Tag Archives: metallic nanoparticles

Magic nano ink

Colour changes © Nature Communications 2017 / MPI [Max Planck Institute] for Intelligent Systems

A March 1, 2017 news item on Nanowerk helps to explain the image seen above (Note: A link has been removed),

Plasmonic printing produces resolutions several times greater than conventional printing methods. In plasmonic printing, colours are formed on the surfaces of tiny metallic particles when light excites their electrons to oscillate. Researchers at the Max Planck Institute for Intelligent Systems in Stuttgart have now shown how the colours of such metallic particles can be altered with hydrogen (Nature Communications, “Dynamic plasmonic colour display”).

The technique could open the way for animating ultra-high-resolution images and for developing extremely sharp displays. At the same time, it provides new approaches for encrypting information and detecting counterfeits.

A March 1, 2017 Max Planck Institute press release, which originated the news item, provides more  history and more detail about the research,

Glass artisans in medieval times exploited the effect long before it was even known. They coloured the magnificent windows of gothic cathedrals with nanoparticles of gold, which glowed red in the light. It was not until the middle of the 20th century that the underlying physical phenomenon was given a name: plasmons. These collective oscillations of free electrons are stimulated by the absorption of incident electromagnetic radiation. The smaller the metallic particles, the shorter the wavelength of the absorbed radiation. In some cases, the resonance frequency, i.e., the absorption maximum, falls within the visible light spectrum. The unabsorbed part of the spectrum is then scattered or reflected, creating an impression of colour. The metallic particles, which usually appear silvery, copper-coloured or golden, then take on entirely new colours.

A resolution of 100,000 dots per inch

Researchers are also taking advantage of the effect to develop plasmonic printing, in which tailor-made square metal particles are arranged in specific patterns on a substrate. The edge length of the particles is in the order of less than 100 nanometres (100 billionths of a metre). This allows a resolution of 100,000 dots per inch – several times greater than what today’s printers and displays can achieve.

For metallic particles measuring several 100 nanometres across, the resonance frequency of the plasmons lies within the visible light spectrum. When white light falls on such particles, they appear in a specific colour, for example red or blue. The colour of the metal in question is determined by the size of the particles and their distance from each other. These adjustment parameters therefore serve the same purpose in plasmonic printing as the palette of colours in painting.

The trick with the chemical reaction

The Smart Nanoplasmonics Research Group at the Max Planck Institute for Intelligent Systems in Stuttgart also makes use of this colour variability. They are currently working on making dynamic plasmonic printing. They have now presented an approach that allows them to alter the colours of the pixels predictably – even after an image has been printed. “The trick is to use magnesium. It can undergo a reversible chemical reaction in which the metallic character of the element is lost,” explains Laura Na Liu, who leads the Stuttgart research group. “Magnesium can absorb up to 7.6% of hydrogen by weight to form magnesium hydride, or MgH2”, Liu continues. The researchers coat the magnesium with palladium, which acts as a catalyst in the reaction.

During the continuous transition of metallic magnesium into non-metallic MgH2, the colour of some of the pixels changes several times. The colour change and the speed of the rate at which it proceeds follow a clear pattern. This is determined both by the size of and the distance between the individual magnesium particles as well as by the amount of hydrogen present.

In the case of total hydrogen saturation, the colour disappears completely, and the pixels reflect all the white light that falls on them. This is because the magnesium is no longer present in metallic form but only as MgH2. Hence, there are also no free metal electrons that can be made to oscillate.

Minerva’s vanishing act

The scientists demonstrated the effect of such dynamic colour behaviour on a plasmonic print of Minerva, the Roman goddess of wisdom, which also bore the logo of the Max Planck Society. They chose the size of their magnesium particles so that Minerva’s hair first appeared reddish, the head covering yellow, the feather crest red and the laurel wreath and outline of her face blue. They then washed the micro-print with hydrogen. A time-lapse film shows how the individual colours change. Yellow turns red, red turns blue, and blue turns white. After a few minutes all the colours disappear, revealing a white surface instead of Minerva.

The scientists also showed that this process is reversible by replacing the hydrogen stream with a stream of oxygen. The oxygen reacts with the hydrogen in the magnesium hydride to form water, so that the magnesium particles become metallic again. The pixels then change back in reverse order, and in the end Minerva appears in her original colours.

In a similar manner the researchers first made the micro image of a famous Van Gogh painting disappear and then reappear. They also produced complex animations that give the impression of fireworks.

The principle of a new encryption technique

Laura Na Liu can imagine using this principle in a new encryption technology. To demonstrate this, the group formed various letters with magnesium pixels. The addition of hydrogen then caused some letters to disappear over time, like the image of Minerva. “As for the rest of the letters, a thin oxide layer formed on the magnesium particles after exposing the sample in air for a short time before palladium deposition,” Liu explains. This layer is impermeable to hydrogen. The magnesium lying under the oxide layer therefore remains metallic − and visible − because light is able to excite the plasmons in the magnesium.

In this way it is possible to conceal a message, for example by mixing real and nonsensical information. Only the intended recipient is able to make the nonsensical information disappear and filter out the real message. For example, after decoding the message “Hartford” with hydrogen, only the words “art or” would remain visible. To make it more difficult to crack such encrypted messages, the group is currently working on a process that would require a precisely adjusted hydrogen concentration for deciphering.

Liu believes that the technology could also be used some day in the fight against counterfeiting. “For example, plasmonic security features could be printed on banknotes or pharmaceutical packs, which could later be checked or read only under specific conditions unknown to counterfeiters.”

