Monthly Archives: December 2017

Tracks of my tears could power smartphone?

So far the researchers aren’t trying to power anything with tears but they have discovered that tears could be used to generate electricity (from an Oct. 2, 2017 news item on phys.org),

A team of Irish scientists has discovered that applying pressure to a protein found in egg whites and tears can generate electricity. The researchers from the Bernal Institute, University of Limerick (UL), Ireland, observed that crystals of lysozyme, a model protein that is abundant in egg whites of birds as well as in the tears, saliva and milk of mammals can generate electricity when pressed. Their report is published today (October 2) in the journal, Applied Physics Letters.

An Oct. 2, 2017 University of Limerick press release (also on EurekAlert), which originated the news item, offers additional detail,

The ability to generate electricity by applying pressure, known as direct piezoelectricity, is a property of materials such as quartz that can convert mechanical energy into electrical energy and vice versa. Such materials are used in a variety of applications ranging from resonators and vibrators in mobile phones to deep ocean sonars and ultrasound imaging. Bone, tendon and wood are long known to possess piezoelectricity.

“While piezoelectricity is used all around us, the capacity to generate electricity from this particular protein had not been explored. The extent of the piezoelectricity in lysozyme crystals is significant. It is of the same order of magnitude found in quartz. However, because it is a biological material, it is non toxic so it could have many innovative applications such as electroactive anti-microbial coatings for medical implants,” explained Aimee Stapleton, the lead author and an Irish Research Council EMBARK Postgraduate Fellow in the Department of Physics and Bernal Institute of UL.

Crystals of lysozyme are easy to make from natural sources. “The high precision structure of lysozyme crystals has been known since 1965,” said structural biologist at UL and co-author Professor Tewfik Soulimane.
“In fact, it is the second protein structure and the first enzyme structure that was ever solved,” he added, “but we are the first to use these crystals to show the evidence of piezoelectricity”.

According to team leader Professor Tofail Syed of UL’s Department of Physics, “Crystals are the gold-standard for measuring piezoelectricity in non-biological materials. Our team has shown that the same approach can be taken in understanding this effect in biology. This is a new approach as scientists so far have tried to understand piezoelectricity in biology using complex hierarchical structures such as tissues, cells or polypeptides rather than investigating simpler fundamental building blocks”.

The discovery may have wide reaching applications and could lead to further research in the area of energy harvesting and flexible electronics for biomedical devices. Future applications of the discovery may include controlling the release of drugs in the body by using lysozyme as a physiologically mediated pump that scavenges energy from its surroundings. Being naturally biocompatible and piezoelectric, lysozyme may present an alternative to conventional piezoelectric energy harvesters, many of which contain toxic elements such as lead.

Professor Luuk van der Wielen, Director of Bernal Institute and Bernal Professor of Biosystems Engineering and Design expressed his delight at this breakthrough by UL scientists.

“The €109-million Bernal Institute has the ambition to impact the world on the basis of top science in an increasingly international context. The impact of this discovery in the field of biological piezoelectricity will be huge and Bernal scientists are leading from the front the progress in this field,” he said.

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

The direct piezoelectric effect in the globular protein lysozyme featured by A. Stapleton, M. R. Noor, J. Sweeney, V. Casey, A. L. Kholkin, C. Silien, A. A. Gandhi, T. Soulimane, and S. A. M. Tofail. Appl. Phys. Lett. 111, 142902 (2017); doi: http://dx.doi.org/10.1063/1.4997446

This paper is open access.

As for Tracks of My Tears,

Llama-derived nanobodies are good for solving crystal structure

This work comes from Denmark, not a locale I associate with llamas (from an Oct. 2, 2017 news item on Nanowerk; Note: A link has been removed),

Aarhus University [Denmark] scientists have developed miniature antibodies (nanobodies) that can be labelled on certain amino acids (Acta Crystallographica Section D, “Introducing site-specific cysteines into nanobodies for mercury labelling allows de novo phasing of their crystal structures”).

This provides a direct route for solving new X-ray crystal structures of protein complexes important for gaining mechanistic understanding of cellular processes, which is important in the development of drugs.

An Oct. 2, 2017 Aarhus University press release on EurekAlert, which originated the news item, provides more detail,

Nanobodies are miniature antibodies derived from naturally circulating heavy-chain only antibodies in llamas. Over the past years, nanobodies and their applications have expanded enormously, both in basic research but also in drug development.

Nanobodies have proven to be well suited as protein stabilizers, which is particularly important during crystallization of a protein where millions of molecules have to arrange in a well-defined lattice. In this way, nanobodies can act as crystallization chaperones.

In an X-ray diffraction experiment, a critical piece of information – called the phases – is lost, which makes it difficult to determine new crystal structures. To overcome this phase problem in crystallography, heavy atoms are needed in the crystal. However, it is challenging to insert heavy atoms into a crystal. The scientists at Aarhus University used a nanobody as the vehicle for introducing mercury atoms. They developed a method to site-specifically label the nanobody with a heavy atom, and in this way, they could overcome the phase problem.

Since the scientists know which specific residues in the nanobodies can be modified and labelled, the technique used at Aarhus University opens for a range of other application. One exciting perspective is the insertion of fluorescent dyes into the nanobody to follow the location and distribution of target proteins in living organisms, which can give essential information on functional and regulatory processes.

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

Introducing site-specific cysteines into nanobodies for mercury labelling allows de novo phasing of their crystal structures by S. B. Hansen, N. S. Laursen, G. R. Andersen and K. R. Andersen. Acta Cryst. (2017). D73 https://doi.org/10.1107/S2059798317013171

This paper is open access.

Here’s an image illustrating the work,

Caption: Nanobodies have proven to be well suited as protein stabilizers, which is particularly important during crystallization of a protein where millions of molecules have to arrange in a well-defined lattice. Credit: Kasper Røjkjær Andersen

A pumpkin-shaped molecule for the first real-time methamphetamine and amphetamine sensor

A Sept. 28,2017 news item on Nanowerk announces a portable, inexpensive sensor for drugs (Note: A link has been renewed),

Speed, uppers, chalk, glass, crystal, or whatever you prefer to call them, can be instantly detected from biological fluids with a new portable kit that costs as little as $50. Scientists at the Center for Self-Assembly and Complexity, within the Institute for Basic Science (IBS, South Korea), in collaboration with Pohang University of Science and Technology (POSTECH), have devised the first methamphetamine and amphetamine sensor that can detect minute concentrations of these drugs from a single drop of urine in real-time.

Published in the journal Chem (“Point-of-Use Detection of Amphetamine-Type Stimulants with Host-Molecule-Functionalized Organic Transistors”), this simple and flexible sensor, which can be attached to a wristband and connected to an Android app via Bluetooth, could move drug screening from the labs to the streets.

