Category Archives: risk

DNA damage from engineered nanoparticles (zinc oxide, silver, silicon dioxide, cerium oxide and iron oxide)

Before launching into this research, there are a few provisos. This work was done in a laboratory, a highly specialized environment that does not mimic real-life conditions, and performed on animal cells (a hamster’s). As well, naturally occurring nanoparticles were not included (my Nov. 24, 2011 post has some information about naturally occurring nanomaterials including nanosilver which we have been ingesting for centuries).

That said, the studies from the Massachusetts Institute of Techology (MIT) and the Harvard School of Public Health (HSPH; last mentioned here in an April 2, 2014 post) are concerning (from an April 9, 2014 news item on Azonano).

A new study from MIT and the Harvard School of Public Health (HSPH) suggests that certain nanoparticles can also harm DNA. This research was led by Bevin Engelward, a professor of biological engineering at MIT, and associate professor Philip Demokritou, director of HSPH’s Center for Nanotechnology and Nanotoxicology.

The researchers found that zinc oxide nanoparticles, often used in sunscreen to block ultraviolet rays, significantly damage DNA. Nanoscale silver, which has been added to toys, toothpaste, clothing, and other products for its antimicrobial properties, also produces substantial DNA damage, they found.

The findings, published in a recent issue of the journal ACS Nano, relied on a high-speed screening technology to analyze DNA damage. This approach makes it possible to study nanoparticles’ potential hazards at a much faster rate and larger scale than previously possible.

More details about current testing requirements and the specific nanoparticles studied can be found in the April 8, 2014 MIT news release, which originated the news item,

The Food and Drug Administration does not require manufacturers to test nanoscale additives for a given material if the bulk material has already been shown to be safe. However, there is evidence that the nanoparticle form of some of these materials may be unsafe: Due to their immensely small size, these materials may exhibit different physical, chemical, and biological properties, and penetrate cells more easily.

“The problem is that if a nanoparticle is made out of something that’s deemed a safe material, it’s typically considered safe. There are people out there who are concerned, but it’s a tough battle because once these things go into production, it’s very hard to undo,” Engelward says.

The researchers focused on five types of engineered nanoparticles — silver, zinc oxide, iron oxide, cerium oxide, and silicon dioxide (also known as amorphous silica) — that are used industrially. Some of these nanomaterials can produce free radicals called reactive oxygen species, which can alter DNA. Once these particles get into the body, they may accumulate in tissues, causing more damage.

“It’s essential to monitor and evaluate the toxicity or the hazards that these materials may possess. There are so many variations of these materials, in different sizes and shapes, and they’re being incorporated into so many products,” says Christa Watson, a postdoc at HSPH and the paper’s lead author. “This toxicological screening platform gives us a standardized method to assess the engineered nanomaterials that are being developed and used at present.”

The researchers hope that this screening technology could also be used to help design safer forms of nanoparticles; they are already working with partners in industry to engineer safer UV-blocking nanoparticles. Demokritou’s lab recently showed that coating zinc oxide particles with a nanothin layer of amorphous silica can reduce the particles’ ability to damage DNA.

Given that Demokritou was part of a team that recently announced a new testing platform (Volumetric Centrifugation Method [VCM]) for nanoparticles as mentioned in my April 2, 2014 post, I was a little curious about the  platform for this project ( the CometChip) and, as always, curious about the results for all the tested engineered nanoparticles (Note: A link has been removed), from the news release,

Until now, most studies of nanoparticle toxicity have focused on cell survival after exposure. Very few have examined genotoxicity, or the ability to damage DNA — a phenomenon that may not necessarily kill a cell, but one that can lead to cancerous mutations if the damage is not repaired.

A common way to study DNA damage in cells is the so-called “comet assay,” named for the comet-shaped smear that damaged DNA forms during the test. The procedure is based on gel electrophoresis, a test in which an electric field is applied to DNA placed in a matrix, forcing the DNA to move across the gel. During electrophoresis, damaged DNA travels farther than undamaged DNA, producing a comet-tail shape.

Measuring how far the DNA can travel reveals how much DNA damage has occurred. This procedure is very sensitive, but also very tedious.

In 2010, Engelward and MIT professor Sangeeta Bhatia developed a much more rapid version of the comet assay, known as the CometChip. Using microfabrication technology, single cells can be trapped in tiny microwells within the matrix. This approach makes it possible to process as many as 1,000 samples in the time that it used to take to process just 30 samples — allowing researchers to test dozens of experimental conditions at a time, which can be analyzed using imaging software.

Wolfgang Kreyling, an epidemiologist at the German Research Center for Environmental Health who was not involved in the study, says this technology should help toxicologists catch up to the rapid rate of deployment of engineered nanoparticles (ENPs).

“High-throughput screening platforms are desperately needed,” Kreyling says. “The proposed approach will be not only an important tool for nanotoxicologists developing high-throughput screening strategies for the assessment of possible adverse health effects associated with ENPs, but also of great importance for material scientists working on the development of novel ENPs and safer-by-design approaches.”

Using the CometChip, the MIT and HSPH researchers tested the nanoparticles’ effects on two types of cells that are commonly used for toxicity studies: a type of human blood cells called lymphoblastoids, and an immortalized line of Chinese hamster ovary cells.

Zinc oxide and silver produced the greatest DNA damage in both cell lines. At a concentration of 10 micrograms per milliliter — a dose not high enough to kill all of the cells — these generated a large number of single-stranded DNA breaks.

