Tag Archives: nanotoxicity

People for the Ethical Treatment of Animals (PETA) and a grant for in vitro nanotoxicity testing

This grant seems to have gotten its start at a workshop held at the US Environmental Protection Agency (EPA) in Washington, D.C., Feb. 24-25, 2015 as per this webpage on the People for Ethical Treatment of Animals (PETA) International Science Consortium Limited website,

The invitation-only workshop included experts from different sectors (government, industry, academia and NGO) and disciplines (in vitro and in vivo inhalation studies of NMs, fibrosis, dosimetry, fluidic models, aerosol engineering, and regulatory assessment). It focused on the technical details for the development and preliminary assessment of the relevance and reliability of an in vitro test to predict the development of pulmonary fibrosis in cells co-cultured at the air-liquid interface following exposure to aerosolized multi-walled carbon nanotubes (MWCNTs). During the workshop, experts made recommendations on cell types, exposure systems, endpoints and dosimetry considerations required to develop the in vitro model for hazard identification of MWCNTs.

The method is intended to be included in a non-animal test battery to reduce and eventually replace the use of animals in studies to assess the inhalation toxicity of engineered NMs. The long-term vision is to develop a battery of in silico and in vitro assays that can be used in an integrated testing strategy, providing comprehensive information on biological endpoints relevant to inhalation exposure to NMs which could be used in the hazard ranking of substances in the risk assessment process.

A September 1, 2015 news item on Azonano provides an update,

The PETA International Science Consortium Ltd. announced today the winners of a $200,000 award for the design of an in vitro test to predict the development of lung fibrosis in humans following exposure to nanomaterials, such as multi-walled carbon nanotubes.

Professor Dr. Barbara Rothen-Rutishauser of the Adolphe Merkle Institute at the University of Fribourg, Switzerland and Professor Dr. Vicki Stone of the School of Life Sciences at Heriot-Watt University, Edinburgh, U.K. will jointly develop the test method. Professor Rothen-Rutishauser co-chairs the BioNanomaterials research group at the Adolphe Merkle Institute, where her research is focused on the study of nanomaterial-cell interactions in the lung using three-dimensional cell models. Professor Vicki Stone is the Director of the Nano Safety Research Group at Heriot-Watt University and the Director of Toxicology for SAFENANO.

The Science Consortium is also funding MatTek Corporation for the development of a three-dimensional reconstructed primary human lung tissue model to be used in Professors Rothen-Rutishauser and Stone’s work. MatTek Corporation has extensive expertise in manufacturing human cell-based, organotypic in vitro models for use in regulatory and basic research applications. The work at MatTek will be led by Dr. Patrick Hayden, Vice President of Scientific Affairs, and Dr. Anna Maione, head of MatTek’s airway models research group.

I was curious about MatTek Corporation and found this on company’s About Us webpage,

MatTek Corporation was founded in 1985 by two chemical engineering professors from MIT. In 1991 the company leveraged its core polymer surface modification technology into the emerging tissue engineering market.

MatTek Corporation is at the forefront of tissue engineering and is a world leader in the production of innovative 3D reconstructed human tissue models. Our skin, ocular, and respiratory tissue models are used in regulatory toxicology (OECD, EU guidelines) and address toxicology and efficacy concerns throughout the cosmetics, chemical, pharmaceutical and household product industries.

EpiDerm™, MatTek’s first 3D human cell based in vitro model, was introduced in 1993 and became an immediate technical and commercial success.

I wish them good luck in their research on developing better ways to test toxicity.

Research into nanosilver’s antibiotic properties and nanogold’s detection skills

There is a puzzling and exciting announcement from the Canadian Light Source in a May 27, 2015 news item on Nanowerk,

Precious metals like silver and gold have biomedical properties that have been used for centuries, but how do these materials effectively combat the likes of cancer and bacteria without contaminating the patient and the environment?

These are the questions that researchers from Dalhousie University and the Canadian Light Source are trying to find out.

Perhaps I’m misreading the announcement but the statement that nanosilver and nanogold don’t contaminate the patient or the environment is a bit exuberant. There are published studies examining questions about whether or not nanosilver may affect the environment and health and the answer is that no one is certain yet. You can read more about two studies highlighted in my February 28, 2013 posting titled:  Silver nanoparticles, water, the environment, and toxicity. As for nanosilver and nanogold not contaminating patients, that too is a problematic statement. For example, I have this paper which cites several studies on nanogold and possible toxicity. The paper itself is a plea to standardize testing and protocols so researchers can do a better job of establishing toxicity issues with nanogold.


