Tag Archives: nanoparticles

Nanoparticles in 3D courtesy of x-rays

A Feb. 4, 2015 Deutsches Elektronen-Synchrotron (DESY) press release (also on EurekAlert) announces a 3D first,

For the first time, a German-American research team has determined the three-dimensional shape of free-flying silver nanoparticles, using DESY’s X-ray laser FLASH. The tiny particles, hundreds of times smaller than the width of a human hair, were found to exhibit an unexpected variety of shapes, as the physicists from the Technical University (TU) Berlin, the University of Rostock, the SLAC National Accelerator Laboratory in the United States and from DESY report in the scientific journal Nature Communications. Besides this surprise, the results open up new scientific routes, such as direct observation of rapid changes in nanoparticles.

The press release goes on to describe the work in more detail,

“The functionality of nanoparticles is linked to their geometric form, which is often very difficult to determine experimentally,” explains Dr. Ingo Barke from the University of Rostock. “This is particularly challenging when they are present as free particles, that is, in the absence of contact with a surface or a liquid.”

The nanoparticle shape can be revealed from the characteristic way how it scatters X-ray light. Therefore, X-ray sources like DESY’s FLASH enable a sort of super microscope into the nano-world. So far, the spatial structure of nanoparticles has been reconstructed from multiple two-dimensional images, which were taken from different angles. This procedure is uncritical for particles on solid substrates, as the images can be taken from many different angles to uniquely reconstruct their three-dimensional shape.

“Bringing nanoparticles into contact with a surface or a liquid can significantly alter the particles, such that you can no longer see their actual form,” says Dr. Daniela Rupp from the TU Berlin. A free particle, however, can only be measured one time in flight before it either escapes or is destroyed by the intense X-ray light. Therefore, the scientists looked for a way to record the entire structural information of a nanoparticle with a single X-ray laser pulse.

To achieve this goal, the scientists led by Prof. Thomas Möller from the TU Berlin and Prof. Karl-Heinz Meiwes-Broer and Prof. Thomas Fennel from the University of Rostock employed a trick. Instead of taking usual small-angle scattering images, the physicists recorded the scattered X-rays in a wide angular range. “This approach virtually captures the structure from many different angles simultaneously from a single laser shot,” explains Fennel.

The researchers tested this method on free silver nanoparticles with diameters of 50 to 250 nanometres (0.00005 to 0.00025 millimetres). The experiment did not only verify the feasibility of the tricky method, but also uncovered the surprising result that large nanoparticles exhibit a much greater variety of shapes than expected.

The shape of free nanoparticles is a result of different physical principles, particularly the particles’ effort to minimize their energy. Consequently, large particles composed of thousands or millions of atoms often yield predictable shapes, because the atoms can only be arranged in a particular way to obtain an energetically favourable state.

In their experiment, however, the researchers observed numerous highly symmetrical three-dimensional shapes, including several types known as Platonic and Archimedean bodies. Examples include the truncated octahedron (a body consisting of eight regular hexagons and six squares) and the icosahedron (a body made up of twenty equilateral triangles). The latter is actually only favourable for extremely small particles consisting of few atoms, and its occurrence with free particles of this size was previously unknown. “The results show that metallic nanoparticles retain a type of memory of their structure, from the early stages of growth to a yet unexplored size range,” emphasizes Barke.

Due to the large variety of shapes, it was especially important to use a fast computational method so that the researchers were capable of mapping the shape of each individual particle. The scientists used a two-step process: the rough shape was determined first and then refined using more complex simulations on a super computer. This approach turned out to be so efficient that it could not only determine various shapes reliably, but could also differentiate between varying orientations of the same shape.

This new method for determining the three-dimensional shape and orientation of nanoparticles with a single X-ray laser shot opens up a wide spectrum of new research directions. In future projects, particles could be directly “filmed” in three dimensions during growth or during phase changes. “The ability to directly film the reaction of a nanoparticle to an intense flash of X-ray light has been a dream for many physicists – this dream could now come true, even in 3D!,” emphasises Rupp.

The researchers have provided an image showing their work,

Caption: This is a wide-angle X-ray diffraction image of a truncated twinned tetrahedra nanoparticle. Credit: Hannes Hartmann/University of Rostock

Caption: This is a wide-angle X-ray diffraction image of a truncated twinned tetrahedra nanoparticle.
Credit: Hannes Hartmann/University of Rostock

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

The 3D-architecture of individual free ​silver nanoparticles captured by X-ray scattering by Ingo Barke, Hannes Hartmann, Daniela Rupp, Leonie Flückiger, Mario Sauppe, Marcus Adolph, Sebastian Schorb, Christoph Bostedt, Rolf Treusch, Christian Peltz, Stephan Bartling, Thomas Fennel, Karl-Heinz Meiwes-Broer, & Thomas Möller. Nature Communications 6, Article number: 6187 doi:10.1038/ncomms7187 Published 04 February 2015

This article is open access.

