Tag Archives: Holland

Hitchhikers at the nanoscale show how cells stir themselves

A May 30, 2014 news item on Nanowerk highlights some molecule-tracking research,

Chemical engineers from Rice University and biophysicists from Georg-August Universität Göttingen in Germany and the VU University Amsterdam in the Netherlands have successfully tracked single molecules inside living cells with carbon nanotubes.

Through this new method, the researchers found that cells stir their interiors using the same motor proteins that serve in muscle contraction.

A May 29, 2014 Rice University news release by Mike Williams, which originated the news item, describes the researchers’ work,

The team attached carbon nanotubes to transport molecules known as kinesin motors to visualize and track them as they moved through the cytoplasm of living cells.

Carbon nanotubes are hollow cylinders of pure carbon with one-atom-thick walls. They naturally fluoresce with near-infrared wavelengths when exposed to visible light, a property discovered at Rice by Professor Rick Smalley a decade ago and then leveraged by Rice Professor Bruce Weisman to image carbon nanotubes. When attached to a molecule, the hitchhiking nanotubes serve as tiny beacons that can be precisely tracked over long periods of time to investigate small, random motions inside cells.

“Any probe that can hitch the length and breadth of the cell, rough it, slum it, struggle against terrible odds, win through and still know where its protein is, is clearly a probe to be reckoned with,” said lead author Nikta Fakhri, paraphrasing “The Hitchhiker’s Guide to the Galaxy.” Fakhri, who earned her Rice doctorate in Pasquali’s lab in 2011, is currently a Human Frontier Science Program Fellow at Göttingen.

“In fact, the exceptional stability of these probes made it possible to observe intracellular motions from times as short as milliseconds to as long as hours,” she said.

For long-distance transport, such as along the long axons of nerve cells, cells usually employ motor proteins tied to lipid vesicles, the cell’s “cargo containers.” This process involves considerable logistics: Cargo needs to be packed, attached to the motors and sent off in the right direction.

“This research has helped uncover an additional, much simpler mechanism for transport within the cell interior,” said principal investigator Christoph Schmidt, a professor of physics at Göttingen. “Cells vigorously stir themselves, much in the way a chemist would accelerate a reaction by shaking a test tube. This will help them to move objects around in the highly crowded cellular environment.”

The researchers showed the same type of motor protein used for muscle contraction is responsible for stirring. They reached this conclusion after exposing the cells to drugs that suppressed these specific motor proteins. The tests showed that the stirring was suppressed as well.

The mechanical cytoskeleton of cells consists of networks of protein filaments, like actin. Within the cell, the motor protein myosin forms bundles that actively contract the actin network for short periods. The researchers found random pinching of the elastic actin network by many myosin bundles resulted in the global internal stirring of the cell. Both actin and myosin play a similar role in muscle contraction.

The highly accurate measurements of internal fluctuations in the cells were explained in a theoretical model developed by VU co-author Fred MacKintosh, who used the elastic properties of the cytoskeleton and the force-generation characteristics of the motors.

“The new discovery not only promotes our understanding of cell dynamics, but also points to interesting possibilities in designing ‘active’ technical materials,” said Fakhri, who will soon join the Massachusetts Institute of Technology faculty as an assistant professor of physics. “Imagine a microscopic biomedical device that mixes tiny samples of blood with reagents to detect disease or smart filters that separate squishy from rigid materials.”

There is an accompanying video,

This video is typical of the kind of visual image that nanoscientists look at and provides an interesting contrast to ‘nano art’ where colours and other enhancements are added. as per this example, NanoOrchard, from a May 13, 2014 news item on Nanowerk about the 2014 Materials Research Society spring meeting and their Science as Art competition,

NanoOrchard – Electrochemically overgrown CuNi nanopillars. (Image courtesy of the Materials Research Society Science as Art Competition and Josep Nogues, Institut Catala de Nanociencia i Nanotecnologia (ICN2), Spain, and A. Varea, E. Pellicer, S. Suriñach, M.D. Baro, J. Sort, Univ. Autonoma de Barcelona) [downloaded from http://www.nanowerk.com/nanotechnology-news/newsid=35631.php]

NanoOrchard – Electrochemically overgrown CuNi nanopillars. (Image courtesy of the Materials Research Society Science as Art Competition and Josep Nogues, Institut Catala de Nanociencia i Nanotecnologia (ICN2), Spain, and A. Varea, E. Pellicer, S. Suriñach, M.D. Baro, J. Sort, Univ. Autonoma de Barcelona) [downloaded from http://www.nanowerk.com/nanotechnology-news/newsid=35631.php]

Getting back to the carbon nanotube hitchhikers, here’s a link to and a citation for the paper,

High-resolution mapping of intracellular fluctuations using carbon nanotubes by Nikta Fakhri, Alok D. Wessel, Charlotte Willms, Matteo Pasquali, Dieter R. Klopfenstein, Frederick C. MacKintosh, and Christoph F. Schmidt. Science 30 May 2014: Vol. 344 no. 6187 pp. 1031-1035 DOI: 10.1126/science.1250170

This article is behind a paywall.

One final comment, I am delighted by the researcher’s reference to the Hitchhiker’s Guide to the Galaxy.

Toxicity, nanoparticles, soil, and Europe’s NANO-ECOTOXICITY Project

I have featured pieces on nanoparticles, toxicity, and soil in the past (this Aug. 15, 2011 posting about Duke University’s mesocosm project is probably the most relevant) but this study is the first one I’ve seen focusing on earthworms. From the Sept. 23, 2013 news item on Nanowerk (Note: A link has been removed),

From the clothes and make-up we wear to the electronic devices we use every day, nanotechnology is becoming ubiquitous. But while industry has mastered the production of such materials, little is known about their fate once their service life comes to an end. The NANO-ECOTOXICITY project looked into their impact on soil organisms.