It doesn’t necessarily have to be hydrogen

Laura Na Liu knows that the use of hydrogen makes some applications difficult and impractical for everyday use such as in mobile displays. “We see our work as a starting shot for a new principle: the use of chemical reactions for dynamic printing,” the Stuttgart physicist says. It is certainly conceivable that the research will soon lead to the discovery of chemical reactions for colour changes other than the phase transition between magnesium and magnesium dihydride, for example, reactions that require no gaseous reactants.

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

Dynamic plasmonic colour display by Xiaoyang Duan, Simon Kamin, & Na Liu. Nature Communications 8, Article number: 14606 (2017) doi:10.1038/ncomms14606 Published online: 24 February 2017

This paper is open access.

Metallic nanoflowers produce neuron-like fractals

I was a bit surprised to find that this University of Oregon story was about a patent. Here’s more from a July 28, 2015 news item on Azonano,

Richard Taylor’s vision of using artificial fractal-based implants to restore sight to the blind — part of a far-reaching concept that won an innovation award this year from the White House — is now covered under a broad U.S. patent.

The patent goes far beyond efforts to use the emerging technology to restore eyesight. It covers all fractal-designed electronic implants that link signaling activity with nerves for any purpose in animal and human biology.

Fractals are objects with irregular curves or shapes. “They are a trademark building block of nature,” said Taylor, a professor of physics and director of the Materials Science Institute at the University of Oregon [UO]. “In math, that property is self-similarity. Trees, clouds, rivers, galaxies, lungs and neurons are fractals. What we hope to do is adapt the technology to nature’s geometry.”

Named in U.S. patent 9079017 are Taylor, the UO, Taylor’s research collaborator Simon Brown, and Brown’s home institution, the University of Canterbury in New Zealand.

A July 28, 2015 University of Oregon news release (also on EurekAlert) by Jim Barlow, which originated the news item, continues the patent celebration,

“We’re very delighted,” Taylor said. “The U.S. Patent and Trademark Office has recognized the novelty and utility of our general concept, but there is a lot to do. We want to get all of the fundamental science sorted out. We’re looking at least another couple of years of basic science before moving forward.”

The patent solidifies the relationship between the two universities, said Charles Williams, associate vice president for innovation at the UO. “This is still in the very early days. This project has attracted national attention, awards and grants.

“We hope to engage the right set of partners to develop the technology over time as the concept moves into potentially vast forms of medical applications,” Williams added. “Dr. Taylor’s interdisciplinary science is a hallmark of the creativity at the University of Oregon and a great example of the international research collaborations that our faculty engage in every day.”

Here’s an image illustrating the ‘fractal neurons’,

FractalImplant

Caption: Retinal neurons, outlined in yellow, attach to and follows branches of a fractal interconnect. Such connections, says University of Oregon physicist Richard Taylor, could some day help to treat eye diseases such as macular degeneration. Credit: Courtesy of Richard Taylor

The news release goes on to describe the ‘fractal approach’ to eye implants which is markedly different from the implants entering the marketplace,

Taylor raised the idea of a fractal-based approach to treat eye diseases in a 2011 article in Physics World, writing that it could overcome problems associated with efforts to insert photodiodes behind the eyes. Current chip technology doesn’t allow sufficient connections with neurons.

“The wiring — the neurons — in the retina is fractal, but the chips are not fractal,” Taylor said. His vision, based on research with Brown, is to grow nanoflowers seeded from nanoparticles of metals that self assemble in a natural process, producing fractals that mimic and communicate with neurons.

It is conceivable, Taylor said, that fractal interconnects — as the implants are called in the patent — could be shaped so they network with like-shaped neurons to address narrow needs, such as a feedback loop for the sensation of touch from a prosthetic arm or leg to the brain.

Such implants would overcome the biological rejection of implants with smooth surfaces or those randomly patterned that have been developed in a trial-and-error approach to link to neurons.

Once perfected, he said, the implants would generate an electrical field that would fool a sea of glial cells that insulate and protect neurons from foreign invaders. Fractal interconnects would allow electrical signals to operate in “a safety zone biologically” that avoids toxicity issues.

“The patent covers any generic interface for connecting any electronics to any nerve,” Taylor said, adding that fractal interconnects are not electrodes. “Our interface is multifunctional. The primary thing is to get the electrical field into the system so that reaches the neurons and induces the signal.”

Taylor’s proposal for using fractal-based technology earned the top prize in a contest held by the innovation company InnoCentive. Taylor was honored in April [2015] at a meeting of the White House Office of Science and Technology Policy.

The competition was sponsored by a collaboration of science philanthropies including the Research Corporation for Science Advancement, the Gordon and Betty Moore Foundation, the W.M. Keck Foundation, the Kavli Foundation, the Templeton Foundation and the Burroughs Wellcome Fund.

You can find out more about InnoCentive here. As for other types of artificial eye implants, the latest here is a June 30, 2015 post titled, Clinical trial for bionic eye (artificial retinal implant) shows encouraging results (safety and efficacy).

Metallic nanoparticles: measuring their discrete quantum states

I tend to forget how new nanotechnology is and unconsciously take for granted stunning feats such as measuring a metallic nanoparticle’s electronic properties. A June 15, 2015 news item on Nanowerk provides a reminder with its description of the difficulties and a new technique to make it easier (Note:  A link has been removed),

How do you measure the electronic properties of individual nanoparticles or molecules that are only a few nanometers in size? Conventional methods using electron transport spectroscopy rely on contacting a material with two contacts, a source and a drain electrode. By applying a small potential difference over the electrodes and monitoring the resulting current, valuable information about the electronic properties are extracted. For example if a material is metallic or semiconducting.
But this becomes quite a challenge if the material is only a few nm in size. Even the most sophisticated fabrication tools such as electron-beam lithography have a resolution of about 10 nm at best, which is not precise enough. Scientists have developed workarounds such as creating small gaps in narrow metallic wires in which a nanoparticle can be trapped if it matches the gap size. However, even though there have been some notable successes using this approach, this method has a low yield and is not very reproducible.