A Sept. 28 (?), 2017 IBS press release by Letizia Diamante (also on EurekAlert), which originated the news item, expands on the theme,

Easy to synthesize and cheaper than heroin or cocaine, amphetamine-based drugs are the most abused drugs in the world, after cannabis. Conventional drug detection methods require a long time, as the sample must be taken into a lab for the analysis. It also needs experts to run the expensive equipment. The technology reported in this study is instead small, portable, cheap, fast and easy to use.

The idea for this technology came from the IBS chemist HWANG Ilha: “I was watching a TV news report on the usage of illegal drugs, and I thought to check what the chemical structure of methamphetamine looks like.” Soon after, the scientist anticipated that the drug would form a tight complex with a family of hollow pumpkin-shaped molecules, called cucurbituril (CB) members. The team then discovered that cucurbit[7]uril (CB[7])’s empty cavity binds well with amphetamine-based drugs and can be used as the drug recognition unit of a sensor. Cucurbiturils’ hollow chamber has already been studied for various technological uses, but this is the first device application in amphetamine-based drug detection.


▲ Figure 1: Wireless sensor for amphetamine-based drug detection.The kit is made of an organic field-effect transistor (OFET) device, an electric circuit board with a rechargeable battery and an antenna. The OFET device surface is coated with CB[7], whose function is to bind amphetamine and methamphetamine drugs in solution. The binding event is instantly converted to current, whose magnitude is proportional to the concentration of the drug. The app on the smartphone shows a peak as soon as a drop of urine with the drug is applied to the device. Moreover the entire kit can fit in a handy wristband.


▲ Video 1: The detector in action.
[Click text not image]
As soon as a drop of water with 0.0001 ng/mL (1 pM) of amphetamine is applied to the kit, the app shows a peak in current proportional to the concentration of drug. When the liquid is removed, the current level goes back to baseline, and the sensor can be reused. (Modified from Jang et al, Chem 2017)

Combining a transistor coated with CB[7], flexible materials, rechargeable batteries and a Bluetooth antenna, the research team developed a detector wristband connected to an app. In the presence of the drug, the molecular recognition between CB[7] and the drug molecule triggers an electrical signal which appears as a peak on the smartphone screen.

Current drug detection based on immunoassay or liquid chromatography/mass spectrometry techniques has a detection limit of about 10 ng/mL. On the contrary, the sensitivity of this new sensor is about 0.0001 ng/mL in water and 0.1 ng/mL in urine. Therefore, it is expected that this method will allow the detection of drug molecules in biological fluids, like urine and sweat, for a longer time after drug consumption.


▲ Figure 2: Graphic representation of the drug detection platform.Binding of drug molecules to the hollow cucurbit[7]uril (CB[7])’s cavity changes the current signal flowing in the transistor and therefore can be used as a detection system. The molecular structure of amphetamine and methamphetamine bound to cucurbit[7]uril (CB[7]) was confirmed with X-ray crystallography. Each color indicates a different atom (blue: nitrogen, red: oxygen, gray: carbon, and white: hydrogen). CB[7]’s hydrogen atoms have been omitted for clarity.


▲ Figure 3: Humorous view of the pumpkin-shaped molecule, cucurbit[7]uril (CB[7]), able to bind and detect amphetamine and methamphetamine molecules.(Credits: Modified from Titusurya – Freepik.com)

“Real time detection of amphetamine drugs on location would bring a big change to society,” explains another corresponding author KIM Kimoon. “In the same way as police can use a breathalyzer to detect alcohol on the spot, we aim to achieve the same with this device.”

False positives cannot be excluded yet, as urine contains a rich mixture of proteins and other metabolites that could affect the reading. Therefore, before commercializing it, clinical trials with drug users’ biological fluids are necessary. The researchers have patented the technology and they will continue to do further research in the near future.s

“Combining basic science with the latest technology, we can expect that this research will also lead to other new sensors, useful for our daily life,” concludes the third corresponding author OH Joon Hak. Indeed, the team is also keen on developing sensors for other kinds of drugs, as well as kits for the detection of dangerous substances, environmental monitoring, healthcare and safety.

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

Point-of-Use Detection of Amphetamine-Type Stimulants with Host-Molecule-Functionalized Organic Transistors by Yoonjung Jang, Moonjeong Jang, Hyoeun Kim, Sang Jin Lee, Eunyeong Jin, Jin Young Koo, In-Chul Hwang, Yonghwi Kim, Young Ho Ko, Ilha Hwang., Joon Hak Oh, Kimoon Kim. Chem (2017). DOI: 10.1016/j.chempr.2017.08.015 Publication stage: In Press Corrected Proof

This paper appears to be behind a paywall.

2017 proceedings for the Canadian Science Policy Conference

I received (via email) a December 11, 2017 notice from the Canadian Science Policy Centre that the 2017 Proceedings for the ninth annual conference (Nov. 1 – 3, 2017 in Ottawa, Canada) can now be accessed,

The Canadian Science Policy Centre is pleased to present you the Proceedings of CSPC 2017. Check out the reports and takeaways for each panel session, which have been carefully drafted by a group of professional writers. You can also listen to the audio recordings and watch the available videos. The proceedings page will provide you with the opportunity to immerse yourself in all of the discussions at the conference. Feel free to share the ones you like! Also, check out the CSPC 2017 reports, analyses, and stats in the proceedings.

Click here for the CSPC 2017 Proceedings

CSPC 2017 Interviews

Take a look at the 70+ one-on-one interviews with prominent figures of science policy. The interviews were conducted by the great team of CSPC 2017 volunteers. The interviews feature in-depth perspectives about the conference, panels, and new up and coming projects.

Click here for the CSPC 2017 interviews

Amongst many others, you can find a video of Governor General Julie Payette’s notorious remarks made at the opening ceremonies and which I highlighted in my November 3, 2017 posting about this year’s conference.