Of airborne nanomaterials, bacterial microbiomes, viral microbiomes, and paper sensors

There’s a Jan. 14, 2015 news item on Nanowerk from the Virginia Polytechnic Institute (Virginia Tech) which is largely a personal profile featuring some basic information (useful for those new to the topic) about airborne nanoparticles (Note: A link has been removed),

The Harvard educated undergraduate [Linsey Marr,  professor of civil and environmental engineering, Virginia Tech] who obtained her Ph.D. from University of California at Berkeley and trained as a postdoctoral researcher with a Nobel laureate of chemistry at MIT is now among a handful of researchers in the world who are addressing concerns about engineered nanomaterials in the atmosphere.

Marr is part of the National Science Foundation’s Center for the Environmental Implications of Nanotechnology and her research group has characterized airborne nanoparticles at every point of their life cycle. This cycle includes production at a commercial manufacturing facility, use by consumers in the home, and disposal via incineration.

A Jan. 14, 2015 Virginia Tech news release, which originated the news item, quotes Marr on the current thinking about airborne nanoparticles,

“Results have shown that engineered nanomaterials released into the air are often aggregated with other particulate matter, such as combustion soot or ingredients in consumer spray products, and that the size of such aggregates may range from smaller than 10 nanometers to larger than 10 microns,” Marr revealed. She was referring to studies completed by research group members Marina Quadros Vance of Florianopolis, Brazil, a research scientist with the Virginia Tech Institute of Critical Technology and Applied Science, and Eric Vejerano, of Ligao, Philippines, a post-doctoral associate in civil and environmental engineering.

Size matters if these aggregates are inhaled.

Another concern is the reaction of a nanomaterial such as a fullerene with ozone at environmentally relevant concentration levels. Marr’s graduate student, Andrea Tiwari, of Mankato, Minnesota, said the resulting changes in fullerene could lead to enhanced toxicity.

The story then segues into airborne pathogens and viruses eventually honing in on virus microbiomes and bacterial microbiomes (from the news release),

Marr is a former Ironman triathlete who obviously has strong interests in what she is breathing into her own body. So it would be natural for her to expand her study of engineered nanoparticles traveling in the atmosphere to focus on airborne pathogens.

She did so by starting to consider the influenza virus as an airborne pollutant. She applied the same concepts and tools used for studying environmental contaminants and ambient aerosols to the examination of the virus.

She looked at viruses as “essentially self-assembled nanoparticles that are capable of self-replication.”

Her research team became the first to measure influenza virus concentrations in ambient air in a children’s day care center and on airplanes. When they conducted their studies, the Virginia Tech researchers collected samples from a waiting room of a health care center, two toddlers’ rooms and one babies’ area of a childcare center, as well as three cross-country flights between Roanoke, Virginia., and San Francisco. They collected 16 samples between Dec. 10, 2009 and Apr. 22, 2010.

“Half of the samples were confirmed to contain aerosolized influenza A viruses,” Marr said. The childcare samples were the most infected at 75 percent. Next, airplane samples reached 67 percent contamination, and health center numbers came in at 33 percent.

This study serves as a foundation for new work started about a year ago in her lab.

Marr collaborated with Aaron J. Prussin II, of Blacksburg, Virginia, and they successfully secured for him a postdoctoral fellowship from the Alfred P. Sloan Foundation to characterize the bacterial and viral microbiome — the ecological community of microorganisms — of the air in a daycare center.

They are now attempting to determine seasonal changes of both the viral microbiome and the bacterial microbiome in a daycare setting, and examine how changes in the microbiome are related to naturally occurring changes in the indoor environment.

“Little is known about the viral component of the microbiome and it is important because viruses are approximately 10 times more abundant than bacteria, and they help shape the bacterial community. Research suggests that viruses do have both beneficial and harmful interactions with bacteria,” Prussin said.

With Prussin and Marr working together they hope to verify their hypothesis that daycare centers harbor unique, dynamic microbiomes with plentiful bacteria and viruses. They are also looking at what seasonal changes might bring to a daycare setting.

They pointed to the effect of seasonal changes because in previous work, Marr, her former graduate student Wan Yang, of Shantou, China, and Elankumaran Subbiah, a virologist in the biomedical sciences and pathobiology department of the Virginia-Maryland College of Veterinary Medicine, measured the influenza A virus survival rate at various levels of humidity.

Their 2012 study presented for the first time the relationship between the influenza A virus viability in human mucus and humidity over a large range of relative humidities, from 17 percent to 100 percent. They found the viability of the virus was highest when the relative humidity was either close to 100 percent or below 50 percent. The results in human mucus may help explain influenza’s seasonality in different regions.