Now an international collaboration including researchers in Japan, the university [sic] of Cambridge and the LCN [London Centre for Nanotechnology] in the UK have approached this in a different way as described in a paper in Nature’s Scientific Reports (“Radio-frequency capacitance spectroscopy of metallic nanoparticles”). Their method only requires a single electrode to be in direct contact with a nanoparticle or molecule, thus significantly simplifying fabrication.

A June 15, 2015 (?) LCN press release, which originated the news item, describes the achievement,

The researchers demonstrated the potential of the radio-frequency reflectometry technique by measurements on Au nanoparticles of only 2.7 nm in diameter. For such small particles, the electronic spectrum is discrete which was indeed observed in the measurements and in very good agreement with theoretical models. The researchers now plan to extend these measurements to other nanoparticles and molecules with applications in a range of areas such as biomedicine, spintronics and quantum information processing.

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

Radio-frequency capacitance spectroscopy of metallic nanoparticles by James C. Frake, Shinya Kano, Chiara Ciccarelli, Jonathan Griffiths, Masanori Sakamoto,  Toshiharu Teranishi, Yutaka Majima, Charles G. Smith & Mark R. Buitelaar. Scientific RepoRts 5:10858 DOi: 10.1038/srep10858 Published June 4, 2015

This is an open access paper.

Metal nanoparticles and gut microbiomes

What happens when you eat or drink nanoparticles, metallic or otherwise? No one really knows. Part of the problem with doing research now is there are no benchmarks for the quantity we’ve been ingesting over the centuries. Nanoparticles do occur naturally, as well, people who’ve eaten with utensils made of or coated with silver or gold have ingested silver or gold nanoparticles that were shed by those very utensils. In short, we’ve been ingesting any number of nanoparticles through our food, drink, and utensils in addition to the engineered nanoparticles that are found in consumer products. So, part of what researchers need to determine is the point at which we need to be concerned about nanoparticles. That’s trickier than it might seem since we ingest our nanoparticles and recycle them into the environment (air, water, soil) to reingest (inhale, drink, eat, etc.) them at a later date. The endeavour to understand what impact engineered nanoparticles in particular will have on us as more are used in our products is akin to assembling a puzzle.

There’s a May 5, 2015 news item on Azonano which describes research into the effects that metallic nanoparticles have on the micriobiome (bacteria) in our guts,

Exposure of a model human colon to metal oxide nanoparticles, at levels that could be present in foods, consumer goods, or treated drinking water, led to multiple, measurable differences in the normal microbial community that inhabits the human gut. The changes observed in microbial metabolism and the gut microenvironment with exposure to nanoparticles could have implications for overall human health, as discussed in an article published in Environmental Engineering Science, a peer-reviewed journal from Mary Ann Liebert, Inc., publishers. The article is available free on the Environmental Engineering Science website until June 1, 2015.

A May 4, 2015 Mary Ann Liebert publisher news release on EurekAlert, which originated the news item, describes the research in more detail (Note: A link has been removed),

Alicia Taylor, Ian Marcus, Risa Guysi, and Sharon Walker, University of California, Riverside, individually introduced three different nanoparticles–zinc oxide, cerium dioxide, and titanium dioxide–commonly used in products such as toothpastes, cosmetics, sunscreens, coatings, and paints, into a model of the human colon. The model colon mimics the normal gut environment and contains the microorganisms typically present in the human microbiome.

In the article “Metal Oxide Nanoparticles Induce Minimal Phenotypic Changes in a Model Colon Gut Microbiota” the researchers described changes in both specific characteristics of the microbial community and of the gut microenvironment after exposure to the nanoparticles.

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

Metal Oxide Nanoparticles Induce Minimal Phenotypic Changes in a Model Colon Gut Microbiota by Alicia A. Taylor, Ian M. Marcus Ian, Risa L., Guysi, and Sharon L. Walker. Environmental Engineering Science. DOI:10.1089/ees.2014.0518 Online Ahead of Print: April 24, 2015

I’ve taken a quick look at the research while it’s still open access (till June 1, 2015) to highlight the bits I consider interesting. There’s this about the nanoparticle (NP) quantities used in the study (Note: Links have been removed),

Environmentally relevant NP concentrations were chosen to emulate human exposures to NPs through ingestion of both food and drinking water at 0.01 μg/L ZnO NP, 0.01 μg/L CeO2 NP, and 3 mg/L TiO2 NP (Gottschalk et al., 2009; Kiser et al., 2009, 2013; Weir et al., 2012; Keller and Lazareva, 2013). Recent work has also indicated that adults in the USA ingest 5 mg TiO2 per day, half of which is in the nano-size range (Lomer et al., 2000; Powell et al., 2010). Exposure routes and reliable dosing information of NPs that are embedded in solid matrices are difficult to predict, and this is often a limitation of analytical techniques (Nowack et al., 2012; Yang and Westerhoff, 2014). The exposure levels used in this study were predominately selected from literature values that give predictions on amount of NPs in water and food sources (Gottschalk et al., 2009; Kiser et al., 2009; Weir et al., 2012; Keller and Lazareva, 2013; Keller et al., 2013).

For anyone unfamiliar with chemical notations, ZnO NP is zinc oxide nanoparticle, 0.01 μg/L is one/one hundredth of a microgram per litre,  CeO2 is cesisum dioxide NP, and TiO2 is titanium dioxide NP while 3 mg/L, is 3 milligrams per litre.