The proceedings are organized by day with links to individual pages for each session held that day. Here’s a sample of what is offered on Day 1: Artificial Intelligence and Discovery Science: Playing to Canada’s Strengths,

Artificial Intelligence and Discovery Science: Playing to Canada’s Strengths

Conference Day:
Day 1 – November 1st 2017

Organized by: Friends of the Canadian Institutes of Health Research

Keynote: Alan Bernstein, President and CEO, CIFAR, 2017 Henry G. Friesen International Prizewinner

Speakers: Brenda Andrews, Director, Andrew’s Lab, University of Toronto; Doina Precup, Associate Professor, McGill University; Dr Rémi Quirion, Chief Scientist of Quebec; Linda Rabeneck, Vice President, Prevention and Cancer Control, Cancer Care Ontario; Peter Zandstra, Director, School of Biomedical Engineering, University of British Columbia

Discussants: Henry Friesen, Professor Emeritus, University of Manitoba; Roderick McInnes, Acting President, Canadian Institutes of Health Research and Director, Lady Davis Institute, Jewish General Hospital, McGill University; Duncan J. Stewart, CEO and Scientific Director, Ottawa Hospital Research Institute; Vivek Goel, Vice President, Research and Innovation, University of Toronto

Moderators: Eric Meslin, President & CEO, Council of Canadian Academies; André Picard, Health Reporter and Columnist, The Globe and Mail

Takeaways and recommendations:

The opportunity for Canada

  • The potential impact of artificial intelligence (AI) could be as significant as the industrial revolution of the 19th century.
  • Canada’s global advantage in deep learning (a subset of machine learning) stems from the pioneering work of Geoffrey Hinton and early support from CIFAR and NSERC.
  • AI could mark a turning point in Canada’s innovation performance, fueled by the highest levels of venture capital financing in nearly a decade, and underpinned by publicly funded research at the federal, provincial and institutional levels.
  • The Canadian AI advantage can only be fully realized by developing and importing skilled talent, accessible markets, capital and companies willing to adopt new technologies into existing industries.
  • Canada leads in the combination of functional genomics and machine learning which is proving effective for predicting the functional variation in genomes.
  • AI promises advances in biomedical engineering by connecting chronic diseases – the largest health burden in Canada – to gene regulatory networks by understanding how stem cells make decisions.
  • AI can be effectively deployed to evaluate health and health systems in the general population.

The challenges

  • AI brings potential ethical and economic perils and requires a watchdog to oversee standards, engage in fact-based debate and prepare for the potential backlash over job losses to robots.
  • The ethical, environmental, economic, legal and social (GEL3S) aspects of genomics have been largely marginalized and it’s important not to make the same mistake with AI.
  • AI’s rapid scientific development makes it difficult to keep pace with safeguards and standards.
  • The fields of AI’s and pattern recognition are strongly connected but here is room for improvement.
  • Self-learning algorithms such as Alphaville could lead to the invention of new things that humans currently don’t know how to do. The field is developing rapidly, leading to some concern over the deployment of such systems.

Training future AI professionals

  • Young researchers must be given the oxygen to excel at AI if its potential is to be realized.
  • Students appreciate the breadth of training and additional resources they receive from researchers with ties to both academia and industry.
  • The importance of continuing fundamental research in AI is being challenged by companies such as Facebook, Google and Amazon which are hiring away key talent.
  • The explosion of AI is a powerful illustration of how the importance of fundamental research may only be recognized and exploited after 20 or 30 years. As a result, support for fundamental research, and the students working in areas related to AI, must continue.

A couple comments

To my knowledge, this is the first year the proceedings have been made so easily accessible. In fact, I can’t remember another year where they have been open access. Thank you!

Of course, I have to make a comment about the Day 2 session titled: Does Canada have a Science Culture? The answer is yes and it’s in the province of Ontario. Just take a look at the panel,

Organized by: Kirsten Vanstone, Royal Canadian Institute for Science and Reinhart Reithmeier, Professor, University of Toronto [in Ontario]

Speakers: Chantal Barriault, Director, Science Communication Graduate Program, Laurentian University [in Ontario] and Science North [in Ontario]; Maurice Bitran, CEO, Ontario Science Centre [take a wild guess as to where this institution is located?]; Kelly Bronson, Assistant Professor, Faculty of Social Sciences, University of Ottawa [in Ontario]; Marc LePage, President and CEO, Genome Canada [in Ontario]

Moderator: Ivan Semeniuk, Science Reporter, The Globe and Mail [in Ontario]

In fact, all of the institutions are in southern Ontario, even, the oddly named Science North.

I know from bitter experience it’s hard to put together panels but couldn’t someone from another province have participated?

Ah well, here’s hoping for 2018 and for a new location. After Ottawa as the CSPC site for three years in a row, please don’t make it a fourth year in a row.

Popping (nano)bubbles!

Who doesn’t love to pop bubbles? Well, there’s probably someone out there but it does seem to be a near universal delight (especially with the advent of bubble wrap which I’ve seen more than one person happily popping). Scientists are no more immune to that impulse than the rest of us although they approach the whole endeavour from a more technical perspective where popping bubbles becomes destabilization and bubble rupture. From a Sept. 28, 2017 American Institute of Physics (AIP) news release (also on EurekAlert),

Nanobubbles have recently gained popularity for their unique properties and expansive applications. Their large surface area and high stability in saturated liquids make nanobubbles ideal candidates for food science, medicine and environmental advancements. Nanobubbles also have long lifetimes of hours or days, and greater applicability than traditional macrobubbles, which typically only last for seconds.

The stability of nanobubbles is well understood, but the mechanisms causing their eventual destabilization are still in question. Using molecular dynamics simulations (MDS), researchers from the Beijing University of Chemical Technology explored the effect of surfactants — components that lower surface tension — on the stabilization of nanobubbles. They report their findings on the surprising mechanisms of destabilization [emphasis mine] for both soluble and insoluble surfactants this week [Sept. 25-29, 2017] in Applied Physics Letters, from AIP Publishing.

Researchers investigated the differences between soluble and insoluble surfactants and their varying influence on nanobubble stability using MDS software. They created a controled model system where the only variables that could be manipulated were the number of surfactants and the interaction between the surfactant and the substrate, the base of the model where the bubble is formed, to measure the direct influence of surfactants on nanobubble stability.

Analyzing both soluble and insoluble surfactants, the group focused on two possible mechanisms of destabilization: contact line depinning, where the surfactant flexibility reduces the forces responsible for stabilizing the bubble shape, causing it to rupture from lack of inner surface force; and surface tension reduction, causing a liquid to vapor phase transition.

The found soluble surfactants initiated nanobubble depinning when a large amount, roughly 80 percent, of the surfactant was adsorbed by the substrate, eventually causing the nanobubbles to burst.

“However, when small concentrations of soluble surfactant were introduced it remained dissolved, and adsorption onto the substrate was insignificant, generating a negligible effect on nanobubble stability,” said Xianren Zhang at Beijing University of Chemical Technology.

Simulations with insoluble surfactants showed comparable results to soluble surfactants when interacting heavily with substrates, but a new mechanism was discovered demonstrating a liquid-to-vapor transition model of bubble rupture [emphasis mine].

The transition is similar to how we traditionally envision bubbles popping, occurring when a surfactant significantly reduces the surface tension on the outside of the nanobubble. Nanobubbles destabilize in this fashion when a large amount of surfactant is present, but little — around 40 percent — surfactant-substrate interaction occurs.

These findings are critical to understanding nanobubble stability and have implications for nanobubble interaction with other molecules, including proteins and contaminants. Nanobubble applications could revolutionize aspects of modern medicine such as ultrasound techniques, expand functions in food science, and improve waste water treatment. But better characterizing basic properties like instability is essential to fully utilizing their potential in these applications.