Reservations aside, it’s good to learn of some Canadian research in this area. From a May 26, 2015 Canadian Light Source news release, which originated the news item, provides more details about the research and its current focus on nanosilver,

“Gold and silver are both exciting materials,” said Peng Zhang, Associate Professor of Chemistry at Dalhousie. “We can use gold to either detect or kill cancer cells. Silver is also excited and a very promising material as an antibacterial agents.”

Zhang said that if you compare silver to current antibiotics, silver does not show drug-resistant behaviour. “But with silver, so far, we are not finding that,” he added.

Finding out why silver is such a great antibacterial agent is the focus of Zhang’s research, recently published in the journal Langmuir.

“We want to understand the relationship between the atomic structure and bioactivity of nanosilver as to why it is so efficient at inhibiting bacterial activity. It’s a big puzzle.”

Zhang said it is very hard to understand what is happening at the atomic level. Using small nanosilver particles is the most effective way, because when you make silver small, you can expect higher activity because of the increased surface area.

This poses another problem however, as the nanosilver needs to be stabilized with a coating or the silver particles will bond together forming large pieces of silver that do not efficiently interact with the bacteria.

Zhang’s group used two different coatings to compare the effectiveness of the silver as an antibacterial agent. The first was a small amino acid coating and the other was a larger polymer coating. And after testing the interactions between the nanosilver and the bacteria, and looking at the atomic structure of nanosilver using the CLS and the Advanced Photon Source, the researchers were surprised to find that the thicker, larger polymer coating actually created a better delivery method for sliver to inhibit the bacteria.

“We proposed that the small amino acid coating would bind so tightly to the silver surface that it would be difficult for  the silver atoms to interact with the bacteria, whereas the polymers are actually very good at staying in place and still releasing sufficient amount of silver with the bacteria.”

Zhang said the next steps will be to find out if the nanosilver is actually attacking good cells in living systems before they can make any further progress on determining whether nanosilver is an effective and efficient antibactieral agent that could be used to cure human and animal diseases.

Here’s an illustration provided by the researchers,

The atomic structure of nanosilver, revealed by synchrotron X-ray spectroscopy, is proving to be a determinant of silver’s antibacterial activity. Padmos, J. Daniel, et al. "Impact of Protecting Ligands on Surface Structure and Antibacterial Activity of Silver Nanoparticles." Langmuir 31.12 (2015): 3745-3752.

The atomic structure of nanosilver, revealed by synchrotron X-ray spectroscopy, is proving to be a determinant of silver’s antibacterial activity.
Padmos, J. Daniel, et al. “Impact of Protecting Ligands on Surface Structure and Antibacterial Activity of Silver Nanoparticles.” Langmuir 31.12 (2015): 3745-3752.

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

Impact of Protecting Ligands on Surface Structure and Antibacterial Activity of Silver Nanoparticles by J. Daniel Padmos, Robert T. M. Boudreau, Donald F. Weaver, and Peng Zhang. Langmuir, 2015, 31 (12), pp 3745–3752
DOI: 10.1021/acs.langmuir.5b00049 Publication Date (Web): March 15, 2015

Copyright © 2015 American Chemical Society

This paper is behind a paywall.

Copper nanoparticles, toxicity research, colons, zebrafish, and septic tanks

Alicia Taylor, a graduate student at UC Riverside, surrounded by buckets of effluent from the septic tank system she used for her research. Courtesy: University of California at Riverside

Alicia Taylor, a graduate student at UC Riverside, surrounded by buckets of effluent from the septic tank system she used for her research. Courtesy: University of California at Riverside

Those buckets of efflluent are strangely compelling. I think it’s the abundance of orange. More seriously, a March 2, 2015 news item on Nanowerk poses a question about copper nanoparticles,

What do a human colon, septic tank, copper nanoparticles and zebrafish have in common?

They were the key components used by researchers at the University of California, Riverside and UCLA [University of California at Los Angeles] to study the impact copper nanoparticles, which are found in everything from paint to cosmetics, have on organisms inadvertently exposed to them.

The researchers found that the copper nanoparticles, when studied outside the septic tank, impacted zebrafish embryo hatching rates at concentrations as low as 0.5 parts per million. However, when the copper nanoparticles were released into the replica septic tank, which included liquids that simulated human digested food and household wastewater, they were not bioavailable and didn’t impact hatching rates.

