Tag Archives: Switzerland

Carrot-based helmets: a nanocellulose commercialization story

NanoCelluComp, a European Commission-funded project, whose name bears a close resemblance to a Scottish company, CelluComp, ended last year (my March 5, 2014 post). Both, NanoCelluComp and CelluComp, were/are involved in research featuring carrots and nanocellulose.

An Aug. 6, 2015 news item on ScienceDaily describes some Swiss/Scottish research into using carrot nanofibers in helmets,

Crackpot idea or recipe for success? This is a question entrepreneurs often face. Is it worth converting the production process to a new, ecologically better material? Empa [Swiss Federal Laboratories for Materials Science and Technology or Eidgenössische Materialprüfungs- und Forschungsansta] has developed an analysis method that enables companies to simulate possible scenarios — and therefore avoid bad investments. Here’s an example: Nanofibers made of carrot waste from the production of carrot juice, which can be used to reinforce synthetic parts.

All over the world, research is being conducted into biodegradable and recyclable synthetics. However, fiber-reinforced components remain problematic — if glass or carbon fibers are used. Within the scope of an EU research project, the Scottish company Cellucomp Limited has now developed a method to obtain nanofibers from carrot waste. [emphasis mine] These fibers would be both cost-effective and biodegradable. However, is the method, which works in the lab, also marketable on a large scale?

Here’s a composite image illustrating the notion of a carrot-based helmet,

Motorcycle helmets consist of fiber-reinforced synthetic material. Instead of glass fibers, a biological alternative is now also possible: plant fibers from the production of carrot juice. Empa researchers are now able to analyze whether this kind of production makes sense from an ecological and economical perspective – before money is actually invested in production plants.  Photo: 4ever.eu, composite photo: Empa

Motorcycle helmets consist of fiber-reinforced synthetic material. Instead of glass fibers, a biological alternative is now also possible: plant fibers from the production of carrot juice. Empa researchers are now able to analyze whether this kind of production makes sense from an ecological and economical perspective – before money is actually invested in production plants.
Photo: 4ever.eu, composite photo: Empa

An Aug. 6, 2015 Empa press release (also on EurekAlert), which originated the news item, provides more details abut the drive to commercialize this nanocellulose product,

An MPAS (multi-perspective application selection) method developed at Empa helps identify the industrial sectors where new materials might be useful from a technical and economical perspective. At the same time, MPAS also considers the ecological aspect of these new materials. The result for our example: Nanofibers made of carrot waste might be used in the production of motorcycle helmets or side walls for motorhomes in the future.

Three-step analysis

In order to clarify a new material’s market potential, Empa researchers Fabiano Piccinno, Roland Hischier and Claudia Som proceed in three steps for the MPAS method. First of all, the field of possible applications is defined: Which applications come into question based on the technical properties and what categories can they be divided into? Can the new material replace an existing one?

The second step concerns the technical feasibility and market potential: Can the material properties required be achieved with the technical process? Might the product quality vary from one production batch to the next? Can the lab process be upgraded to an industrial scale cost-effectively? Is the material more suited to the low-cost sector or expensive luxury goods? And finally: Does the product meet the legal standards and the customers’ certification needs?

In the third step, the ecological aspect is eventually examined: Is this new material for the products identified really more environmentally friendly – once all the steps from product creation to recycling have been factored in? Which factors particularly need to be considered during production stage to manufacture the material in as environmentally friendly a way as possible?

Industrial production on a five-ton scale – calculated theoretically

The MPAS approach enables individual scenarios for a future production to be calculated with an extremely high degree of accuracy. In the case of the carrot waste nanofibers, for instance, it is crucial whether five tons of fresh carrots or only 209 kilograms of carrot waste (fiber waste from the juicing process) are used as the base material for their production. The issue of whether the solvent is ultimately recycled or burned affects the production costs. And the energy balance depends on how the enzymes that loosen the fibers from the carrots are deactivated. In the lab, this takes place via heat; for production on an industrial level, the use of bleaching agents would be more cost-effective.

Conclusion: six possible applications for “carrot fibers“

For fiber production from carrot waste, the MPAS analysis identified six possible customer segments for the Scottish manufacturer Cellucomp that are worth taking a closer look at: Protective equipment and devices for recreational sport, special vehicles, furniture, luxury consumer goods and industrial manufacturing. The researchers listed the following examples: Motorcycle helmets and surfboards, side walls for motorhomes, dining tables, high-end loudspeaker boxes and product protection mats for marble-working businesses. Similarly detailed analyses can also be conducted for other renewable materials – before a lot of money is actually invested in production plants.

There are other attempts to commercialize nanocellulose (as I understand it, cellulose is one of the most common materials on earth and can be derived from several sources including trees, bananas, pineapples, and more) mentioned in my July 30, 2015 post. I will repeat a question from that post, where are the Canadian research efforts to develop and commercialize nanocellulose? If you have information, please do let me know.

