porous three-dimensional crystals with a very large internal surface that can adsorb and store enormous quantities of molecules. A potential application is capture and storage of carbon dioxide, or using COF’s as a catalyst to make useful molecules from carbon dioxide.

Complex structure determined in Stockholm

The research is led by Professor Omar Yaghi at University of California Berkeley. At Stockholm University Professor Osamu Terasaki, PhD Student Yanhang Ma and Researcher Peter Oleynikov have contributed to determine the structure of COF-505 at atomic level from a nano-crystal, using electron crystallography methods.

– It is a difficult, complicated structure and it was very demanding to resolve. We’ve spent lot of time and efforts on the structure solution. Now we know exactly where the copper is and we can also replace the metal. This opens up many possibilities to make other materials, says Yanhang Ma, PhD Student at the Department of Materials and Environmental Chemistry at Stockholm University.

Another of the collaborating institutions, US Department of Energy Lawrence Berkeley National Laboratory issued a Jan. 21, 2016 news release on EurekAlert, providing a different perspective and some additional details,

There are many different ways to make nanomaterials but weaving, the oldest and most enduring method of making fabrics, has not been one of them – until now. An international collaboration led by scientists at the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California (UC) Berkeley, has woven the first three-dimensional covalent organic frameworks (COFs) from helical organic threads. The woven COFs display significant advantages in structural flexibility, resiliency and reversibility over previous COFs – materials that are highly prized for their potential to capture and store carbon dioxide then convert it into valuable chemical products.

“Weaving in chemistry has been long sought after and is unknown in biology,” Yaghi says [Omar Yaghi, chemist who holds joint appointments with Berkeley Lab’s Materials Sciences Division and UC Berkeley’s Chemistry Department and is the co-director of the Kavli Energy NanoScience Institute {Kavli-ENSI}]. “However, we have found a way of weaving organic threads that enables us to design and make complex two- and three-dimensional organic extended structures.”

COFs and their cousin materials, metal organic frameworks (MOFs), are porous three-dimensional crystals with extraordinarily large internal surface areas that can absorb and store enormous quantities of targeted molecules. Invented by Yaghi, COFs and MOFs consist of molecules (organics for COFs and metal-organics for MOFs) that are stitched into large and extended netlike frameworks whose structures are held together by strong chemical bonds. Such frameworks show great promise for, among other applications, carbon sequestration.

Through another technique developed by Yaghi, called “reticular chemistry,” these frameworks can also be embedded with catalysts to carry out desired functions: for example, reducing carbon dioxide into carbon monoxide, which serves as a primary building block for a wide range of chemical products including fuels, pharmaceuticals and plastics.

In this latest study, Yaghi and his collaborators used a copper(I) complex as a template for bringing threads of the organic compound “phenanthroline” into a woven pattern to produce an immine-based framework they dubbed COF-505. Through X-ray and electron diffraction characterizations, the researchers discovered that the copper(I) ions can be reversibly removed or restored to COF-505 without changing its woven structure. Demetalation of the COF resulted in a tenfold increase in its elasticity and remetalation restored the COF to its original stiffness.

“That our system can switch between two states of elasticity reversibly by a simple operation, the first such demonstration in an extended chemical structure, means that cycling between these states can be done repeatedly without degrading or altering the structure,” Yaghi says. “Based on these results, it is easy to imagine the creation of molecular cloths that combine unusual resiliency, strength, flexibility and chemical variability in one material.”

Yaghi says that MOFs can also be woven as can all structures based on netlike frameworks. In addition, these woven structures can also be made as nanoparticles or polymers, which means they can be fabricated into thin films and electronic devices.

“Our weaving technique allows long threads of covalently linked molecules to cross at regular intervals,” Yaghi says. “These crossings serve as points of registry, so that the threads have many degrees of freedom to move away from and back to such points without collapsing the overall structure, a boon to making materials with exceptional mechanical properties and dynamics.”

###

This research was primarily supported by BASF (Germany) and King Abdulaziz City for Science and Technology (KACST).

It’s unusual that neither Stockholm University not the Lawrence Berkeley National Laboratory list all of the institutions involved. To get a sense of this international collaboration’s size, I’m going to list them,

  • 1Department of Chemistry, University of California, Berkeley, Materials Sciences Division, Lawrence Berkeley National Laboratory, and Kavli Energy NanoSciences Institute, Berkeley, CA 94720, USA.
  • 2Department of Materials and Environmental Chemistry, Stockholm University, SE-10691 Stockholm, Sweden.
  • 3Department of New Architectures in Materials Chemistry, Materials Science Institute of Madrid, Consejo Superior de Investigaciones Científicas, Madrid 28049, Spain.
  • 4Nanomaterials Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8565, Japan.
  • 5NSF Nanoscale Science and Engineering Center (NSEC), University of California at Berkeley, 3112 Etcheverry Hall, Berkeley, CA 94720, USA.
  • 6Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
  • 7King Abdulaziz City of Science and Technology, Post Office Box 6086, Riyadh 11442, Saudi Arabia.
  • 8Material Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA.
  • 9School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China.