According to the news release Marr and her colleagues have developed a fast and cheap technology for detection of airborne pathogens (Note: A link has been removed),

With the urgent need to understand the dynamics of airborne pathogens, especially as one considers the threats of bioterrorism, pandemic influenza, and other emerging infectious diseases, Marr said “a breakthrough technology is required to enable rapid, low-cost detection of pathogens in air.”

Along with Subbiah and Peter Vikesland,  professor of civil and environmental engineering, they want to develop readily deployable, inexpensive, paper-based sensors for airborne pathogen detection.

In 2013 they received funding of almost $250,000 from Virginia Tech’s Institute for Critical Technology and Applied Science, a supporter of the clustering of research groups, to support their idea of creating paper-based sensors based on their various successes to date.

Marr explained the sensors “would use a sandwich approach. The bottom layer is paper containing specialized DNA that will immobilize the virus. The middle layer is the virus, which sticks to the specialized DNA on the bottom layer. The top layer is additional specialized DNA that sticks to the virus. This DNA is attached to gold nanoparticles that are easily detectable using a technique known as Raman microscopy.”

They key to their approach is that it combines high-tech with low-tech in the hopes of keeping the assay costs low. Their sampling method will use a bicycle pump, and low cost paper substrates. They hope that they will be able to incorporate smart-phone based signal transduction for the detection. Using this approach, they believe “even remote corners of the world” would be able to use the technique.

Vikesland previously received funding from the Gates Foundation to detect the polio virus via paper-based diagnostics. Polio is still found in countries on the continents of Asia and Africa.

I have previously mentioned Linsey Marr in an Oct. 18, 2013 post about the revival of the Nanotechnology Consumer Products Inventory (originally developed by the Project for Emerging Nanotechnologies) by academics at Virginia Tech and first mentioned CEINT in an Aug. 15, 2011 post about a special project featuring a mesocosm at Duke University (North Carolina).

Two books: Science Ruining Everything and Nanoparticles before nanotechnology

With 20 days left of its Kickstarter campaign, the SCIENCE: Ruining Everything Since 1543 (an SMBC [Saturday Morning Breakfast Cereal] Collection) has amassed $184, 562 for a project with a goal of $20,000.  Some of the more expensive incentives have been snapped but there are still lots of choices. From the campaign page,

SMBC (short for “Saturday Morning Breakfast Cereal”) is a daily-updated comic strip about all sorts of topics. Its author, Zach Weinersmith, is a giant dork who also has many other geeky projects such as producing SMBC Theater, writing for Snowflakes, his science blog the Weinerworks, and his science-themed podcast The Weekly Weinersmith (which he co-hosts with his wife, the parasitologist Kelly Weinersmith).

So it will come as no huge surprise that this, the third SMBC printed collection, is a compendium of his finest science-related strips.

Phil Plait in a Jan. 23, 2013 article for Slate.com describes the project and his involvement,

Today, Zach [Weiner] announced a new and exciting project: He’s collecting his science comics into a single compendium which he’s calling “Science: Ruining Everything Since 1543”. And it’s not just old comics; he’s also written some new ones for the book. He’s creating this book as a Kickstarter project. Give him money, and when it’s done he’ll send you the book.

And there’s more, too: He asked some well-known scientists on the web to send him a personal story about science in their lives, regaling how it’s affected them, and Zach will draw them up as a comic to put in the book. And guess who he asked? Well, the only one he told me about is me, but he assures me there are others. So I sent him an All-True Tale of Bad Astronomy Past, and he created a multi-panel comic about it.

Here’s a representative image of the artwork,

Science: Ruining Everything Since 1543. It's true. Image credit: Zach Weiner [downloaded from http://www.slate.com/blogs/bad_astronomy/2013/01/23/saturday_morning_breakfast_cereal_new_science_book_of_web_comics.html]

Science: Ruining Everything Since 1543. It’s true.
Image credit: Zach Weiner [downloaded from http://www.slate.com/blogs/bad_astronomy/2013/01/23/saturday_morning_breakfast_cereal_new_science_book_of_web_comics.html]

If you go to Phil Plait’s article , you can will find some panels from the collection or you can visit the Science: Ruining Everything campaign page to view a video presentation and learn more about the various incentives.

Meanwhile, the folks at the Nanowiki website have published their third book, Nanoparticles Before Nanotechnology. From the Nanowiki introduction page,

This year we chose the subject of Nanoparticles Before Nanotechnology simply because we were suspicious that nanoparticles are too often, in scientific and non-scientific circles, perceived as invented, while we think they should be understood as discovered.

Nanomaterials are claimed to be so new that people become scared. However, before nanotechnology, one can find nanoparticles in the works of both nature and Man, although they passed unnoticed by us until recently. The origin of nanoparticles in nature is basically i) biogenic, ii) geogenic (and also at the bio-inorganic interface), or iii) cosmogenic, while the nanoparticles produced by men come unintentionally from origins as burning wood and oil or unnoticed in crafted stuff such as cosmetics and colored glass and ceramics.