Silicon dioxide, which is commonly added during food and drug production, generated very low levels of DNA damage. Iron oxide and cerium oxide also showed low genotoxicity.

Happily the researchers are taking a pragmatic approach to the results (from the news release),

More studies are needed to determine how much exposure to metal oxide nanoparticles could be unsafe for humans, the researchers say.

“The biggest challenge we have as people concerned with exposure biology is deciding when is something dangerous and when is it not, based on the dose level. At low levels, probably these things are fine,” Engelward says. “The question is: At what level does it become problematic, and how long will it take for us to notice?”

One of the areas of greatest concern is occupational exposure to nanoparticles, the researchers say. Children and fetuses are also potentially at greater risk because their cells divide more often, making them more vulnerable to DNA damage.

The most common routes that engineered nanoparticles follow into the body are through the skin, lungs, and stomach, so the researchers are now investigating nanoparticle genotoxicity on those cell types. They are also studying the effects of other engineered nanoparticles, including metal oxides used in printer and photocopier toner, which can become airborne and enter the lungs.

Kudos to the writer for the clarity and care shown here (I think it’s Anne Trafton but MIT is not including bylines as it did previously, so I’m uncertain).

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

High-Throughput Screening Platform for Engineered Nanoparticle-Mediated Genotoxicity Using CometChip Technology by Christa Watson, Jing Ge, Joel Cohen, Georgios Pyrgiotakis, Bevin P. Engelward, and Philip Demokritou. ACS Nano, 2014, 8 (3), pp 2118–2133 DOI: 10.1021/nn404871p Publication Date (Web): March 11, 2014
Copyright © 2014 American Chemical Society

This article is behind a paywall.

Nanomaterials and safety: Europe’s non-governmental agencies make recommendations; (US) Arizona State University initiative; and Japan’s voluntary carbon nanotube management

I have three news items which have one thing in common, they concern nanomaterials and safety. Two of these of items are fairly recent; the one about Japan has been sitting in my drafts folder for months and I’m including it here because if I don’t do it now, I never will.

First, there’s an April 7, 2014 news item on Nanowerk (h/t) about European non-governmental agencies (CIEL; the Center for International Environmental Law and its partners) and their recommendations regarding nanomaterials and safety. From the CIEL April 2014 news release,

CIEL and European partners* publish position paper on the regulation of nanomaterials at a meeting of EU competent authorities

*ClientEarth, The European Environmental Bureau, European citizen’s Organization for Standardisation, The European consumer voice in Standardisation –ANEC, and Health Care Without Harm, Bureau of European Consumers

… Current EU legislation does not guarantee that all nanomaterials on the market are safe by being assessed separately from the bulk form of the substance. Therefore, we ask the European Commission to come forward with concrete proposals for a comprehensive revision of the existing legal framework addressing the potential risks of nanomaterials.

1. Nanomaterials are different from other substances.

We are concerned that EU law does not take account of the fact that nano forms of a substance are different and have different intrinsic properties from their bulk counterpart. Therefore, we call for this principle to be explicitly established in the REACH, and Classification Labeling and Packaging (CLP) regulations, as well as in all other relevant legislation. To ensure adequate consideration, the submission of comprehensive substance identity and characterization data for all nanomaterials on the market, as defined by the Commission’s proposal for a nanomaterial definition, should be required.

Similarly, we call on the European Commission and EU Member States to ensure that nanomaterials do not benefit from the delays granted under REACH to phase-in substances, on the basis of information collected on their bulk form.

Further, nanomaterials, due to their properties, are generally much more reactive than their bulk counterpart, thereby increasing the risk of harmful impact of nanomaterials compared to an equivalent mass of bulk material. Therefore, the present REACH thresholds for the registration of nanomaterials should be lowered.

Before 2018, all nanomaterials on the market produced in amounts of over 10kg/year must be registered with ECHA on the basis of a full registration dossier specific to the nanoform.

2. Risk from nanomaterials must be assessed

Six years after the entry into force of the REACH registration requirements, only nine substances have been registered as nanomaterials despite the much wider number of substances already on the EU market, as demonstrated by existing inventories. Furthermore, the poor quality of those few nano registration dossiers does not enable their risks to be properly assessed. To confirm the conclusions of the Commission’s nano regulatory review assuming that not all nanomaterials are toxic, relevant EU legislation should be amended to ensure that all nanomaterials are adequately assessed for their hazardous properties.

Given the concerns about novel properties of nanomaterials, under REACH, all registration dossiers of nanomaterials must include a chemical safety assessment and must comply with the same information submission requirements currently required for substances classified as Carcinogenic, Mutagenic or Reprotoxic (CMRs).

3. Nanomaterials should be thoroughly evaluated

Pending the thorough risk assessment of nanomaterials demonstrated by comprehensive and up-to-date registration dossiers for all nanoforms on the market, we call on ECHA to systematically check compliance for all nanoforms, as well as check the compliance of all dossiers which, due to uncertainties in the description of their identity and characterization, are suspected of including substances in the nanoform. Further, the Community Roling Action Plan (CoRAP) list should include all identified substances in the nanoform and evaluation should be carried out without delay.

4. Information on nanomaterials must be collected and disseminated

All EU citizens have the right to know which products contain nanomaterials as well as the right to know about their risks to health and environment and overall level of exposure. Given the uncertainties surrounding nanomaterials, the Commission must guarantee that members of the public are in a position to exercise their right to know and to make informed choices pending thorough risk assessments of nanomaterials on the market.