Given that some of the money came from a German company, I’m surprised not one German institution was involved.

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

Weaving of organic threads into a crystalline covalent organic framework by Yuzhong Liu, Yanhang Ma, Yingbo Zhao, Xixi Sun, Felipe Gándara, Hiroyasu Furukawa, Zheng Liu, Hanyu Zhu, Chenhui Zhu, Kazutomo Suenaga, Peter Oleynikov, Ahmad S. Alshammari, Xiang Zhang, Osamu Terasaki, Omar M. Yaghi. Science  22 Jan 2016: Vol. 351, Issue 6271, pp. 365-369 DOI: 10.1126/science.aad4011

This paper is behind a paywall.

Self-assembly with porphine molecules

A Jan. 12, 2016 American Institute of Physics (AIP) news release by John Arnst (also on EurekAlert but dated Jan. 14, 2016) describes computational research into self-assembling nanodevices based on porphine molecules,

As we continue to shrink electronic components, top-down manufacturing methods begin to approach a physical limit at the nanoscale. Rather than continue to chip away at this limit, one solution of interest involves using the bottom-up self-assembly of molecular building blocks to build nanoscale devices.

Successful self-assembly is an elaborately choreographed dance, in which the attractive and repulsive forces within molecules, between each molecule and its neighbors, and between molecules and the surface that supports them, have to all be taken into account. To better understand the self-assembly process, researchers at the Technical University of Munich have characterized the contributions of all interaction components, such as covalent bonding and van der Waals interactions between molecules and between molecules and a surface.

“In an ideal case, the smallest possible device has the size of a single atom or molecule,” said Katharina Diller, who worked as a postdoctoral researcher in the group of Karsten Reuter at the Technical University of Munich. Reuter and his colleagues present their work this week in The Journal of Chemical Physics, from AIP Publishing.

One such example is a single-porphyrin switch, which occupies a surface area of only one square nanometer. [emphasis mine] The porphine molecule, which was the object of this study, is even smaller than this. Porphyrins are a group of ringed chemical compounds which notably include heme – responsible for transporting oxygen and carbon dioxide in the bloodstream – and chlorophyll. In synthetically-derived applications, porphyrins are studied for their potential uses as sensors, light-sensitive dyes in organic solar cells, and molecular magnets.

The researchers from TU Munich assessed the interactions of the porphyrin molecule 2H-porphine by using density functional theory, a quantum mechanical computational modelling method used to describe the electronic properties of molecules and materials. Their simulations were performed at the high-performance supercomputer SuperMUC at Leibniz-Rechenzentrum in Garching.

The metallic substrates the researchers chose for the porphyrin molecules to assemble on, the close packed single crystal surfaces of copper and silver, are widely used as substrates in surface science. This is due to the densely packed nature of the surfaces, which allow the molecules to exhibit a smooth adsorption environment. Additionally, copper and silver each react differently with porhyrins – the molecule adsorbs more strongly on copper, whereas silver does a better job of keeping the electronic structure of the molecule intact – allowing the researchers to monitor a variety of competing effects for future applications.

In their simulation, porphyrin molecules were placed on a copper or silver slab, which was repeated periodically to simulate an extended surface. After finding the optimal geometry in which the molecules would adsorb on the surface, the researchers altered the size of the metal slab to increase or decrease the distance between molecules, thus simulating different molecular coverages. The computational setup gave them a switch to turn the energy contributions of neighboring molecules on and off, in order to observe the interplay of the individual interactions.

Diller and Reuter, along with colleagues Reinhard Maurer and Moritz Müller, who is first author on the paper, found that the weak long-range van der Waals interactions yielded the largest contribution to the molecule-surface interaction, and showed that the often employed methods to quantify the electronic charges in the system have to be used with caution. Surprisingly, while interactions directly between molecules are negligible, the researcher found indications for surface-mediated molecule-molecule interactions at higher molecular coverages.

“The analysis of the electronic structure and the individual interaction components allows us to better understand the self-assembly of porphine adsorbed on copper and silver, and additionally enables predictions for more complex porphyrine analogues,” Diller said. “These conclusions, however, come without yet considering the effects of atomic motion at finite temperature, which we did not study in this work.”