The Sept. 23, 2013 CORDIS (European Commission Community Research and Development Information Service) news release, which originated the new item, offers a Q&A (Question and Answer) with the project research leader,

Dr Maria Diez-Ortiz, research leader of the NANO-ECOTOXICITY project, tells us about her research findings and how she expects them to help increase knowledge and shape tools allowing for standard environmental hazard and risk-assessment methodologies.

What is the background of the NANO-ECOTOXICITY project?

Nanotechnology is based on the idea that, by engineering the size and shape of materials at the scale of atoms, i.e. nanometres (nm), distinct optical, electronic, or magnetic properties can be tuned to produce novel properties of commercial value. However, there is an obvious concern that such novel properties may also lead to novel behaviour when interacting with biological organisms, and thus to potentially novel toxic effects.

Since nanoparticles (NPs) are similar in size to viruses, their uptake by and transport through tissues are based on mechanisms distinct from those of molecular uptake and transport. Therefore, there is concern that standard toxicological tests may not be applicable or reliable in relation to NPs, hence compromising current risk-assessment procedures.

The majority of research on nano-safety in the environment has so far focused on the aquatic environment. Current research on environmental fate, however, indicates that soils will become the biggest environmental sink for nanoparticles. Following their entry into liquid waste streams, nanoparticles will pass through wastewater-treatment. processes, ending up in waste sludge which may accumulate in the agricultural land where this sludge is often applied.

What are the main objectives of the project?

This project deals with the toxicokinetics – that is, the rate at which a chemical enters a body and affects it – of metal nanoparticles coming into contact with soil-dwelling organisms. The aim is to determine NPs’ fate and effects in terrestrial ecosystems by means of case studies with zinc oxide and silver NPs, which represent different fate kinetics.

The project’s main objectives are to assess the toxicity of metal nanoparticles in soils in the short and long term; the main route of exposure for earthworms and whether it differs from those of ionic metals; and, finally, the influence of the exposure media on metal nanoparticle toxicity.

What is new or innovative about the project and the way it is addressing these issues?

We have been running a long-term study where soils with AgNP [silver nanoparticles] were stored and left to age for up to a year; their toxicity was tested at the start and after three, seven and 12 months of ageing. The results showed that silver toxicity increased over time, meaning that short-term standard toxicity tests may underestimate the environmental risk of silver nanoparticles.

In parallel, we found that organisms exposed to silver nanoparticles in short-term studies accumulated higher silver concentrations than organisms that were exposed to the same mass concentration of ionic silver. However, these NP exposed organisms actually suffered lower toxic effects. This observation contradicts the prevailing assumption in toxicology that the internalised concentration is directly related to chemical concentration at the target site and hence to its toxicity. This observation creates a new paradigm for nano-ecotoxicology.

What is not yet known is whether the accumulated NP metal may in the longer-term ultimately become toxic (e.g. through dissolution and ion release) in cells and tissues where AgNPs may be stored. Should this occur, the high concentrations accumulated may ultimately result in greater long-term toxicity for NPs than for ionic forms. This may reveal these accumulated NPs as internalised ‘time bombs’ relevant to long-term effects and toxicity.

However, it has to be borne in mind that the redicted environmental concentrations resulting from current use of nanoparticles (e.g. results from EU projects like NANOFATE2) are many times smaller than those used in these studies, meaning that such accumulations of nanoparticle-related silver are unlikely to occur in the environment or, ultimately, in humans.

What difficulties did you encounter and how did you solve them?

The main problems encountered relate to the tracking of nanoparticles inside the tissues and soils, as both are complex matrices. The analysis of the particles is a challenge in itself, even when in water, but to get information about their state in these matrices often requires unrealistic exposure concentrations (due to low detection limits of the highly specialised techniques used for analysis) or extraction of the particles from the matrices, which could potentially change the state of the particles.

In this project, I travelled to University of Kentucky to work with Jason Unrine and used gentle water-based extractions of soil samples immediately before analysing them using ‘Field-flow fractionation’ and ‘Inductively coupled plasma mass spectrometry’ to identify the state of nanoparticles in my aged soils.

To look at what form (speciation) of silver and zinc from the nanoparticle exposures could be found inside worms I collaborated with NANOFATE researchers at Cardiff University who fixed and thinly sectioned the worm tissues. I was lucky to be given the time to use specialist facilities like the UK’s Diamond Light Source synchrotron to investigate where and in what form the metals and potential nanoparticles could be found in these tissues.

The main challenge is that as soon as you take nanoparticles out of the manufacturers’ bottle they start changing, particularly when put into environments likes natural soils and waters, or even organisms. Therefore a lot of characterisation is needed during exposure to establish the state of the nanoparticles the organisms have been exposed to and how fast they are changing from pristine particles to dissolved ions, or particles with completely different surfaces.

Technical solutions to characterisation have been found during this short project, but this will remain a logistical challenge for many years to come as the analysis equipment is still very specialised and expensive and therefore not generally available.

What are the concrete results from the research so far?

The project has helped us draw various conclusions regarding the impact of NPs on the environment and how to assess them. First, we now know that soil acidity, or pH, influences the dissolution and toxicity of ZnO nanoparticles [zinc oxide].

Then, we found that toxicity of silver nanoparticles’ increases over time and that the particles’ coating affects their toxicity to soil invertebrates.

As previously mentioned, earthworms exposed to silver nanoparticles for 28 days accumulated higher silver concentrations than earthworms exposed to silver ions, without the excess silver from the nanoparticles having a toxic effect. [emphasis mine] Moreover, soil ingestion was identified as the main route of exposure to AgNP and ZnONP in earthworms.

How can industry and decision-makers ensure that nanomaterials do not impact our environment?

We hope that this project, and the larger EU project NANOFATE to which it is linked, will provide knowledge and tools enabling standard environmental-hazard and risk-assessment methodologies to be applied to engineered nanoparticles (ENPs) with just a few judicious modifications. The current systems and protocols for chemical risk assessment have been developed over decades, and where no novel toxic mechanisms exist, our results tend to say that nano fits in as long as we measure the right things and characterise realistic exposures properly.