Therefore, a publicly accessible inventory of nanomaterials and consumer products containing nanomaterials must be established at European level. Moreover, specific nano-labelling or declaration requirements must be established for all nano-containing products (detergents, aerosols, sprays, paints, medical devices, etc.) in addition to those applicable to food, cosmetics and biocides which are required under existing obligations.

5. REACH enforcement activities should tackle nanomaterials

REACH’s fundamental principle of “no data, no market” should be thoroughly implemented. Therefore, nanomaterials that are on the market without a meaningful minimum set of data to allow the assessment of their hazards and risks should be denied market access through enforcement activities. In the meantime, we ask the EU Member States and manufacturers to use a precautionary approach in the assessment, production, use and disposal of nanomaterials

This comes on the heels of CIEL’s March 2014 news release announcing a new three-year joint project concerning nanomaterials and safety and responsible development,

Supported by the VELUX foundations, CIEL and ECOS (the European Citizen’s Organization for Standardization) are launching a three-year project aiming to ensure that risk assessment methodologies and risk management tools help guide regulators towards the adoption of a precaution-based regulatory framework for the responsible development of nanomaterials in the EU and beyond.

Together with our project partner the German Öko-Institut, CIEL and ECOS will participate in the work of the standardization organizations Comité Européen de Normalisation and International Standards Organization, and this work of the OECD [Organization for Economic Cooperation and Development], especially related to health, environmental and safety aspects of nanomaterials and exposure and risk assessment. We will translate progress into understandable information and issue policy recommendations to guide regulators and support environmental NGOs in their campaigns for the safe and sustainable production and use of nanomaterials.

The VILLUM FOUNDATION and the VELUX FOUNDATION are non-profit foundations created by Villum Kann Rasmussen, the founder of the VELUX Group and other entities in the VKR Group, whose mission it is to bring daylight, fresh air and a better environment into people’s everyday lives.

Meanwhile in the US, an April 6, 2014 news item on Nanowerk announces a new research network, based at Arizona State University (ASU), devoted to studying health and environmental risks of nanomaterials,

Arizona State University researchers will lead a multi-university project to aid industry in understanding and predicting the potential health and environmental risks from nanomaterials.

Nanoparticles, which are approximately 1 to 100 nanometers in size, are used in an increasing number of consumer products to provide texture, resiliency and, in some cases, antibacterial protection.

The U.S. Environmental Protection Agency (EPA) has awarded a grant of $5 million over the next four years to support the LCnano Network as part of the Life Cycle of Nanomaterials project, which will focus on helping to ensure the safety of nanomaterials throughout their life cycles – from the manufacture to the use and disposal of the products that contain these engineered materials.

An April 1, 2014 ASU news release, which originated the news item, provides more details and includes information about project partners which I’m happy to note include nanoHUB and the Nanoscale Informal Science Education Network (NISENet) in addition to the other universities,

Paul Westerhoff is the LCnano Network director, as well as the associate dean of research for ASU’s Ira A. Fulton Schools of Engineering and a professor in the School of Sustainable Engineering and the Built Environment.

The project will team engineers, chemists, toxicologists and social scientists from ASU, Johns Hopkins, Duke, Carnegie Mellon, Purdue, Yale, Oregon’s state universities, the Colorado School of Mines and the University of Illinois-Chicago.

Engineered nanomaterials of silver, titanium, silica and carbon are among the most commonly used. They are dispersed in common liquids and food products, embedded in the polymers from which many products are made and attached to textiles, including clothing.

Nanomaterials provide clear benefits for many products, Westerhoff says, but there remains “a big knowledge gap” about how, or if, nanomaterials are released from consumer products into the environment as they move through their life cycles, eventually ending up in soils and water systems.

“We hope to help industry make sure that the kinds of products that engineered nanomaterials enable them to create are safe for the environment,” Westerhoff says.

“We will develop molecular-level fundamental theories to ensure the manufacturing processes for these products is safer,” he explains, “and provide databases of measurements of the properties and behavior of nanomaterials before, during and after their use in consumer products.”

Among the bigger questions the LCnano Network will investigate are whether nanomaterials can become toxic through exposure to other materials or the biological environs they come in contact with over the course of their life cycles, Westerhoff says.

The researchers will collaborate with industry – both large and small companies – and government laboratories to find ways of reducing such uncertainties.

Among the objectives is to provide a framework for product design and manufacturing that preserves the commercial value of the products using nanomaterials, but minimizes potentially adverse environmental and health hazards.

In pursuing that goal, the network team will also be developing technologies to better detect and predict potential nanomaterial impacts.

Beyond that, the LCnano Network also plans to increase awareness about efforts to protect public safety as engineered nanomaterials in products become more prevalent.

The grant will enable the project team to develop educational programs, including a museum exhibit about nanomaterials based on the LCnano Network project. The exhibit will be deployed through a partnership with the Arizona Science Center and researchers who have worked with the Nanoscale Informal Science Education Network.

The team also plans to make information about its research progress available on the nanotechnology industry website Nanohub.org.

“We hope to use Nanohub both as an internal virtual networking tool for the research team, and as a portal to post the outcomes and products of our research for public access,” Westerhoff says.

The grant will also support the participation of graduate students in the Science Outside the Lab program, which educates students on how science and engineering research can help shape public policy.