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

Interfacial charge rearrangement and intermolecular interactions: Density-functional theory study of free-base porphine adsorbed on Ag(111) and Cu(111) by Moritz Müller, Katharina Diller, Reinhard J. Maurer, and Karsten Reuter. J. Chem. Phys. 144, 024701 (2016); http://dx.doi.org/10.1063/1.4938259

This paper appears to be open access.

Finally, the researchers have made this illustrative diagram titled ‘Energy’ available,

Caption: Schematic depiction of different energy terms contributing to the adsorption energy, and charge density difference of 2H-P after adsorption onto Cu(111) at 12.8 Angstrom separation. Credit: M. Müller/TU Munich

Caption: Schematic depiction of different energy terms contributing to the adsorption energy, and charge density difference of 2H-P after adsorption onto Cu(111) at 12.8 Angstrom separation. Credit: M. Müller/TU Munich

Spermbot alternative for infertility issues

A German team that’s been working with sperm to develop a biological motor has announced it may have an alternative treatment for infertility, according to a Jan. 13, 2016 news item on Nanowerk,

Sperm that don’t swim well [also known as low motility] rank high among the main causes of infertility. To give these cells a boost, women trying to conceive can turn to artificial insemination or other assisted reproduction techniques, but success can be elusive. In an attempt to improve these odds, scientists have developed motorized “spermbots” that can deliver poor swimmers — that are otherwise healthy — to an egg. …

A Jan. 13, 2016 American Chemical Society (ACS) news release (*also on EurekAlert*), which originated the news item, expands on the theme,

Artificial insemination is a relatively inexpensive and simple technique that involves introducing sperm to a woman’s uterus with a medical instrument. Overall, the success rate is on average under 30 percent, according to the Human Fertilisation & Embryology Authority of the United Kingdom. In vitro fertilization can be more effective, but it’s a complicated and expensive process. It requires removing eggs from a woman’s ovaries with a needle, fertilizing them outside the body and then transferring the embryos to her uterus or a surrogate’s a few days later. Each step comes with a risk for failure. Mariana Medina-Sánchez, Lukas Schwarz, Oliver G. Schmidt and colleagues from the Institute for Integrative Nanosciences at IFW Dresden in Germany wanted to see if they could come up with a better option than the existing methods.

Building on previous work on micromotors, the researchers constructed tiny metal helices just large enough to fit around the tail of a sperm. Their movements can be controlled by a rotating magnetic field. Lab testing showed that the motors can be directed to slip around a sperm cell, drive it to an egg for potential fertilization and then release it. The researchers say that although much more work needs to be done before their technique can reach clinical testing, the success of their initial demonstration is a promising start.

For those who prefer to watch their news, there’s this,


This team got a flurry of interest in 2014 when they first announced their research on using sperm as a biological motor. Tracy Staedter in a Jan. 15, 2014 article for Discovery.com describes their then results,

To create these tiny robots, the scientists first had to catch a few. First, they designed microtubes, which are essentially thin sheets of titanium and iron — which have a magnetic property — rolled into conical tubes, with one end wider than the other. Next, they put the microtubes into a solution in a Petri dish and added bovine sperm cells, which are similar size to human sperm. When a live sperm entered the wider end of the tube, it became trapped down near the narrow end. The scientists also closed the wider end, so the sperm wouldn’t swim out. And because sperm are so determined, the trapped cell pushed against the tube, moving it forward.

Next, the scientists used a magnetic field to guide the tube in the direction they wanted it to go, relying on the sperm for the propulsion.

The quick swimming spermbots could use controlled from outside a person body to deliver payloads of drugs and even sperm itself to parts of the body where its needed, whether that’s a cancer tumor or an egg.

This work isn’t nanotechnology per se but it has been published in ACS Nano Letters. Here’s a link to and a citation for the paper,

Cellular Cargo Delivery: Toward Assisted Fertilization by Sperm-Carrying Micromotors by Mariana Medina-Sánchez, Lukas Schwarz, Anne K. Meyer, Franziska Hebenstreit, and Oliver G. Schmidt. Nano Lett., 2016, 16 (1), pp 555–561 DOI: 10.1021/acs.nanolett.5b04221 Publication Date (Web): December 21, 2015

Copyright © 2015 American Chemical Society

This paper is behind a paywall.

*'(also on EurekAlert)’ text and link added Jan. 14, 2016.

