Tag Archives: Empa-Swiss Federal Laboratories for Materials Testing and Research

Bandage with a voice (sort of)

Researchers at Empa (Swiss Federal Laboratories for Materials Testing and Research) have not developed a talking bandage despite the title (Bandage with a Voice) for a July 4, 2017 Empa press release  (also a July 4, 2017 news item on Nanowerk),

A novel bandage alerts the nursing staff as soon as a wound starts healing badly. Sensors incorporated into the base material glow with a different intensity if the wound’s pH level changes. This way even chronic wounds could be monitored at home.

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Using a UV lamp, the pH level in the wound can be verified without removing the bandage and the healing process can continue unimpeded. Image: Empa / CSEM

All too often, changing bandages is extremely unpleasant, even for smaller, everyday injuries. It stings and pulls, and sometimes a scab will even start bleeding again. And so we prefer to wait until the bandage drops off by itself.

It’s a different story with chronic wounds, though: normally, the nursing staff has to change the dressing regularly – not just for reasons of hygiene, but also to examine the wound, take swabs and clean it. Not only does this irritate the skin unnecessarily; bacteria can also get in, the risk of infection soars. It would be much better to leave the bandage on for longer and have the nursing staff “read” the condition of the wound from outside.

The idea of being able to see through a wound dressing gave rise to the project Flusitex (Fluorescence sensing integrated into medical textiles), which is being funded by the Swiss initiative Nano-Tera. Researchers from Empa teamed up with ETH Zurich, Centre Suisse d’Electronique et de Microtechnique (CSEM) and University Hospital Zurich to develop a high-tech system that is supposed to supply the nursing staff with relevant data about the condition of a wound. As Luciano Boesel from Empa’s Laboratory for Biomimetic Membranes and Textiles, who is coordinating the project at Empa, explains: “The idea of a smart wound dressing with integrated sensors is to provide continuous information on the state of the healing process without the bandages having to be changed any more frequently than necessary.” This would mean a gentler treatment for patients, less work for the nursing staff and, therefore, lower costs: globally, around 17 billion $ were spent on treating wounds last year.

When wounds heal, the body produces specific substances in a complex sequence of biochemical processes, which leads to a significant variation in a number of metabolic parameters. For instance, the amount of glucose and oxygen rises and falls depending on the phase of the healing process; likewise does the pH level change. All these variations can be detected with specialized sensors. With this in mind, Empa teamed up with project partner CSEM to develop a portable, cheap and easy-to-use device for measuring fluorescence that is capable of monitoring several parameters at once. It should enable nursing staff to keep tabs on the pH as well as on glucose and oxygen levels while the wound heals. If these change, conclusions about other key biochemical processes involved in wound healing can be drawn.

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The bandage reveals ist measurings in UV light.
A high pH signals chronic wounds

The pH level is particularly useful for chronic wounds. If the wound heals normally, the pH rises to 8 before falling to 5 or 6. If a wound fails to close and becomes chronic, however, the pH level fluctuates between 7 and 8. Therefore, it would be helpful if a signal on the bandage could inform the nursing staff that the wound pH is permanently high. If the bandage does not need changing for reasons of hygiene and pH levels are low, on the other hand, they could afford to wait.

But how do the sensors work? The idea: if certain substances appear in the wound fluid, “customized” fluorescent sensor molecules respond with a physical signal. They start glowing and some even change color in the visible or ultra-violet (UV) range. Thanks to a color scale, weaker and stronger changes in color can be detected and the quantity of the emitted substance be deduced.

Empa chemist Guido Panzarasa from the Laboratory for Biomimetic Membranes and Textiles vividly demonstrates how a sample containing sensor molecules begins to fluoresce in the lab. He carefully drips a solution with a pH level of 7.5 into a dish. Under a UV light, the change is plain to see. He adds another solution and the luminescence fades. A glance at the little bottle confirms it: the pH level of the second solution is lower.