A March 2, 2015 University of California at Riverside (UCR) news release (also on EurekAlert), which originated the news item, provides more detail about the research,

“The results are encouraging because they show with a properly functioning septic tank we can eliminate the toxicity of these nanoparticles,” said Alicia Taylor, a graduate student working in the lab of Sharon Walker, a professor of chemical and environmental engineering at the University of California, Riverside’s Bourns College of Engineering.

The research comes at a time when products with nanoparticles are increasingly entering the marketplace. While the safety of workers and consumers exposed to nanoparticles has been studied, much less is known about the environmental implications of nanoparticles. The Environmental Protection Agency is currently accessing the possible effects of nanomaterials, including those made of copper, have on human health and ecosystem health.

The UC Riverside and UCLA [University of California at Los Angeles] researchers dosed the septic tank with micro copper and nano copper, which are elemental forms of copper but encompass different sizes and uses in products, and CuPRO, a nano copper-based material used as an antifungal agent to spray agricultural crops and lawns.

While these copper-based materials have beneficial purposes, inadvertent exposure to organisms such as fish or fish embryos has not received sufficient attention because it is difficult to model complicated exposure environments.

The UC Riverside researchers solved that problem by creating a unique experimental system that consists of the replica human colon and a replica two-compartment septic tank, which was originally an acyclic septic tank. The model colon is made of a custom-built 20-inch-long glass tube with a 2-inch diameter with a rubber stopper at both ends and a tube-shaped membrane typically used for dialysis treatments within the glass tube.

To simulate human feeding, 100 milliliters of a 20-ingredient mixture that replicated digested food was pumped into the dialysis tube at 9 a.m., 3 p.m. and 9 p.m. for five-day-long experiments over nine months.

The septic tank was filled with waste from the colon along with synthetic greywater, which is meant to simulate wastewater from sources such as sinks and bathtubs, and the copper nanoparticles. The researchers built a septic tank because 20 to 30 percent of American households rely on them for sewage treatment. Moreover, research has shown up to 40 percent of septic tanks don’t function properly. This is a concern if the copper materials are disrupting the function of the septic system, which would lead to untreated waste entering the soil and groundwater.

Once the primary chamber of the septic system was full, liquid began to enter the second chamber. Once a week, the effluent was drained from the secondary chamber and it was placed into sealed five-gallon containers. The effluent was then used in combination with zebrafish embryos in a high content screening process using multiwall plates to access hatching rates.

The remaining effluent has been saved and sits in 30 five-gallon buckets in a closet at UC Riverside because some collaborators have requested samples of the liquid for their experiments.

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

Understanding the Transformation, Speciation, and Hazard Potential of Copper Particles in a Model Septic Tank System Using Zebrafish to Monitor the Effluent* by Sijie Lin, Alicia A. Taylor, Zhaoxia Ji, Chong Hyun Chang, Nichola M. Kinsinger, William Ueng, Sharon L. Walker, and André E. Nel. ACS Nano, 2015, 9 (2), pp 2038–2048 DOI: 10.1021/nn507216f
Publication Date (Web): January 27, 2015

Copyright © 2015 American Chemical Society

This paper is behind a paywall.

* Link added March 10, 2015.

Cute, adorable roundworms help measure nanoparticle toxicity

Caption: Low-cost experiments to test the toxicity of nanomaterials focused on populations of roundworms. Rice University scientists were able to test 20 nanomaterials in a short time, and see their method as a way to determine which nanomaterials should undergo more extensive testing. Credit: Zhong Lab/Rice University

Caption: Low-cost experiments to test the toxicity of nanomaterials focused on populations of roundworms. Rice University scientists were able to test 20 nanomaterials in a short time, and see their method as a way to determine which nanomaterials should undergo more extensive testing.
Credit: Zhong Lab/Rice University

Until now, ‘cute’ and ‘adorable’ are not words I would have associated with worms of any kind or with Rice University, for that matter. It’s amazing what a single image can do, eh?

A Feb. 3, 2015 news item on Azonano describes how roundworms have been used in research investigating the toxicity of various kinds of nanoparticles,

The lowly roundworm is the star of an ambitious Rice University project to measure the toxicity of nanoparticles.

The low-cost, high-throughput study by Rice scientists Weiwei Zhong and Qilin Li measures the effects of many types of nanoparticles not only on individual organisms but also on entire populations.