After assuring the quantities used in the study are the same as they expect humans to be ingesting on a regular basis, the researchers describe some of the factors which may affect the interaction between the tested nanoparticles and the bacteria (Note: Links have been removed),

It is essential to note that interactions between NPs and bacteria in the intestines may be dependent on numerous factors: the surface charge of the NPs and bacteria, the chemical composition and surface charge of the digested food, and variability in diet. These factors may ultimately correlate to effects seen in humans on an individual basis. In fact, similar work has demonstrated that exposing common NPs found in food to stomach-like conditions will change their surface chemistry from negative to neutral or positive, causing the NPs to interact with negatively charged mucus proteins in the gastrointestinal tract and, in turn, affecting the transport of NPs within the intestine (McCracken et al., 2013). The purpose of this work was to measure responses of the microbial community during the NP exposures. Based on previous research, it is anticipated that the NPs altered by stomach-like conditions would also cause changes in the gut environment (McCracken et al., 2013).

Here’s some of what they discovered,

Our initial hypothesis, that NPs induce phenotypic changes in a gut microbial community, was affirmed through significant measurable effects seen in the data. Tests that supported that NPs caused changes in the phenotype included hydrophobicity, EPM, sugar content of the EPS, cell size, conductivity, and SFCA (specifically butyric acid) production. Data for cell concentration and the protein content of the EPS demonstrated no significant results. Data were inconclusive for pH. With such a complex biological system, it is very likely that the phenotypic and biochemical changes observed are combinations of responses happening in parallel. The effects seen may be attributed to both changes induced by the NPs and natural phenomena associated with microbial community activity and other metabolic processes in a multifaceted environment such as the gut. Some examples of natural processes that could also influence the phenotypic and biochemical parameters are osmolarity, active metabolites, and electrolyte concentrations (Miller and Wood, 1996; Record et al., 1998).

Here’s the concluding sentence from the abstract,

Overall, the NPs caused nonlethal, significant changes to the microbial community’s phenotype, which may be related to overall health effects. [emphasis mine]

This research like the work I featured in a June 27, 2013 posting points to some issues with researching the impact that nanoparticles may have on our bodies. There was no cause for immediate alarm in 2013 and it appears that is still the case in 2015. However, that assumes quantities being ingested don’t increase significantly.

Poopy gold, silver, platinum, and more

In the future, gold rushes could occur in sewage plants. Precious metals have been found in large quantity by researchers investigating waste and the passage of nanoparticles (gold, silver, platinum, etc.) into our water. From a Jan. 29, 2015 news article by Adele Peters for Fast Company (Note: Links have been removed),

One unlikely potential source of gold, silver, platinum, and other metals: Sewage sludge. A new study estimates that in a city of a million people, $13 million of metals could be collecting in sewage every year, or $280 per ton of sludge. There’s gold (and silver, copper, and platinum) in them thar poop.

Funded in part by a grant for “nano-prospecting,” the researchers looked at a huge sample of sewage from cities across the U.S., and then studied several specific waste treatment plants. “Initially we thought gold was at just one or two hotspots, but we find it even in smaller wastewater treatment plants,” says Paul Westerhoff, an engineering professor at Arizona State University, who led the new study.

Some of the metals likely come from a variety of sources—we may ingest tiny particles of silver, for example, when we eat with silverware or when we drink water from pipes that have silver alloys. Medical diagnostic tools often use gold or silver. …

The metallic particles Peters is describing are nanoparticles some of which are naturally occurring  as she notes but, increasingly, we are dealing with engineered nanoparticles making their way into the environment.

Engineered or naturally occurring, a shocking quantity of these metallic nanoparticles can be found in our sewage. For example, a waste treatment centre in Japan recorded 1,890 grammes of gold per tonne of ash from incinerated sludge as compared to the 20 – 40 grammes of gold per tonne of ore recovered from one of the world’s top producing gold mines (Miho Yoshikawa’s Jan. 30, 2009 article for Reuters).

While finding it is one thing, extracting it is going to be something else as Paul Westerhoff notes in Peters’ article. For the curious, here’s a link to and a citation for the research paper,

Characterization, Recovery Opportunities, and Valuation of Metals in Municipal Sludges from U.S. Wastewater Treatment Plants Nationwide by Paul Westerhoff, Sungyun Lee, Yu Yang, Gwyneth W. Gordon, Kiril Hristovski, Rolf U. Halden, and Pierre Herckes. Environ. Sci. Technol., Article ASAP DOI: 10.1021/es505329q Publication Date (Web): January 12, 2015

Copyright © 2015 American Chemical Society

This paper is behind a paywall.

On a completely other topic, this is the first time I’ve noticed this type of note prepended to an abstract,

 Note

This article published January 26, 2015 with errors throughout the text. The corrected version published January 27, 2015.

Getting back to the topic at hand, I checked into nano-prospecting and found this Sept. 19, 2013 Arizona State University news release describing the project launch,

Growing use of nanomaterials in manufactured products is heightening concerns about their potential environmental impact – particularly in water resources.

Tiny amounts of materials such as silver, titanium, silica and platinum are being used in fabrics, clothing, shampoos, toothpastes, tennis racquets and even food products to provide antibacterial protection, self-cleaning capability, food texture and other benefits.

Nanomaterials are also put into industrial polishing agents and catalysts, and are released into the environment when used.

As more of these products are used and disposed of, increasing amounts of the nanomaterials are accumulating in soils, waterways and water-systems facilities. That’s prompting efforts to devise more effective ways of monitoring the movement of the materials and assessing their potential threat to environmental safety and human health.

Three Arizona State University faculty members will lead a research project to help improve methods of gathering accurate information about the fate of the materials and predicting when, where and how they may pose a hazard.