Our research aims to determine the minimum methodological tweaks needed. So far everything indicates that the potential benefits from nanotechnology can be realised and managed safely alongside other chemicals. While we are fairly confident at this stage that ENPs impose no greater acute effects on important biological parameters – like reproduction – than their ionic forms, the NANO-ECOTOXICITY results demonstrate that we have some way to go before we can state loud and clear that we do not believe there is any novel low-level or long-term effect.

As for all chemicals, proving such a negative is impossible using short-term tests. We think the final conclusions by industry and regulators on safe use of nanoparticles should and will have to be made according to a ‘weight of evidence’ approach – proving there is a gap between predicted likely exposure levels and those levels seen to cause any effects or accumulations within ecosystem species.

What are the next topics for your research?

This project has finished but the next step for any other funding opportunity would be to address increasingly environmentally relevant exposure scenarios by analysing how nanoparticles modify in the environment and interact with living tissues and organisms at different trophic levels. I would like to investigate nanoparticle transformation and interactions in living tissues. To date, the studies that have identified this ‘excess’ accumulation of non-toxic metal loads in nanoparticleexposed organisms have only been short term.

Apart from the obviously increased food-chain transfer potential, is also not known whether, over the longer term, the accumulated NP-derived metal ultimately becomes toxic when present in tissues and cells. Such transformation and release of metal ions within tissues may ultimately result in greater longterm toxicity for NPs than for ionic forms.

Furthermore, I want to test exposures in a functioning model ecosystem including interspecific interactions and trophic transfer. Since interactions between biota and nanoparticles are relevant in natural soil systems, caution is needed when attempting to predict the ecological consequences of nanoparticles based on laboratory assays conducted with only a single species. In the presence of the full complement of biological components of soil systems, complex NPs may follow a range of pathways in which coatings may be removed and replaced with exudate materials. Studies to quantify the nature of these interactions are therefore needed to identify the fate, bioavailability and toxicity of realistic ‘non-pristine’ forms of NPs present in real soil environments.

New to me was the material about ageing silver nanoparticles and their increased toxicity over time. While this is an interesting piece of information it’s not necessarily all that useful. It seems even with their increased uptake compared to silver ions, silver nanoparticles (Diez-Ortiz doesn’t indicate whether or not * they tested variously aged silver nanoparticles) did not have toxic effects on the earthworms tested.

The NANO-ECOTOXICITY website doesn’t appear to exist anymore but you can find the NANOFATE (Nanoparticle Fate Assessment and Toxicity in the Environment) website here.

* ‘not’ removed to clarify meaning, Oct. 9, 2013. (Note: I had on Oct. 8, 2013 removed ‘not’ in a second place from the sentence in an attempt t o clarify the meaning and ended up not making any sense at all.) Please read Maria Diez-Ortiz in the Comments, as she clarifies matters in a way I could never hope to.

Archivists, rejoice! Fused quartz stores data for millions of years at the University of Southampton (UK)

There’s a July 9,  2013 news item on Nanowerk touting nanostructured glass device which is being compared to Superman’s memory crystal (see this Wikipedia essay on Superman’s Fortress of Solitude for a description of Superman’s memory crystals),

Using nanostructured glass, scientists at the University of Southampton have, for the first time, experimentally demonstrated the recording and retrieval processes of five dimensional digital data by femtosecond laser writing. The storage allows unprecedented parameters including 360 TB/disc data capacity, thermal stability up to 1000°C and practically unlimited lifetime.

Coined as the ‘Superman’ memory crystal, as the glass memory has been compared to the “memory crystals” used in the Superman films, the data is recorded via self-assembled nanostructures created in fused quartz, which is able to store vast quantities of data for over a million years. The information encoding is realised in five dimensions: the size and orientation in addition to the three dimensional position of these nanostructures. [emphases mine]

The July 9, 2013 University of Southampton news release, which originated the news item, provides more details,

A 300 kb digital copy of a text file was successfully recorded in 5D using ultrafast laser, producing extremely short and intense pulses of light. The file is written in three layers of nanostructured dots separated by five micrometres (one millionth of a metre).

The self-assembled nanostructures change the way light travels through glass, modifying polarisation of light that can then be read by combination of optical microscope and a polariser, similar to that found in Polaroid sunglasses.

The research is led by Jingyu Zhang from the University’s Optoelectronics Research Centre (ORC) and conducted under a joint project with Eindhoven University of Technology.

“We are developing a very stable and safe form of portable memory using glass, which could be highly useful for organisations with big archives. At the moment companies have to back up their archives every five to ten years because hard-drive memory has a relatively short lifespan,” says Jingyu. [emphasis mine]

“Museums who want to preserve information or places like the national archives where they have huge numbers of documents, would really benefit.”

This work was presented at the CLEO 2013 (Conference on Lasers and Electro-Optics in San Jose [US]). Here’s a link to and a citation for the 2 pp presentation paper,

5D Data Storage by Ultrafast Laser Nanostructuring in Glass by Jingyu Zhang, Mindaugas Gecevičius, Martynas Beresna, and Peter G. Kazansky. Presentation paper for CLEO 2013

© 2013 Optical Society of America OCIS codes (140.3390) Laser materials processing, (210.0210) Optical data storage

This research was conducted as part of the European Union’s Femtoprint project, which is funded under the Framework Programme 7 initiative. Here’s more about Femtoprint from the homepage,

FEMTOPRINT is to develop a printer for microsystems with nano-scale features fabricated out of glass. Our ultimate goal is to provide a large pool of users from industry, research and universities with the capability of producing their own micro-systems, in a rapid-manner without the need for expensive infrastructures and specific expertise. Recent researches have shown that one can form three-dimensional patterns in glass material using low-power femtosecond laser beam. This simple process opens interesting new opportunities for a broad variety of microsystems with feature sizes down to the nano-scale. These patterns can be used to form integrated optics components or be ‘developed’ by chemically etching to form three-dimensional structures like fluidic channels and micro-mechanical components. Worth noticing, sub-micron resolution can be achieved and sub-pattern smaller than the laser wavelength can be formed. Thanks to the low-energy required to pattern the glass, femtosecond laser consisting simply of an oscillator are sufficient to produce such micro- and nano- systems.