A Feb. 2, 2015 Rice University news release (also on EurekAlert), which originated the news item, provides more details about the research,

The Rice researchers tested 20 types of nanoparticles and determined that five, including the carbon-60 molecules (“buckyballs”) discovered at Rice in 1985, showed little to no toxicity.

Others were moderately or highly toxic to Caenorhabditis elegans, several generations of which the researchers observed to see the particles’ effects on their health.

The results were published by the American Chemical Society journal Environmental Sciences and Technology. They are also available on the researchers’ open-source website.

“Nanoparticles are basically new materials, and we don’t know much about what they will do to human health and the health of the ecosystem,” said Li, an associate professor of civil and environmental engineering and of materials science and nanoengineering. “There have been a lot of publications showing certain nanomaterials are more toxic than others. So before we make more products that incorporate these nanomaterials, it’s important that we understand we’re not putting anything toxic into the environment or into consumer products.

“The question is, How much cost can we bear?” she said. “It’s a long and expensive process to do a thorough toxicological study of any chemical, not just nanomaterials.” She said that due to the large variety of nanomaterials being produced at high speed and at such a large scale, there is “an urgent need for high-throughput screening techniques to prioritize which to study more extensively.”

Rice’s pilot study proves it is possible to gather a lot of toxicity data at low cost, said Zhong, an assistant professor of biosciences, who has performed extensive studies on C. elegans, particularly on their gene networks. Materials alone for each assay, including the worms and the bacteria they consumed and the culture media, cost about 50 cents, she said.

The researchers used four assays to see how worms react to nanoparticles: fitness, movement, growth and lifespan. The most sensitive assay of toxicity was fitness. In this test, the researchers mixed the nanoparticles in solutions with the bacteria that worms consume. Measuring how much bacteria they ate over time served as a measure of the worms’ “fitness.”

“If the worms’ health is affected by the nanoparticles, they reproduce less and eat less,” Zhong said. “In the fitness assay, we monitor the worms for a week. That is long enough for us to monitor toxicity effects accumulated through three generations of worms.” C. elegans has a life cycle of about three days, and since each can produce many offspring, a population that started at 50 would number more than 10,000 after a week. Such a large number of tested animals also enabled the fitness assay to be highly sensitive.

The researchers’ “QuantWorm” system allowed fast monitoring of worm fitness, movement, growth and lifespan. In fact, monitoring the worms was probably the least time-intensive part of the project. Each nanomaterial required specific preparation to make sure it was soluble and could be delivered to the worms along with the bacteria. The chemical properties of each nanomaterial also needed to be characterized in detail.

The researchers studied a representative sampling of three classes of nanoparticles: metal, metal oxides and carbon-based. “We did not do polymeric nanoparticles because the type of polymers you can possibly have is endless,” Li explained.

They examined the toxicity of each nanoparticle at four concentrations. Their results showed C-60 fullerenes, fullerol (a fullerene derivative), titanium dioxide, titanium dioxide-decorated nanotubes and cerium dioxide were the least damaging to worm populations.

Their “fitness” assay confirmed dose-dependent toxicity for carbon black, single- and multiwalled carbon nanotubes, graphene, graphene oxide, gold nanoparticles and fumed silicon dioxide.

They also determined the degree to which surface chemistry affected the toxicity of some particles. While amine-functionalized multiwalled nanotubes proved highly toxic, hydroxylated nanotubes had the least toxicity, with significant differences in fitness, body length and lifespan.

A complete and interactive toxicity chart for all of the tested materials is available online.

Zhong said the method could prove its worth as a rapid way for drug or other companies to narrow the range of nanoparticles they wish to put through more expensive, dedicated toxicology testing.

“Next, we hope to add environmental variables to the assays, for example, to mimic ultraviolet exposure or river water conditions in the solution to see how they affect toxicity,” she said. “We also want to study the biological mechanism by which some particles are toxic to worms.”

Here’s a citation for the paper and links to the paper and to the researchers’ website,

A multi-endpoint, high-throughput study of nanomaterial toxicity in Caenorhabditis elegans by Sang-Kyu Jung, Xiaolei Qu, Boanerges Aleman-Meza, Tianxiao Wang, Celeste Riepe, Zheng Liu, Qilin Li, and Weiwei Zhong. Environ. Sci. Technol., Just Accepted Manuscript DOI: 10.1021/es5056462 Publication Date (Web): January 22, 2015
Copyright © 2015 American Chemical Society

Nanomaterial effects on C. elegans

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This heat map indicates whether a measurement for the nanomaterial-exposed worms is higher (yellow), or lower (blue) than the control worms. Black indicates no effects from nanomaterial exposure.