Luminous molecules under UV

The Empa team designed a molecule composed of benzalkonium chloride and pyranine. While benzalkonium chloride is a substance also used for conventional medical soap to combat bacteria, fungi and other microorganisms, pyranine is a dye found in highlighters that glows under UV light. “This biomarker works really well,” says Panzarasa; “especially at pH levels between 5.5 and 7.5. The colors can be visualized with simple UV lamps available in electronics stores.” The Empa team recently published their results in the journal “Sensors and Actuators”.

The designer molecule has another advantage: thanks to the benzalkonium chloride, it has an antimicrobial effect, as researchers from Empa’s Laboratory for Biointerfaces confirmed for the bacteria strain Staphylococcus aureus. Unwelcome bacteria might potentially also be combatted by selecting the right bandage material in future. As further investigations, such as on the chemical’s compatibility with cells and tissues, are currently lacking, however, the researchers do not yet know how their sensor works in a complex wound.

Keen interest from industry

In order to illustrate what a smart wound dressing might actually look like in future, Boesel places a prototype on the lab bench. “You don’t have to cover the entire surface of wound dressings with sensors,” he explains. “It’s enough for a few small areas to be impregnated with the pyranine benzalkonium molecules and integrated into the base material. This means the industrial wound dressings won’t be much pricier than they are now – only up to 20% more expensive.” Empa scientists are currently working on this in the follow-up project FlusiTex-Gateway in cooperation with industrial partners Flawa, Schöller, Kenzen and Theranoptics.
Panzarasa now drips various liquids with different pH levels onto all the little cylinders on the wound pad prototype. Sure enough, the lighter and darker dots are also clearly discernible as soon as the UV lamp is switched on. They are even visible to the naked eye and glow in bright yellow if liquids with a high pH come into contact with the sensor. The scientists are convinced: since the pH level is so easy to read and provides precise information about the acidic or alkaline state of the sample, this kind of wound dressing is just the ticket as a diagnostic tool. Using the fluorescence meter developed by CSEM, more accurate, quantitative measure-ments of the pH level can be accomplished for medical purposes.

According to Boesel, it might one day even be possible to read the signals with the aid of a smartphone camera. Combined with a simple app, nursing staff and doctors would have a tool that enables them to easily and conveniently read the wound status “from outside”, even without a UV lamp. And patients would then also have the possibility of detecting the early onset of a chronic wound at home.

I wonder how long or even if this innovation will ever make its way into medical practice. I’m guessing this stage would be described as ‘proof of concept’ and that clinical testing is still many years away.

The metaphor in the press release’s title helped to wake me up. Thank you to whoever wrote it.

The Swiss come to a better understanding of nanomaterials

Just to keep things interesting, after the report suggesting most of the information that the OECD (Organization for Economic Cooperation and Development) has on nanomaterials is of little value for determining risk (see my April 5, 2017 posting for more) the Swiss government has released a report where they claim an improved understanding of nanomaterials than they previously had due to further research into the matter. From an April 6, 2017 news item on Nanowerk,

In the past six years, the [Swiss] National Research Programme “Opportunities and Risks of Nanomaterials” (NRP 64) intensively studied the development, use, behaviour and degradation of engineered nanomaterials, including their impact on humans and on the environment.

Twenty-three research projects on biomedicine, the environment, energy, construction materials and food demonstrated the enormous potential of engineered nanoparticles for numerous applications in industry and medicine. Thanks to these projects we now know a great deal more about the risks associated with nanomaterials and are therefore able to more accurately determine where and how they can be safely used.

An April 6, 2017 Swiss National Science Foundation press release, which originated the news item, expands on the theme,

“One of the specified criteria in the programme was that every project had to examine both the opportunities and the risks, and in some cases this was a major challenge for the researchers,” explains Peter Gehr, President of the NRP 64 Steering Committee.

One development that is nearing industrial application concerns a building material strengthened with nanocellulose that can be used to produce a strong but lightweight insulation material. Successful research was also carried out in the area of energy, where the aim was to find a way to make lithium-ion batteries safer and more efficient.

Promising outlook for nanomedicine

A great deal of potential is predicted for the field of nanomedicine. Nine of the 23 projects in NRP 64 focused on biomedical applications of nanoparticles. These include their use for drug delivery, for example in the fight against viruses, or as immune modulators in a vaccine against asthma. Another promising application concerns the use of nanomagnets for filtering out harmful metallic substances from the blood. One of the projects demonstrated that certain nanoparticles can penetrate the placenta barrier, which points to potential new therapy options. The potential of cartilage and bone substitute materials based on nanocellulose or nanofibres was also studied.