Nano (?) diamonds used in mechanical system to control quantum states

We do end up back in the world of spin but, first, there are the nano (I think) diamonds in an Aug. 3, 2015 news item on Nanotechnology Now,

Scientists at the Swiss Nanoscience Institute at the University of Basel have used resonators made from single-crystalline diamonds to develop a novel device in which a quantum system is integrated into a mechanical oscillating system. For the first time, the researchers were able to show that this mechanical system can be used to coherently manipulate an electron spin embedded in the resonator – without external antennas or complex microelectronic structures. …

A July 16, 2014 University of Basel press release (also on EurekAlert), which originated the news item, provides more detail about the work,

In previous publications, the research team led by Georg H. Endress Professor Patrick Maletinsky described how resonators made from single-crystalline diamonds with individually embedded electrons are highly suited to addressing the spin of these electrons. These diamond resonators were modified in multiple instances so that a carbon atom from the diamond lattice was replaced with a nitrogen atom in their crystal lattices with a missing atom directly adjacent. In these “nitrogen-vacancy centers,” individual electrons are trapped. Their “spin” or intrinsic angular momentum is examined in this research.

When the resonator now begins to oscillate, strain develops in the diamond’s crystal structure. This, in turn, influences the spin of the electrons, which can indicate two possible directions (“up” or “down”) when measured. The direction of the spin can be detected with the aid of fluorescence spectroscopy.

Extremely fast spin oscillation

In this latest publication, the scientists have shaken the resonators in a way that allows them to induce a coherent oscillation of the coupled spin for the first time. This means that the spin of the electrons switches from up to down and vice versa in a controlled and rapid rhythm and that the scientists can control the spin status at any time. This spin oscillation is fast compared with the frequency of the resonator. It also protects the spin against harmful decoherence mechanisms.

It is conceivable that this diamond resonator could be applied to sensors – potentially in a highly sensitive way – because the oscillation of the resonator can be recorded via the altered spin. These new findings also allow the spin to be coherently rotated over a very long period of close to 100 microseconds, making the measurement more precise. Nitrogen-vacancy centers could potentially also be used to develop a quantum computer. In this case, the quick manipulation of its quantum states demonstrated in this work would be a decisive advantage.

Unfortunately, the researchers do not indicate the measurement scale for the diamonds so I’m guessing, given the descriptions, that these were nanoscale diamonds being used in the research.

In any event, here’s a link to and a citation for the paper,

Strong mechanical driving of a single electron spin by A. Barfuss, J. Teissier, E. Neu, A. Nunnenkamp, & P. Maletinsky. Nature Physics (2015)  doi:10.1038/nphys3411 Published online 03 August 2015

This paper is behind a paywall.

Slaughterhouse yarn (scientists looking for business investment)

Not everyone is going to feel comfortable with the idea of using gelatine to create fibres for yarn. Nonetheless, here’s a July 29, 2015 ETH Zurich (Swiss Federal Institute of Technology in Zurich, [Eidgenössische Technische Hochschule Zürich]) press release (also on EurekAlert) describes the research (a plea for business investment follows),

Some 70 million tonnes of fibres are traded worldwide every year. Man-made fibres manufactured from products of petroleum or natural gas account for almost two-thirds of this total. The most commonly used natural fibres are wool and cotton, but they have lost ground against synthetic fibres.

Despite their environmental friendliness, fibres made of biopolymers from plant or animal origin remain very much a niche product. At the end of the 19th century, there were already attempts to refine proteins into textiles. For example, a patent for textiles made of gelatine was filed in 1894. After the Second World War, however, the emerging synthetic fibres drove biological protein fibres swiftly and thoroughly from the market.

Over the past few years, there has been increased demand for natural fibres produced from renewable resources using environmentally friendly methods. Wool fibre in particular has experienced a renaissance in performance sportswear made of merino wool. And a few years ago, a young entrepreneur in Germany started making high-quality textiles from the milk protein casein.

New use for waste product

Now Philipp Stössel, a 28-year-old PhD student in Professor Wendelin Stark’s Functional Materials Laboratory (FML), is presenting a new method for obtaining high-quality fibres from gelatine. The method was developed in cooperation with the Advanced Fibers Laboratory at Empa St. Gallen. Stössel was able to spin the fibres into a yarn from which textiles can be manufactured.

Gelatine consists chiefly of collagen, a main component of skin, bone and tendons. Large quantities of collagen are found in slaughterhouse waste and can be easily made into gelatine. For these reasons, Stark and Stössel decided to use this biomaterial for their experiments.

Coincidence helps provide a solution

In his experiments, Stössel noticed that when he added an organic solvent (isopropyl) to a heated, aqueous gelatine solution, the protein precipitated at the bottom of the vessel. He removed the formless mass using a pipette and was able to effortlessly press an elastic, endless thread from it. This was the starting point for his unusual research work.

As part of his dissertation, Stössel developed and refined the method, which he has just recently presented in an article for the journal Biomacromolecules.