There researchers have made this image illustrating their work available,

Several typical snapshots for nanobubbles losing their stability with various concentrations of surfactants and levels of interaction with substrates. In each picture, top panel shows evolution of the system with all involved particles, while in the bottom panel, solvent molecules are not shown to clarify the effect of surfactants. CREDIT: Qianxiang Xiao, Yawei Liu, Zhenjiang Guo, Zhiping Liu, and Xianren Zhang

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

How nanobubbles lose stability: Effects of surfactants featured by Qianxiang Xiao, Yawei Liu, Zhenjiang Guo, Zhiping Liua, and Xianren Zhang. Appl. Phys. Lett. 111, 131601 (2017); doi: http://dx.doi.org/10.1063/1.5000831

This paper is open access.

Manipulating graphene’s conductivity with honey

Honey can be used for many things, to heal wounds, for advice (You catch more flies with honey), to clean your hair (see suggestion no. 19 here) and, even, scientific inspiration according to a Sept. 22, 2017 news item on phys.org,

Dr. Richard Ordonez, a nanomaterials scientist at the Space and Naval Warfare Systems Center Pacific (SSC Pacific), was having stomach pains last year. So begins the story of the accidental discovery that honey—yes, the bee byproduct—is an effective, non-toxic substitute for the manipulation of the current and voltage characteristics of graphene.

The news item was originated by a Sept. 22, 2017 article by Katherine Connor (who works for  the US Space and Naval warfare Center) and placed in cemag.us,

Ordonez’ lab mate and friend Cody Hayashi gave him some store-bought honey as a Christmas gift and anti-inflammatory for his stomach, and Ordonez kept it near his work station for daily use. One day in the lab, the duo was investigating various dielectric materials they could use to fabricate a graphene transistor. First, the team tried to utilize water as a top-gate dielectric to manipulate graphene’s electrical conductivity. This approach was unsuccessful, so they proceeded with various compositions of sugar and deionized water, another electrolyte, which still resulted in negligible performance. That’s when the honey caught Ordonez’ eye, and an accidental scientific breakthrough was realized.

The finding is detailed in a paper in Nature Scientific Reports, in which the team describes how honey produces a nanometer-sized electric double layer at the interface with graphene that can be used to gate the ambipolar transport of graphene.

“As a top-gate dielectric, water is much too conductive, so we moved to sugar and de-ionized water to control the ionic composition in hopes we could reduce conductivity,” Ordonez explains. “However, sugar water didn’t work for us either because, as a gate-dielectric, there was still too much leakage current. Out of frustration, literally inches away from me was the honey Cody had bought, so we decided to drop-cast the honey on graphene to act as top-gate dielectric — I thought maybe the honey would mimic dielectric gels I read about in literature. To our surprise — everyone said it’s not going to work — we tried and it did.”

Image of the liquid-metal graphene field-effect transistor (LM-GFET) and representation of charge distribution in electrolytic gate dielectrics comprised of honey. Image: Space and Naval Warfare Systems Center

 

Ordonez, Hayashi, and a team of researchers from SSC Pacific, in collaboration with the University of Hawai′i at Mānoa, have been developing novel graphene devices as part of a Navy Innovative Science and Engineering (NISE)-funded effort to imbue the Navy with inexpensive, lightweight, flexible graphene-based devices that can be used as next-generation sensors and wearable devices.

“Traditionally, electrolytic gate transistors are made with ionic gel materials,” Hayashi says. “But you must be proficient with the processes to synthesize them, and it can take several months to figure out the correct recipe that is required for these gels to function in the environment. Some of the liquids are toxic, so experimentation must be conducted in an atmospheric-controlled environment. Honey is completely different — it performs similarly to these much more sophisticated materials, but is safe, inexpensive, and easier to use. The honey was an intermediate step towards using ionic gels, and possibly a replacement for certain applications.”

Ordonez and Hayashi envision the honey-based version of graphene products being used for rapid prototyping of devices, since the devices can be created quickly and easily redesigned based on results. Instead of having to spend months developing the materials before even beginning to incorporate it into devices, using honey allows the team to get initial tests underway without waiting for costly fabrication equipment.

Ordonez also sees a use for such products in science, technology, engineering, and math (STEM) outreach efforts, since the honey is non-toxic and could be used to teach students about graphene.

This latest innovation and publication was a follow-on from the group’s discovery last year that liquid metals can be used in place of rigid electrodes such as gold and silver to electrically contact graphene. This, coupled with research on graphene and multi-spectral detection, earned them the Federal Laboratory Consortium Far West Regional Award in the category of Outstanding Technology Development.

SSC Pacific is the naval research and development lab responsible for ensuring Information Warfare superiority for warfighters, including the areas of cyber, command and control, intelligence, surveillance and reconnaissance, and space systems.

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

Rapid Fabrication of Graphene Field-Effect Transistors with Liquid-metal Interconnects and Electrolytic Gate Dielectric Made of Honey by Richard C. Ordonez, Cody K. Hayashi, Carlos M. Torres, Jordan L. Melcher, Nackieb Kamin, Godwin Severa, & David Garmire. Scientific Reports 7, Article number: 10171 (2017) doi:10.1038/s41598-017-10043-4 Published online: 31 August 2017

This paper is open access.

Calligraphy ink and cancer treatment

Courtesy of ACS Omega and the researchers

Nice illustration! I wish I could credit the artist. For anyone who needs a little text to make sense of it, there’s a Sept. 27, 2017 news item on Nanowerk (Note: A link has been removed),

For hundreds of years, Chinese calligraphers have used a plant-based ink to create beautiful messages and art. Now, one group reports in ACS Omega (“New Application of Old Material: Chinese Traditional Ink for Photothermal Therapy of Metastatic Lymph Nodes”) that this ink could noninvasively and effectively treat cancer cells that spread, or metastasize, to lymph nodes.

A Sept. 27, 2017 American Chemical Society (ACS) news release, which originated the news item, reveals more about the research,

As cancer cells leave a tumor, they frequently make their way to lymph nodes, which are part of the immune system. In this case, the main treatment option is surgery, but this can result in complications. Photothermal therapy (PTT) is an emerging noninvasive treatment option in which nanomaterials are injected and accumulate in cancer cells. A laser heats up the nanomaterials, and this heat kills the cells. Many of these nanomaterials are expensive, difficult-to-make and toxic. However, a traditional Chinese ink called Hu-Kaiwen ink (Hu-ink) has similar properties to the nanomaterials used in PTT. For example, they are the same color, and are both carbon-based and stable in water. So Wuli Yang and colleagues wanted to see if Hu-ink could be a good alternative material for PTT.