The examination of potential health risks was the focus of NRP 64. A number of projects examined what happens when nanoparticles are inhaled, while two focused on ingestion. One of these investigated whether the human gut is able to absorb iron more efficiently if it is administered in the form of iron nanoparticles in a food additive, while the other studied silicon nanoparticles as they occur in powdered condiments. It was ascertained that further studies will be required in order to determine the doses that can be used without risking an inflammatory reaction in the gut.

What happens to engineered nanomaterials in the environment?

The aim of the seven projects focusing on environmental impact was to gain a better understanding of the toxicity of nanomaterials and their degradability, stability and accumulation in the environment and in biological systems. Here, the research teams monitored how engineered nanoparticles disseminate along their lifecycle, and where they end up or how they can be discarded.

One of the projects established that 95 per cent of silver nanoparticles that are washed out of textiles are collected in sewage treatment plants, while the remaining particles end up in sewage sludge, which in Switzerland is incinerated. In another project a measurement device was developed to determine how aquatic microorganisms react when they come into contact with nanoparticles.

Applying results and making them available to industry

“The findings of the NRP 64 projects form the basis for a safe application of nanomaterials,” says Christoph Studer from the Federal Office of Public Health. “It has become apparent that regulatory instruments such as testing guidelines will have to be adapted at both national and international level.” Studer has been closely monitoring the research programme in his capacity as the Swiss government’s representative in NRP 64. In this context, the precautionary matrix developed by the government is an important instrument by means of which companies can systematically assess the risks associated with the use of nanomaterials in their production processes.

The importance of standardised characterisation and evaluation of engineered nanomaterials was highlighted by the close cooperation among researchers in the programme. “The research network that was built up in the framework of NRP 64 is functioning smoothly and needs to be further nurtured,” says Professor Bernd Nowack from Empa, who headed one of the 23 projects.

The results of NRP 64 show that new key technologies such as the use of nanomaterials need to be closely monitored through basic research due to the lack of data on its long-term effects. As Peter Gehr points out, “We now know a lot more about the risks of nanomaterials and how to keep them under control. However, we need to conduct additional research to learn what happens when humans and the environment are exposed to engineered nanoparticles over longer periods, or what happens a long time after a one-off exposure.”

You can find out more about the Opportunities and Risks of Nanomaterials; National Research Programme (NRP 64) here.

Natural nanoparticles and perfluorinated compounds in soil

The claim in a Sept. 9, 2015 news item on Nanowerk is that ‘natural’ nanoparticles are being used to remove perfluorinated compounds (PFC) from soil,

Perfluorinated compounds (PFC) are a new type of pollutants found in contaminated soils from industrial sites, airports and other sites worldwide.

In Norway, The Environment Agency has published a plan to eliminate PFOS [perfluorooctanesulfonic acid or perfluorooctane sulfonate] from the environment by 2020. In other countries such as China and the United States, the levels are far higher, and several studies show accumulation of PFOS in fish and animals, however no concrete measures have been taken.

The Norwegian company, Fjordforsk AS, which specializes in nanosciences and environmental methods, has developed a method to remove PFOS from soil by binding them to natural minerals. This method can be used to extract PFOS from contaminated soil and prevent leakage of PFOS to the groundwater.

Electron microscopy images show that the minerals have the ability to bind PFOS on the surface of the natural nanoparticles. [emphasis mine] The proprietary method does not contaminate the treated grounds with chemicals or other parts from remediation process and uses only natural components.

Electron microscopy images and more detail can be found in the Nanowerk news item.

I can’t find the press release, which originated the news item but there is a little additional information about Fjoorkforsk’s remediation efforts on the company’s “Purification of perfluorinated compounds from soil samples” project page,

Project duration: 2014 –

Project leader: Manzetti S.

Collaborators: Prof Lutz Ahrens. Swedish Agricultural University. Prof David van der Spoel, Uppsala University.