Other ASU faculty members involved in the LCnano Network project are:

• Pierre Herckes, associate professor, Department of Chemistry and Biochemistry, College of Liberal Arts and Sciences
• Kiril Hristovski, assistant professor, Department of Engineering, College of Technology and Innovation
• Thomas Seager, associate professor, School of Sustainable Engineering and the Built Environment
• David Guston, professor and director, Consortium for Science, Policy and Outcomes
• Ira Bennett, assistant research professor, Consortium for Science, Policy and Outcomes
• Jameson Wetmore, associate professor, Consortium for Science, Policy and Outcomes, and School of Human Evolution and Social Change

I hope to hear more about the LCnano Network as it progresses.

Finally, there was this Nov. 12, 2013 news item on Nanowerk about instituting  voluntary safety protocols for carbon nanotubes in Japan,

Technology Research Association for Single Wall Carbon Nanotubes (TASC)—a consortium of nine companies and the National Institute of Advanced Industrial Science and Technology (AIST) — is developing voluntary safety management techniques for carbon nanotubes (CNTs) under the project (no. P10024) “Innovative carbon nanotubes composite materials project toward achieving a low-carbon society,” which is sponsored by the New Energy and Industrial Technology Development Organization (NEDO).

Lynn Bergeson’s Nov. 15, 2013 posting on nanotech.lawbc.com provides a few more details abut the TASC/AIST carbon nanotube project (Note: A link has been removed),

Japan’s National Institute of Advanced Industrial Science and Technology (AIST) announced in October 2013 a voluntary guidance document on measuring airborne carbon nanotubes (CNT) in workplaces. … The guidance summarizes the available practical methods for measuring airborne CNTs:  (1) on-line aerosol measurement; (2) off-line quantitative analysis (e.g., thermal carbon analysis); and (3) sample collection for electron microscope observation. …

You can  download two protocol documents (Guide to measuring airborne carbon nanotubes in workplaces and/or The protocols of preparation, characterization and in vitro cell based assays for safety testing of carbon nanotubes), another has been published since Nov. 2013, from the AIST’s Developing voluntary safety management techniques for carbon nanotubes (CNTs): Protocol and Guide webpage., Both documents are also available in Japanese and you can link to the Japanese language version of the site from the webpage.

New method for measuring risks and quantities of engineered nanomaterials delivered to cells

Despite all the talk about testing engineered nanoparticles and their possible effects on cells, there are problems with the testing process which researchers at the Harvard School of Public Health (HSPH) claim to have addressed (h/t Nanowerk, March 28, 2014).

A March 28, 2014 HSPH press release explains the interest in testing the effects of engineered nanomaterials/nanoparticles on health and describes some of the problems associated with testing their interaction with cells,

Thousands of consumer products containing engineered nanoparticles — microscopic particles found in everyday items from cosmetics and clothing to building materials — enter the market every year. Concerns about possible environmental health and safety issues of these nano-enabled products continue to grow with scientists struggling to come up with fast, cheap, and easy-to-use cellular screening systems to determine possible hazards of vast libraries of engineered nanomaterials. However, determining how much exposure to engineered nanoparticles could be unsafe for humans requires precise knowledge of the amount (dose) of nanomaterials interacting with cells and tissues such as lungs and skin.

With chemicals, this is easy to do but when it comes to nanoparticles suspended in physiological media, this is not trivial. Engineered nanoparticles in biological media interact with serum proteins and form larger agglomerates which alter both their so called effective density and active surface area and ultimately define their delivery to cell dose and bio-interactions. This behavior has tremendous implications not only in measuring the exact amount of nanomaterials interacting with cells and tissue but also in defining hazard rankings of various engineered nanomaterials (ENMs). As a result, thousands of published cellular screening assays are difficult to interpret and use for risk assessment purposes.

The press release goes on to describe the new technique (Note: Links have been removed),

Scientists at the Center for Nanotechnology and Nanotoxicology at Harvard School of Public Health (HSPH) have discovered a fast, simple, and inexpensive method to measure the effective density of engineered nanoparticles in physiological fluids, thereby making it possible to accurately determine the amount of nanomaterials that come into contact with cells and tissue in culture.

The method, referred to as the Volumetric Centrifugation Method (VCM), was published in the March 28, 2014 Nature Communications.

The new discovery will have a major impact on the hazard assessment of engineered nanoparticles, enabling risk assessors to perform accurate hazard rankings of nanomaterials using cellular systems. Furthermore, by measuring the composition of nanomaterial agglomerates in physiologic fluids, it will allow scientists to design more effective nano-based drug delivery systems for nanomedicine applications.

“The biggest challenge we have in assessing possible health effects associated with nano exposures is deciding when something is hazardous and when it is not, based on the dose level. At low levels, the risks are probably miniscule,” said senior author Philip Demokritou, associate professor of aerosol physics in the Department of Environmental Health at HSPH. “The question is: At what dose level does nano-exposure become problematic? The same question applies to nano-based drugs when we test their efficiency using cellular systems. How much of the administered nano-drug will come in contact with cells and tissue? This will determine the effective dose needed for a given cellular response,” Demokritou said.

Federal regulatory agencies do not require manufacturers to test engineered nanoparticles, if the original form of the bulk material has already been shown to be safe. However, there is evidence that some of these materials could be more harmful in the nanoscale — a scale at which materials may penetrate cells and bypass biological barriers more easily and exhibit unique physical, chemical, and biological properties compared to larger size particles. Nanotoxicologists are struggling to develop fast and cheap toxicological screening cellular assays to cope with the influx of vast forms of engineered nanomaterials and avoid laborious and expensive animal testing. However, this effort has been held back due to the lack of a simple-to-use, fast, method to measure the dose-response relationships and possible toxicological implications. While biological responses are fairly easy to measure, scientists are struggling to develop a fast method to assess the exact amount or dose of nanomaterials coming in contact with cells in biological media.