The researchers analyzed Hu-ink and found that it consists of nanoparticles and thin layers of carbon. When Hu-ink was heated with a laser, its temperature rose by 131 degrees Fahrenheit, much higher than current nanomaterials. Under PPT conditions, the Hu-ink killed cancer cells in a laboratory dish, but under normal conditions, the ink was non-toxic. This was also the scenario observed in mice with tumors. The researchers also noted that Hu-ink could act as a probe to locate tumors and metastases because it absorbs near-infrared light, which goes through skin.

Being a little curious about Hu-ink’s similarity to nanomaterial, I looked for more detail in the the paper (Note: Links have been removed), From the: Introduction,

Photothermal therapy (PTT) is an emerging tumor treatment strategy, which utilizes hyperthermia generated from absorbed near-infrared (NIR) light energy by photoabsorbing agents to kill tumor cells.(7-13) Different from chemotherapy, surgical treatment, and radiotherapy, PTT is noninvasive and more efficient.(7, 14, 15) In the past decade, PTT with diverse nanomaterials to eliminate cancer metastases lymph nodes has attracted extensive attention by several groups, including our group.(3, 16-20) For instance, Liu and his co-workers developed a treatment method based on PEGylated single-walled carbon nanotubes for PTT of tumor sentinel lymph nodes and achieved remarkably improved treatment effect in an animal tumor model.(21) To meet the clinical practice, the potential metastasis of deeper lymph nodes was further ablated in our previous work, using magnetic graphene oxide as a theranostic agent.(22) However, preparation of these artificial nanomaterials usually requires high cost, complicated synthetic process, and unavoidably toxic catalyst or chemicals,(23, 24) which impede their future clinical application. For the clinical application, exploring an environment-friendly material with simple preparation procedure, good biocompatibility, and excellent therapeutic efficiency is still highly desired. [emphases mine]

From the: Preparation and Characterization of Hu-Ink

To obtain an applicable sample, the condensed Hu-ink was first diluted into aqueous dispersion with a lower concentration. The obtained Hu-ink dispersion without any further treatment was black in color and stable in physiological environment, including water, phosphate-buffered saline (PBS), and Roswell Park Memorial Institute (RPMI) 1640; furthermore, no aggregation was observed even after keeping undisturbed for 3 days (Figure 2a). The nanoscaled morphology of Hu-ink was examined by transmission electron microscopy (TEM) (Figure 2b), which demonstrates that Hu-ink mainly exist in the form of small aggregates. These small aggregates consist of a few nanoparticles with diameter of about 20–50 nm. Dynamic light scattering (DLS) measurement (Figure 2c) further shows that Hu-ink aqueous dispersion possesses a hydrodynamic diameter of about 186 nm (polydispersity index: 0.18), which was a crucial prerequisite for biomedical applications.(29) In the X-ray diffraction (XRD) pattern, no other characteristic peaks are found except carbon peak (Figure S1, Supporting Information), which confirms that the main component of Hu-ink is carbon.(25) Raman spectroscopy was a common tool to characterize graphene-related materials.(30) D band (∼1300 cm–1, corresponding to the defects) and G band (∼1600 cm–1, related to the sp2 carbon sites) peaks could be observed in Figure 2d with the ratio ID/IG = 0.96, which confirms the existence of graphene sheetlike structure in Hu-ink.(31) The UV–vis–NIR spectra (Figure 2e) also revealed that Hu-ink has high absorption in the NIR region around 650–900 nm, in which hemoglobin and water, the major absorbers of biological tissue, have their lowest absorption coefficient.(32) The high NIR absorption capability of Hu-ink encouraged us to investigate its photothermal properties.(33-35) Hu-ink dispersions with different concentrations were irradiated under an 808 nm laser (the commercial and widely used wavelength in photothermal therapy).(8-13) [emphases mine]

Curiosity satisfied! For those who’d like to investigate even further, here’s a link to and a citation for the paper,

New Application of Old Material: Chinese Traditional Ink for Photothermal Therapy of Metastatic Lymph Nodes by Sheng Wang, Yongbin Cao, Qin Zhang, Haibao Peng, Lei Liang, Qingguo Li, Shun Shen, Aimaier Tuerdi, Ye Xu, Sanjun Cai, and Wuli Yang. ACS Omega, 2017, 2 (8), pp 5170–5178 DOI: 10.1021/acsomega.7b00993 Publication Date (Web): August 30, 2017

Copyright © 2017 American Chemical Society

This paper appears to be open access.

Limitless energy and the International Thermonuclear Experimental Reactor (ITER)

Over 30 years in the dreaming, the International Thermonuclear Experimental Reactor (ITER) is now said to be 1/2 way to completing construction. A December 6, 2017 ITER press release (received via email) makes the joyful announcement,

WORLD’S MOST COMPLEX MACHINE IS 50 PERCENT COMPLETED
ITER is proving that fusion is the future source of clean, abundant, safe and economic energy_

The International Thermonuclear Experimental Reactor (ITER), a project to prove that fusion power can be produced on a commercial scale and is sustainable, is now 50 percent built to initial operation. Fusion is the same energy source from the Sun that gives the Earth its light and warmth.

ITER will use hydrogen fusion, controlled by superconducting magnets, to produce massive heat energy. In the commercial machines that will follow, this heat will drive turbines to produce electricity with these positive benefits:

* Fusion energy is carbon-free and environmentally sustainable, yet much more powerful than fossil fuels. A pineapple-sized amount of hydrogen offers as much fusion energy as 10,000 tons of coal.

* ITER uses two forms of hydrogen fuel: deuterium, which is easily extracted from seawater; and tritium, which is bred from lithium inside the fusion reactor. The supply of fusion fuel for industry and megacities is abundant, enough for millions of years.

* When the fusion reaction is disrupted, the reactor simply shuts down-safely and without external assistance. Tiny amounts of fuel are used, about 2-3 grams at a time; so there is no physical possibility of a meltdown accident.

* Building and operating a fusion power plant is targeted to be comparable to the cost of a fossil fuel or nuclear fission plant. But unlike today’s nuclear plants, a fusion plant will not have the costs of high-level radioactive waste disposal. And unlike fossil fuel plants,
fusion will not have the environmental cost of releasing CO2 and other pollutants.

ITER is the most complex science project in human history. The hydrogen plasma will be heated to 150 million degrees Celsius, ten times hotter than the core of the Sun, to enable the fusion reaction. The process happens in a donut-shaped reactor, called a tokamak(*), which is surrounded by giant magnets that confine and circulate the superheated, ionized plasma, away from the metal walls. The superconducting magnets must be cooled to minus 269°C, as cold as interstellar space.

The ITER facility is being built in Southern France by a scientific partnership of 35 countries. ITER’s specialized components, roughly 10 million parts in total, are being manufactured in industrial facilities all over the world. They are subsequently shipped to the ITER worksite, where they must be assembled, piece-by-piece, into the final machine.

Each of the seven ITER members-the European Union, China, India, Japan, Korea, Russia, and the United States-is fabricating a significant portion of the machine. This adds to ITER’s complexity.