The refined method replaces the pipette with several syringe drivers in a parallel arrangement. Using an even application of pressure, the syringes push out fine endless filaments, which are guided over two Teflon-coated rolls. The rolls are kept constantly moist in an ethanol bath; this prevents the filaments from sticking together and allows them to harden quickly before they are rolled onto a conveyor belt. Using the spinning machine he developed, Stössel was able to produce 200 metres of filaments a minute. He then twisted around 1,000 individual filaments into a yarn with a hand spindle and had a glove knitted from the yarn as a showpiece.

Attractive luster

Extremely fine, the individual fibres have a diameter of only 25 micrometres, roughly half the thickness of a human hair. With his first laboratory spinning machines, the fibre thickness was 100 micrometres, Stössel recalls. That was too thick for yarn production.

Whereas natural wool fibres have tiny scales, the surface of the gelatine fibres is smooth. “As a result, they have an attractive luster,” Stössel says. Moreover, the interior of the fibres is filled with cavities, as shown by the researchers’ electron microscope images. This might also be the reason for the gelatine yarn’s good insulation, which Stössel was able to measure in comparison with a glove made of merino wool.

Water-resistant fibres

Gelatine’s major drawback is that it its water-solubility. Stössel had to greatly improve the water resistance of the gelatine yarn through various chemical processing stages. First he treated the glove with an epoxy in order to bond the gelatine components more firmly together. Next, he treated the material with formaldehyde so that it would harden better. Finally, he impregnated the yarn with lanolin, a natural wool grease, to make it supple.

As he completes his dissertation over the coming months, Stössel will research how to make the gelatine fibres even more water-resistant. Sheep’s wool is still superior to the gelatine yarn in this respect. However, Stössel is convinced that he is very close to his ultimate goal: making a biopolymer fibre from a waste product.

It’s been a few months since I’ve seen one of these pleas for commercial interest/partnership (from the press release),

Three years ago, the researchers applied for a patent on their invention. Stössel explains that they have reached the point where their capacity in the laboratory is at its limit, but commercial production will only be possible if they can find partners and funding.

Here’s a link to and a citation for the researchers’ latest published paper (there are also two previous paper listed in the press release),

Porous, Water-Resistant Multifilament Yarn Spun from Gelatin by Philipp R. Stoessel, Urs Krebs, Rudolf Hufenus, Marcel Halbeisen, Martin Zeltner, Robert N. Grass, and Wendelin J. Stark. Biomacromolecules, 2015, 16 (7), pp 1997–2005 DOI: 10.1021/acs.biomac.5b00424 Publication Date (Web): June 2, 2015

Copyright © 2015 American Chemical Society

This paper is behind a paywall.

Putting the speed on spin, spintronics that is

This is for physics fans, if you plan on looking at the published paper. Otherwise, the July 20, 2015 news item on ScienceDaily is more accessible to the rest of us,

In a tremendous boost for spintronic technologies, EPFL scientists have shown that electrons can jump through spins much faster than previously thought.

Electrons spin around atoms, but also spin around themselves, and can cross over from one spin state to another. A property which can be exploited for next-generation hard drives. However, “spin cross-over” has been considered too slow to be efficient. Using ultrafast measurements, EPFL scientists have now shown for the first time that electrons can cross spins at least 100,000 times faster than previously thought. Aside for its enormous implications for fundamental physics, the finding can also propel the field of spintronics forward. …

A July 20, 2015 EPFL press release on EurekAlert, which originated the news item, provides context for the research,

The rules of spin

Although difficult to describe in everyday terms, electron spin can be loosely compared to the rotation of a planet or a spinning top around its axis. Electrons can spin in different manners referred to as “spin states” and designated by the numbers 0, 1/2, 1, 3/2, 2 etc. During chemical reactions, electrons can cross from one spin state to another, e.g. from 0 to 1 or 1/2 to 3/2.

Spin cross-over is already used in many technologies, e.g. optical light-emitting devices (OLED), energy conversion systems, and cancer phototherapy. Most prominently, spin cross-over is the basis of the fledgling field of spintronics. The problem is that spin cross-over has been thought to be too slow to be efficient enough in circuits.

Spin cross-over is extremely fast

The lab of Majed Chergui at EPFL has now demonstrated that spin cross-over is considerably faster than previously thought. Using the highest time-resolution technology in the world, the lab was able to “see” electrons crossing through four spin states within 50 quadrillionths of a second — or 50 femtoseconds.

“Time resolution has always been a limitation,” says Chergui. “Over the years, labs have used techniques that could only measure spin changes to a billionth to a millionth of a second. So they thought that spin cross-over happened in this timeframe.”

Chergui’s lab focused on materials that show much promise in spintronics applications. In these materials, electrons jump through four spin-states: from 0 to 1 to 2. In 2009, Chergui’s lab pushed the boundaries of time resolution to show that this 0-2 “jump” can happen within 150 femtoseconds — suggesting that it was a direct event. Despite this, the community still maintained that such spin cross-overs go through intermediate steps.