Clicking on colored blocks to see detailed experimental data.

The published paper is open access but you need an American Chemical Society site registration to access it. The researchers’ site is open access.

Two-organ tests (body-on-a-chip) show liver damage possible from nanoparticles

This is the first time I’ve seen testing of two organs for possible adverse effects from nanoparticles. In this case, the researchers were especially interested in the liver. From an Aug. 12, 2014 news item on Azonano,

Nanoparticles in food, sunscreen and other everyday products have many benefits. But Cornell [University] biomedical scientists are finding that at certain doses, the particles might cause human organ damage.

A recently published study in Lab on a Chip by the Royal Society of Chemistry and led by senior research associate Mandy Esch shows that nanoparticles injure liver cells when they are in microfluidic devices designed to mimic organs of the human body. The injury was worse when tested in two-organ systems, as opposed to single organs – potentially raising concerns for humans and animals.

Anne Ju’s Aug. 11, 2014 article for Cornell University’s Chronicle describes the motivation for this work and the research itself in more detail,

“We are looking at the effects of what are considered to be harmless nanoparticles in humans,” Esch said. “These particles are not necessarily lethal, but … are there other consequences? We’re looking at the non-lethal consequences.”

She used 50-nanometer carboxylated polystyrene nanoparticles, found in some animal food sources and considered model inert particles. Shuler’s lab specializes in “body-on-a-chip” microfluidics, which are engineered chips with carved compartments that contain cell cultures to represent the chemistry of individual organs.

In Esch’s experiment, she made a human intestinal compartment, a liver compartment and a compartment to represent surrounding tissues in the body. She then observed the effects of fluorescently labeled nanoparticles as they traveled through the system.

Esch found that both single nanoparticles as well as small clusters crossed the gastrointestinal barrier and reached liver cells, and the liver cells released an enzyme called aspartate transaminase, known to be released during cell death or damage.

It’s unclear exactly what damage is occurring or why, but the results indicate that the nanoparticles must be undergoing changes as they cross the gastrointestinal barrier, and that these alterations may change their toxic potential, Esch said. Long-term consequences for organs in proximity could be a concern, she said.

“The motivation behind this study was twofold: one, to show that multi-organ, in vitro systems give us more information when testing for the interaction of a substance with the human body, and two … to look at nanoparticles because they have a huge potential for medicine, yet adverse effects have not been studied in detail yet,” Esch said.

Mary Macleod’s July 3, 2014 article for Chemistry World features a diagram of the two-organ system and more technical details about the research,

Schematic of the two-organ system [downloaded from http://www.rsc.org/chemistryworld/2014/07/nanoparticle-liver-gastrointestinal-tract-microfluidic-chip]

Schematic of the two-organ system [downloaded from http://www.rsc.org/chemistryworld/2014/07/nanoparticle-liver-gastrointestinal-tract-microfluidic-chip]

HepG2/C3A cells were used to represent the liver, with the intestinal cell co-culture consisting of enterocytes (Caco-2) and mucin-producing (HT29-MTX) cells. Carboxylated polystyrene nanoparticles were fluorescently labelled so their movement between the chambers could be tracked. Levels of aspartate transaminase, a cytosolic enzyme released into the culture medium upon cell death, were measured to give an indication of liver damage.

The study saw that single nanoparticles and smaller nanoparticle aggregates were able to cross the GI barrier and reach the liver cells. The increased zeta potentials of these nanoparticles suggest that crossing the barrier may raise their toxic potential. However, larger nanoparticles, which interact with cell membranes and aggregate into clusters, were stopped much more effectively by the GI tract barrier.

The gastrointestinal tract is an important barrier preventing ingested substances crossing into systemic circulation. Initial results indicate that soluble mediators released upon low-level injury to liver cells may enhance the initial injury by damaging the cells which form the GI tract. These adverse effects were not seen in conventional single-organ tests.

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

Body-on-a-chip simulation with gastrointestinal tract and liver tissues suggests that ingested nanoparticles have the potential to cause liver injury by Mandy B. Esch, Gretchen J. Mahler, Tracy Stokol, and Michael L. Shuler. Lab Chip, 2014,14, 3081-3092 DOI: 10.1039/C4LC00371C First published online 27 Jun 2014

This paper is open access until Aug. 12, 2014.