“Dosimetric considerations are too complicated to consider in nano-bio assessments, but too important to ignore,” Demokritou said. “Comparisons of biological responses to nano-exposures usually rely on guesstimates based on properties measured in the dry powder form (e.g., mass, surface area, and density), without taking into account particle-particle and particle-fluid interactions in biological media. When suspended in fluids, nanoparticles typically form agglomerates that include large amounts of the suspending fluid, and that therefore have effective densities much lower than that of dry material. This greatly influences the particle delivery to cells, and reduces the surface area available for interactions with cells,” said Glen DeLoid, research associate in the Department of Environmental Health, one of the two lead authors of the study. “The VCM method will help nanobiologists and regulators to resolve conflicting in vitro cellular toxicity data that have been reported in the literature for various nanomaterials. These disparities likely result from lack of or inaccurate dosimetric considerations in nano-bio interactions in a cellular screening system,” said Joel Cohen, doctoral student at HSPH and one of the two lead authors of the study.

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

Estimating the effective density of engineered nanomaterials for in vitro dosimetry by Glen DeLoid, Joel M. Cohen, Tom Darrah, Raymond Derk, Liying Rojanasakul, Georgios Pyrgiotakis, Wendel Wohlleben, & Philip Demokritou. Nature Communications 5, Article number: 3514 doi:10.1038/ncomms4514 Published 28 March 2014

This paper is behind a paywall but a free preview is available via ReadCube Access.

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,

OECD. ENVIRONMENT DIRECTORATE.
JOINT MEETING OF THE CHEMICALS COMMITTEE AND
THE WORKING PARTY ON CHEMICALS, PESTICIDES AND BIOTECHNOLOGY. Environment, Health and Safety Publications
Series on the Safety of Manufactured Nanomaterials. ENV/JM/MONO(2014)1

ECOTOXICOLOGY AND ENVIRONMENTAL FATE OF MANUFACTURED NANOMATERIALS:
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),

OECD. ENVIRONMENT DIRECTORATE JOINT MEETING OF THE CHEMICALS COMMITTEE AND
THE WORKING PARTY ON CHEMICALS, PESTICIDES AND BIOTECHNOLOGY. Environment, Health and Safety Publications. ENV/JM/MONO(2014)1/ADD

ADDENDUM TO EXOTOXICOLOGY AND ENVIRONMENTAL FATE OF MANUFACTURED
NANOMATERIALS: TEST GUIDELINES

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.

Surprising facts about silver nanoparticles from the University of Michigan

Dr. Andrew Maynard, Director of the University of Michigan’s Risk Science Center, has featured seven surprising facts about silver nanoparticles in his latest video in the Risk Bites series. Before getting to the video,here’s an introduction to the topic of silver nanoparticles from a Feb. 18, 2014 posting by Ishani Hewage on the University of Michigan’s Risk Sense blog (Note: A link has been removed),

Silver – known for its germ-killing capabilities – has been used for thousands of years. In recent times though, concerns have been raised over the potential health and environmental risks associated with one particular form of silver that has been used increasingly in a range of products: engineered silver nanoparticle. In this week’s Risk Bites, Andrew Maynard, director of the Risk Science Center, rounds-up seven aspects of silver nanoparticles that might help you weigh up their risks and benefits.

“Silver has long been used for its medicinal properties,” says Andrew. “People used to intentionally dose themselves with silver nanoparticles in the form a silver laced tonic as a cure-all.”

Nowadays, the use of silver nanoparticles is not just limited to the medical field. The military, athletes and manufactures are increasingly using them to develop smart new technologies that inhibit bacterial growth and enhance overall performance.  These microscopically small particles make it easier to get silver into products without compromising them …

Without more ado, here’s the video, ’7 surprising facts about silver nanoparticles and health’:

Both the blog posting and this link will lead you to more information about silver nanoparticles.

Nanoscale metal oxides and lung cells

Bear in mind while reading further that all of this research has not taken place in any situation resembling real life conditions: researchers at the Missouri University of Science and Technology (Missouri S&T; located in the US) have found that metal oxides at the nanoscale can be highly toxic to human lung cells according to a Jan. 28, 2014 news item on Nanowerk (Note: A link has been removed),

Nanoparticles are used in all kinds of applications — electronics, medicine, cosmetics, even environmental clean-ups. More than 2,800 commercially available applications are now based on nanoparticles, and by 2017, the field is expected to bring in nearly $50 billion worldwide.

But this influx of nanotechnology is not without risks, say researchers at Missouri University of Science and Technology.

“There is an urgent need to investigate the potential impact of nanoparticles on health and the environment,” says Yue-Wern Huang, professor of biological sciences at Missouri S&T.

Huang and his colleagues have been systematically studying the effects of transition metal oxide nanoparticles on human lung cells (“Cytotoxicity in the age of nano: The role of fourth period transition metal oxide nanoparticle physicochemical properties”). These nanoparticles are used extensively in optical and recording devices, water purification systems, cosmetics and skin care products, and targeted drug delivery, among other applications.

The Jan. 27, 2014 Missouri S&T news release by Linda Fulps, which originated the news item, describes the research in more detail,

“In their typical coarse powder form, the toxicity of these substances is not dramatic,” says Huang. “But as nanoparticles with diameters of only 16-80 nanometers, the situation changes significantly.”