But Chergui had his doubts. Working with his postdoc Gerald Auböck, they used the lab’s world-recognized expertise in ultrafast spectroscopy to “crank up” the time resolution. Briefly, a laser shines on the material sample under investigation, causing its electrons to move. Another laser measures their spin changes over time in the ultraviolet light range.

The finding essentially demolishes the notion of intermediate steps between spin jumps, as it does not allow enough time for them: only 50 quadrillionths of a second to go from the “0” to the “2” spin state. This is the first study to ever push time resolution to this limit in the ultraviolet domain. “This probably means that it’s even faster,” says Chergui. “But, more importantly, that it is a direct process.”

From observation to explanation

With profound implications for both technology and fundamental physics and chemistry, the study is an observation without an explanation. Chergui believes that the key is electrons shuttling back-and-forth between the iron atom at the center of the material’s molecules and its surrounding elements. “When the laser light shines on the atom, it changes the electron’s spin angle, affecting the entire spin dynamics in the molecule.”

It is now up to theoreticians to develop a new model for ultrafast spin changes. On the experimental side of things, Chergui’s lab is now focusing on actually observing electrons shuttling inside the molecules. This will require even more sophisticated approaches, such as core-level spectroscopy. Nonetheless, the study challenges ideas about spin cross-over, and might offer long-awaited solutions to the limitations of spintronics.

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

Sub-50-fs photoinduced spin crossover in [Fe(bpy)3]2+ by Gerald Auböck & Majed Chergui. Nature Chemistry (2015) doi:10.1038/nchem.2305 Published online 20 July 2015

This paper is behind a paywall.

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).

Saharan silver ants: the nano of it all (science and technology)

Researchers at Columbia University (US) are on quite a publishing binge lately. The latest is a biomimicry story where researchers (from Columbia amongst other universities and including Brookhaven National Laboratory, which has issued its own news release) have taken a very close look at Saharan silver ants to determine how they stay cool in one of the hottest climates in the world. From a June 18, 2015 Columbia University news release (also on EurekAlert), Note: Links have been removed,

Nanfang Yu, assistant professor of applied physics at Columbia Engineering, and colleagues from the University of Zürich and the University of Washington, have discovered two key strategies that enable Saharan silver ants to stay cool in one of the hottest terrestrial environments on Earth. Yu’s team is the first to demonstrate that the ants use a coat of uniquely shaped hairs to control electromagnetic waves over an extremely broad range from the solar spectrum (visible and near-infrared) to the thermal radiation spectrum (mid-infrared), and that different physical mechanisms are used in different spectral bands to realize the same biological function of reducing body temperature. Their research, “Saharan silver ants keep cool by combining enhanced optical reflection and radiative heat dissipation,” is published June 18 [2015] in Science magazine.

The Columbia University news release expands on the theme,

“This is a telling example of how evolution has triggered the adaptation of physical attributes to accomplish a physiological task and ensure survival, in this case to prevent Saharan silver ants from getting overheated,” Yu says. “While there have been many studies of the physical optics of living systems in the ultraviolet and visible range of the spectrum, our understanding of the role of infrared light in their lives is much less advanced. Our study shows that light invisible to the human eye does not necessarily mean that it does not play a crucial role for living organisms.”

The project was initially triggered by wondering whether the ants’ conspicuous silvery coats were important in keeping them cool in blistering heat. Yu’s team found that the answer to this question was much broader once they realized the important role of infrared light. Their discovery that there is a biological solution to a thermoregulatory problem could lead to the development of novel flat optical components that exhibit optimal cooling properties.

“Such biologically inspired cooling surfaces will have high reflectivity in the solar spectrum and high radiative efficiency in the thermal radiation spectrum,” Yu explains. “So this may generate useful applications such as a cooling surface for vehicles, buildings, instruments, and even clothing.”

Saharan silver ants (Cataglyphis bombycina) forage in the Saharan Desert in the full midday sun when surface temperatures reach up to 70°C (158°F), and they must keep their body temperature below their critical thermal maximum of 53.6°C (128.48°F) most of the time. In their wide-ranging foraging journeys, the ants search for corpses of insects and other arthropods that have succumbed to the thermally harsh desert conditions, which they are able to endure more successfully. Being most active during the hottest moment of the day also allows these ants to avoid predatory desert lizards. Researchers have long wondered how these tiny insects (about 10 mm, or 3/8” long) can survive under such thermally extreme and stressful conditions.

Using electron microscopy and ion beam milling, Yu’s group discovered that the ants are covered on the top and sides of their bodies with a coating of uniquely shaped hairs with triangular cross-sections that keep them cool in two ways. These hairs are highly reflective under the visible and near-infrared light, i.e., in the region of maximal solar radiation (the ants run at a speed of up to 0.7 meters per second and look like droplets of mercury on the desert surface). The hairs are also highly emissive in the mid-infrared portion of the electromagnetic spectrum, where they serve as an antireflection layer that enhances the ants’ ability to offload excess heat via thermal radiation, which is emitted from the hot body of the ants to the cold sky. This passive cooling effect works under the full sun whenever the insects are exposed to the clear sky.