Mega science (e.g., a Large Hadron Collider) for agriculture

They are not talking about smashing plants together at high speeds when they suggest creating a CERN LHC (European Particle Physics Laboratory Large Hadron Collider) for agricultural sciences. Rather, three scientists have published a discussion paper about enabling large scale collaborations amongst agricultural scientists in Europe, according to a Jan. 5, 2016 news item on phys.org,

The Large Hadron Collider, a.k.a. CERN, found success in a simple idea: Invest in a laboratory that no one institution could sustain on their own and then make it accessible for physicists around the world. Astronomers have done the same with telescopes, while neuroscientists are collaborating to build brain imaging observatories. Now, in Trends in Plant Science on January 5 [2016], agricultural researchers present their vision for how a similar idea could work for them.

Rather than a single laboratory, the authors want to open a network of research stations across Europe—from a field in Scotland to an outpost in Sicily. Not only would this provide investigators with easy access to a range of different soil properties, temperatures, and atmospheric conditions to study plant/crop growth, it would allow more expensive equipment (for example, open-field installations to create artificial levels of carbon dioxide) to be a shared resource.

A Jan. 5, 2016 Cell Press news release on EurekAlert, which originated the news item, expands on the theme,

“Present field research facilities are aimed at making regional agriculture prosperous,” says co-author Hartmut Stützel of Leibniz Universität Hannover in Germany. “To us, it is obvious that the ‘challenges’ of the 21st century–productivity increase, climate change, and environmental sustainability–will require more advanced research infrastructures covering a wider range of environments.”

Stützel and colleagues, including Nicolas Brüggemann of Forschungszentrum Jülich in Germany and Dirk Inzé of VIB and Ghent University in Belgium, are just at the beginning of the process of creating their network, dubbed ECOFE (European Consortium for Open Field Experimentation). The idea was born last February at a meeting of Science Europe and goes back to discussions within a German Research Foundation working group starting four years ago. Now, they are approaching European ministries to explore the possibilities for ECOFE’s creation.

In addition to finding financial and political investment, ECOFE’s success will hinge on whether scientists at the various institutional research stations will be able to sacrifice a bit of their autonomy to focus on targeted research projects, Stützel says. He likens the network to a car sharing service, in which researchers will be giving up the autonomy and control of their own laboratories to have access to facilities in different cities. If ECOFE catches on, thousands of scientists could be using the network to work together on a range of “big picture” agricultural problems.

“It will be a rather new paradigm for many traditional scientists, but I think the communities are ready to accept this challenge and understand that research in the 21st century requires these types of infrastructures,” Stützel say. “We must now try to make political decision makers aware that a speedy implementation of a network for open field experimentation is fundamental for future agricultural research.”

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

The Future of Field Trials in Europe: Establishing a Network Beyond Boundaries by Hartmut Stützel, Nicolas Brüggemann, Dirk Inzé. Publication stage: In Press Corrected Proof DOI: http://dx.doi.org/10.1016/j.tplants.2015.12.003 Published Online: January 05, 2016

This paper appears to be open access.

Nanoparticles for infections delivered via hair follicles and Syrian refugee scientists are being welcomed

Hair follicles, nanoparticles, and infections

This first story does mention a Syrian researcher in a subtle fashion which suggests that immigrants (and I imagine refugees too) are welcome as they can be a huge boost to a country, in this case, the UK.

A Dec. 15, 2015 news item on ScienceDaily announces some research focused on using hair follicles to deliver nanoparticles carrying medication,

Many surgery patients develop infections and are a major source of prolonged illness and significant cause of death. Now, a research project is investigating the use of nanoparticles as a way to disinfect wounds. It could prove to be much more effective than existing techniques because the particles would be tiny enough to enter the skin via hair follicles, ensuring much better penetration of the area affected by surgery.

Here’s a close up of some hairy skin,

Courtesy: University Huddersfield

Courtesy: University Huddersfield

A Dec. 14, 2015 University of Huddersfield (UK) press release, which originated the news item, expands on the theme (Note: Links have been removed),

Infections contracted during surgical operations are a serious healthcare problem, leading to death in some cases.  Now, a research project at the University of Huddersfield is investigating the use of nanoparticles as a way to disinfect wounds.  It could prove to be much more effective than existing techniques because the particles would be tiny enough to enter the skin via hair follicles, ensuring much better penetration of the area affected by surgery.

The University’s Head of Pharmacy, Professor Barbara Conway (…), has developed the nanoparticle concept and it will now be further refined during a doctoral programme that she supervises.  Syrian-born [emphasis mine] researcher Khaled Aljammal has begun work on the project and receives funding via a new scheme, which means he is part of a network of bioscience and health researchers at go-ahead universities around the UK.

The issue addressed by Professor Conway’s project is that of surgical site infections, or SSIs.  It is estimated that every year, five per cent of patients who undergo surgery in England and Wales develop one of these infections and they are major source of prolonged illness and a significant cause of death in patients.  Also, they add strain on healthcare resources and fighting the infections is becoming more difficult because of growing resistance to antibiotics.