Project description:

Perfluorinated compounds (PFCs) are emerging pollutants used in flame retardants on a large scale on airports and other sites of heavy industrial activity. Perfluroinated compounds are toxic and represent an ultra-persistent class of chemicals which can accumulate in animals and humans and have been found to remain in the body for over 5 years after uptake. Perfluorinated compounds can also affect the nerve-system and have recently been associated with high- priority pollutants to be discontinued and to be removed from the environment. Using non-toxic methods, this project develops an approach to sediment perfluorinated compounds from contaminated soil samples using nanoparticles, in order to remove the ecotoxic and ground-water contaminating potential of PFCs from afflicted sites and environments.

The only mineral that I know is used for soil remediation is nano zero-valent iron (nZVI). A very fast search for more information yielded a 2010 EMPA [Swiss Federal Laboratories for Materials Science and Technology] report titled “Nano zero valent iron – THE solution for water and soil remediation? ” (32 pp. pdf) published by ObservatoryNANO.

As for the claim that the company is using ‘natural’ nanoparticles for their remediation efforts, it’s not clear what they mean by that. I suspect they’re using the term ‘natural’ to mean that engineered nanoparticles are being derived from a naturally occurring material, e.g. iron.

Nanotechnology research protocols for Environment, Health and Safety Studies in US and a nanomedicine characterization laboratory in the European Union

I have two items relating to nanotechnology and the development of protocols. The first item concerns the launch of a new web portal by the US National Institute of Standards and Technology.

US National Institute of Standards and Technology (NIST)

From a July 1, 2015 news item on Azonano,

As engineered nanomaterials increasingly find their way into commercial products, researchers who study the potential environmental or health impacts of those materials face a growing challenge to accurately measure and characterize them. These challenges affect measurements of basic chemical and physical properties as well as toxicology assessments.

To help nano-EHS (Environment, Health and Safety)researchers navigate the often complex measurement issues, the National Institute of Standards and Technology (NIST) has launched a new website devoted to NIST-developed (or co-developed) and validated laboratory protocols for nano-EHS studies.

A July 1, 2015 NIST news release on EurekAlert, which originated the news item, offers more details about the information available through the web portal,

In common lab parlance, a “protocol” is a specific step-by-step procedure used to carry out a measurement or related activity, including all the chemicals and equipment required. Any peer-reviewed journal article reporting an experimental result has a “methods” section where the authors document their measurement protocol, but those descriptions are necessarily brief and condensed, and may lack validation of any sort. By comparison, on NIST’s new Protocols for Nano-EHS website the protocols are extraordinarily detailed. For ease of citation, they’re published individually–each with its own unique digital object identifier (DOI).

The protocols detail not only what you should do, but why and what could go wrong. The specificity is important, according to program director Debra Kaiser, because of the inherent difficulty of making reliable measurements of such small materials. “Often, if you do something seemingly trivial–use a different size pipette, for example–you get a different result. Our goal is to help people get data they can reproduce, data they can trust.”

A typical caution, for example, notes that if you’re using an instrument that measures the size of nanoparticles in a solution by how they scatter light, it’s important also to measure the transmission spectrum of the particles if they’re colored, because if they happen to absorb light strongly at the same frequency as your instrument, the result may be biased.

“These measurements are difficult because of the small size involved,” explains Kaiser. “Very few new instruments have been developed for this. People are adapting existing instruments and methods for the job, but often those instruments are being operated close to their limits and the methods were developed for chemicals or bulk materials and not for nanomaterials.”

“For example, NIST offers a reference material for measuring the size of gold nanoparticles in solution, and we report six different sizes depending on the instrument you use. We do it that way because different instruments sense different aspects of a nanoparticle’s dimensions. An electron microscope is telling you something different than a dynamic light scattering instrument, and the researcher needs to understand that.”

The nano-EHS protocols offered by the NIST site, Kaiser says, could form the basis for consensus-based, formal test methods such as those published by ASTM and ISO.

NIST’s nano-EHS protocol site currently lists 12 different protocols in three categories: sample preparation, physico-chemical measurements and toxicological measurements. More protocols will be added as they are validated and documented. Suggestions for additional protocols are welcome at nanoprotocols@nist.gov.