The researchers exposed both healthy and cancerous human lung cells to nanoparticles composed of titanium, chromium, manganese, iron, nickel, copper and zinc compounds — transition metal oxides that are on the fourth row of the periodic table. The researchers discovered that the nanoparticles’ toxicity to the cells, or cytotoxicity, increased as they moved right on the periodic table.

“About 80 percent of the cells died in the presence of nanoparticles of copper oxide and zinc oxide,” says Huang. “These nanoparticles penetrated the cells and destroyed their membranes. The toxic effects are related to the nanoparticles’ surface electrical charge and available docking sites.”

Huang says that certain nanoparticles released metal ions — called ion dissolution — which also played a significant role in cell death.

Huang is now working on new research that may help reduce nanoparticles’ toxicity and shed light on how nanoparticles interact with cells.

“We are coating toxic zinc oxide nanoparticles with non-toxic nanoparticles to see if zinc oxide’s toxicity can be reduced,” Huang says. “We hope this can mitigate toxicity without compromising zinc oxide’s intended applications. We’re also investigating whether nanoparticles inhibit cell division and influence cell cycle.”

Concerning results? Yes. But, before determining how alarmed you should be, there are a few questions you might want to ask while reading the news release and/or the research paper :

  1. How were these cells exposed to the metal nanoparticles? ‘Breathing’ or were they sitting in a solution?
  2. What was the concentration of metal nanoparticles? (even good things can be bad for you at high concentrations)

This isn’t an attempt to dismiss the findings but rather to point out how much painstaking research has to take place before conclusions of any kind can be drawn. It’s why scientists tend to quite careful in their comments.

In looking at this work, I was reminded of the research into ‘nanosunscreens’ and concerns about the metal oxide nanoparticles (zinc oxides and/or titanium dioxide) penetrating the skin barrier and building up to toxic levels in the body.  In an Oct. 4, 2012 posting about zinc oxide nanoparticles and penetrating the skin barrier, I mentioned this in the context of some then recent research at Bath University (UK),

I missed the fact that this study was an in vitro test, which is always less convincing than in vivo testing. In my Nov. 29, 2011 posting about some research into nano zinc oxide I mentioned in vitro vs. in vivo testing and Brian Gulson’s research,

I was able to access the study and while I’m not an expert by any means I did note that the study was ‘in vitro’, in this case, the cells were on slides when they were being studied. It’s impossible to draw hard and fast conclusions about what will happen in a body (human or otherwise) since there are other systems at work which are not present on a slide.

… here’s what Brian Gulson had to say about nano zinc oxide concentrations in his work and about a shortcoming in his study (from an Australian Broadcasting Corporation [ABC] Feb. 25, 2010 interview with Ashley Hall,

BRIAN GULSON: I guess the critical thing was that we didn’t find large amounts of it getting through the skin. The sunscreens contain 18 to 20 per cent zinc oxide usually and ours was about 20 per zinc. So that’s an awful lot of zinc you’re putting on the skin but we found tiny amounts in the blood of that tracer that we used.

ASHLEY HALL: So is it a significant amount?

BRIAN GULSON: No, no it’s really not.

ASHLEY HALL: But Brian Gulson is warning people who use a lot of sunscreen over an extended period that they could be at risk of having elevated levels of zinc.

BRIAN GULSON: Maybe with young children where you’re applying it seven days a week, it could be an issue but I’m more than happy to continue applying it to my grandchildren.

ASHLEY HALL: This study doesn’t shed any light on the question of whether the nano-particles themselves played a part in the zinc absorption.

BRIAN GULSON: That was the most critical thing. This isotope technique cannot tell whether or not it’s a zinc oxide nano-particle that got through skin or whether it’s just zinc that was dissolved up in contact with the skin and then forms zinc ions or so-called soluble ions. So that’s one major deficiency of our study.

Of course, I have a question about Gulson’s conclusion  that very little of the nano zinc oxide was penetrating the skin based on blood and urine samples taken over the course of the study. Is it possible that after penetrating the skin it was stored in the cells  instead of being eliminated?

Here’s a link to and a citation for Yue-Wern Huang and his team’s latest research,

Cytotoxicity in the age of nano: The role of fourth period transition metal oxide nanoparticle physicochemical properties by Charles C. Chusuei, Chi-Heng Wu, Shravan Mallavarapu, Fang Yao Stephen Hou, Chen-Ming Hsu, Jeffrey G. Winiarz, Robert S. Aronstam, Yue-Wern Huang. Chemico-Biological Interactions, Volume 206, Issue 2, 25 November 2013, Pages 319–326.

This paper is behind a paywall.

Few nanoparticles shed in nanopaint tests

Empa, Swiss Federal Laboratories for Materials Science and Technology, led a 3.5 year project, NanoHouse, investigating whether or not nanoparticles added to paint used on building facades might prove a health hazard. From a Jan. 13, 2014 news item on Nanowerk (Note: A link has been removed),

 After 42 months the EU research project “NanoHouse” has ended, and the verdict is a cautious “all clear” – nanoparticles in the paint used on building façades do not represent a particular health risk. In the course of a “Technology Briefing” Empa researchers discussed these results with specialists from the construction industry.

Five Empa laboratories were involved in the EU NanoHouse project, along with four other European research institutes and four industrial partners. The aim of the project was to investigate the opportunities and risks presented by the nanomaterials used in the surface coatings applied to building façades. For the first time not only were freshly manufactured products studied to see if they set free nanoparticles, but also aged samples.