Additionally, to bring nano closer to society, following the same demystifying aims, we present a set of experiments, Hands On, in which some basics and useful nanoscale phenomena can be easily observed, such as preparing photonic crystals that look like opals, disinfecting water, or harvesting energy.

You can find many options (paper and various e-pub choices)  for getting the book if you follow the link provided previously or you can access the low res web version here as I did. Gorgeous images festoon the book and I wish they’d listed the sources or credits for them. They are truly stunning, even in low res. As for the text, I think they’ve provided a thoughtful compilation of information and organized it very well (I scanned the book quickly). I particularly appreciate having links so I can easily check out the sources for myself and I found a few things I didn’t know about, always a thrill.

In common with most emerging technology topics, knowledge about nanoparticles and other aspects of nanotechnology can change quickly as new data extends or contradicts what was previously believed. Within that context, this is one of the best resources I’ve seen and I’m thankful these folks took the time to pull this book together.

Flesh-eating fungus, ivy and other inspirations from nature

Michael Berger has featured Dr. Mingjun Zhang’s team’s fascinating work on flesh-eating fungus in a Dec. 18, 2012 Spotlight article on Nanowerk,

“Most studies on naturally occurring organic nanoparticles have focused on higher organisms,” Mingjun Zhang, an associate professor of biomedical engineering at the University of Tennessee, Knoxville, tells Nanowerk. “Given the earth’s rich biological diversity, it is reasonable to hypothesize that naturally occurring nanoparticles, of various forms and functions, may be produced by a wide range of organisms from microbes to metazoans.”

In his research, Zhang has focused on looking at nature for inspirations for solutions to challenges in engineering and medicine, especially in small-scale, such as bioinspired nanomaterials, bioinspired energy-efficient propulsive systems, and bioinspired nanobio systems for interfacing with cellular systems.

In new work, Zhang and his research associate Dr. Yongzhong Wang have turned their focus to Arthrobotrys oligospora, a representative flesh eater with a predatory life stage in the fungal kingdom.

The researchers have published their work in Advanced Functional Materials ((early online publication behind a paywall),

Naturally Occurring Nanoparticles from Arthrobotrys oligospora as a Potential Immunostimulatory and Antitumor Agent by Yongzhong Wang, Leming Sun, Sijia Yi, Yujian Huang, Scott C. Lenaghan, and Mingjun Zhang in Advanced Functional Materials

Article first published online: 4 DEC 2012 DOI: 10.1002/adfm.201202619

Here’s the abstract,

Arthrobotrys oligospora, a representative flesh eater in the fungal kingdom, is a potential source for natural-based biomaterials due to the presence of specialized 3D adhesive traps that can capture, penetrate, and digest free-living nematodes in diverse environments. The purpose of this study is to discover novel nanoparticles that occur naturally in A. oligospora and to exploit its potential biomedical applications. A new culture method, fungal sitting drop culture method, is established in order to monitor the growth of A. oligospora in situ, and observe the nanoparticle production without interfering or contamination from the solid media. Abundant spherical nanoparticles secreted from the fungus are first revealed by scanning electron microscopy and atomic force microscopy. They have an average size of 360–370 nm, with a zeta potential of –33 mV at pH 6.0. Further analyses reveal that there is ≈28 μg of glycosaminoglycan and ≈550 μg of protein per mg of nanoparticles. Interestingly, the nanoparticles significantly induce TNF-α secretion in RAW264.7mouse macrophages, indicating a potential immunostimulatory effect. The nanoparticles themselves are also found slightly cytotoxic to mouse melanoma B16BL6 and human lung cancer A549 cells, and show a synergistic cytotoxic effect upon conjugation with doxorubicin against both cells. This study proposes a new approach for producing novel organic nanoparticles secreted from microorganisms under controlled conditions. The findings here also highlight the potential roles of the naturally occurring nanoparticles from A. oligospora as an immunostimulatory and antitumor agent for cancer immunochemotherapy.

In more generalized language (from Berger’s Spotlight article),

“It is really exciting to use a natural microbe system to produce nanoparticles for potential cancer therapy,” says Zhang. “Originally, we were trying to understand how the fungus secretes an adhesive trap that can capture, penetrate, and digest free-living nematodes in diverse environments. By doing that we almost accidentally discovered the nanoparticles produced.”

Zhang’s team investigated the fungal nanoparticles’ potential as a stimulant for the immune system, and found through an in vitro study that the nanoparticles activate secretion of an immune-system stimulant within a white blood cell line. They also investigated the nanoparticles’ potential as an antitumor agent by testing in vitro the toxicity to cells using two tumor cell lines, and discovered nanoparticles do kill cancer cells.