“To appreciate the effect of thermal radiation, think of the chilly feeling when you get out of bed in the morning,” says Yu. “Half of the energy loss at that moment is due to thermal radiation since your skin temperature is temporarily much higher than that of the surrounding environment.”

The researchers found that the enhanced reflectivity in the solar spectrum and enhanced thermal radiative efficiency have comparable contributions to reducing the body temperature of silver ants by 5 to 10 degrees compared to if the ants were without the hair cover. “The fact that these silver ants can manipulate electromagnetic waves over such a broad range of spectrum shows us just how complex the function of these seemingly simple biological organs of an insect can be,” observes Norman Nan Shi, lead author of the study and PhD student who works with Yu at Columbia Engineering.

Yu and Shi collaborated on the project with Rüdiger Wehner, professor at the Brain Research Institute, University of Zürich, Switzerland, and Gary Bernard, electrical engineering professor at the University of Washington, Seattle, who are renowned experts in the study of insect physiology and ecology. The Columbia Engineering team designed and conducted all experimental work, including optical and infrared microscopy and spectroscopy experiments, thermodynamic experiments, and computer simulation and modeling. They are currently working on adapting the engineering lessons learned from the study of Saharan silver ants to create flat optical components, or “metasurfaces,” that consist of a planar array of nanophotonic elements and provide designer optical and thermal radiative properties.

Yu and his team plan next to extend their research to other animals and organisms living in extreme environments, trying to learn the strategies these creatures have developed to cope with harsh environmental conditions.

“Animals have evolved diverse strategies to perceive and utilize electromagnetic waves: deep sea fish have eyes that enable them to maneuver and prey in dark waters, butterflies create colors from nanostructures in their wings, honey bees can see and respond to ultraviolet signals, and fireflies use flash communication systems,” Yu adds. “Organs evolved for perceiving or controlling electromagnetic waves often surpass analogous man-made devices in both sophistication and efficiency. Understanding and harnessing natural design concepts deepens our knowledge of complex biological systems and inspires ideas for creating novel technologies.”

Next, there’s the perspective provided by Brookhaven National Laboratory in a June 18, 2015 news item on Nanowerk (Note: It is very similar to the Columbia University news release but it takes a turn towards the technical challenges as you’ll see if you keep reading),

The paper, published by Columbia Engineering researchers and collaborators—including researchers from the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory—describes how the nanoscale structure of the hairs helps increase the reflectivity of the ant’s body in both visible and near-infrared wavelengths, allowing the insects to deflect solar radiation their bodies would otherwise absorb. The hairs also enhance emissivity in the mid-infrared spectrum, allowing heat to dissipate efficiently from the hot body of the ants to the cool, clear sky.

A June 18, 2015 BNL news release by Alasdair Wilkins, which originated the Nanowerk news item, describes the collaboration between the researchers and the special adjustments made to the equipment in service of this project (Note: A link has been removed),

In a typical experiment involving biological material such as nanoscale hairs, it would usually be sufficient to use an electron microscope to create an image of the surface of the specimen. This research, however, required Yu’s group to look inside the ant hairs and produce a cross-section of the structure’s interior. The relatively weak beam of electrons from a standard electron microscope would not be able to penetrate the surface of the sample.

The CFN’s dual beam system solves the problem by combining the imaging of an electron microscope with a much more powerful beam of gallium ions.  With 31 protons and 38 neutrons, each gallium ion is about 125,000 times more massive than an electron, and massive enough to create dents in the nanoscale structure – like throwing a stone against a wall. The researchers used these powerful beams to drill precise cuts into the hairs, revealing the crucial information hidden beneath the surface. Indeed, this particular application, in which the system was used to investigate a biological problem, was new for the team at CFN.

“Conventionally, this tool is used to produce cross-sections of microelectronic circuits,” said Camino. “The focused ion beam is like an etching tool. You can think of it like a milling tool in a machine shop, but at the nanoscale. It can remove material at specific places because you can see these locations with the SEM. So locally you remove material and you look at the under layers, because the cuts give you access to the cross section of whatever you want to look at.”

The ant hair research challenged the CFN team to come up with novel solutions to investigate the internal structures without damaging the more delicate biological samples.

“These hairs are very soft compared to, say, semiconductors or crystalline materials. And there’s a lot of local heat that can damage biological samples. So the parameters have to be carefully tuned not to do much damage to it,” he said. “We had to adapt our technique to find the right conditions.”

Another challenge lay in dealing with the so-called charging effect. When the dual beam system is trained on a non-conducting material, electrons can build up at the point where the beams hit the specimen, distorting the resulting image. The team at CFN was able to solve this problem by placing thin layers of gold over the biological material, making the sample just conductive enough to avoid the charging effect.

Revealing Reflectivity

While Camino’s team focused on helping Yu’s group investigate the structure of the ant hairs, Matthew Sfeir’s work with high-brightness Fourier transform optical spectroscopy helped to reveal how the reflectivity of the hairs helped Saharan silver ants regulate temperature. Sfeir’s spectrometer revealed precisely how much those biological structures reflect light across multiple wavelengths, including both visible and near-infrared light.