While this research is deeply concerning, it should be noted the researchers are being very careful in their conclusions as per Ju’s article, “It’s unclear exactly what damage is occurring or why, but the results indicate that the nanoparticles must be undergoing changes as they cross the gastrointestinal barrier, and that these alterations may change their toxic potential … Long-term consequences for organs in proximity could be a concern … .”

Reducing animal testing for nanotoxicity—PETA (People for the Ethical Treatment of Animals) presentation at NanoTox 2014

Writing about nanotechnology can lead you in many different directions such as the news about PETA (People for the Ethical Treatment of Animals) and its poster presentation at the NanoTox 2014 conference being held in Antalya, Turkey from April 23 – 26, 2014. From the April 22, 2014 PETA news release on EurekAlert,

PETA International Science Consortium Ltd.’s nanotechnology expert will present a poster titled “A tiered-testing strategy for nanomaterial hazard assessment” at the 7th International Nanotoxicology Congress [NanoTox 2014] to be held April 23-26, 2014, in Antalya, Turkey.

Dr. Monita Sharma will outline a strategy consistent with the 2007 report from the US National Academy of Sciences, “Toxicity Testing in the 21st Century: A Vision and a Strategy,” which recommends use of non-animal methods involving human cells and cell lines for mechanistic pathway–based toxicity studies.

Based on the current literature, the proposed strategy includes thorough characterization of nanomaterials as manufactured, as intended for use, and as present in the final biological system; assessment using multiple in silico and in vitro model systems, including high-throughput screening (HTS) assays and 3D systems; and data sharing among researchers from government, academia, and industry through web-based tools, such as the Nanomaterial Registry and NanoHUB

Implementation of the proposed strategy will generate meaningful information on nanomaterial properties and their interaction with biological systems. It is cost-effective, reduces animal use, and can be applied for assessing risk and making intelligent regulatory decisions regarding the use and disposal of nanomaterials.

PETA’s International Science Consortium has recently launched a nanotechnology webpage which provides a good overview of the basics and, as one would expect from PETA, a discussion of relevant strategies that eliminate the use of animals in nanotoxicity assessment,

What is nano?

The concept of fabricating materials at an atomic scale was introduced in 1959 by physicist Richard Feynman in his talk entitled “There’s Plenty of Room at the Bottom.” The term “nano” originates from the Greek word for “dwarf,” which represents the very essence of nanomaterials. In the International System of Units, the prefix “nano” means one-billionth, or 10-9; therefore, one nanometer is one-billionth of a meter, which is smaller than the thickness of a sheet of paper or a strand of hair.  …

Are there different kinds of nano?

The possibility of controling biological processes using custom-synthesized materials at the nanoscale has intrigued researchers from different scientific fields. With the ever increasing sophistication of nanomaterial synthesis, there has been an exponential increase in the number and type of nanomaterials available or that can be custom synthesized. Table 1 lists some of the nanomaterials that are currently available.


Oddly, given the question ‘Are there different kinds of nano?’, there’s no mention of nanobots.  Still it’s understandable that they’d focus on nanomaterials which are, as far as I know, the only ‘nano’ anything tested for toxicity. On that note, PETA’s Nanotechnology page offers this revelatory listing (scroll down about 3/4 of the way),

The following are some of the web-based tools being used by nanotoxicologists and material scientists:

Getting back to the NanoTox conference being held now in Antalya, I noticed a couple of familiar names on the list of keynote speakers (scroll down about 15% of the way), Kostas Kostarelos (last mentioned in a Feb. 28, 2014 posting about scientific publishing and impact factors’ scroll down about 1/2 way) and Mark Wiesner (last mentioned in a Nov. 13, 2013 posting about a major grant for one of his projects).

Ecotoxicology and environmental fate of manufactured nanomaterials—testing guidelines from Organization for Economic Cooperation and Development (OECD)

The Organization for Economic Cooperation and Development (OECD) has released guidelines for testing manufactured nanomaterials according to a March 11, 2014 news item on Nanowerk,

As part of its Programme on the Safety of Manufactured Nanomaterials, and in particular work on the testing and assessment of manufactured nanomaterials, OECD initiated a series of expert meetings to improve the applicability of the OECD Test Guidelines to nanomaterials. With this in mind, the Working Party on Manufactured Nanomaterials agreed to address the ecotoxicology and environmental fate of manufactured nanomaterials.