Their “nanoprospecting” endeavor is supported by a recently awarded $300,000 grant from the National Science Foundation.

You can find out more about Paul Westerhoff and his work here.

FOE, nano, and food: part three of three (final guidance)

The first part of this food and nano ‘debate’ started off with the May 22, 2014 news item on Nanowerk announcing the Friends of the Earth (FOE) report ‘Way too little: Our Government’s failure to regulate nanomaterials in food and agriculture‘. Adding energy to FOE’s volley was a Mother Jones article written by Tom Philpott which had Dr. Andrew Maynard (Director of the University of Michigan’s Risk Science Center) replying decisively in an article published both on Nanowerk and on the Conversation.

The second part of this series focused largely on a couple of  research efforts (a June 11, 2014 news item on Nanowerk highlights a Franco-German research project, SolNanoTox) and in the US (a  June 19, 2014 news item on Azonano about research from the University of Arizona focusing on nanoscale additives for dietary supplement drinks) and noted another activist group’s (As You Sow) initiative with Dunkin’ Donuts (a July 11, 2014 article by Sarah Shemkus in a sponsored section in the UK’s Guardian newspaper0).

This final part in the series highlights the US Food and Drug Administration’s (FDA) final guidance document on nanomaterials and food issued some five weeks after the FOE’s report and an essay by a Canadian academic on the topic of nano and food.

A July 9, 2014 news item on Bloomberg BNA sums up the FDA situation,

The Food and Drug Administration June 24 [2014] announced new guidance to provide greater regulatory clarity for industry on the use of nanotechnology in FDA-regulated products, including drugs, devices, cosmetics and food.

In this final guidance, the agency said that nanotechnology “can be used in a broad array of FDA-regulated products, including medical products (e.g., to increase bioavailability of a drug), foods (e.g., to improve food packaging) and cosmetics (e.g., to affect the look and feel of cosmetics).”

Also on the agency website, the FDA said it “does not make a categorical judgment that nanotechnology is inherently safe or harmful. We intend our regulatory approach to be adaptive and flexible and to take into consideration the specific characteristics and the effects of nanomaterials in the particular biological context of each product and its intended use.”

This July 18, 2014 posting by Jeannie Perron, Miriam Guggenheimm and Allan J. Topol of Covington & Burling LLP on the National Law Review blog provides a better summary and additional insight,

On June 24, 2014, the Food and Drug Administration (FDA) released three final guidance documents addressing the agency’s general approach to nanotechnology and its use by the food and cosmetics industries, as well as a draft guidance on the use of nanomaterials in food for animals.

These guidance documents reflect FDA’s understanding of nanomaterials as an emerging technology of major importance with the potential to be used in novel ways across the entire spectrum of FDA- regulated products.

The documents suggest that FDA plans to approach nanotechnology-related issues cautiously, through an evolving regulatory structure that adapts to manufacturers’ changing uses of this technology. FDA has not established regulatory definitions of “nanotechnology,” “nanomaterial,” “nanoscale,” or other related terms. …

The notion of an “evolving regulatory structure” is very appealing in situations with emerging technologies with high levels of uncertainty. It’s surprising that more of the activist groups don’t see an opportunity with this approach. An organization that hasn’t devised a rigid regulatory structure has no investment in defending it. Activist groups can make the same arguments, albeit from a different perspective, about an emerging technology as the companies do and, theoretically, the FDA has become a neutral party with the power to require a company to prove its products’ safety.

You can find the FDA final guidance and other relevant documents here.

Finally, Sylvain Charlebois, associate dean at the College of Business and Economics at the University of Guelph, offers a rather provocative (and not from the perspective you might expect given his credentials) opinion on the topic of ‘nano and food’  in a July 18, 2014 article for TheRecord.com,

Nanotechnology and nanoparticles have been around for quite some time. In fact, consumers have been eating nanoparticles for years without being aware they are in their food.

Some varieties of Dentyne gum and Jell-O, M&M’s, Betty Crocker whipped cream frosting, Kool-Aid, Pop-Tarts, you name it, contain them. Even food packaging, such as plastic containers and beer bottles, have nanoparticles.

While consumers and interest groups alike are registering their concerns about genetically modified organisms, the growing role of nanotechnology in food and agriculture is impressive. When considering the socio-economic and ethical implications of nanotechnology, comparisons to the genetic modification debate are unavoidable.

The big picture is this. For years, capitalism has demonstrated its ability to create wealth while relying on consumers’ willingness to intrinsically trust what is being offered to them. With trans fats, genetically modified organisms and now nanoparticles, our food industry is literally playing with fire. [emphasis mine]

Most consumers may not have the knowledge to fully comprehend the essence of what nanotechnology is or what it can do. However, in an era where data access in almost constant real-time is king, the industry should at least give public education a shot.

In the end and despite their tactics, the activist groups do have a point. The food and agricultural industries need to be more frank about what they’re doing with our food. As Charlebois notes, they might want to invest in some public education, perhaps taking a leaf out of the Irish Food Board’s book and presenting the public with information both flattering and nonflattering about their efforts with our food.

Part one (an FOE report is published)

Part two (the problem with research)

ETA Aug. 22, 2014: Coincidentally, Michael Berger has written an Aug. 22, 2014 Nanowerk Spotlight article titled: How to identify nanomaterials in food.

ETA Sept. 1, 2014: Even more coincidentally, Michael Berger has written a 2nd Nanowerk Spotlight (dated Aug. 25, 2014) on the food and nano topic titled, ‘Nanotechnology in Agriculture’ based on the European Union’s Joint Research Centre’s ‘Workshop on Nanotechnology for the agricultural sector: from research to the field”, held on November 21-22 2013’.