“It’s a multiplexed measurement,” Sfeir said, explaining his team’s spectrometer. “Instead of tuning through this wavelength and this wavelength, that wavelength, you do them all in one swoop to get all the spectral information in one shot. It gives you very fast measurements and very good resolution spectrally. Then we optimize it for very small samples. It’s a rather unique capability of CFN.”

Sfeir’s spectroscopy work draws on knowledge gained from his work at another key Brookhaven facility: the original National Synchrotron Light Source, where he did much of his postdoc work. His experience was particularly useful in analyzing the reflectivity of the biological structures across many different wavelengths of the electromagnetic spectrum.

“This technique was developed from my experience working with the infrared synchrotron beamlines,” said Sfeir. “Synchrotron beamlines are optimized for exactly this kind of thing. I thought, ‘Hey, wouldn’t it be great if we could develop a similar measurement for the type of solar devices we make at CFN?’ So we built a bench-top version to use here.”

Fascinating, non? At last, here’s a link to and a citation for the paper,

Keeping cool: Enhanced optical reflection and heat dissipation in silver ants by Norman Nan Shi, Cheng-Chia Tsai, Fernando Camino, Gary D. Bernard, Nanfang Yu, and Rüdiger Wehner. Science DOI: 10.1126/science.aab3564 Published online June 18, 2015

This paper is behind a paywall.

Tanzanian research into nanotechnology-enabled water filters

Inexpensive 99.9999…% filtration of metals, bacteria, and viruses from water is an accomplishment worthy of a prize as the UK’s Royal Academy of Engineering noted by awarding its first ever International Innovation Prize of £25,000 ($38,348 [USD?]) to Askwar Hilonga, a Tanzanian academic and entrepreneur. A June 11, 2015 article by Sibusiso Tshabalala for Quartz.com describes the water situation in Tanzania and Hilonga’s accomplishment (Note: Links have been removed),

Despite Tanzania’s proximity to three major lakes almost half of it’s population cannot access potable water.

Groundwater is often the alternative, but the supply is not always clean. Mining waste (pdf, pg 410) and toxic drainage systems easily leak into fresh groundwater, leaving the water contaminated.

Enter Askwar Hilonga: a 38-year old chemical engineer PhD and entrepreneur. With 33 academic journal articles on nanotechnology to his name, Hilonga aims to solve Tanzania’s water contamination problems by using nanotechnology to customize water filters.

There are other filters available (according to Tshabalala’s article) but Hilonga’s has a unique characteristic in addition to being highly efficient and inexpensive,

Purifying water using nanotechnology is hardly a new thing. In 2010, researchers at the Yi Cui Lab at Stanford University developed a synthetic “nanoscanvenger” made out of two silver layers that enable nanoparticles to disinfect water from contaminating bacteria.

What makes Hilonga’s water filter different from the Stanford-developed “nanoscavenger”, or the popular LifeStraw developed by the Swiss-based health innovation company Vestergaard 10 years ago?

“It is customized. The filter can be tailored for specific individual, household and communal use,” says Hilonga.

A June 2, 2015 news item about the award on BBC (British Broadcasting Corporation) online describes how the filter works,

The sand-based water filter that cleans contaminated drinking water using nanotechnology has already been trademarked.

“I put water through sand to trap debris and bacteria,” Mr Hilonga told the BBC’s Newsday programme about the filter.

“But sand cannot remove contaminants like fluoride and other heavy metals so I put them through nano materials to remove chemical contaminants.”

Hilonga describes the filter in a little more detail in his May 30, 2014 video submitted for for the UK Royal Academy of Engineering’s prize (Africa Prize for Engineering Innovation)

Finalists for the prize (there were four) received a six month mentorship which included help to develop the technology further and with business plans. Hilonga has already enabled 23 entrepreneurs to develop nanofilter businesses, according to the Tshabalala article,

Through the Gongali Model Company, a university spin-off company which he co-founded, Hilonga has already enabled 23 entrepreneurs in Karatu to set up their businesses with the filters, and local schools to provide their learners with clean drinking water.

With this prize money, Hilonga will be able to lower the price of his filter ($130 [USD?) according to the BBC news item.

Congratulations to Dr. Hilonga and his team! For anyone curious about the Gongali Model Company, you can go here.

An efficient method for signal transmission from nanocomponents

A May 23, 2015 news item on Nanotechnology Now describes research into perfecting the use of nanocomponents in electronic circuits,

Physicists have developed an innovative method that could enable the efficient use of nanocomponents in electronic circuits. To achieve this, they have developed a layout in which a nanocomponent is connected to two electrical conductors, which uncouple the electrical signal in a highly efficient manner. The scientists at the Department of Physics and the Swiss Nanoscience Institute at the University of Basel have published their results in the scientific journal Nature Communications together with their colleagues from ETH Zurich.