These systems are nowadays table-top and cost a fraction of conventional clean-room equipments. It is highly foreseeable that within 3 to 5 years such laser systems will fit in a shoe-box. The project specific objectives are:

1/ Develop a femtosecond laser suitable for glass micro-/nano- manufacturing that fits in a shoe-box

2/ Integrate the laser in a machine similar to a printer that can position and manipulate glass sheets of various thicknesses

3/ Demonstrate the use of the printer to fabricate a variety of micro-/nano-systems with optical, mechanical and fluid-handling capabilities. A clear and measurable outcome of Femtoprint will be to be in a situation to commercialize the ‘femtoprinter’ through the setting-up of a consortium spin-off. The potential economical impact is large and is expected in various industrial sectors.

I think any archivist hearing about data storage that can last a million years will be thrilled although I suspect it’s going to be a long, long time before these 5D ‘memory’ crystals are going to be storing any data for anyone. In the meantime, there are efforts such as the Council of Canadian Academies’ (CCA) Memory Institutions and the Digital Revolution assessment (mentioned 2/3 of the way down in my June 5, 2013 posting).

Prosthetics and the human brain

On the heels of research which suggests that humans tend to view their prostheses, including wheel chairs, as part of their bodies, researchers in Europe  have announced the development of a working exoskeleton powered by the wearer’s thoughts.

First, there’s the ‘wheelchair’ research, from the Mar. 6, 2013 news item on ScienceDaily,

People with spinal cord injuries show strong association of wheelchairs as part of their body, not extension of immobile limbs.

The human brain can learn to treat relevant prosthetics as a substitute for a non-working body part, according to research published March 6 in the open access journal PLOS ONE by Mariella Pazzaglia and colleagues from Sapienza University and IRCCS Fondazione Santa Lucia of Rome in Italy, supported by the International Foundation for Research in Paraplegie.

The researchers found that wheelchair-bound study participants with spinal cord injuries perceived their body’s edges as being plastic and flexible to include the wheelchair, independent of time since their injury or experience with using a wheelchair. Patients with lower spinal cord injuries who retained upper body movement showed a stronger association of the wheelchair with their body than those who had spinal cord impairments in the entire body.

According to the authors, this suggests that rather than being thought of only as an extension of the immobile limbs, the wheelchairs had become tangible, functional substitutes for the affected body part. …

As I mentioned in a Jan. 30, 2013 posting,

There have been some recent legal challenges as to what constitutes one’s body (from The Economist article, You, robot? [you can find the article here: http://www.economist.com/node/21560986]),

If you are dependent on a robotic wheelchair for mobility, for example, does the wheelchair count as part of your body? Linda MacDonald Glenn, an American lawyer and bioethicist, thinks it does. Ms Glenn (who is not involved in the RoboLaw project) persuaded an initially sceptical insurance firm that a “mobility assistance device” damaged by airline staff was more than her client’s personal property, it was an extension of his physical body. The airline settled out of court.

According to the Mar. 6, 2013 news release on EurekAlert from the Public Library of Science (PLoS), the open access article by Pazzaglia and her colleagues can be found here (Note: I have added a link),

Pazzaglia M, Galli G, Scivoletto G, Molinari M (2013) A Functionally Relevant Tool for the Body following Spinal Cord Injury. PLOS ONE 8(3): e58312.doi:10.1371/journal.pone.0058312

At almost the same time as Pazzaglia’s work,  a “Mind-controlled Exoskeleton” is announced in a Mar. 7, 2013 news item on ScienceDaily,

Every year thousands of people in Europe are paralysed by a spinal cord injury. Many are young adults, facing the rest of their lives confined to a wheelchair. Although no medical cure currently exists, in the future they could be able to walk again thanks to a mind-controlled robotic exoskeleton being developed by EU-funded researchers.

The system, based on innovative ‘Brain-neural-computer interface’ (BNCI) technology — combined with a light-weight exoskeleton attached to users’ legs and a virtual reality environment for training — could also find applications in there habilitation of stroke victims and in assisting astronauts rebuild muscle mass after prolonged periods in space.

The Mar. 7, 2013 news release on CORDIS, which originated the news item, offers a description of the “Mindwalker” project,

‘Mindwalker was proposed as a very ambitious project intended to investigate promising approaches to exploit brain signals for the purpose of controlling advanced orthosis, and to design and implement a prototype system demonstrating the potential of related technologies,’ explains Michel Ilzkovitz, the project coordinator at Space Applications Services in Belgium.

The team’s approach relies on an advanced BNCI system that converts electroencephalography (EEG) signals from the brain, or electromyography (EMG) signals from shoulder muscles, into electronic commands to control the exoskeleton.

The Laboratory of Neurophysiology and Movement Biomechanics at the Université Libre de Bruxelles (ULB) focused on the exploitation of EEG and EMG signals treated by an artificial neural network, while the Foundation Santa Lucia in Italy developed techniques based on EMG signals modelled by the coupling of neural and biomechanical oscillators.

One approach for controlling the exoskeleton uses so-called ‘steady-state visually evoked potential’, a method that reads flickering visual stimuli produced at different frequencies to induce correlated EEG signals. Detection of these EEG signals is used to trigger commands such as ‘stand’, ‘walk’, ‘faster’ or ‘slower’.

A second approach is based on processing EMG signals generated by the user’s shoulders and exploits the natural arm-leg coordination in human walking: arm-swing patterns can be perceived in this way and converted into control signals commanding the exoskeleton’s legs.

A third approach, ‘ideation’, is also based on EEG-signal processing. It uses the identification and exploitation of EEG Theta cortical signals produced by the natural mental process associated with walking. The approach was investigated by the Mindwalker team but had to be dropped due to the difficulty, and time needed, in turning the results of early experiments into a fully exploitable system.