Berger’s article in addition to giving more details about Zhang’s current work and his work with ivy and possible applications for ivy-based nanoparticles in sunscreens also provides some discussion of naturally occurring nanoparticles as opposed to engineered (or man-made)  nanoparticles.

The University of Tennessee’s Dec. 4, 2012 press release is also a good source of information on Zhang’s latest work on flesh-eating fungus. For the indefatiguable who are interested in Zhang’s work on ivy and potential nanosunscreens, there’s also my July 22, 2010 posting.

Toxicology convo heats up: OECD releases report on inhalation toxicity testing and Nature Nanotechnology publishes severe critique of silver toxicity overanalysis

This has to be one of the rawest reports I’ve seen and that’s not a criticism. The OECD (Organization for Economic Cooperation and Development) has released no. 35 in its Series on the Safety of Manufactured Nanomaterials titled, INHALATION TOXICITY TESTING: EXPERT MEETING ON POTENTIAL REVISIONS TO OECD TEST GUIDELINES AND GUIDANCE DOCUMENT.

This report is the outcome of a meeting which took place in fall 2011 according to the July 4, 2012 news item on Nanowerk,

The expert meeting on Inhalation Toxicity Testing for Nanomaterials was held on 19-20 October 2011 in The Hague, hosted by the Netherlands, with the aim of discussing the results of the OECD Sponsorship Programme (under the responsibility of SG3) on this specific topic and addressing issues relevant to inhalation toxicity. Fifty experts from the WPMN as well as the OECD Working Group of the National Coordinators for the Test Guidelines programme (WNT) participated in the meeting.

This is a partial list of recommendations from the report,

Recommendations raised by the speakers for the discussion

7. Various recommendations were raised by the speakers that served as points for discussion. These recommendations do not necessarily reflect a general agreement. …

• “Provide explicit guidance for the generation of aerosols (sample preparation) based on the exposure scenario”. Hans Muijser

• “Generation of a test atmosphere should have workplace characteristics, but should be adapted to adjust for rodent respirability”. Günter Oberdörster

• “A choice for a dry aerosol or a liquid aerosol should depend on the given test substance and planned test approach (hazard- or risk driven)”. Otto Creutzenberg

• “Aerosol characterization should include size distribution, mass, number and morphology of the material”. Günter Oberdörster

• “Mass concentration is not sufficient for comparison of nanomaterials of the same chemical composition”. Flemming Cassee

• “Dry powders will appear as agglomerate upon aerosolization, which needs to be addressed in the sample preparation guidelines”. Flemming Cassee

• “Dissolution behaviour of the test substance should be assessed in physiological fluids mimicking various lung-specific pH ambiences (neutral, acid)”. Otto Creutzenberg

• “Data analysis should include interpretation of aerosol characteristics, NOAEL, risk assessment implications, mode of action and a strategy for dosimetric extrapolation to humans. The inclusion of biokinetic data is important”. Günter Oberdörster

• “Include biokinetics in the guidance, since different distribution patterns in the whole organism are likely dependent on physicochemical characteristics of nanoparticle aerosols and the dose at the target site will therefore be different. This will allow the assessment of accumulation of nanomaterials in the body at low exposure levels and long-term exposure. A way to perform it is by radiolabelled materials, chemical elemental analysis to determine organ concentrations and transmission electron microscopy”. Wolfgang Kreyling. Others who have suggested inclusion of biokinetics or recognized the importance were Otto Creutzenberg, Frieke Kuper, Günter Oberdörster and David Warheit. (p. 13)

You actually see who made the recommendations! Speakers discussed carbon nanotubes, titanium dioxide, cerium oxide, zinc oxide and more, all of which you can read about in summary form in this 38 pp. report.

Meanwhile, Nature Nanotechnology has published an incendiary commentary about nanosilver and the latest request by the European Commission for another study.  Michael Berger has devoted a July 4, 2012 Nanowerk Spotlight article to the commentary,

A commentary by Steffen Foss Hansen and Anders Baun in this week’s Nature Nanotechnology (“When enough is enough”  [behind a paywall]) pointedly asks “when will governments and regulatory agencies stop asking for more reports and reviews, and start taking regulatory action?”

Hansen and Baun, both from the Technical University of Denmark’s Department of Environmental Engineering, take issue with yet another scientific opinion on nanosilver that has been requested by the European Commission in late 2011: “SCENIHR – Request for a scientific opinion on Nanosilver: safety, health and environmental effects and role in antimicrobial resistance” (pdf). Specifically, the EC wants SCENIHR to answer four questions under the general heading of ‘Nanosilver: safety, health and environmental effects, and role in antimicrobial resistance’.

“Most of these questions – and possibly all of them – have already been addressed by no less than 18 review articles in scientific journals, the oldest dating back to 2008, plus at least seven more reviews and reports commissioned and/or funded by governments and other organizations” Hansen tells Nanowerk. “Many of these reviews and reports go through the same literature, cover the same ground and identify many of the same data gaps and research needs.”