More effective use of antiseptics to treat the area affected by surgery is vital.  Professor Conway’s strategy is to develop a system of delivering the antiseptic drugs via minute particles less than a billionth of a metre in dimension.

“Making them nanoparticle size will help them to carry things into the skin better than current antiseptic regimes,” said the Professor.  “We think they will penetrate the skin better by the hair follicle route – and that is the site where bacteria will sit in the skin.”

Professor Conway – who is a member of the University of Huddersfield’s Institute of Skin Integrity and Infection Prevention – has been working for several years on methods for improving the delivery of antiseptics to reduce the incidence of SSIs.  Now, she is exploring the use of nano-sized formulations that have an antiseptic drug incorporated into them.  They could be administered in the form of a liquids, gels or even creams.

Khaled Al-Jammal (…) will be carrying out lab-based research aimed at developing and demonstrating the practicality of nanoparticle drug delivery.  He has been awarded full funding through the recently-launched Doctoral Training Alliance (DTA), an initiative of University Alliance, the organisation that unites UK universities with a mission to provide high-quality teaching and research that makes a real-world impact.

The Syrian researcher is one of two University of Huddersfield researchers who have begun their doctoral programmes under the DTA.  His gained his first degree in his native Syria before relocating to the UK four years ago for a Master’s in Pharmaceutical Technology.  This was followed by a spell working as a formulation scientist for the company Lena Nanoceutics.

His passion for research then led him to apply for the DTA project supervised at Huddersfield by Professor Conway.  As the project progress, it is intended that scientific articles and presentations will reveal its findings and these will be used to inform improved strategies to reduce the incidence and severity of such infections.

While the UK seems to be opening up its arms to scientists and researchers from Syria in an understated way, the Germans are being more direct.

A welcome mat for Syrian scientists

A Dec. 17, 2015 Deutsche Forschungsgemeinschaft (DFG; German Research Foundation) press release on EurekAlert describes an initiative developed for refugee scientists,

The Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) plans to help scientists and academics who have fled their home countries to participate in DFG-funded research projects and thus contribute to the integration of refugees in research and society. DFG President Professor Dr. Peter Strohschneider has presented a package of measures to the Joint Committee of Germany’s largest research funding organisation. The basic aim of these measures is to allow supplemental proposals to be submitted for existing funding projects which would enable the participation of qualified researchers or those in training.

“The integration of people who have been forced to flee in fear of their lives is a duty for all groups in society. The academic and research community, which has always been based on openness and plurality, can and must do its part,” said Strohschneider. “Although we cannot say for sure how many, it is certain that the people now coming to us as refugees include researchers at the training stage or people already established as researchers. We know this from enquiries that have already been sent to the DFG regarding funding opportunities.”

To use DFG funds to help improve the situation at least a little for refugee scientists and academics, there is no need to set up new funding programmes, the DFG President continued. In fact, there is already scope within existing project funding to integrate qualified individuals into funded projects. In particular, this can be achieved through supplemental proposals for existing projects, which the original applicants are free to submit in certain circumstances – for example if additional researchers, whose participation would bring additional benefit to the research, become available after the project is approved.

“We want to expressly encourage all higher education institutions and project leaders to make use of these additional opportunities,” said Strohschneider.

Various concrete options are available to refugees with an academic research background. For the short-term integration of refugees at all academic qualification levels, supplemental proposals can be submitted for guest funding. For the longer-term integration of established researchers, the Mercator module is a suitable option. This can be used to cover accommodation and travel costs and also provide remuneration at a level which, as with guest funding, is based on academic qualification. Both guest funding and Mercator funding can be applied for in all DFG funding programmes. The budget for this will be dependent on the number of people who can be integrated in funded projects in this way.

Refugee scientists and academics can also participate in Research Training Groups, Collaborative Research Centres and other DFG-funded coordinated projects. The financial resources for this do not have to be specially requested with a supplemental proposal; appropriate measures can also be financed from previously approved funds. For example, refugees with a bachelor’s degree or comparable qualification can receive a qualifying fellowship for later doctoral research in a Research Training Group or be accepted directly into such a group.

Project leaders and higher education institutions are responsible for deciding how researchers should be integrated in a project, said the DFG President. It is also up to the higher education institutions to work out the legal details, such as appraisal of academic qualifications or the signing of fellowship or employment contracts.

Strohschneider concluded: “We as the DFG want to create the financial and organisational framework needed for participation in the projects we fund in an efficient, flexible way. We are confident that this will make a positive contribution to the integration of refugees in our research system and our society.”