Regardless of which method is used, the BNCI signals have to be filtered and processed before they can be used to control the exoskeleton. To achieve this, the Mindwalker researchers fed the signals into a ‘Dynamic recurrent neural network'(DRNN), a processing technique capable of learning and exploiting the dynamic character of the BNCI signals.

‘This is appealing for kinematic control and allows a much more natural and fluid way of controlling an exoskeleton,’ Mr Ilzkovitz says.

The team adopted a similarly practical approach for collecting EEG signals from the user’s scalp. Most BNCI systems are either invasive, requiring electrodes to be placed directly into brain tissue, or require users to wear a ‘wet’ capon their head, necessitating lengthy fitting procedures and the use of special gels to reduce the electrical resistance at the interface between the skin and the electrodes. While such systems deliver signals of very good quality and signal-to-noise ratio, they are impractical for everyday use.

The Mindwalker team therefore turned to a ‘dry’ technology developed by Berlin-based eemagine Medical Imaging Solutions: a cap covered in electrodes that the user can fit themselves, and which uses innovative electronic components to amplify and optimise signals before sending them to the neural network.

‘The dry EEG cap can be placed by the subject on their head by themselves in less than a minute, just like a swimming cap,’ Mr Ilzkovitz says.

Before proceeding any further with details, here’s what the Mindwalker looks like,

© MINDWALKER (downladed from http://cordis.europa.eu/fetch?CALLER=OFFR_TM_EN&ACTION=D&RCN=10601)

© MINDWALKER (downloaded from http://cordis.europa.eu/fetch?CALLER=OFFR_TM_EN&ACTION=D&RCN=10601)

After finding a way to collect the EEG/EMG signals and interpret them, the researchers needed to create the exoskeleton (from the CORDIS news release),

The universities of Delft and Twente in the Netherlands proposed an innovative approach for the design of the exoskeleton and its control. The exoskeletonis designed to be sufficiently robust to bear the weight of a 100 kg adult and powerful enough to recover balance from external causes of instability such as the user’s own torso movements during walking or a gentle push from the back or side. Compared to other exoskeletons developed to date it is relatively light, weighing less than 30 kg without batteries, and, because a final version of the system should be self-powered, it is designed to minimise energy consumption.

The Mindwalker researchers achieved energy efficiency through the use of springs fitted inside the joints that are capable of absorbing and recovering some of the energy otherwise dissipated during walking, and through the development of an efficient strategy for controlling the exoskeleton.

Most exoskeletons are designed to be balanced when stationary or quasi-static and to move by little steps inside their ground stability perimeter, an approach known as ‘Zero moment point’, or ZMP. Although this approach is commonly used for controlling humanoid robots, when applied to exoskeletons, it makes them heavy and slow – and usually requires users to be assisted by a walking frame, sticks or some other support device when they move.

Alternatively, a more advanced and more natural control strategy can replicate the way humans actually walk, with a controlled loss of balance in the walking direction.

‘This approach is called “Limit-cycle walking” and has been implemented using model predictive control to predict the behaviour of the user and exoskeleton and for controlling the exoskeleton during the walk. This was the approach investigated in Mindwalker,’ Mr Ilzkovitz says.

To train users to control the exoskeleton, researchers from Space Applications Services developed a virtual-reality training platform, providing an immersive environment in which new users can safely become accustomed to using the system before testing it out in a clinical setting, and, the team hope, eventually using it in everyday life.

By the end of this year, tests with able-bodied trial users will be completed. The system will then be transferred to the Foundation Santa Lucia for conducting a clinical evaluation until May 2013 with five to 10volunteers suffering from spinal cord injuries. These trials will help identify shortcomings and any areas of performance improvement, the project coordinator says.

In the meantime, the project partners are continuing research on different components for a variety of potential applications. The project coordinator notes, for example, that elements of the system could be adapted for the rehabilitation of stroke victims or to develop easy-to-use exoskeletons for elderly people for mobility support.

Space Applications Services, meanwhile, is also exploring applications of the Mindwalker technology to train astronauts and help them rebuild muscle mass after spending long periods of time in zero-gravity environments.

There’s more about the European Commission’s Seventh Programme-funded Mindwalker project here.

Parallel with these developments in Europe, Miguel Nicolelis of Duke University has stated that he will have a working exoskeleton (Walk Again Project)  for the kickoff by a paraplegic individual for the opening of the World Cup (soccer/football) in Brazil in 2014. I mentioned Nicolelis and his work most recently in a Mar. 4, 2013 posting.

Taken together, this research which strongly suggests that people can perceive prostheses as being part of their bodies and exoskeletons that are powered by the wearer’s thoughts, we seem to be edging closer to a world where machines and humans become one.

Connecting the dots in quantum computing—the secret is in the spins

The Feb. 26, 2013 University of Pittsburgh news release puts it a lot better than I can,

Recent research offers a new spin on using nanoscale semiconductor structures to build faster computers and electronics. Literally.

University of Pittsburgh and Delft University of Technology researchers reveal in the Feb. 17 [2013]online issue of Nature Nanotechnology a new method that better preserves the units necessary to power lightning-fast electronics, known as qubits (pronounced CUE-bits). Hole spins, rather than electron spins, can keep quantum bits in the same physical state up to 10 times longer than before, the report finds.

“Previously, our group and others have used electron spins, but the problem was that they interacted with spins of nuclei, and therefore it was difficult to preserve the alignment and control of electron spins,” said Sergey Frolov, assistant professor in the Department of Physics and Astronomy within Pitt’s Kenneth P. Dietrich School of Arts and Sciences, who did the work as a postdoctoral fellow at Delft University of Technology in the Netherlands.

Whereas normal computing bits hold mathematical values of zero or one, quantum bits live in a hazy superposition of both states. It is this quality, said Frolov, which allows them to perform multiple calculations at once, offering exponential speed over classical computers. However, maintaining the qubit’s state long enough to perform computation remains a long-standing challenge for physicists.