In a message dispatched on December 1 [2017] to top-level officials in ITER member governments, the ITER project reported that it had completed 50 percent of the “total construction work scope through First Plasma” (**). First Plasma, scheduled for December 2025, will be the first stage of operation for ITER as a functional machine.

“The stakes are very high for ITER,” writes Bernard Bigot, Ph.D., Director-General of ITER. “When we prove that fusion is a viable energy source, it will eventually replace burning fossil fuels, which are non-renewable and non-sustainable. Fusion will be complementary with wind, solar, and other renewable energies.

“ITER’s success has demanded extraordinary project management, systems engineering, and almost perfect integration of our work.

“Our design has taken advantage of the best expertise of every member’s scientific and industrial base. No country could do this alone. We are all learning from each other, for the world’s mutual benefit.”

The ITER 50 percent milestone is getting significant attention.

“We are fortunate that ITER and fusion has had the support of world leaders, historically and currently,” says Director-General Bigot. “The concept of the ITER project was conceived at the 1985 Geneva Summit between Ronald Reagan and Mikhail Gorbachev. When the ITER Agreement was signed in 2006, it was strongly supported by leaders such as French President Jacques Chirac, U.S. President George W. Bush, and Indian Prime Minister Manmohan Singh.

“More recently, President Macron and U.S. President Donald Trump exchanged letters about ITER after their meeting this past July. One month earlier, President Xi Jinping of China hosted Russian President Vladimir Putin and other world leaders in a showcase featuring ITER and fusion power at the World EXPO in Astana, Kazakhstan.

“We know that other leaders have been similarly involved behind the scenes. It is clear that each ITER member understands the value and importance of this project.”

Why use this complex manufacturing arrangement?

More than 80 percent of the cost of ITER, about $22 billion or EUR18 billion, is contributed in the form of components manufactured by the partners. Many of these massive components of the ITER machine must be precisely fitted-for example, 17-meter-high magnets with less than a millimeter of tolerance. Each component must be ready on time to fit into the Master Schedule for machine assembly.

Members asked for this deal for three reasons. First, it means that most of the ITER costs paid by any member are actually paid to that member’s companies; the funding stays in-country. Second, the companies working on ITER build new industrial expertise in major fields-such as electromagnetics, cryogenics, robotics, and materials science. Third, this new expertise leads to innovation and spin-offs in other fields.

For example, expertise gained working on ITER’s superconducting magnets is now being used to map the human brain more precisely than ever before.

The European Union is paying 45 percent of the cost; China, India, Japan, Korea, Russia, and the United States each contribute 9 percent equally. All members share in ITER’s technology; they receive equal access to the intellectual property and innovation that comes from building ITER.

When will commercial fusion plants be ready?

ITER scientists predict that fusion plants will start to come on line as soon as 2040. The exact timing, according to fusion experts, will depend on the level of public urgency and political will that translates to financial investment.

How much power will they provide?

The ITER tokamak will produce 500 megawatts of thermal power. This size is suitable for studying a “burning” or largely self-heating plasma, a state of matter that has never been produced in a controlled environment on Earth. In a burning plasma, most of the plasma heating comes from the fusion reaction itself. Studying the fusion science and technology at ITER’s scale will enable optimization of the plants that follow.

A commercial fusion plant will be designed with a slightly larger plasma chamber, for 10-15 times more electrical power. A 2,000-megawatt fusion electricity plant, for example, would supply 2 million homes.

How much would a fusion plant cost and how many will be needed?

The initial capital cost of a 2,000-megawatt fusion plant will be in the range of $10 billion. These capital costs will be offset by extremely low operating costs, negligible fuel costs, and infrequent component replacement costs over the 60-year-plus life of the plant. Capital costs will decrease with large-scale deployment of fusion plants.

At current electricity usage rates, one fusion plant would be more than enough to power a city the size of Washington, D.C. The entire D.C. metropolitan area could be powered with four fusion plants, with zero carbon emissions.

“If fusion power becomes universal, the use of electricity could be expanded greatly, to reduce the greenhouse gas emissions from transportation, buildings and industry,” predicts Dr. Bigot. “Providing clean, abundant, safe, economic energy will be a miracle for our planet.”

*     *     *

FOOTNOTES:

* “Tokamak” is a word of Russian origin meaning a toroidal or donut-shaped magnetic chamber. Tokamaks have been built and operated for the past six decades. They are today’s most advanced fusion device design.

** “Total construction work scope,” as used in ITER’s project performance metrics, includes design, component manufacturing, building construction, shipping and delivery, assembly, and installation.

It is an extraordinary project on many levels as Henry Fountain notes in a March 27, 2017 article for the New York Times (Note: Links have been removed),

At a dusty construction site here amid the limestone ridges of Provence, workers scurry around immense slabs of concrete arranged in a ring like a modern-day Stonehenge.

It looks like the beginnings of a large commercial power plant, but it is not. The project, called ITER, is an enormous, and enormously complex and costly, physics experiment. But if it succeeds, it could determine the power plants of the future and make an invaluable contribution to reducing planet-warming emissions.

ITER, short for International Thermonuclear Experimental Reactor (and pronounced EAT-er), is being built to test a long-held dream: that nuclear fusion, the atomic reaction that takes place in the sun and in hydrogen bombs, can be controlled to generate power.

ITER will produce heat, not electricity. But if it works — if it produces more energy than it consumes, which smaller fusion experiments so far have not been able to do — it could lead to plants that generate electricity without the climate-affecting carbon emissions of fossil-fuel plants or most of the hazards of existing nuclear reactors that split atoms rather than join them.

Success, however, has always seemed just a few decades away for ITER. The project has progressed in fits and starts for years, plagued by design and management problems that have led to long delays and ballooning costs.

ITER is moving ahead now, with a director-general, Bernard Bigot, who took over two years ago after an independent analysis that was highly critical of the project. Dr. Bigot, who previously ran France’s atomic energy agency, has earned high marks for resolving management problems and developing a realistic schedule based more on physics and engineering and less on politics.

The site here is now studded with tower cranes as crews work on the concrete structures that will support and surround the heart of the experiment, a doughnut-shaped chamber called a tokamak. This is where the fusion reactions will take place, within a plasma, a roiling cloud of ionized atoms so hot that it can be contained only by extremely strong magnetic fields.

Here’s a rendering of the proposed reactor,

Source: ITER Organization

It seems the folks at the New York Times decided to remove the notes which help make sense of this image. However, it does get the idea across.

If I read the article rightly, the official cost in March 2017 was around 22 B Euros and more will likely be needed. You can read Fountain’s article for more information about fusion and ITER or go to the ITER website.