The OECD Expert Meeting on Ecotoxicology and Environmental Fate took place on 29th-31st January 2013 in Berlin, Federal Press Office. The event was hosted by the German delegation and funded by the German Federal Ministry of the Environment, Nature Conservation and Nuclear Safety (BMU) as well as the United States Environment Protection Agency (US EPA).

Three documents were published one of which being a preview,

The OECD expert meeting on ecotoxicology and environmental fate — Towards the development of improved OECD guidelines for the testing of nanomaterials by Dana Kühnel and Carmen Nickel. Science of The Total Environment Volume 472, 15 February 2014, Pages 347–353 http://dx.doi.org/10.1016/j.scitotenv.2013.11.055

This document is open access.

The report itself,

Series on the Safety of Manufactured Nanomaterials. ENV/JM/MONO(2014)1

TEST GUIDELINES Expert Meeting Report
Series on the Safety of Manufactured Nanomaterials No. 40

Ecotoxicology and Environmental Fate of Manufactured Nanomaterials: Test Guidelines

There’s an addendum which includes the presentations made at the meeting (you can find both the report, proper, and the addendum on this page scroll to report no. 40),



Series on the Safety of Manufactured Nanomaterials No. 40
Ecotoxicology and Environmental Fate of Manufactured Nanomaterials:
Test Guidelines.

As it can get a little tricky accessing OECD documents, I’ve tried to give a couple different links and as much identifying information as possible. Good luck!

Danish scientists provide insights into celllular response to silver nanoparticles

The conclusions are concerning but the scientists at the University of Southern Denmark are careful to note that this research on silver nanopartices was performed in a laboratory setting which does not necessarily predict what might happen under real life conditions.

As for the research itself, a Feb. 28, 2014 news item on Azonano has this to say,

Endocrine disrupters are not the only worrying chemicals that ordinary consumers are exposed to in everyday life. Also nanoparticles of silver, found in e.g. dietary supplements, cosmetics and food packaging, now worry scientists. A new study from the University of Southern Denmark shows that nano-silver can penetrate our cells and cause damage.

Silver has an antibacterial effect and therefore the food and cosmetic industry often coat their products with silver nanoparticles. Nano-silver can be found in e.g. drinking bottles, cosmetics, band aids, toothbrushes, running socks, refrigerators, washing machines and food packagings.

“Silver as a metal does not pose any danger, but when you break it down to nano-sizes, the particles become small enough to penetrate a cell wall. If nano-silver enters a human cell, it can cause changes in the cell”, explain Associate Professor Frank Kjeldsen and PhD Thiago Verano-Braga, Department of Biochemistry and Molecular Biology at the University of Southern Denmark.

A Feb. 27, 2014 University of Southern Denmark news release, which originated the news item, provides more detail about the research,

The researchers examined human intestinal cells, as they consider these to be most likely to come into contact with nano-silver, ingested with food.

“We can confirm that nano-silver leads to the formation of harmful, so called free radicals in cells. We can also see that there are changes in the form and amount of proteins. This worries us”, say Frank Kjeldsen and Thiago Verano-Braga.

A large number of serious diseases are characterized by the fact that there is an overproduction of free radicals in cells. This applies to cancer and neurological diseases such as Alzheimer’s and Parkinson’s.

Kjeldsen and Verano-Braga emphasizes that their research is conducted on human cells in a laboratory, not based on living people. They also point out that they do not know how large a dose of nano-silver, a person must be exposed to for the emergence of cellular changes.

“We don’t know how much is needed, so we cannot conclude that nano-silver can make you sick. But we can say that we must be very cautious and worried when we see an overproduction of free radicals in human cells”, they say.

Nano-silver is also sold as a dietary supplement, promising to have an antibacterial, anti-flu and cancer-inhibatory effect. The nano-silver should also help against low blood counts and bad skin. In the EU, the marketing of dietary supplements and foods with claims to have medical effects is not allowed. But the nano-silver is easy to find and buy online.

In the wake of the SDU-research, the Danish Veterinary and Food Administration now warns against taking dietary supplements with nano-silver.

“The recent research strongly suggests that it can be dangerous”, says Søren Langkilde from the Danish Veterinary and Food Administration to the Danish Broadcasting Corporation (DR).