Here’s a prediction from Hansen and Baun as to what will be in the next report due in 2013  (from the Nature Nanotechnology commentary When enough is enough in 7, 409–411 (2012) published online  July 1, 2012 [Note: I have removed links and footnotes]),

… we predict that the SCENIHR’s upcoming review will consist of five main sections summarizing: the properties and uses of nanosilver; human and environmental toxicity; microbial resistance; risk assessment; and research needs. We also predict that the SCENIHR’s report will say something along the following lines: “Nanosilver is reportedly one of the most widely used nanomaterials in consumer products today but the scale of production and use is unknown. The antibacterial properties of nanosilver are exploited in a very diverse set of products and applications including dietary supplements, personal care products, powdered colours, textile, paper, kitchenware and food storage.” And like many previous reviews and reports, the new report is likely to cite the Consumer Product Inventory maintained by the Project on Emerging Nanotechnologies.

We acknowledge that answering the question of how to regulate the use of nanosilver is not easy given the different views of the different stakeholders in this debate and the complex regulatory landscape associated with the many applications of nanosilver. …

Arguably, we all want that the pros and cons of regulatory policy options be based on the best available science while taking broader socio-economical and ethical aspects into consideration before deciding on the appropriate regulatory measures concerning human and environmental exposure to nanosilver. Although it is common for independent scientific experts to be commissioned to gather, analyse and review the available scientific information, and to provide recommendations on how to address a given risk, we do not see the need for further reviews. It is time for the European Commission to decide on the regulatory measures that are appropriate for nanosilver. These measures should then be implemented wholeheartedly and their effectiveness monitored.

I predict this commentary will provoke some interesting responses and I will try to add the ones I can find to this posting as they become available.

ETA July 6, 2012: Dexter Johnson weighed in with his July 5, 2012 posting (Note: I have removed a link),

What may make the matter even worse is that we may already have a pretty substantial framework—in the US, at least—on which to base nanosilver regulations, which dates back to the 1950s. It concerned what was called at the time collodial silver, which is essentially what today is called nanosilver.

But getting back to current stagnant state of affairs, it’s hard to know exactly what’s causing the paralysis. It could be concern over implementing regulations in a depressed economy, or just a fear of taking a position. But in both these instances, the lack of action is making the situation worse. …

Change your gloves frequently if you’re handling nanoparticles

Québec’s IRSST (Institut de recherche Robert-Sauvé en santé et en sécurité du travail) has issued a May 16, 2012 news release about the results of a study on gloves and nanoparticles,

After developing a sampling protocol and selecting the best analysis and measurement techniques, the research team carried out preliminary tests using four models of nitrile, latex, neoprene and butyl rubber protective gloves and commercial titanium dioxide (TiO2) nanoparticles in powder and colloidal solution form. “The results appear to indicate that powder nanoparticles penetrated the disposable nitrile gloves after seven hours of repeated deformation, while the butyl gloves appeared to be impermeable,” explained investigator Patricia Dolez, the main author of the report. “As for nanoparticles in colloidal solutions, we measured a possibility of penetration through the gloves, in particular when the gloves were subjected to repeated deformation. These preliminary data, which need to be validated by additional studies, show that it is important to continue work in this field.”

Based on the results, the research team recommends that care be taken when choosing and using this type of personal protective equipment. “We recommend replacing, at regular intervals, protective gloves that are worn, especially thinner gloves, and gloves that have been exposed to nanoparticles in colloidal solutions,” Dr. Dolez concluded.

H/T to the June 14, 2012 news item on Nanowerk for alerting me to this work.

You can get a copy of the study, Développement d’une méthode de mesure de la pénétration des nanoparticules à travers les matériaux de gants de protection dans des conditions simulant l’utilisation en milieu de travail , but it is in French only, as of today June 14, 2012. The abstract has been translated into English. I last mentioned one of the investigators, Patricia Dolez, in passing in my Oct. 14, 2009 posting.

ETA June 14, 2012: I should also have mentioned that this was joint project with researchers from the École de technologie supérieure, École Polytechnique, and Université de Montréal were working on this project with the team from IRSST.

Nanoparticles go boom!

MIKE3 test apparatus. (image taken from "Fire and explosion properties of nanopowders", Research Report RR782, UK Health and Safety Executive)

Michael Berger at Nanowerk has written a Spotlight essay on the explosivity of nanoparticles. From the March 20, 2012 essay,

Recent studies have found that nanomaterials – in this case dusts and powders having nanosize particles – exhibit an explosion severity which is not disproportionate to micrometer-sized materials, but the likelihood of explosion is quite high due to very low ignition energies and temperatures.