I could have sworn a local (Vancouver area) company called General Fusion was involved in the ITER project but I can’t track down any sources for confirmation. The sole connection I could find is in a documentary about fusion technology,

Here’s a little context for the film from a July 4, 2017 General Fusion news release (Note: A link has been removed),

A new documentary featuring General Fusion has captured the exciting progress in fusion across the public and private sectors.

Let There Be Light made its international premiere at the South By Southwest (SXSW) music and film festival in March [2017] to critical acclaim. The film was quickly purchased by Amazon Video, where it will be available for more than 70 million users to stream.

Let There Be Light follows scientists at General Fusion, ITER and Lawrenceville Plasma Physics in their pursuit of a clean, safe and abundant source of energy to power the world.

The feature length documentary has screened internationally across Europe and North America. Most recently it was shown at the Hot Docs film festival in Toronto, where General Fusion founder and Chief Scientist Dr. Michel Laberge joined fellow fusion physicist Dr. Mark Henderson from ITER at a series of Q&A panels with the filmmakers.

Laberge and Henderson were also interviewed by the popular CBC radio science show Quirks and Quarks, discussing different approaches to fusion, its potential benefits, and the challenges it faces.

It is yet to be confirmed when the film will be release for streaming, check Amazon Video for details.

You can find out more about General Fusion here.

Brief final comment

ITER is a breathtaking effort but if you’ve read about other large scale projects such as building a railway across the Canadian Rocky Mountains, establishing telecommunications in an  astonishing number of countries around the world, getting someone to the moon, eliminating small pox, building the pyramids, etc., it seems standard operating procedure both for the successes I’ve described and for the failures we’ve forgotten. Where ITER will finally rest on the continuum between success and failure is yet to be determined but the problems experienced so far are not necessarily a predictor.

I wish the engineers, scientists, visionaries, and others great success with finding better ways to produce energy.

Europe’s cathedrals get a ‘lift’ with nanoparticles

That headline is a teensy bit laboured but I couldn’t resist the levels of wordplay available to me. They’re working on a cathedral close to the leaning Tower of Pisa in this video about the latest in stone preservation in Europe.

I have covered the topic of preserving stone monuments before (most recently in my Oct. 21, 2014 posting). The action in this field seems to be taking place mostly in Europe, specifically Italy, although other countries are also quite involved.

Finally, getting to the European Commission’s latest stone monument preservation project, Nano-Cathedral, a Sept. 26, 2017 news item on Nanowerk announces the latest developments,

Just a few meters from Pisa’s famous Leaning Tower, restorers are defying scorching temperatures to bring back shine to the city’s Cathedral.

Ordinary restoration techniques like laser are being used on much of the stonework that dates back to the 11th century. But a brand new technique is also being used: a new material made of innovative nanoparticles. The aim is to consolidate the inner structure of the stones. It’s being applied mainly on marble.

A March 7, 2017 item on the Euro News website, which originated the Nanowerk news item, provides more detail,

“Marble has very low porosity, which means we have to use nanometric particles in order to go deep inside the stone, to ensure that the treatment is both efficient while still allowing the stone to breathe,” explains Roberto Cela, civil engineer at Opera Della Primaziale Pisana.

The material developed by the European research team includes calcium carbonate, which is a mix of calcium oxide, water and carbon dioxide.

The nano-particles penetrate the stone cementing its decaying structure.

“It is important that these particles have the same chemical nature as the stones that are being treated, so that the physical and mechanical processes that occur over time don’t lead to the break-up of the stones,” says Dario Paolucci, chemist at the University of Pisa.

Vienna’s St Stephen’s is another of the five cathedrals where the new restoration materials are being tested.

The first challenge for researchers is to determine the mechanical characteristics of the cathedral’s stones. Since there are few original samples to work on, they had to figure out a way of “ageing” samples of stones of similar nature to those originally used.

“We tried different things: we tried freeze storage, we tried salts and acids, and we decided to go for thermal ageing,” explains Matea Ban, material scientist at the University of Technology in Vienna. “So what happens is that we heat the stone at certain temperatures. Minerals inside then expand in certain directions, and when they expand they build up stresses to neighbouring minerals and then they crack, and we need those cracks in order to consolidate them.”

Consolidating materials were then applied on a variety of limestones, sandstones and marble – a selection of the different types of stones that were used to build cathedrals around Europe.

What researchers are looking for are very specific properties.

“First of all, the consolidating material has to be well absorbed by the stone,” says petrologist Johannes Weber of the University of Applied Arts in Vienna. “Then, as it evaporates, it has to settle properly within the stone structure. It should not shrink too much. All materials shrink when drying, including consolidating materials. They should adhere to the particles of the stone but shouldn’t completely obstruct its pores.”

Further tests are underway in cathedrals across Europe in the hope of better protecting our invaluable cultural heritage.

There’s a bit more detail about Nano-Cathedral on the Opera della Primaziale Pisana (O₽A) website (from their Nano-Cathedral project page),

With the meeting of June 3 this year the Nano Cathedral project kicked off, supported by the European Union within the nanotechnology field applied to Horizon 2020 cultural heritage with a fund of about 6.5 million euro.

A total of six monumental buildings will be for three years under the eyes and hands of petrographers, geologists, chemists and restorers of the institutes belonging to the Consortium: five cathedrals have been selected to represent the cultural diversity within Europe from the perspective of developing shared values and transnational identity, and a contemporary monumental building entirely clad in Carrara marble, the Opera House of Oslo.

Purpose: the testing of nanomaterials for the conservation of marble and the outer surfaces of our ‘cathedrals’.
The field of investigation to check degradation, testing new consolidating and protective products is the Cathedral of Pisa together with the Cathedrals of Cologne, Vienna, Ghent and Vitoria.
For the selection of case studies we have crosschecked requirements for their historical and architectural value but also for the different types of construction materials – marble, limestone and sandstone – as well as the relocation of six monumental buildings according to European climates.

The Cathedral of Pisa is the most southern, fully positioned in Mediterranean climate, therefore subject to degradation and very different from those which the weather conditions of the Scandinavian peninsula recorded; all the intermediate climate phases are modulated through Ghent, Vitoria, Cologne and Vienna.

At the conclusion of the three-year project, once the analysis in situ and in the laboratory are completed and all the experiments are tested on each different identified portion in each monumental building, an intervention protocol will be defined in detail in order to identify the mineralogical and petrographic characteristics of stone materials and of their degradation, the assessment of the causes and mechanisms of associated alteration, including interactions with factors of environmental pollution. Then we will be able to identify the most appropriate method of restoration and testing of nanotechnology products for the consolidation and protection of different stone materials.

In 2018 we hope to have new materials to protect and safeguard the ‘skin’ of our historic buildings and monuments for a long time.

Back to my headline and the second piece of wordplay, ‘lift’ as in ‘skin lift’ in that last sentence.

I realize this is a bit off topic but it’s worth taking a look at ORA’s home page,

Gabriele D’Annunzio effectively condenses the wonder and admiration that catch whoever visits the Duomo Square of Pisa.