The next item concerns European nanomedicine.

CEA-LETI and Europe’s first nanomedicine characterization laboratory

A July 1, 2015 news item on Nanotechnology Now describes the partnership which has led to launch of the new laboratory,

CEA-Leti today announced the launch of the European Nano-Characterisation Laboratory (EU-NCL) funded by the European Union’s Horizon 2020 research and innovation programm[1]e. Its main objective is to reach a level of international excellence in nanomedicine characterisation for medical indications like cancer, diabetes, inflammatory diseases or infections, and make it accessible to all organisations developing candidate nanomedicines prior to their submission to regulatory agencies to get the approval for clinical trials and, later, marketing authorization.

“As reported in the ETPN White Paper[2], there is a lack of infrastructure to support nanotechnology-based innovation in healthcare,” said Patrick Boisseau, head of business development in nanomedicine at CEA-Leti and chairman of the European Technology Platform Nanomedicine (ETPN). “Nanocharacterisation is the first bottleneck encountered by companies developing nanotherapeutics. The EU-NCL project is of most importance for the nanomedicine community, as it will contribute to the competiveness of nanomedicine products and tools and facilitate regulation in Europe.”

EU-NCL is partnered with the sole international reference facility, the Nanotechnology Characterization Lab of the National Cancer Institute in the U.S. (US-NCL)[3], to get faster international harmonization of analytical protocols.

“We are excited to be part of this cooperative arrangement between Europe and the U.S.,” said Scott E. McNeil, director of U.S. NCL. “We hope this collaboration will help standardize regulatory requirements for clinical evaluation and marketing of nanomedicines internationally. This venture holds great promise for using nanotechnologies to overcome cancer and other major diseases around the world.”

A July 2, 2015 EMPA (Swiss Federal Laboratories for Materials Science and Technology) news release on EurekAlert provides more detail about the laboratory and the partnerships,

The «European Nanomedicine Characterization Laboratory» (EU-NCL), which was launched on 1 June 2015, has a clear-cut goal: to help bring more nanomedicine candidates into the clinic and on the market, for the benefit of patients and the European pharmaceutical industry. To achieve this, EU-NCL is partnered with the sole international reference facility, the «Nanotechnology Characterization Laboratory» (US-NCL) of the US-National Cancer Institute, to get faster international harmonization of analytical protocols. EU-NCL is also closely connected to national medicine agencies and the European Medicines Agency to continuously adapt its analytical services to requests of regulators. EU-NCL is designed, organized and operated according to the highest EU regulatory and quality standards. «We are excited to be part of this cooperative project between Europe and the U.S.,» says Scott E. McNeil, director of US-NCL. «We hope this collaboration will help standardize regulatory requirements for clinical evaluation and marketing of nanomedicines internationally. This venture holds great promise for using nanotechnologies to overcome cancer and other major diseases around the world.»

Nine partners from eight countries

EU-NCL, which is funded by the EU for a four-year period with nearly 5 million Euros, brings together nine partners from eight countries: CEA-Tech in Leti and Liten, France, the coordinator of the project; the Joint Research Centre of the European Commission in Ispra, Italy; European Research Services GmbH in Münster Germany; Leidos Biomedical Research, Inc. in Frederick, USA; Trinity College in Dublin, Ireland; SINTEF in Oslo, Norway; the University of Liverpool in the UK; Empa, the Swiss Federal Laboratories for Materials Science and Technology in St. Gallen, Switzerland; Westfälische Wilhelms-Universität (WWU) and Gesellschaft für Bioanalytik, both in Münster, Germany. Together, the partnering institutions will provide a trans-disciplinary testing infrastructure covering a comprehensive set of preclinical characterization assays (physical, chemical, in vitro and in vivo biological testing), which will allow researchers to fully comprehend the biodistribution, metabolism, pharmacokinetics, safety profiles and immunological effects of their medicinal nano-products. The project will also foster the use and deployment of standard operating procedures (SOPs), benchmark materials and quality management for the preclinical characterization of medicinal nano-products. Yet another objective is to promote intersectoral and interdisciplinary communication among key drivers of innovation, especially between developers and regulatory agencies.