FOE, nano, and food: part two of three (the problem with research)

The first part of this roughly six week food and nano ‘debate’ started off with the May 22, 2014 news item on Nanowerk announcing the Friends of the Earth (FOE) report ‘Way too little: Our Government’s failure to regulate nanomaterials in food and agriculture‘. Adding energy to FOE’s volley was a Mother Jones article written by Tom Philpott which had Dr. Andrew Maynard (Director of the University of Michigan’s Risk Science Center) replying decisively in an article published both on Nanowerk and on the Conversation.

Coincidentally or not, there were a couple of news items about ‘nano and food’ research efforts during the ‘debate’. A June 11, 2014 news item on Nanowerk highlights a Franco-German research project into the effects that nanomaterials have on the liver and the intestines while noting the scope of the task researchers face,

What mode of action do nanomaterials ingested via food have in liver and intestine? Which factors determine their toxicity? Due to the large number of different nanomaterials, it is hardly possible to test every one for its toxic properties. [emphasis mine] For this reason, specific properties for the classification of nanomaterials are to be examined within the scope of the Franco-German research project “SolNanoTox”, which began on 1 March 2014. The [German] Federal Institute for Risk Assessment (BfR) requires data on bioavailability for its assessment work, in particular on whether the solubility of nanomaterials has an influence on uptake and accumulation in certain organs, such as liver and intestine. “We want to find out in our tests whether the criterion ‘soluble or insoluble’ is a determining factor for uptake and toxicity of nanomaterials,” says BfR President Professor Dr. Andreas Hensel.

A June 13, 2014 German Federal Institute for Risk Assessment (BfR) press release, which originated the news item, details the research and the participating agencies,

A risk assessment of nanomaterials is hardly possible at the moment and involves a very high degree of uncertainty, as important toxicological data on their behaviour in tissue and cells are still missing. [emphasis mine] The German-French SolNanoTox research project examines which role the solubility of nanomaterials plays with regard to their accumulation and potential toxic properties. The project is to run for three and a half years during which the BfR will work closely with its French sister organisation ANSES. Other partners are the Institut des Sciences Chimiques de Rennes and Universität Leipzig. The German Research Foundation and French Agence Nationale de la Recherche (ANR) are funding the project.

The tasks of the BfR include in vitro tests (e.g. the investigation of the influence of the human gastrointestinal system) and analysis of biological samples with regard to the possible accumulation of nanomaterials. In addition to this, the BfR uses modern methods of mass spectrometry imaging to find out whether nanoparticles alter the structure of biomolecules, e.g. the structure of the lipids of the cellular membrane. So far, these important tests, which are necessary for assessing possible changes in DNA or cellular structures caused by nanomaterials in food, have not been conducted.

Metallic nanoparticles are to be studied (from the press release),

In the project, two fundamentally different types of nanoparticles are examined as representatives for others of their type: titanium dioxide as representative of water insoluble nanoparticles and aluminium as an example of nanomaterials which show a certain degree of water solubility after oxidation. [emphases mine] It is examined whether the degree of solubility influences the distribution of the nanomaterials in the body and whether soluble materials may possibly accumulate more in other organs than insoluble ones. The object is to establish whether there is a direct toxic effect of insoluble nanomaterials in general after oral uptake due to their small size.

Different innovative analytical methods are combined in the project with the aim to elucidate the behaviour of nanomaterials in tissue and their uptake into the cell. The main focus is on effects which can trigger genotoxic damage and inflammation. At first, the effects of both materials are examined in human cultures of intestinal and liver cells in an artificial environment (in vitro). In the following, it has to be verified by animal experimentation whether the observed effects can also occur in humans. This modus operandi allows to draw conclusions on effects and mode of action of orally ingested nanomaterials with different properties. The goal is to group nanomaterials on the basis of specific properties and to allocate the corresponding toxicological properties to these groups. Motivation for the project is the enormous number of nanomaterials with large differences in physicochemical properties. Toxicological tests cannot be conducted for all materials.

In the meantime, a June 19, 2014 news item on Azonano (also on EurekAlert but dated June 18, 2014) features some research into metallic nanoparticles in dietary supplement drinks,

Robert Reed [University of Arizona] and colleagues note that food and drink manufacturers use nanoparticles in and on their products for many reasons. In packaging, they can provide strength, control how much air gets in and out, and keep unwanted microbes at bay. As additives to food and drinks, they can prevent caking, deliver nutrients and prevent bacterial growth. But as nanoparticles increase in use, so do concerns over their health and environmental effects. Consumers might absorb some of these materials through their skin, and inhale and ingest them. What doesn’t get digested is passed in urine and feces to the sewage system. A handful of initial studies on nanomaterials suggest that they could be harmful, but Reed’s team wanted to take a closer look.

They tested the effects of eight commercial drinks containing nano-size metal or metal-like particles on human intestinal cells in the lab. The drinks changed the normal organization and decreased the number of microvilli, finger-like projections on the cells that help digest food. In humans, if such an effect occurs as the drinks pass through the gastrointestinal tract, these materials could lead to poor digestion or diarrhea, they say. The researchers’ analysis of sewage waste containing these particles suggests that much of the nanomaterials from these products are likely making their way back into surface water, where they could potentially cause health problems for aquatic life.

This piece is interesting for two reasons. First, the researchers don’t claim that metallic nanoparticles cause digestion or diarrhea due to any action in the gastrointestinal tract. They studied the impact that metallic nanoparticles in supplementary drinks had on cells (in vitro testing) from the gastrointestinal tract. Based on what they observed in the laboratory, “… these materials could lead to poor digestion or diarrhea… .” The researchers also suggest a problem could occur as these materials enter surface water in increasing quantities.