The January 13, 2014 Empa press release, which originated the news item, provides more details about the recent  NanoHouse technology briefing,

… Claudia Som briefly introduced the «NanoHouse» project, for which she acted as Empa coordinator. This project, which is financially supported through the EU’s 7th Research Framework Program, began in 2010 with the aim of investigating possible health effects caused by nanoparticles in building materials and houses. Various aspects of the research program included rubbing tests on model façades, attempts to wash out nanoparticles from surface coatings and an analysis of the biological effects on humans and the environment.

Tina Kuenniger, an Empa expert on the protection of wood surfaces against weathering, explained how nanoparticles work in paint. Some paints containing silicon dioxide are water repellent, easy to clean and scratch resistant. Nano titanium-dioxide has photocatalytic properties and can decompose air pollutants. Nano titanium-dioxide, along with nano zinc-oxide and nano-iron oxide, can be used to provide UV protection and, depending on the size of the particles used, also to protect against infrared radiation, i.e. heat. Similarly, nanoparticles can protect against attack by blue stain fungus and algae. Whilst many laboratory studies have confirmed the effectiveness of nanoparticles, in practice one question remains open: how much of the nanomaterial does one have to mix with the paint to ensure that it functions as expected? For this reason only a few products for external façades containing nano-materials are available on the market to date. The greatest opportunity nanoparticles offer lies in the combination of various functional properties, for example scratch resistance and easy (or self) cleaning characteristics.

The results of the tests surprised researchers from Empa and other consortium members (from the press release),

Bernd Nowack, head of Empa’s Environmental Risk Assessment and Management group, then presented the results of the investigations into how much nanomaterial is set free from façades. The release rate is generally very low – only 1 to 2% of the nanoparticles find their way into the environment. And in most cases they are released not as nanoparticles but bound to large paint particles, which significantly reduces their nano-scale effects. “We were very surprised at how few nanoparticles were actually set free”, Nowack admitted. The researchers had expected that the catalytically active nanoparticles would also attack the paint surrounding them, leading to more frequent release.

Jean–Pierre Kaiser showed by means of his toxicological studies that paints containing nanoparticles have the same effect on the behaviour of cells from the gastrointestinal tract and immune system as do similar paints which do not contain nanoparticles. The Empa researcher does not therefore expect that these nanoparticle-containing paints will represent a new, acute health risk. However, the investigations did at the same time show that nanoparticles are absorbed by the cells. Whether this accumulation of nanoparticles in the cells might lead to longer-term effects cannot yet be definitively determined.

Empa environmental scientist Roland Hischier made a plea for a reasonable balance in the assessment of the possible environmental damage. For a house with an assumed lifetime of eighty years, painting the façade with nanomaterial based paint would be more economic if this lasted for 30% longer than conventional coatings. Then, over the lifetime of the house, one would have to repaint the façade one time fewer, avoiding all the environmental effects caused by manufacturing the paint and disposing of the leftover material.

This theory remains somewhat controversial however –houses are frequently repainted for aesthetic reasons and not because a new coating is strictly necessary. In this case the advantage offered by the longer lifetime of nanoparticle-based coatings becomes completely irrelevant.

The researchers performed an industry survey revealing what professional paint companies believe to be true about nanoparticles in paint (from the press release),

… Ingrid Hincapie, a risk researcher on the Empa staff, reported on the results of her industrial survey. Many companies expected paint containing nanoparticles to have a longer lifetime than conventional paint. Some expected it to be easy to handle, for example because it dries faster. But exactly how one correctly disposes of leftover paint containing nanoparticles is something that only a handful of respondents knew.

Peter Seehafer of the Painter’s and Plasterer’s Association, gave the view from the sharp end, where quite simply the customer is king, and sometimes demands the latest in paint technology. On the other hand, about half of all painters are female, so protection from possibly unhealthy chemicals is therefore particularly important. “Our professional association needs more information, so that we can take up a clear position with respect to our customers and our employees”, demanded Seehafer.

Finally, André Hauser of the Swiss Federal Office of the Environment explained the current regulations covering the disposal of waste material containing nanoparticles. On its website www.bafu.admin.ch/abfall/01472/12850 the SFOE offers tips on how to dispose of such material properly. The current regulations relating to safe working practices with nanomaterials were explained by Kaspar Schmid of the Swiss government’s State Secretariat for Economic Affairs (SECO). The essential point here is that the manufacturer of the material must provide a Material Safety Data Sheet, as is the case with other chemicals.

In addition to the NanoHouse link given earlier, there is this Empa NanoHouse webpage which provides more information about the work including the survey of nanopaint producers from the project’s Survey webpage,

A survey of industrial producers of nanoparticles and paints showed that the most mentioned potential benefits of nano-enhanced façade coatings are: water and dirt repellent “easy to clean”, followed by UV-protection, antimicrobial resistance and protection from mechanical wear (i.e. scratch resistance). The ENP [engineered nanopartilces], which are the most used in Europe to improve the different functionalities of the façade coatings were: Ag [silver], functionalised silanes, TiO2  [titanium dioxide] and SiO2.[silicon dioxide]

The quality of a nano-paint compared to a traditional paint could be gradually (25% of responses) and noticeably (25%) improved, but 50% of the respondents reported no functionality improvement. The companies gave relevance on studies from the specialised press (90%), on participating in dialogue events (80%) (e.g. with authorities or taking part in projects such as NanoHouse), on getting expert opinions (70%) and on toxicology test (20%).