The goal: to bring safe and efficient nano-therapeutics faster to the patient

Within EU-NCL, six analytical facilities will offer transnational access to their existing analytical services for public and private developers, and will also develop new or improved analytical assays to keep EU-NCL at the cutting edge of nanomedicine characterization. A complementary set of networking activities will enable EU-NCL to deliver to European academic or industrial scientists the high-quality analytical services they require for accelerating the industrial development of their candidate nanomedicines. The Empa team of Peter Wick at the «Particles-Biology Interactions» lab will be in charge of the quality management of all analytical methods, a key task to guarantee the best possible reproducibility and comparability of the data between the various analytical labs within the consortium. «EU-NCL supports our research activities in developing innovative and safe nanomaterials for healthcare within an international network, which will actively shape future standards in nanomedicine and strengthen Empa as an enabler to facilitate the transfer of novel nanomedicines from bench to bedside», says Wick.

You can find more information about the laboratory on the Horizon 2020 (a European Union science funding programme) project page for the EU-NCL laboratory. For anyone curious about CEA-Leti, it’s a double-layered organization. CEA is France’s Commission on Atomic Energy and Alternative Energy (Commissariat à l’énergie atomique et aux énergies alternatives); you can go here to their French language site (there is an English language clickable option on the page). Leti is one of the CEA’s institutes and is known as either Leti or CEA-Leti. I have no idea what Leti stands for. Here’s the Leti website (this is the English language version).

Bespoke (custom made) carbon nanotubes

Researchers have found a way to create single-walled carbon nanotubes (SWCNTs) that  are consistent and, hopefully, designed for specific applications if I’m reading the research rightly, (I have an embedded video in a March 15, 2013 posting which illustrates some of the issues with producing carbon nanotubes.) Getting back to this latest research, it suggests that we could order SWCNTs-on-demand. An Aug. 14, 2014 news item on Azonano provides more insight,

In future, it will be possible to specifically equip carbon nanotubes with properties which they need for electronic applications, for example. Researchers at Empa in Dübendorf/Switzerland and the Max Planck Institute for Solid State Research in Stuttgart [Germany] have succeeded for the first time in growing single-walled carbon nanotubes (CNTs) with only a single, prespecified structure.

The nanotubes thereby have identical electronic properties. The decisive trick here: The team has taken up an idea which originated from the Stuttgart-based Max Planck researchers and produced the CNT from custom-made organic precursor molecules. The researchers started with these precursor molecules and have built up the nanotubes on a platinum surface, as they report in the latest issue of the scientific journal Nature. Such CNTs could be used in future, for instance, in ultra-sensitive light detectors and very tiny transistors.

An Aug. 13, 2014 Max Planck Institute press release, which originated the news item, provides more detail,

For 20 years, material scientists working on the development of carbon nanotubes for a range of applications have been battling a problem – now an elegant solution is at hand. With their unusual mechanical, thermal and electronic properties, the tiny tubes with their honeycomb lattice of graphitic carbon have become the embodiment of nanomaterials. They could be used to manufacture the next generation of electronic and electro-optical components so that they are even smaller and with even faster switching times than before. But to achieve this, the material scientists must specifically equip the nanotubes with desired properties, and these depend on their structure. The production methods used to date, however, always result in a mixture of different CNTs. The team from Empa  and the Max Planck Institute for Solid State Research has now remedied the situation with a new production path for single-walled nanotubes.

Carbon nanotubes with the best possible varietal purity are in demand

With a diameter of around one nanometre, single-walled CNTs (SWCNTs) are deemed to be quantum structures; very tiny structural differences, in the diameter, for example, or in the orientation of the atomic lattice, can dramatically change the electronic properties: one SWCNT can be a metal, while one with a slightly different structure is semi-conducting. Correspondingly great is the interest in reliable methods for producing SWCNTs with the best possible varietal purity. Researchers working with Martin Jansen, Director Emeritus at the Max Planck Institute for Solid State Research, have been pursuing suitable concepts for the synthesis for ten years. But it is only now that the surface physicists at Empa and the chemists at the Stuttgart-based Max Planck Institute have succeeded in implementing one of these ideas in the laboratory. The researchers allowed structurally identical SWCNTs to grow on a platinum surface in a self-organised process and were able to unambiguously define their electronic properties.