The Opera della Primaziale Pisana (O₽A) is a non-profit organisation which was established in order to oversee the first works for the construction of the monuments in the Piazza del Duomo, subject to its own charter which includes the protection, promotion and enhancement of its heritage, in order to pass the religious and artistic meaning onto future generations.

«L’Ardea roteò nel cielo di Cristo, sul prato dei Miracoli.»
Gabriele d’Annunzio in Forse che sì forse che no (1910)

If you go to the home page, you can buy tickets to visit the monuments surrounding the square and there are other notices including one for a competition (it’s too late to apply but the details are interesting) to construct four stained glass windows for the Pisa cathedral.

Liquid circuitry, shape-shifting fluids and more

I’d have to see it to believe it but researchers at the US Dept. of Energy (DOE) Lawrence Berkeley National Laboratory (LBNL) have developed a new kind of ‘bijel’ which would allow for some pretty nifty robotics. From a Sept. 25, 2017 news item on ScienceDaily,

A new two-dimensional film, made of polymers and nanoparticles and developed by researchers at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab), can direct two different non-mixing liquids into a variety of exotic architectures. This finding could lead to soft robotics, liquid circuitry, shape-shifting fluids, and a host of new materials that use soft, rather than solid, substances.

The study, reported today in the journal Nature Nanotechnology, presents the newest entry in a class of substances known as bicontinuous jammed emulsion gels, or bijels, which hold promise as a malleable liquid that can support catalytic reactions, electrical conductivity, and energy conversion.

A Sept. 25, 2017 LBNL news release (also on EurekAlert), which originated the news item, expands on the theme,

Bijels are typically made of immiscible, or non-mixing, liquids. People who shake their bottle of vinaigrette before pouring the dressing on their salad are familiar with such liquids. As soon as the shaking stops, the liquids start to separate again, with the lower density liquid – often oil – rising to the top.

Trapping, or jamming, particles where these immiscible liquids meet can prevent the liquids from completely separating, stabilizing the substance into a bijel. What makes bijels remarkable is that, rather than just making the spherical droplets that we normally see when we try to mix oil and water, the particles at the interface shape the liquids into complex networks of interconnected fluid channels.

Bijels are notoriously difficult to make, however, involving exact temperatures at precisely timed stages. In addition, the liquid channels are normally more than 5 micrometers across, making them too large to be useful in energy conversion and catalysis.

“Bijels have long been of interest as next-generation materials for energy applications and chemical synthesis,” said study lead author Caili Huang. “The problem has been making enough of them, and with features of the right size. In this work, we crack that problem.”

Huang started the work as a graduate student with Thomas Russell, the study’s principal investigator, at Berkeley Lab’s Materials Sciences Division, and he continued the project as a postdoctoral researcher at DOE’s Oak Ridge National Laboratory.

Creating a new bijel recipe

The method described in this new study simplifies the bijel process by first using specially coated particles about 10-20 nanometers in diameter. The smaller-sized particles line the liquid interfaces much more quickly than the ones used in traditional bijels, making the smaller channels that are highly valued for applications.

Illustration shows key stages of bijel formation. Clockwise from top left, two non-mixing liquids are shown. Ligands (shown in yellow) with amine groups are dispersed throughout the oil or solvent, and nanoparticles coated with carboxylic acids (shown as blue dots) are scattered in the water. With vigorous shaking, the nanoparticles and ligands form a “supersoap” that gets trapped at the interface of the two liquids. The bottom panel is a magnified view of the jammed nanoparticle supersoap. (Credit: Caili Huang/ORNL)

“We’ve basically taken liquids like oil and water and given them a structure, and it’s a structure that can be changed,” said Russell, a visiting faculty scientist at Berkeley Lab. “If the nanoparticles are responsive to electrical, magnetic, or mechanical stimuli, the bijels can become reconfigurable and re-shaped on demand by an external field.”

The researchers were able to prepare new bijels from a variety of common organic, water-insoluble solvents, such as toluene, that had ligands dissolved in it, and deionized water, which contained the nanoparticles. To ensure thorough mixing of the liquids, they subjected the emulsion to a vortex spinning at 3,200 revolutions per minute.

“This extreme shaking creates a whole bunch of new places where these particles and polymers can meet each other,” said study co-author Joe Forth, a postdoctoral fellow at Berkeley Lab’s Materials Sciences Division. “You’re synthesizing a lot of this material, which is in effect a thin, 2-D coating of the liquid surfaces in the system.”

The liquids remained a bijel even after one week, a sign of the system’s stability.

Russell, who is also a professor of polymer science and engineering at the University of Massachusetts-Amherst, added that these shape-shifting characteristics would be valuable in microreactors, microfluidic devices, and soft actuators.

Nanoparticle supersoap

Nanoparticles had not been seriously considered in bijels before because their small size made them hard to trap in the liquid interface. To resolve that problem, the researchers coated nano-sized particles with carboxylic acids and put them in water. They then took polymers with an added amine group – a derivative of ammonia – and dissolved them in the toluene.

At left is a vial of bijel stabilized with nanoparticle surfactants. On the right is the same vial after a week of inversion, showing that the nanoparticle kept the liquids from moving. (Credit: Caili Huang/ORNL)

This configuration took advantage of the amine group’s affinity to water, a characteristic that is comparable to surfactants, like soap. Their nanoparticle “supersoap” was designed so that the nanoparticles join ligands, forming an octopus-like shape with a polar head and nonpolar legs that get jammed at the interface, the researchers said.

“Bijels are really a new material, and also excitingly weird in that they are kinetically arrested in these unusual configurations,” said study co-author Brett Helms, a staff scientist at Berkeley Lab’s Molecular Foundry. “The discovery that you can make these bijels with simple ingredients is a surprise. We all have access to oils and water and nanocrystals, allowing broad tunability in bijel properties. This platform also allows us to experiment with new ways to control their shape and function since they are both responsive and reconfigurable.”

The nanoparticles were made of silica, but the researchers noted that in previous studies they used graphene and carbon nanotubes to form nanoparticle surfactants.

“The key is that the nanoparticles can be made of many materials,” said Russell.  “The most important thing is what’s on the surface.”

This is an animation of the bijel

3-D rendering of the nanoparticle bijel taken by confocal microscope. (Credit: Caili Huang/ORNL [Oak Ridge National Laboratory] and Joe Forth/Berkeley Lab)

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

Bicontinuous structured liquids with sub-micrometre domains using nanoparticle surfactants by Caili Huang, Joe Forth, Weiyu Wang, Kunlun Hong, Gregory S. Smith, Brett A. Helms & Thomas P. Russell. Nature Nanotechnology (2017) doi:10.1038/nnano.2017.182 25 September 2017

This paper is behind a paywall.