The review concludes that nanomaterials present a dust explosion hazard, with metallic nanoparticles being particularly reactive. Nanomaterials have been shown to display lower ignition energy and temperature requirements than larger particles. Due to this high sensitivity, explosion hazards may exist for many processes including, but not limited to, mixing, grinding, drilling, sanding, and cleaning.

The essay is well worth a read as Berger synthesizes information from more than one study and he provides some technical detail.

Gold in them thar fuel cells

There’s a lot of interest in fuel cells where I live due primarily to the existence of Ballard Power Systems, which was founded here in the province of British Columbia, Canada. Here’s what it says on the About Ballard page,

Ballard Power Systems, Inc. is a global leader in PEM (proton exchange membrane) fuel cell technology. We provide clean energy fuel cell products enabling optimized power systems for a range of applications. Ballard offers smarter solutions for a clean energy future.

We are actively putting fuel cells to work in high-value commercial uses every day. In fact, Ballard has designed and shipped close to 150 MW of hydrogen fuel cell technology to date.

In addition to Ballard, Canada’s National Research Council located its Institute for Fuel Cell Innovation in Vancouver, British Columbia (after much lobbying from the province).

Despite all the excitement over the years (especially in the beginning), the fuel cell industry in British Columbia has yet to become the revenue producer that was promised.

According to some observers, one of the keys issues has been the metals used as catalysts and once the situation is resolved, fuel cells will come into their own. Researchers at Brown University have developed a nanoparticle that outperforms other metallic catalysts. From the March 12, 2012 news item on Nanowerk,

Advances in fuel-cell technology have been stymied by the inadequacy of metals studied as catalysts. The drawback to platinum, other than cost, is that it absorbs carbon monoxide in reactions involving fuel cells powered by organic materials like formic acid. A more recently tested metal, palladium, breaks down over time.

Now chemists at Brown University have created a triple-headed metallic nanoparticle that they say outperforms and outlasts all others at the anode end in formic-acid fuel-cell reactions. In a paper published in the Journal of the American Chemical Society (“Structure-Induced Enhancement in Electrooxidation of Trimetallic FePtAu Nanoparticles”), the researchers report a 4-nanometer iron-platinum-gold nanoparticle (FePtAu), with a tetragonal crystal structure, generates higher current per unit of mass than any other nanoparticle catalyst tested. Moreover, the trimetallic nanoparticle at Brown performs nearly as well after 13 hours as it did at the start. By contrast, another nanoparticle assembly tested under identical conditions lost nearly 90 percent of its performance in just one-quarter of the time.

The March 12, 2012 news release from Brown University describes how gold improves performance,

Gold plays key roles in the reaction. First, it acts as a community organizer of sorts, leading the iron and platinum atoms into neat, uniform layers within the nanoparticle. The gold atoms then exit the stage, binding to the outer surface of the nanoparticle assembly. Gold is effective at ordering the iron and platinum atoms because the gold atoms create extra space within the nanoparticle sphere at the outset. When the gold atoms diffuse from the space upon heating, they create more room for the iron and platinum atoms to assemble themselves. Gold creates the crystallization chemists want in the nanoparticle assembly at lower temperature.

Gold atoms create orderly places for iron and platinum atoms, then retreat to the periphery of the fuel cell, where they scrub carbon monoxide from fuel reactions. The tighter organization and cleaner reactions extend the cell's performance life. Credit: Sun Lab/Brown University

The researchers note that other metals may be substituted for gold as the best combinations are tested for combination and durability. (You can find more technical details in either the news item on Nanowerk or the news release at Brown University.)

Dexter Johnson at his Nanoclast blog (on the Institute of Electrical and Electronics Engineers [IEEE] website) provides a contrasting opinion as to why fuel cells have not become popular in his March 9, 2012 posting,

One of the fundamental problems with fuel cells has been the cost of producing hydrogen. While hydrogen is, of course, the most abundant element, it attaches itself to other elements like nitrogen or fluorine, and perhaps most ubiquitously to oxygen to create the water molecule. The process used to separate hydrogen out into hydrogen gas for powering fuel cells now relies on electricity produced from fossil fuels, negating some of the potential environmental benefits. So in the last few years, a new line of research has emerged that uses nanomaterials to imitate photosynthesis and break water down into hydrogen and oxygen thereby creating a more cost-effective and environmentally-friendly method for producing hydrogen.

If you’re interested, Dexter goes on to describe some promising areas of research that mimic photosynthesis.

In that odd area where coincidences meet, the latest work that Dexter discusses is taking place in California, a major centre for the gold rush of the 1800s. As it turns out, British Columbia was also a major destination in the days of the gold rush.

Nanoparticle size doesn’t matter

Does size matter when regulating nanomaterials? As I’ve noted (more than once), I waffle on this issue. Earlier this week, I featured my thoughts on Health Canada’s definition of nanomaterial (Oct. 24, 2011)  and posted an interview with Dr. Andrew Maynard (Oct. 24, 2011) where he expressed reservations about basing nanomaterial regulations on definitions which rely on  nanoparticle size.