The Max Planck research team headed by Martin Jansen had the idea of starting with small precursor molecules to synthesise carbon nanotubes. They felt it should be possible to achieve controlled conversion of the precursor molecules into a cap which acts as the seed for a SWCNT and thus unambiguously specify the structure of the nanotube. With this concept, they approached the Empa team working with Roman Fasel, head of Empa’s «nanotech@surfaces» department and titular professor at the Department of Chemistry and Biochemistry of the University of Bern. This group has already been working for some time on how molecules on a surface can be converted or combined into complex nanostructures according to the principle of molecular self-organisation. “The challenge now consists in finding the right precursor molecule which would actually grow on a smooth surface,” says Roman Fasel. This was ultimately achieved by Andreas Mueller and Konstantin Amsharov from the Max Planck Institute in Stuttgart with the synthesis of a hydrocarbon molecule from a not-inconsiderable 150 atoms.

Molecular origami on the platinum surface

What exactly is the process in which the carbon nanotube forms? In the first step, the flat precursor molecule must – as is the case in origami – convert into a three-dimensional object, the seed. This takes place on a hot platinum surface with the aid of a catalytic reaction, whereby hydrogen atoms split off from the precursor molecule and form new carbon-carbon bonds at very specific positions. The seed folds up from the flat molecule: a tiny, domed shape with open rim, which sits on the platinum surface. This so-called end cap forms the top of the growing SWCNT.

In a second chemical process, further carbon atoms, which are formed during the catalytic decomposition of ethanol on the platinum surface, are taken up. They deposit on the open rim between end cap and platinum surface and lift the cap higher and higher; the tube slowly grows upwards. The atomic structure of the nanotube is determined solely by the shape of the seed. The researchers proved this by analysing the vibrational modes of the SWCNTs and taking measurements with the scanning tunnelling microscope. Further investigations at Empa showed that the SWCNTs produced were over 300 nanometres in length.

Different nanotubes are formed from suitable precursor molecules

The researchers have thus proved that they can unambiguously specify the growth and thus the structure of long SWCNTs using custom-made molecular seeds. The SWCNTs synthesised in this study can exist in two forms, which correspond to an object and its mirror image. By choosing the precursor molecule appropriately, the researchers were able to influence which of the two variants forms. Depending on how the honeycomb atomic lattice is derived from the original molecule – straight or oblique with respect to the CNT axis – it is also possible for helically wound tubes, i.e. with right- or left-handed rotation, and with non-mirror symmetry to form. And it is precisely this structure that then determines which electronic, thermo-electric and optical properties of the material. In principle, the researchers can therefore specifically produce materials with different properties through their choice of precursor molecule.

In further steps, Roman Fasel and his colleagues want to gain an even better understanding of how SWCNTs establish themselves on a surface. Even if well in excess of 100 million nanotubes per square centimetre already grow on the platinum surface, only a relatively small fraction of the seeds actually develop into «mature» nanotubes. The question remains as to which processes are responsible for this, and how the yield can be increased.

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

Controlled synthesis of single-chirality carbon nanotubes by Juan Ramon Sanchez-Valencia, Thomas Dienel, Oliver Gröning, Ivan Shorubalko, Andreas Mueller, Martin Jansen, Konstantin Amsharov, Pascal Ruffieux, & Roman Fasel. Nature 512, 61–64 (07 August 2014) doi:10.1038/nature13607

Published online 06 August 2014

This paper is behind a paywall.

Threats to increase anti-science violence

Andy Coghlan has a May 29, 2012 article on the New Scientist’s website outlining the recent history of violence and renewed threats against scientists,

It’s like something out of Kafka. Anti-science anarchists in Italy appear to be ramping up their violent and frankly surreal campaign. Having claimed responsibility for shooting the boss of a nuclear engineering company in Genoa, the group has vowed to target Finmeccanica, the Italian aerospace and defence giant.