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

Supplement Drinks and Assessment of Their Potential Interactions after Ingestion by Robert B. Reed, James J. Faust, Yu Yang, Kyle Doudrick, David G. Capco, Kiril Hristovski, and Paul Westerhoff. ACS Sustainable Chem. Eng., 2014, 2 (7), pp 1616–1624 DOI: 10.1021/sc500108m Publication Date (Web): June 2, 2014

Copyright © 2014 American Chemical Society

With Paul Westerhoff as one of the authors and the reference to metallic nanoparticles entering water supplies, I’m guessing that this research is associated with the LCnano (lifecycle nano) project headquartered at Arizona State university (April 8, 2014 posting).

Getting back to the Franco-German SolNanoTox project, scientists do not know what happens when the cells in your intestines, liver, etc. encounter metallic or other nanoparticles, some of which may be naturally occurring. It should also be noted that we have likely been ingesting metallic nanoparticles for quite some time. After all, anyone who has used silver cutlery has ingested some silver nanoparticles.

There are many, many questions to be asked and answered with regard to nanomaterials in our foods.  Here are a few of mine:

  • How many metallic and other nanoparticles did we ingest before the advent of ‘nanomaterials in food’?
  • What is the biopersistence of naturally occurring and engineered metallic and other nanoparticles in the body?
  • Is there an acceptable dose versus a fatal dose? (Note: There’s naturally occurring formaldehyde in pears as per my May 19, 2014 post about doses, poisons, and the Sense about Science group’s campaign/book, Making Sense of Chemical Stories.)
  • What happens as the metallic and other engineered nanoparticles are added to food and drink and eventually enter our water, air, and soil?

Returning to the ‘debate’, a July 11, 2014 article by Sarah Shemkus for a sponsored section in the UK’s Guardian newspaper highlights an initiative taken by an environmental organization, As You Sow, concerning titanium dioxide in Dunkin’ Donuts’ products (Note: A link has been removed),

The activists at environmental nonprofit As You Sow want you to take another look at your breakfast doughnut. The organization recently filed a shareholder resolution asking Dunkin’ Brands, the parent company of Dunkin’ Donuts, to identify products that may contain nanomaterials and to prepare a report assessing the risks of using these substances in foods.

Their resolution received a fair amount of support: at the company’s annual general meeting in May, 18.7% of shareholders, representing $547m in investment, voted for it. Danielle Fugere, As You Sow’s president, claims that it was the first such resolution to ever receive a vote. Though it did not pass, she says that she is encouraged by the support it received.

“That’s a substantial number of votes in favor, especially for a first-time resolution,” she says.

The measure was driven by recent testing sponsored by As You Sow, which found nanoparticles of titanium dioxide in the powdered sugar that coats some of the donut chain’s products. [emphasis mine] An additive widely used to boost whiteness in products from toothpaste to plastic, microscopic titanium dioxide has not been conclusively proven unsafe for human consumption. Then again, As You Sow contends, there also isn’t proof that it is harmless.

“Until a company can demonstrate the use of nanomaterials is safe, we’re asking companies either to not use them or to provide labels,” says Fugere. “It would make more sense to understand these materials before putting them in our food.”

As You Sow is currently having 16 more foods tested. The result should be available later this summer, Fugere says.

I wonder if As You Sow will address the question of whether the nanoscale titanium dioxide they find indicates that nanoscale particles are being deliberately added or whether the particles are the inadvertent consequence of the production process. That said, I find it hard to believe no one in the food industry is using engineered nanoscale additives as they claim  (the other strategy is to offer a nonanswer) in Shemkus’ article (Note: Links have been removed).,

In a statement, Dunkin’ Donuts argues that the titanium dioxide identified by As You Sow does not qualify as a nanomaterial according to European Union rules or draft US Food and Drug Administration regulations. The company also points out that there is no agreed-upon standard method for identifying nanoparticles in food.

In 2008, As You Sow filed nanomaterial labeling resolutions with McDonald’s and Kraft Foods. In response, McDonald’s released a statement declaring that it does not support the use of nanomaterials in its food, packaging or toys. Kraft responded that it would make sure to address health and safety concerns before ever using nanomaterials in its products.

While Shemkus’ article appears in the Guardian’s Food Hub which is sponsored by the Irish Food Board, this article manages to avoid the pitfalls found in Philpott’s nonsponsored article.

Coming next: the US Food and Drug Administration Guidance issued five weeks after the FOE kicks off the ‘nano and food’ debate in May 2014 with its ‘Way too little: Our Government’s failure to regulate nanomaterials in food and agriculture‘ report.

Part one (an FOE report is published)

Part three (final guidance)

FOE, nano, and food: part one of three (an FOE report is published)

It seems the food and nano debate of Spring/Summer 2014 has died down, for a while at least. The first volley (from my perspective) was the May 2014 release of ‘Way too little: Our Government’s failure to regulate nanomaterials in food and agriculture’ by the Friends of the Earth (FOE) Australia. Here’s how the report is described in a May 22, 2014 news item on Nanowerk,

Friends of the Earth’s new report, Way too little (pdf), looks at the now widespread presence of nanomaterials in our food chain and how little Food Standards Australia New Zealand (FSANZ) is doing to ensure our safety.

You can find the following passage on p. 6 of FOE’s report ‘Way too little: Our Government’s failure to regulate nanomaterials in food and agriculture‘,

This report will examine the changes since our 2008 report including the development of new food, food contact and agricultural products. It will review the current literature relating to the potential environmental, health and safety impacts associated with nanotechnology and summarise the Australian regulatory responses to date.