Hours after posting my thoughts and the interview with Andrew, I came across this Oct. 24, 2011 news item on Nanowerk titled, Nanoparticles and their size may not be big issues. From the news item,

If you’ve ever eaten from silverware or worn copper jewelry, you’ve been in a perfect storm in which nanoparticles were dropped into the environment, say scientists at the University of Oregon.

Since the emergence of nanotechnology, researchers, regulators and the public have been concerned that the potential toxicity of nano-sized products might threaten human health by way of environmental exposure.

Now, with the help of high-powered transmission electron microscopes, chemists captured never-before-seen views of miniscule metal nanoparticles naturally being created by silver articles such as wire, jewelry and eating utensils in contact with other surfaces. It turns out, researchers say, nanoparticles have been in contact with humans for a long, long time. [emphasis mine]

“Our findings show that nanoparticle ‘size’ may not be static, especially when particles are on surfaces. For this reason, we believe that environmental health and safety concerns should not be defined — or regulated — based upon size,” said James E. Hutchison, who holds the Lokey-Harrington Chair in Chemistry. [emphasis mine] “In addition, the generation of nanoparticles from objects that humans have contacted for millennia suggests that humans have been exposed to these nanoparticles throughout time. Rather than raise concern, I think this suggests that we would have already linked exposure to these materials to health hazards if there were any.”

This discussion is becoming quite interesting.

Nanoparticles in diesel pollution and honeybees

The honey bee collapse, more properly colony collapse disorder (CCD), has been news in North America and Europe  for quite some time. There are any number of reasons for the disorder being suggested. (As I understand the current thinking on this issue, the collapse is a consequence of a number of different factors.) Recently, scientists at the United Nations have suggested CCD is becoming a global problem. From a March 10, 2011 news article by Michael McCarthy for The Independent,

Declines in bee colonies date back to the mid 1960s in Europe, but have accelerated since 1998, while in North America, losses of colonies since 2004 have left the continent with fewer managed pollinators than at any time in the past 50 years, says the report [Global Honey Bee Colony Disorders and Other Threats to Insect Pollinators {a United Nations Environment Programme Emerging Issues Report}].

Now Chinese beekeepers have recently “faced several inexplicable and complex symptoms of colony losses in both species”, the report says. And it has been reported elsewhere that some Chinese farmers have had to resort to pollinating fruit trees by hand because of the lack of insects.

Furthermore, a quarter of beekeepers in Japan “have recently been confronted with sudden losses of their bee colonies”, while in Africa, beekeepers along the Egyptian Nile have been reporting signs of “colony collapse disorder” – although to date there are no other confirmed reports from the rest of the continent.

The report lists a number of factors which may be coming together to cause the decline and they include:

* Habitat degradation, including the loss of flowering plant species that provide food for bees;

* Some insecticides, including the so-called “systemic” insecticides which can migrate to the entire plant as it grows and be taken in by bees in nectar and pollen;

* Parasites and pests, such as the well-known Varroa mite;

* Air pollution, which may be interfering with the ability of bees to find flowering plants and thus food – scents that could travel more than 800 metres in the 1800s now reach less than 200 metres from a plant.

Here’s one more possibility: scientists from the University of Southampton are suggesting nanoparticles in diesel fuel may be a contributing factor in CCD. From the Oct. 7, 2011 news item on Nanowerk,

Professor Guy Poppy, an ecologist, Dr Tracey Newman, a neuroscientist, and their team from the University of Southampton believe that minuscule particles, or ‘nanoparticles’, emitted from diesel engines could be affecting bees’ brains and damaging their inbuilt ‘sat-navs’. They believe this may stop worker bees finding their way back to the hive.

The team is also investigating the possibility that nanoparticles are one of a number of stress factors that could lead to a tipping point in bee health, which in turn could contribute to bee colony collapse.

“Diesel road-traffic is increasing in the UK and research from the US has shown that nanoparticles found in its fumes can be detrimental to the brains of animals when they are exposed to large doses. We want to find out if bees are affected in the same way – and answer the question of why bees aren’t finding their way back to the hive when they leave to find food,” explains Professor Poppy.

The team from the University of Southampton, including biologists, nanotechnology researchers and ecologists will test the behavioural and neurological changes in honey bees, after exposure to diesel nanoparticles.

If I understand this correctly, the nanoparticles have not been added to the diesel fuel; they are a by-product of its use, which means we’ve been emitting diesel fuel nanoparticles for quite some time.

In any event, having a number of contributing factors for CCD suggests that a comprehensive strategy will be needed to solve the problems. In short, international cooperation will be required to ban chemicals, change habitat use, etc.