The researchers supplied this image to illustrate the abstract for their paper (link and citation to follow),

Courtesy University of Southern Denmark

Courtesy University of Southern Denmark

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

Insights into the Cellular Response Triggered by Silver Nanoparticles Using Quantitative Proteomics by Thiago Verano-Braga, Rona Miethling-Graff, Katarzyna Wojdyla, Adelina Rogowska-Wrzesinska, Jonathan R. Brewer, Helmut Erdmann, and Frank Kjeldsen. ACS Nano, Article ASAP DOI: 10.1021/nn4050744 Publication Date (Web): February 10, 2014
Copyright © 2014 American Chemical Society

This paper is behind a paywall.

Silver ions in the environment

Earlier this week (Feb. 24, 2014), I published a post featuring Dr. Andrew Maynard, Director of the University of Michigan’s Risk Science Center in an introductory video describing seven surprising facts about silver nanoparticles. For those who want to delve more deeply, there’s a Feb. 25, 2014 news item on Nanowerk describing some Swiss research into silver nanoparticles and ions in aquatic environments,

It has long been known that, in the form of free ions, silver particles can be highly toxic to aquatic organisms. Yet to this day, there is a lack of detailed knowledge about the doses required to trigger a response and how the organisms deal with this kind of stress. To learn more about the cellular processes that occur in the cells, scientists from the Aquatic Research Institute, Eawag [Swiss Federal Institute of Aquatic Science and Technology], subjected algae to a range of silver concentrations.

In the past, silver mostly found its way into the environment in the vicinity of silver mines or via wastewater [emphasis mine] emanating from the photo industry. More recently, silver nanoparticles have become commonplace in many applications – as ingredients in cosmetics, food packaging, disinfectants, and functional clothing. Though a recent study conducted by the Swiss National Science Foundation revealed that the bulk of silver nanoparticles is retained in wastewater treatment plants, only little is known about the persistence and the impact of the residual nano-silver in the environment.

The Feb. 25, 2014 Eawag media release, which originated the news item, describes the research in further detail,

Smitha Pillai from the Eawag Department of Environmental Toxicology and her colleagues from EPF Lausanne and ETH Zürich studied the impact of various concentrations of waterborne silver ions on the cells of the green algae Chlamydomonas reinhardtii. Silver is chemically very similar to copper, an essential metal due to its importance in several enzymes. Because of that, silver can exploit the cells’ copper transport mechanisms and sneak into them undercover. This explains why, already after a short time, concentrations of silver in the intracellular fluid can reach up to one thousand times those in the surrounding environment.

A prompt response

Because silver damages key enzymes involved in energy metabolism, even low concentrations can cut photosynthesis and growth rates by a half in just 15 minutes. Over the same time period, the researchers also detected changes in the activity of about 1000 other genes and proteins, which they interpreted as a response to the stressor – an attempt to repair silver-induced damage. At low concentrations, the cells’ photosynthesis apparatus recovered within five hours, and recovery mechanisms were sufficient to deal with all but the highest concentrations tested.

A number of unanswered questions

At first glance, the results are reassuring because the silver concentrations that the algae are subject to in the environment are rarely as high as those applied in the lab, which allows them to recover quickly – at least externally. But the experiments also showed that even low silver concentrations have a significant effect on intracellular processes and that the algae divert their energy to repairing damage incurred. This can pose a problem when other stressors act in parallel, such as increased UV-radiation or other chemical compounds. Moreover, it remains unknown to this day whether the cells have an active mechanism to shuttle out the silver. Lacking such a mechanism, the silver could have adverse effects on higher organisms, given that algae are at the bottom of the food chain.

You can find the researchers’ paper here,

Linking toxicity and adaptive responses across the transcriptome, proteome, and phenotype of Chlamydomonas reinhardtii exposed to silver by Smitha Pillai, Renata Behra, Holger Nestler, Marc J.-F. Suter, Laura Sigg, and Kristin Schirmer. Proceedings of the National Academy of Sciences (PNAS) – early edition 18.February 2014, www.pnas.org/cgi/doi/10.1073/pnas.1319388111

The paper is available through the PNAS open access option.

I have published a number of pieces about aquatic enviornments and wastewater and nanotechnology-enabled products as useful for remediation efforts and as a source of pollution. Here’s a Feb. 28, 2013 posting where I contrasted two pieces of research on silver nanoparticles. The first was research in an aquatic environment and the other concerned wastewater.