I have yet to hear of any other countries specifically focused on refugee scientists but perhaps this is just the beginning.

International NanoCar race: 1st ever to be held in Autumn 2016

They have a very intriguing set of rules for the 1st ever International NanoCar Race to be held in Toulouse, France in October 2016. From the Centre d’Élaboration de Matériaux et d’Études Structurales (CEMES) Molecule-car Race International page (Note: A link has been removed),

1) General regulations

The molecule-car of a registered team has at its disposal a runway prepared on a small portion of the (111) face of the same crystalline gold surface. The surface is maintained at a very low temperature that is 5 Kelvin = – 268°C (LT) in ultra-high vacuum that is 10-8 Pa or 10-10 mbar 10-10 Torr (UHV) for at least the duration of the competition. The race itself last no more than 2 days and 2 nights including the construction time needed to build up atom by atom the same identical runway for each competitor. The construction and the imaging of a given runway are obtained by a low temperature scanning tunneling microscope (LT-UHV-STM) and certified by independent Track Commissioners before the starting of the race itself.

On this gold surface and per competitor, one runway is constructed atom by atom using a few surface gold metal ad-atoms. A molecule-car has to circulate around those ad-atoms, from the starting to the arrival lines, each line being delimited by 2 gold ad-atoms. The spacing between two metal ad-atoms along a runway is less than 4 nm. A minimum of 5 gold ad-atoms line has to be constructed per team and per runway.

The organizers have included an example of a runway,

A preliminary runway constructed by C. Manzano and We Hyo Soe (A*Star, IMRE) in Singapore, with the 2 starting gold ad-atoms, the 5 gold ad-atoms for the track and the 2 gold ad-atoms had been already constructed atom by atom.

A preliminary runway constructed by C. Manzano and We Hyo Soe (A*Star, IMRE) in Singapore, with the 2 starting gold ad-atoms, the 5 gold ad-atoms for the track and the 2 gold ad-atoms had been already constructed atom by atom.

A November 25, 2015 [France] Centre National de la Recherche Scientifique (CNRS) press release notes that five teams presented prototypes at the Futurapolis 2015 event preparatory to the upcoming Autumn 2016 race,

The French southwestern town of Toulouse is preparing for the first-ever international race of molecule-cars: five teams will present their car prototype during the Futurapolis event on November 27, 2015. These cars, which only measure a few nanometers in length and are propelled by an electric current, are scheduled to compete on a gold atom surface next year. Participants will be able to synthesize and test their molecule-car until October 2016 prior to taking part in the NanoCar Race organized at the CNRS Centre d’élaboration des matériaux et d’études structurales (CEMES) by Christian Joachim, senior researcher at the CNRS and Gwénaël Rapenne, professor at Université Toulouse III-Paul Sabatier, with the support of the CNRS.

There is a video describing the upcoming 2016 race (English, spoken and in subtitles),


NanoCar Race, the first-ever race of molecule-cars by CNRS-en

A Dec. 14, 2015 Rice University news release provides more detail about the event and Rice’s participation,

Rice University will send an entry to the first international NanoCar Race, which will be held next October at Pico-Lab CEMES-CNRS in Toulouse, France.

Nobody will see this miniature grand prix, at least not directly. But cars from five teams, including a collaborative effort by the Rice lab of chemist James Tour and scientists at the University of Graz, Austria, will be viewable through sophisticated microscopes developed for the event.

Time trials will determine which nanocar is the fastest, though there may be head-to-head races with up to four cars on the track at once, according to organizers.

A nanocar is a single-molecule vehicle of 100 or so atoms that incorporates a chassis, axles and freely rotating wheels. Each of the entries will be propelled across a custom-built gold surface by an electric current supplied by the tip of a scanning electron microscope. The track will be cold at 5 kelvins (minus 450 degrees Fahrenheit) and in a vacuum.

Rice’s entry will be a new model and the latest in a line that began when Tour and his team built the world’s first nanocar more than 10 years ago.

“It’s challenging because, first of all, we have to design a car that can be manipulated on that specific surface,” Tour said. “Then we have to figure out the driving techniques that are appropriate for that car. But we’ll be ready.”

Victor Garcia, a graduate student at Rice, is building what Tour called his group’s Model 1, which will be driven by members of Professor Leonhard Grill’s group at Graz. The labs are collaborating to optimize the design.

The races are being organized by the Center for Materials Elaboration and Structural Studies (CEMES) of the French National Center for Scientific Research (CNRS).

The race was first proposed in a 2013 ACS Nano paper by Christian Joachim, a senior researcher at CNRS, and Gwénaël Rapenne, a professor at Paul Sabatier University.