This updated report uncovers the:

•accelerating rate of commercialisation and rapidly increasing number of commercial products containing nanomaterials in the food and agricultural sectors;

•lack of information regarding which nanomaterials have been released and the likely exposure of humans and natural systems to these materials;

•lack of basic steps to allow us to track nanomaterials that have been released, such as
labelling and a register of products containing nanomaterials;

•growing gap between the pace of commercialisation and environmental, health and safety assessments;

•increasingly large body of peer reviewed evidence that certain nanomaterials may cause harm to human health or the environment;

•failure of regulators to respond to the growingevidence of risks;

•lack of basic knowledge that is critical in order to fully analyse the particular environmental, health and safety issues associated with nanotechnology.

Six years ago, inaction was based on a perceived lack of data. Inaction is still the norm but that is no longer an excuse our Government can use. Scientists and scientific bodies such as the US National Research Council have given us more than enough evidence to justify a pro-active regulatory regime and a properly funded R&D program that will effectively target those areas of greatest environmental and health concern.

Unfortunately, our Federal Government seems unwilling to provide the levels of funding required for such work or to adopt appropriate regulation. The notion of precaution has been replaced with an attitude that it is the obligation of industry to determine whether their products are safe and regulators will only act when harm is shown. While France, Belgium and Denmark are implementing a mandatory register for nanomaterials and the EU’s is in the process of implementing a nano food labelling regime, Australian consumers remain in the dark.

This needs to change.

One of the issues with increased regulation and labeling is whether the benefits outweigh disadvantages such as the increased difficulty of getting needed foodstuffs to the marketplace and, of course, cost.

Tom Philpott in a May 28, 2014 article for Mother Jones magazine titled ‘Big Dairy Is Putting Microscopic Pieces of Metal in Your Food’ is a strong proponent for FOE’s position, albeit his geographic focus is the US and he seems most concerned with metallic nanoparticles (Note: Links have been removed),

Examples include Silk Original Soy Milk, Rice Dream Rice Drink, Hershey’s Bliss Dark Chocolate, and Kraft’s iconic American Cheese Singles, all of which now contain nano-size titanium dioxide*. As recently as 2008, only eight US food products were known to contain nanoparticles, according to a recent analysis [May 2014 report] from Friends of the Earth—a more than tenfold increase in just six years.

Philpott goes on to mention the US Food and Drug Administration’s (FDA) 2012 draft guidance on nanomaterials and food,

Back in 2012, the FDA released a draft, pending public comment, of a proposed new framework for bringing nano materials into food. The document reveals plenty of reason for concern. For example: “so-called nano-engineered food substances can have significantly altered bioavailability and may, therefore, raise new safety issues that have not been seen in their traditionally manufactured counterparts.” The report went on to note that “particle size, surface area, aggregation/agglomeration, or shape may impact absorption, distribution, metabolism and excretion (ADME) and potentially the safety of the nano-engineered food substance.”

What FDA is saying here is obvious: If nanoparticles didn’t behave differently, the industry wouldn’t be using them in the first place.

So what’s the remedy? Rather than require rigorous safety studies before companies can lace food with nanoparticles, the FDA’s policy draft proposes “nonbinding recommendations” for such research. Even that rather porous safety net doesn’t yet exist—the agency still hasn’t implemented the draft proposal it released more than two years ago.[emphasis mine]

June 27, 2014, the FDA issued a final ‘food and nanotechnology’ guidance document (more on that later).

In the meantime, Dr. Andrew Maynard (Director of the University of Michigan’s Risk Science Center) strongly countered Philpott’s Mother Jones article with his own article published both on The Conversation (June 3, 2014) and on Nanowerk (June 4, 2014),

Recently the American publication Mother Jones published an article on the dangers of food laced with tiny metal oxide particles. The article, however, is laced with errors and misinformation.

The source material for the article came from a report by the environmental organisation Friends of the Earth, an online database of nanotechnology-based consumer products and a peer-reviewed paper published in 2012. However, the analysis of the information is flawed.

..

Bad journalism

The inventory Philpott cites is the Project on Emerging Nanotechnologies Consumer Products Inventory, which I helped establish in 2006 as a way better understand the increasing number of consumer products that were using engineered nanomaterials. It provides a useful but only qualitative sense of what was being used where, and relies on intermittent web searches and other sources of intelligence. The inventory was never meant to be comprehensive or authoritative.

Briefly, Andrew’s argument is that the FOE report (Way too little) which claims a tenfold increase since 2008 of food products with added nano titanium dioxide (and which Philpotts uses to build his case) is erroneous. In 2006, the inventory was voluntary and there was no oversight. At that time, eight food products had been added to the list. In 2013, the inventory was revived (Oct. 28, 2013 posting) and new information added from a 2012 academic paper. The products from the 2012 paper may have predated the 2006 inventory products, or not. There is no way to tell. Andrew notes this in his measured way,

As someone who works on the risks and benefits of nanotechnology, I can see how errors in translation crept into this story. The 2012 paper was addressing a legitimate concern that little is know about how much titanium dioxide is in the processed food chain. The Consumer Products Inventory provides important and unique insights into nanoparticles being used in products. Friends of the Earth have every right to ask what is known about the potential risks in what we’re eating. And reporters like Philpott have a professional obligation to highlight issues of concern and interest to their readers.

The problem with exaggerated and inflated claims is that FOE proves itself to be an unreliable source and Philpott’s failure to investigate adequately puts his own credibility into question. How can you trust either FOE’s materials or Philpott’s articles? The easiest way to begin rebuilding credibility is to admit one’s mistakes. To date, I have not seen any such attempts from FOE or Philpott.

Coming next: a research initiative into the health effects of nano and food and a research paper on nano in commercial drinks both of which help illustrate why there are concerns and why there is a reluctance to move too quickly.

Part two (the problem with research)

Part three (final guidance)