“To create a viable quantum computer, the demonstration of long-lived quantum bits, or qubits, is necessary,” said Frolov. “With our work, we have gotten one step closer.”

Thankfully, an explanation of the hole spins vs. electron spins issue follows,

The holes within hole spins, Frolov explained, are literally empty spaces left when electrons are taken out. Using extremely thin filaments called InSb (indium antimonide) nanowires, the researchers created a transistor-like device that could transform the electrons into holes. They then precisely placed one hole in a nanoscale box called “a quantum dot” and controlled the spin of that hole using electric fields. This approach- featuring nanoscale size and a higher density of devices on an electronic chip-is far more advantageous than magnetic control, which has been typically employed until now, said Frolov.

“Our research shows that holes, or empty spaces, can make better spin qubits than electrons for future quantum computers.”

“Spins are the smallest magnets in our universe. Our vision for a quantum computer is to connect thousands of spins, and now we know how to control a single spin,” said Frolov. “In the future, we’d like to scale up this concept to include multiple qubits.”

This graphic displays spin qubits within a nanowire. [downloaded from http://www.news.pitt.edu/connecting-quantum-dots]

This graphic displays spin qubits within a nanowire. [downloaded from http://www.news.pitt.edu/connecting-quantum-dots]

From the news release,

Coauthors of the paper include Leo Kouwenhoven, Stevan Nadj-Perge, Vlad Pribiag, Johan van den Berg, and Ilse van Weperen of Delft University of Technology; and Sebastien Plissard and Erik Bakkers from Eindhoven University of Technology in the Netherlands.

The paper, “Electrical control over single hole spins in nanowire quantum dots,” appeared online Feb. 17 in Nature Nanotechnology. The research was supported by the Dutch Organization for Fundamental Research on Matter, the Netherlands Organization for Scientific Research, and the European Research Council.

According to the scientists we’re going to be waiting a bit longer for a quantum computer but this work is promising. Their paper is behind a paywall.

If vat-grown burgers are here, what are the social implications?

The Jan. 17, 2013 news item on Nanowerk about Dr. Neil Stephens and his research into the social implications of vat-grown (aka, in vitro meat) poses some interesting questions,

he [sic] world’s first laboratory-grown hamburger has been produced by Professor Mark Post and his team in Maastricht, representing something radically new in our world. Dr Neil Stephens, Research Associate at Cesagen (Cardiff School of Social Sciences), has been researching the social and ethical issues of this technology and what this innovation in stem cell science might mean for us in 2013.

Will we be eating burgers made in test-tubes in the near future? That is probably unlikely considering Professor Post’s burger costs around £200,000 to produce.

The University of Cardiff Jan. 16, 2013 news release,which originated the news item, goes on to explain why Stephens is conducting this investigation,

However, the benefits this new technology can deliver – according to the scientists – include slaughter-free meat that is healthier and free from animal to human disease. The meat could also be grown during space travel and could have a much smaller environmental impact than today’s whole-animal reared meat. But it is not yet clear if any of these can be delivered in a marketable form.

Since 2008, Dr Stephens has been investigating these ‘social promises’ by interviewing most of the scientists across the world who are involved in this project. He looks to understand how this community of scientists came together and what strategies they use to justify the promises they make.

Professor Mark Post’s work at the University of Maastricht (Holland) was covered extensively last year when it was presented at the 2012 AAAS (American Ass0ciation for the Advancement of Science) meeting in Vancouver. This Feb. 19, 2012 article by Pallab Ghosh for BBC (British Broadcasting Corporation) online highlights some of the discussion which took place then,

Dutch scientists have used stem cells to create strips of muscle tissue with the aim of producing the first lab-grown hamburger later this year.

The aim of the research is to develop a more efficient way of producing meat than rearing animals.

Professor Post’s group at Maastricht University in the Netherlands has grown small pieces of muscle about 2cm long, 1cm wide and about a mm thick.

They are off-white and resemble strips of calamari in appearance. These strips will be mixed with blood and artificially grown fat to produce a hamburger by the autumn [2012].

…Some estimate that food production will have to double within the next 50 years to meet the requirements of a growing population. During this period, climate change, water shortages and greater urbanisation will make it more difficult to produce food.

Prof Sean Smukler from the University of British Columbia said keeping pace with demand for meat from Asia and Africa will be particularly hard as demand from these regions will shoot up as living standards rise. He thinks that lab grown meat could be a good solution.

But David Steele, who is president of Earthsave Canada, said that the same benefits could be achieved if people ate less meat.

“While I do think that there are definite environmental and animal welfare advantages of this high-tech approach over factory farming, especially, it is pretty clear to me that plant-based alternatives… have substantial environmental and probably animal welfare advantages over synthetic meat,” he said.

Dr Steele, who is also a molecular biologist, said he was also concerned that unhealthily high levels of antibiotics and antifungal chemicals would be needed to stop the synthetic meat from rotting.

There doesn’t seem to be any more recent news about vat-grown meat from Post’s team at the University of Maastricht; the interest in Stephens’ sociological work on the topic seems to have been stimulated by his inclusion in the UK’s Economic and Social Research Council’s (ESRC) annual publication, (Britain in magazine) Britain in 2013.

Here’s more about Stephens’ and his sociological inquiry,

Prima donna of nanomaterials (carbon nanotubes) tamed by scientists at Rice University (Texas, US), Teijin Armid (Dutch/Japanese company), and Technion Institute (based in Israel)

The big news is that a multinational team has managed to spin carbon nanotubes (after 10 years of work) into threads that look like black cotton and display both the properties of metal wires and of carbon fibers. Here’s more from the Jan. 10, 2013 news item on ScienceDaily,

“We finally have a nanotube fiber with properties that don’t exist in any other material,” said lead researcher Matteo Pasquali, professor of chemical and biomolecular engineering and chemistry at Rice. “It looks like black cotton thread but behaves like both metal wires and strong carbon fibers.”