In  a diatribe sent on 11 May to Corriere della Sera newspaper on 11 May, the Olga Cell of the Informal Anarchist Federation International Revolutionary Front said it shot Roberto Adinolfi, head of Ansaldo Nucleare, in the leg four days earlier. “With this action of ours, we return to you a tiny part of the suffering that you, man of science, are pouring into this world,” the statement said. It also pledged a “campaign of struggle against Finmeccanica, the murderous octopus”.

This group has also claimed responsiblity for the 2010 attempted attack on a nanotechnology centre in Switzerland (mentioned most recently in my July 25, 2011 posting) and, according to Coghlan’s article, the Informal Anarchist Federation International Revolutionary Front is associated with the, in English,  Individuals Tending to Savagery (ITS) group who claimed responsibility for the August 2011  attacks on ‘nanotechnology researchers’ in Mexico (mentioned in my August 11, 2011 posting).

The anarchists seem to be turning their attention away from nanotechnology to focus on the nuclear industry.  This quote from Coghlan’s article stimulated a new line of thinking on the topic of violence and science  for me (I’ve been horrified by it all),

“At least with animal rights activists, you know what they want, but with these anarchists, I’m not sure,” he says. “Do they want us to stop all scientific experiments, stop driving cars or go back to living in caves? I don’t know.” [Michael Hagman, head of communications at the Empa institute in Duebendorf, Switzerland]

The cynic in me finally awoke when I put that quote together with the group’s shift to a new target. After last year’s Fukushima incident and the huge amount of interest and concern, I imagine the Informal Anarchist Federation International Revolutionary Front has concluded they will get far more attention and notoriety, their primary and only goal,  by focusing on the nuclear industry.

If you’re interested, the details about the most recent attack, the group’s international links,  and some good writing are featured in Coghlan’s article.

ETA Aug. 30, 2012: I corrected the author’s name from Coughlan to Coghlan.

ETA Feb. 21, 2013: Leigh Phillips contacted me to mention that there was a May 28, 2012 article for Nature, Anarchists attack science, which preceded Coghlan’s article for New Scientist and to which Coghlan provides a link. Phillips’ preceding article was subtitled, Armed extremists are targeting nuclear and nanotechnology workers. Phillips opens with the then recent attack on a nuclear engineering executive and subsequently focuses on attacks in the nanotechnology sector.

Sweating out silver nanoparticles

I’ve often wondered if the  silver nanoparticles, which coat the textiles used for clothing that doesn’t smell or need to be cleaned often, gets washed off by your sweat. As Michael Berger noted in his November 4, 2009 article on Nanowerk, researchers have found that silver nanoparticles do get washed off into the water,

Researchers in Switzerland have now examined what happens to these silver nanoparticle-treated textiles during washing. The scientists studied release of nanoparticles in laundry water from nine different textiles, including different brands of commercially available anti-odor socks. Studies like these will help address the question what the chances are of nanoparticles from nanofinished textiles being released into the environment.

“We found that the total released varied considerably from less than 1 to 45 percent of the total nanosilver in the fabric and that most came out during the first wash,” Bernd Nowack, head of the Environmental Risk Assessment and Management Group at the Empa-Swiss Federal Laboratories for Materials Testing and Research, tells Nanowerk. “These results have important implications for the risk assessment of silver textiles and also for environmental fate studies of nanosilver, because they show that under certain conditions relevant to washing, primarily coarse silver-containing particles are released.”

As it turns out, Thai researchers have recently discovered that sweat will also wash off those silver nanoparticles (from the news item on Nanowerk),

A recent study by researchers at National Nanotechnology Center (NANOTEC) in Thailand has provided the data on detecting silver released from antibacterial fabric products using artificial sweat as a model to represent the human skin environment.

“The amount of silver released from fabrics into artificial sweat was dependent upon the initial amount of silver coating, the fabric quality, pH and artificial sweat formulations “said Dr Rawiwan Maniratanachote, head of Nano Safety and Risk Assessment Lab. “The study could be useful to evaluate potential human risk when exposed to silver nanoparticles from textile materials.”

I guess the next couple of questions to be answered are: do the silver nanoparticles being washing off by your sweat penetrate your skin and/or do the silver nanoparticles wash off your skin and into the water supply?