Joining Rice are teams from Ohio University; Dresden University of Technology; the National Institute for Materials Science, Tsukuba, Japan; and Paul Sabatier [Université Toulouse III-Paul Sabatier].

I believe there’s still time to register an entry (from the Molecule-car Race International page; Note: Links have been removed),

To register for the first edition of the molecule-car Grand Prix in Toulouse, a team has to deliver to the organizers well before March 2016:

  • The detail of its institution (Academic, public, private)
  • The design of its molecule-vehicle including the delivery of the xyz file coordinates of the atomic structure of its molecule-car
  • The propulsion mode, preferably by tunneling inelastic effects
  • The evaporation conditions of the molecule-vehicles
  • If possible a first UHV-STM image of the molecule-vehicle
  • The name and nationality of the LT-UHV-STM driver

Those information are used by the organizers for selecting the teams and for organizing training sessions for the accepted teams in a way to optimize their molecule-car design and to learn the driving conditions on the LT-Nanoprobe instrument in Toulouse. Then, the organizers will deliver an official invitation letter for a given team to have the right to experiment on the Toulouse LT-Nanoprobe instrument with their own drivers. A detail training calendar will be determined starting September 2015.

The NanoCar Race website’s homepage notes that it will be possible to view the race in some fashion,

The NanoCar Race is a race where molecular machines compete on a nano-sized track. A NanoCar is a single molecule-car that has wheels and a chassis… and is propelled by a small electric shock.

The race will be invisible to the naked eye: a unique microscope based in Toulouse, France, will make it possible to watch the competition.

The NanoCar race is mostly a fantastic human and scientific adventure that will be broadcast worldwide. [emphasis mine]

Good luck to all the competitors.

A step toward commercializing smart windows with electrochromic film

A Dec. 4, 2015 news item on phys.org has reawakened my dream of electrochromic (smart) windows,

EC [electrochromic] film devices have been hampered in making the move from research to innovation by a number of technical and economic obstacles. EELICON [Enhanced Energy Efficiency and Comfort by Smart Light Transmittance Control] aims to overcome these obstacles by removing equipment limitations, automating processes, and validating a possible high-throughput prototype production process for a cost-effective, high-performance EC film technology.

Retrofitting windows with an electrically dimmable plastic film is a dream that is finally coming close to fruition. According to life cycle assessment studies, considerable energy savings may result when such films are included in architectural glazing, appliance doors, aircraft cabin windows, and vehicle sunroofs; and user comfort is enhanced as well.

The EU [European Union]-funded EELICON (Enhanced Energy Efficiency and Comfort by Smart Light Transmittance Control) project is focusing on an innovative switchable light transmittance technology that was developed in a project previously co-funded by the EU Framework Programmes. The project developed mechanically flexible and light-weight electrochromic (EC) film devices based on a conductive polymer nanocomposite technology with a property profile far beyond the current state-of-the art.

A Dec. 3, 2015 CORDIS (EU Community Research and Development Service) press release, which originated the news item, features an interview with the project coordinator and manager,

Dr. Uwe Posset, project coordinator and Expert Group Manager at ZfAE – Center for Applied Electrochemistry, Fraunhofer ISC, discusses the project’s achievements so far.

Do you have any results to show regarding the objectives that you have defined?

We are indeed working on a demonstration line to roll out a possible production process for electrochromic (EC) films, i.e. plastic films that can change colour upon application of a small voltage. Such films can be used to create smart windows for the control of sunlight and glare in buildings and vehicles. This technology is known to have the potential to save substantial amounts of energy for air conditioning. Darkening the film will decrease heat gain in the interior while maintaining the view through the window. The film provides possibilities to retrofit existing windows.

Do you have results from a life cycle assessment (LCA)?

Yes. The results essentially show that the targeted film technology can be produced with less primary energy than a standard EC window. We are currently working on extending the LCA to demonstrate the energy saving potential of the EC film during the use phase.

How much do you expect the technology to cost? How competitive will it be with existing technologies (e.g. price/performance)?

We target a price level of 200 €/m2, which is about a factor of 4 less than standard EC windows based on glass. To be really competitive, an even lower price may be required, but 200 €/m2 is usually discussed in the community as a threshold price for competitiveness. A full performance evaluation is currently in progress. According to discussions with potential end-users, producers and customers, price is the major driver, while some performance aspects may be negotiable, depending on the application.

How easy or difficult will the technology be to commercialise?

It is a complex process presumably requiring an industrial development phase of 2-3 years after the end of the project and substantial investment (currently estimated: €10 million).

Which are the most promising application areas?

Smart windows for energy-efficient buildings, vehicle sunroofs, smart aircraft cabin windows, switchable appliance doors, smart eyewear and visors.