A May 22, 2015 University of Basel press release (also on EurkeAlert) describes why there is interest in smaller components and some of the challenges once electrodes can be measured in atoms,

Electronic components are becoming smaller and smaller. Components measuring just a few nanometers – the size of around ten atoms – are already being produced in research laboratories. Thanks to miniaturization, numerous electronic components can be placed in restricted spaces, which will boost the performance of electronics even further in the future.

Teams of scientists around the world are investigating how to produce such nanocomponents with the aid of carbon nanotubes. These tubes have unique properties – they offer excellent heat conduction, can withstand strong currents, and are suitable for use as conductors or semiconductors. However, signal transmission between a carbon nanotube and a significantly larger electrical conductor remains problematic as large portions of the electrical signal are lost due to the reflection of part of the signal.

Antireflex increases efficiency

A similar problem occurs with light sources inside a glass object. A large amount of light is reflected by the walls, which means that only a small proportion reaches the outside. This can be countered by using an antireflex coating on the walls.

The press release goes on to describe new technique for addressing the issue,

Led by Professor Christian Schönenberger, scientists in Basel are now taking a similar approach to nanoelectronics. They have developed an antireflex device for electrical signals to reduce the reflection that occurs during transmission from nanocomponents to larger circuits. To do so, they created a special formation of electrical conductors of a certain length, which are coupled with a carbon nanotube. The researchers were therefore able to efficiently uncouple a high-frequency signal from the nanocomponent.

Differences in impedance cause the problem

Coupling nanostructures with significantly larger conductors proved difficult because they have very different impedances. The greater the difference in impedance between two conducting structures, the greater the loss during transmission. The difference between nanocomponents and macroscopic conductors is so great that no signal will be transmitted unless countermeasures are taken. The antireflex device minimizes this effect and adjusts the impedances, leading to efficient coupling. This brings the scientists significantly closer to their goal of using nanocomponents to transmit signals in electronic parts.

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

Clean carbon nanotubes coupled to superconducting impedance-matching circuits by V. Ranjan, G. Puebla-Hellmann, M. Jung, T. Hasler, A. Nunnenkamp, M. Muoth, C. Hierold, A. Wallraff, & C. Schönenberger. Nature Communications 6, Article number: 7165 doi:10.1038/ncomms8165 Published 15 May 2015

This paper is behind a paywall.

A ‘sweat’mometer—sensing your health through your sweat

At this point, it’s more fitness monitor than diagnostic tool, so, you’ll still need to submit blood, stool, and urine samples when the doctor requests it but the device does offer some tantalizing possibilities according to a May 15, 2015 news item on phys.org,

Made from state-of-the-art silicon transistors, an ultra-low power sensor enables real-time scanning of the contents of liquids such as perspiration. Compatible with advanced electronics, this technology boasts exceptional accuracy – enough to manufacture mobile sensors that monitor health.

Imagine that it is possible, through a tiny adhesive electronic stamp attached to the arm, to know in real time one’s level of hydration, stress or fatigue while jogging. A new sensor developed at the Nanoelectronic Devices Laboratory (Nanolab) at EPFL [École Polytechnique Fédérale de Lausanne in Switzerland] is the first step toward this application. “The ionic equilibrium in a person’s sweat could provide significant information on the state of his health,” says Adrian Ionescu, director of Nanolab. “Our technology detects the presence of elementary charged particles in ultra-small concentrations such as ions and protons, which reflects not only the pH balance of sweat but also more complex hydration of fatigues states. By an adapted functionalization I can also track different kinds of proteins.”

A May 15, 2015 EPFL press release by Laure-Anne Pessina, which originated the news item, includes a good technical explanation of the device for non-experts in the field,

Published in the journal ACS Nano, the device is based on transistors that are comparable to those used by the company Intel in advanced microprocessors. On the state-of-the-art “FinFET” transistor, researchers fixed a microfluidic channel through which the fluid to be analyzed flows. When the molecules pass, their electrical charge disturbs the sensor, which makes it possible to deduce the fluid’s composition.

The new device doesn’t host only sensors, but also transistors and circuits enabling the amplification of the signals – a significant innovation. The feat relies on a layered design that isolates the electronic part from the liquid substance. “Usually it is necessary to use separately a sensor for detection and a circuit for computing and signal amplification,” says Sara Rigante, lead author of the publication. “In our chip, sensors and circuits are in the same device – making it a ‘Sensing integrated circuit’. This proximity ensures that the signal is not disturbed or altered. We can thereby obtain extremely stable and accurate measurements.”

But that’s not all. Due to the size of the transistors – 20 nanometers, which is one hundred to one thousand times smaller than the thickness of a hair – it is possible to place a whole network of sensors on one chip, with each sensor locating a different particle. “We could also detect calcium, sodium or potassium in sweat,” the researcher elaborates.