The research team includes academic, government and industrial scientists from Rice; Teijin Aramid’s headquarters in Arnhem, the Netherlands; the Technion-Israel Institute of Technology in Haifa, Israel; and the Air Force Research Laboratory (AFRL) in Dayton, Ohio.

The Jan. 10, 2013 Rice University news release on EurekAlert, which originated the news item, describes some of the problems presented when trying to produce carbon nanotube fiber at an industrial scale,

The phenomenal properties of carbon nanotubes have enthralled scientists from the moment of their discovery in 1991. The hollow tubes of pure carbon, which are nearly as wide as a strand of DNA, are about 100 times stronger than steel at one-sixth the weight. Nanotubes’ conductive properties — for both electricity and heat — rival the best metal conductors. They also can serve as light-activated semiconductors, drug-delivery devices and even sponges to soak up oil.

Unfortunately, carbon nanotubes are also the prima donna of nanomaterials [emphasis mine]; they are difficult to work with, despite their exquisite potential. For starters, finding the means to produce bulk quantities of nanotubes took almost a decade. Scientists also learned early on that there were several dozen types of nanotubes — each with unique material and electrical properties; and engineers have yet to find a way to produce just one type. Instead, all production methods yield a hodgepodge of types, often in hairball-like clumps.

Creating large-scale objects from these clumps of nanotubes has been a challenge. A threadlike fiber that is less than one-quarter the thickness of a human hair will contain tens of millions of nanotubes packed side by side. Ideally, these nanotubes will be perfectly aligned — like pencils in a box — and tightly packed. Some labs have explored means of growing such fibers whole, but the production rates for these “solid-state” fibers have proven quite slow compared with fiber-production methods that rely on a chemical process called “wet spinning.” In this process, clumps of raw nanotubes are dissolved in a liquid and squirted through tiny holes to form long strands.

Thank you to the writer of the Rice University news release for giving me the phrase “prima donna of nanomaterials.”

The news release goes on to describe the years of work and collaboration needed to arrive at this point,

Shortly after arriving at Rice in 2000, Pasquali began studying CNT wet-spinning methods with the late Richard Smalley, a nanotechnology pioneer and the namesake of Rice’s Smalley Institute for Nanoscale Science and Technology. In 2003, two years before his untimely death, Smalley worked with Pasquali and colleagues to create the first pure nanotube fibers. The work established an industrially relevant wet-spinning process for nanotubes that was analogous to the methods used to create high-performance aramid fibers — like Teijin’s Twaron — which are used in bulletproof vests and other products. But the process needed to be refined. The fibers weren’t very strong or conductive, due partly to gaps and misalignment of the millions of nanotubes inside them.

“Achieving very high packing and alignment of the carbon nanotubes in the fibers is critical,” said study co-author Yeshayahu Talmon, director of Technion’s Russell Berrie Nanotechnology Institute, who began collaborating with Pasquali about five years ago.

The next big breakthrough came in 2009, when Talmon, Pasquali and colleagues discovered the first true solvent for nanotubes — chlorosulfonic acid. For the first time, scientists had a way to create highly concentrated solutions of nanotubes, a development that led to improved alignment and packing.

“Until that time, no one thought that spinning out of chlorosulfonic acid was possible because it reacts with water,” Pasquali said. “A graduate student in my lab, Natnael Bahabtu, found simple ways to show that CNT fibers could be spun from chlorosulfonic acid solutions. That was critical for this new process.”

Pasquali said other labs had found that the strength and conductivity of spun fibers could also be improved if the starting material — the clumps of raw nanotubes — contained long nanotubes with few atomic defects. In 2010, Pasquali and Talmon began experimenting with nanotubes from different suppliers and working with AFRL scientists to measure the precise electrical and thermal properties of the improved fibers.

During the same period, Otto [Marcin Otto, Business Development Manager at Teijin Aramid] was evaluating methods that different research centers had proposed for making CNT fibers. He envisaged combining Pasquali’s discoveries, Teijin Aramid’s know-how and the use of long CNTs to further the development of high performance CNT fibers. In 2010, Teijin Aramid set up and funded a project with Rice, and the company’s fiber-spinning experts have collaborated with Rice scientists throughout the project.

“The Teijin scientific and technical help led to immediate improvements in strength and conductivity,” Pasquali said.

Study co-author Junichiro Kono, a Rice professor of electrical and computer engineering, said, “The research showed that the electrical conductivity of the fibers could be tuned and optimized with techniques that were applied after initial production. This led to the highest conductivity ever reported for a macroscopic CNT fiber.”

The fibers reported in Science have about 10 times the tensile strength and electrical and thermal conductivity of the best previously reported wet-spun CNT fibers, Pasquali said. The specific electrical conductivity of the new fibers is on par with copper, gold and aluminum wires, but the new material has advantages over metal wires.

Here’s an explanatory video the researchers have provided,

A more commercial perspective is covered in the Teijin Armid Jan. 11, 2013 news release (Note: A link has been removed),

“Our carbon nanotube fibers combine high thermal and electrical conductivity, like that seen in metals, with the flexibility, robust handling and strength of textile fibers”, explained Marcin Otto, Business Development Manager at Teijin Aramid. “With that novel combination of properties it is possible to use CNT fibers in many applications in the aerospace, automotive, medical and (smart) clothing industries.”

Teijin’s cooperation and involvement was crucial to the project. Twaron technology enabled improved performance, and an industrially scalable production method. That makes it possible to find applications for CNT fibers in a range of commercial or industrial products. “This research and ongoing tests offer us a glimpse into the potential future possibilities of this new fiber. For example, we have been very excited by the interest of innovative medical doctors and scientists exploring the possibilities to use CNT fiber in surgical operations and other applications in the medical field”, says Marcin Otto. Teijin Aramid expects to replace the copper in data cables and light power cables used in the aerospace and automotive industries, to make aircraft and high end cars lighter and more robust at the same time. Other applications could include integrating light weight electronic components, such as antennas, into composites, or replacing cooling systems in electronics where the high thermal conductivity of carbon nanotube fiber can help to dissipate heat.