What are the main benefits provided by the technology (any quantitative data would be welcome in addition to a qualitative description)?

There are many benefits. What we are developing is a film-based technology suitable for window integration and retrofitting. It will have short switching times (<1 min as compared to 10-15 min for state-of-the-art EC windows), and most importantly cost-effective, high-throughput production will be possible (roll-to-roll manufacturing).

Our technology will also have a higher bleached state visual light transmittance as compared to state-of-the-art EC windows (60-65 % vs. 50-55 %); a lower darkened state visual light transmittance as compared to state-of-the-art EC windows (5-10 % vs. 10-15 %); it will be fully colourless (“neutral tint”) bleached state with no residual colour or hue.; it will have an appreciable g-value modulation as opposed to liquid crystal-based smart window film technologies; it is mechanically rugged; and it has a large thermal operation range (-25 to +60 °C).

Once the project is completed, what will be the next steps? How do you see the technology evolving in the future?

We will then have to focus on industrial development – scaling from pilot to production scale. Huge markets will become accessible in the future if the price target can be met and minimum performance requirements are fulfilled.

You can find out more about EELICON here.

I’m glad to see they’re finding a way to make the technology affordable and that they’ve tackled the ‘ruggedness’ issue; see my Oct. 9, 2015 posting about smart windows and their need for anti-aging treatment (apparently the windows are prone to mechanical failures over time).

Combining gold and palladium for catalytic and plasmonic octopods

Hopefully I did not the change meaning when I made the title for this piece more succinct. In any event, this research comes from the always prolific Rice University in Texas, US (from a Nov. 30, 2015 news item on Nanotechnology Now),

Catalysts are substances that speed up chemical reactions and are essential to many industries, including petroleum, food processing and pharmaceuticals. Common catalysts include palladium and platinum, both found in cars’ catalytic converters. Plasmons are waves of electrons that oscillate in particles, usually metallic, when excited by light. Plasmonic metals like gold and silver can be used as sensors in biological applications and for chemical detection, among others.

Plasmonic materials are not the best catalysts, and catalysts are typically very poor for plasmonics. But combining them in the right way shows promise for industrial and scientific applications, said Emilie Ringe, a Rice assistant professor of materials science and nanoengineering and of chemistry who led the study that appears in Scientific Reports.

“Plasmonic particles are magnets for light,” said Ringe, who worked on the project with colleagues in the U.S., the United Kingdom and Germany. “They couple with light and create big electric fields that can drive chemical processes. By combining these electric fields with a catalytic surface, we could further push chemical reactions. That’s why we’re studying how palladium and gold can be incorporated together.”

The researchers created eight-armed specks of gold and coated them with a gold-palladium alloy. The octopods proved to be efficient catalysts and sensors.

A Nov. 30, 2015 Rice University news release (also on EurekAlert), which originated the news item, expands on the theme,

“If you simply mix gold and palladium, you may end up with a bad plasmonic material and a pretty bad catalyst, because palladium does not attract light like gold does,” Ringe said. “But our particles have gold cores with palladium at the tips, so they retain their plasmonic properties and the surfaces are catalytic.”

Just as important, Ringe said, the team established characterization techniques that will allow scientists to tune application-specific alloys that report on their catalytic activity in real time.

The researchers analyzed octopods with a variety of instruments, including Rice’s new Titan Themis microscope, one of the most powerful electron microscopes in the nation. “We confirmed that even though we put palladium on a particle, it’s still capable of doing everything that a similar gold shape would do. That’s really a big deal,” she said.

“If you shine a light on these nanoparticles, it creates strong electric fields. Those fields enhance the catalysis, but they also report on the catalysis and the molecules present at the surface of the particles,” Ringe said.

The researchers used electron energy loss spectroscopy, cathodoluminescence and energy dispersive X-ray spectroscopy to make 3-D maps of the electric fields produced by exciting the plasmons. They found that strong fields were produced at the palladium-rich tips, where plasmons were the least likely to be excited.

Ringe expects further research will produce multifunctional nanoparticles in a variety of shapes that can be greatly refined for applications. Her own Rice lab is working on a metal catalyst to turn inert petroleum derivatives into backbone molecules for novel drugs.

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

Resonances of nanoparticles with poor plasmonic metal tips by Emilie Ringe, Christopher J. DeSantis, Sean M. Collins, Martial Duchamp, Rafal E. Dunin-Borkowski, Sara E. Skrabalak, & Paul A. Midgley.  Scientific Reports 5, Article number: 17431 (2015)  doi:10.1038/srep17431 Published online: 30 November 2015

This is an open access paper,