As to what makes the device special (from the press release),

The technology developed at EPFL stands out from its competitors because it is extremely stable, compatible with existing electronics (CMOS), ultra-low power and easy to reproduce in large arrays of sensors. “In the field of biosensors, research around nanotechnology is intense, particularly regarding silicon nanowires and nanotubes. But these technologies are frequently unstable and therefore unusable for now in industrial applications,” says Ionescu. “In the case of our sensor, we started from extremely powerful, advanced technology and adapted it for sensing need in a liquid-gate FinFET configurations. The precision of the electronics is such that it is easy to clone our device in millions with identical characteristics.”

In addition, the technology is not energy intensive. “We could feed 10,000 sensors with a single solar cell,” Professor Ionescu asserts.

Of course, there does seem to be one shortcoming (from the press release),

Thus far, the tests have been carried out by circulating the liquid with a tiny pump. Researchers are currently working on a means of sucking the sweat into the microfluidic tube via wicking. This would rid the small analyzing “band-aid” of the need for an attached pump.

While they work on eliminating the pump part of the device, here’s  a link to and a citation for the paper,

Sensing with Advanced Computing Technology: Fin Field-Effect Transistors with High-k Gate Stack on Bulk Silicon by Sara Rigante, Paolo Scarbolo, Mathias Wipf, Ralph L. Stoop, Kristine Bedner, Elizabeth Buitrago, Antonios Bazigos, Didier Bouvet, Michel Calame, Christian Schönenberger, and Adrian M. Ionescu. ACS Nano, Article ASAP DOI: 10.1021/nn5064216 Publication Date (Web): March 27, 2015

Copyright © 2015 American Chemical Society

This paper is behind a paywall.

As for the ‘sweat’mometer in the headline, I was combining sweat with thermometer.

Measuring a singular spin of a biological molecule

I gather there are some Swiss scientists excited about obtaining experimental proof for room temperature detection of a  biological molecule’s spin. From a May 11, 2015 news item on Nanowerk (Note: A link has been removed),

Physicists of the University of Basel and the Swiss Nanoscience Institute were able to show for the first time that the nuclear spins of single molecules can be detected with the help of magnetic particles at room temperature.

In Nature Nanotechnology (“High-efficiency resonant amplification of weak magnetic fields for single spin magnetometry at room temperature”), the researchers describe a novel experimental setup with which the tiny magnetic fields of the nuclear spins of single biomolecules – undetectable so far – could be registered for the first time. The proposed concept would improve medical diagnostics as well as analyses of biological and chemical samples in a decisive step forward.

A May 11, 2015 University of Basel press release, which originated the news item, explains why the researchers are excited about a ‘room temperature’ approach to measuring a nuclear spin,

The measurement of nuclear spins is routine by now in medical diagnostics (MRI). However, the currently existing devices need billions of atoms for the analysis and thus are not useful for many small-scale applications. Over many decades, scientists worldwide have thus engaged in an intense search for alternative methods, which would improve the sensitivity of the measurement techniques.

With the help of various types of sensors (SQUID- and Hall-sensors) and with magnetic resonance force microscopes, it has become possible to detect spins of single electrons and achieve structural resolution at the nanoscale. However, the detection of single nuclear spins of complex biological samples – the holy grail in the field – has not been possible so far.

Diamond crystals with tiny defects

The researchers from Basel now investigate the application of sensors made out of diamonds that host tiny defects in their crystal structure. In the crystal lattice of the diamond a Carbon atom is replaced by a Nitrogen atom, with a vacant site next to it. These so-called Nitrogen-Vacancy (NV) centers generate spins, which are ideally suited for detection of magnetic fields. At room temperature, researchers have shown experimentally in many labs before that with such NV centers resolution of single molecules is possible. However, this requires atomistically close distances between sensor and sample, which is not possible for biological material.

A tiny ferromagnetic particle, placed between sample and NV center, can solve this problem. Indeed, if the nuclear spin of the sample is driven at a specific resonance frequency, the resonance of the ferromagnetic particle changes. With the help of an NV center that is in close proximity of the magnetic particle, the scientists can then detect this modified resonance.

Measuring technology breakthrough?

The theoretical analysis and experimental techniques of the researchers in the teams of Prof. Daniel Loss and Prof. Patrick Maletinsky have shown that the use of such ferromagnetic particles can lead to a ten-thousand-fold amplification of the magnetic field of nuclear spins. „I am confident that our concept will soon be implemented in real systems and will lead to a breakthrough in metrology“ [science of measurement], comments Daniel Loss the recent publication, where the first author Dr. Luka Trifunovic, postdoc in the Loss team, made essential contributions and which was performed in collaboration with colleagues from the JARA Institute for Quantum Information (Aachen, Deutschland) and the Harvard University (Cambridge, USA).

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

High-efficiency resonant amplification of weak magnetic fields for single spin magnetometry at room temperature by  Luka Trifunovic, Fabio L. Pedrocchi, Silas Hoffman, Patrick Maletinsky, Amir Yacoby, & Daniel Loss. Nature Nanotechnology (2015) doi:10.1038/nnano.2015.74 Published online 11 May 2015

This paper is behind a paywall.