Teijin Aramid is currently trialing samples of CNT fiber on a small scale with the most active prospective customers. Building up a robust supply chain is high on the project team’s list of priorities. As well as their carbon fiber, aramid fiber and polyethylene tape, this new carbon nanotube fiber is expected to allow Teijin to offer customers an even broader portfolio of high performance materials.

Teijin Group (which is headquartered in Japan) has been mentioned here before notably in a July 19, 2010 posting about a textile inspired by a butterfly’s wing (Morphotex) which, sadly, is no longer being produced as noted in a more recent April 12, 2012 posting about Teijin’s then new fiber ‘Nanofront™’ for use in sports socks.

University of Twente (Holland) researchers love their metaphors: ‘bed of nails’ and ‘soccer balls’

In the last week there have been a couple of news releases from Dutch researchers at the University of Twente’s MESA+ Institute for Nanotechnology which feature some metaphors. The first was a Sept. 20, 2012 news item on Nanowerk (Note: I have removed a link),

Nanotechnology researchers develop ‘bed of nails’ material for clean surfaces

Scientists at the University of Twente’s MESA+ Institute for Nanotechnology have developed a new material that is not only extremely water-repellent but also extremely oil-repellent. It contains minuscule pillars which retain droplets. What makes the material unique is that the droplets stay on top even when they evaporate (slowly getting smaller). This opens the way to such things as smartphone screens that really cannot get dirty. The study appears today in the scientific journal Soft Matter (“Absence of an evaporation-driven wetting transition on omniphobic surfaces”).

The University of Twente Sept. 12, 2012 news release, which originated the news item explores the metaphor and the technology,

Water-repellent surfaces can be used as a coating for windows, obviating the need to clean them ever again. These surfaces have an orderly arrangement of tiny pillars less than one-hundredth of a millimetre high (similar to a bed of nails but on an extremely small scale). Water droplets stay on the tips of the pillars, retaining the shape of perfectly round tiny pearls. As a result they can roll off the surface like marbles, taking all the dirt with them.

Nanotechnologists at the University of Twente have now managed to create a silicon surface that retains not only water droplets but also oil droplets like tiny pearls …. What makes the material unique is that the droplets remain in place even when they evaporate (get smaller).

With existing materials, evaporating droplets drop down between the pillars onto the surface after a while, changing in shape to hemispheres which can no longer simply roll off the surface. The surface can therefore still get dirty. By modifying the edges and the roughness of the minuscule pillars the UT scientists have managed to create a surface on which the droplets do not drop down even when they evaporate but stay neatly on top.

The Sept. 27, 2012 news item on Nanowerk features another metaphor, one which is well known amongst followers of the nanotechnology scene,

Nanotechnologists create miniscule soccer balls

Nanotechnologists at the University of Twente’s MESA+ research institute have developed a method whereby minuscule polystyrene spheres, automatically and under controlled conditions, form an almost perfect ball that looks suspiciously like a football, but about a thousand times smaller. The spheres organize themselves in such a way that they approach the densest arrangement possible, known as ‘closest packing of spheres’. The method provides nanotechnologists with a new way of creating minuscule 3D structures.

Soccer balls usually reference buckminster fullerenes (bucky balls). The news item explains this new use further,

The method developed by the University of Twente scientists involves placing a drop of water containing thousands of polystyrene spheres one micrometre in size (a thousand times smaller than a millimetre) on a superhydrophobic surface. As the drop is allowed to evaporate very slowly under controlled conditions the distances between the spheres become smaller and smaller and surprisingly they form a highly organized 3D structure. The spheres were found to organize themselves of their own accord in such a way that the ball they form approaches the most compact arrangement possible (‘closest packing of spheres’), with 74% of the space filled by the spheres. Like a football, the structures that form are almost perfectly spherical, consisting of a large number of planes. The researchers have therefore dubbed their material ‘microscopic soccer balls’. The minuscule footballs are a hundred to a thousand micrometres in size, containing from ten thousand to as much as a billion of the tiny polystyrene spheres.

There’s more on the University of Twente’s MESA+ Institute for Nanotechnology website but you will need to have Dutch language skills.

It’s always good to see metaphors and I like when scientists (or whoever’s writing the news releases) get create that way.

The Australians want one; the French and the Dutch each have one; a nanomaterials registry

The July 25, 2012 news article by Rachel Carbonell for ABC (Australian Broadcasting Corporation) discusses the current situation in Australia,

The ABC’s revelations that some sunscreen brands are inaccurately promoting themselves as nanotechnology-free have prompted calls for better regulation of nano-materials.

But the push for a mandatory register has suffered a blow, with a Federal Government report labelling it questionable.

The Australian Council of Trade Unions (ACTU) is among those calling for a register, saying the potential risks posed by nano-particles are still unknown.

The Federal Government recently released a study it commissioned to look at the feasibility of a mandatory nanotechnology product register.

The study concluded: “It is clear that some nano-materials behave differently to bulk-form materials and there are associated health, safety and environmental risks.”

“However the challenge presented by nanotechnology can be met through existing regulatory frameworks.

“It is therefore difficult to see a nano-products register delivering a net benefit to the community. The feasibility of a nano-product registry is questionable.”

But groups pushing for a register disagree.

The feasibility report points to the challenge of ensuring safety without stifling innovation, saying nanotechnology is potentially worth $50 billion a year to the Australian economy.

“But the fact that France is already implementing their mandatory register of nano-materials and the Netherlands is following closely, surely demonstrates that it must be possible.” [said Gregory Crocetti from Friends of the Earth]

The discussion presented in Carbonell’s piece is more involved than what I’ve excerpted for this posting so you may want to read her full article.

I  don’t believe I’ve come across that information about nanomaterial registries in France and Holland (Netherlands) before. I’ll see if I can find more about them to confirm their existence and exactly what is being documented.