The overall impression from the survey was that improvement of the environmental performance seems not yet to be in the focus of innovation of ENP in façade coatings.

It’s a bit disappointing that the environmental performance of nanocoatings does not, according to this project’s findings, does not live up to the promises made by the various purveyors of nanotechnology-enabled paint.

 

Czech veterinary research institute tracks nanoparticles

When I first saw the Jan. 7, 2014 news item on Azonano, I was expecting to see some cute animal images mixed with the ‘nano’ talk. While there’s no mild amusement to be had, there is plenty of ‘nano’ talk concerning the work being done at the Veterinary Research Institute (Brno,  Czech republic) on characterizing nanoparticles using some new equipment (Note: Links have been removed),

Malvern [which owns the company, NanoSight] reports on how NanoSight’s Nanoparticle Tracking Analysis, NTA, is being applied in the Veterinary Research Institute, Brno, Czech Republic in the research group of Dr. Jaroslav Turanek in the Department of Pharmacology and Immunotherapy).

The central theme of Dr. Jaroslav Turanek’s research group (Department of Pharmacology and Immunotherapy) at the Veterinary Research Institute in Brno is to apply synthetic and bioorganic chemistry. This work is performed in collaboration with King’s College London and the Institute of Organic Chemistry and Biochemistry, Prague, for the design and construction of therapeutic nanoparticles to develop drug delivery systems (anticancer and antiviral drugs) and nanocarriers for construction of recombinant vaccines.

In parallel, the research group of Dr. Miroslav Machala (Department of Chemistry and Toxicology) at Veterinary Research Institute focuses upon environmental nanoparticulate pollutants. Characterization of airborne particles is conducted using electron microscopy, but in vitro tests on cell culture require knowledge of the real structure of nanoparticles in the tissue culture medium (e.g. aggregation). This enables the group to draw the correct conclusions from in vitro toxicological experiments which can be affected by differences in local nanoparticle concentration owing to sedimentation. Detailed particle distribution and kinetics of aggregation in this heterogeneous system is impossible to obtain using electron microscopy and hence Nanoparticle Tracking Analysis, NTA, is the method of choice. It is noted that some metastable aggregates can disaggregate due to high dilution of the sample required for NTA analysis. For this reason, Dynamic Light Scattering, DLS, and NTA are used as suitable complementary methods in the laboratory.

The Jan. 7, 2014 Malvern Instruments press release on biospace.com, which originated the news item, provides a quote from Dr. Jaroslav Turanek’ describing the NTA system,

Explaining their choice of NanoSight, Dr Turanek said “We chose NTA as a convenient and rapid method for characterization of nanoparticles in heterogeneous preparations like liposomes and their complexes with proteins, DNA and polysaccharides. A set of these techniques is used for the complex characterization of the structure of the nanoparticles, the kinetics of their preparation, the dynamics of morphological transformation and, finally, their stability. NTA perfectly fits our needs and has become a standard method in our methodological portfolio. The most advantageous feature of NTA is that it makes it possible to visualize each nanoparticle and then to obtain more detailed size distributions based on individual particle measurements. DLS is used as precise complementary method for the characterization of nanoparticles below 20 nm for proteins and other biopolymers. Combination of these two methods, NTA and DLS, with separation methods (GPC, FFF) and electron microscopy is preferred to get the full insight to structure and dynamics of nanoparticles in our sample systems.”

It took me quite a while to realize that nanoparticles in a sample are not necessarily homogenous, i.e., similar in size, etc. Unconsciously, I had applied my notions of manufacturing where items are made (stamped, poured into moulds, etc.)  to be identical. As far as I’m aware there is no such production process for nanoparticles which makes characterizing them an important task if the purpose is to better understand their properties.

You can find out more about Malvern Instruments here and about NanoSight here.

Crypton and NANO-TEX together at last

A Jan. 6, 2014 news item on Nanowerk notes that Crypton Fabrics has purchased NANO-TEX,

CRYPTON INC. has acquired NANO-TEX®, announced Randy Rubin, Chairman of The Crypton Companies. The privately held, 20-year-old Crypton Fabrics, based in Bloomfield Hills, Michigan, recently purchased NANO-TEX from private equity and venture capital investors; WL Ross and Co. LLC as major stockholders, in addition to Norwest Venture Partners, Masters Capital Nanotechnology Fund, Firelake Capital Management and Masters Capital Management.

NANO-TEX is a textile technology company whose performance finishes have enhanced leading consumer brands such as GAP, TARGET, MAIDENFORM, BASS PRO SHOPS, NORDSTROM, LAND’S END, FISHER-PRICE and many more.

The Jan. 6, 2014 Crypton (there has to be a Superman or inert gas enthusiast in that company) press release, which can be found on this page under this title: Silicon Valley to Motown, Performance Textile Leader Crypton Purchases Nano-Tex, explains why the NANO-TEX acquisition was so attractive and what it means to NANO-TEX’s major stockholders,

NANO‐TEX employs a proprietary nanotechnology approach to enhance textiles at the molecular level that provides permanent performance attributes such as stain and water resistance, moisture wicking, odor control, static elimination and wrinkle free properties. The end result is performance fabrics that maintain the original comfort, look and feel of the fabric and perform for the life of the product.

In 2013, NANO‐TEX technologies were on $280 million in branded finished products at retail worldwide.

Wilbur Ross, Jr., Chairman of WL Ross said, “We are extremely pleased by Crypton’s acquisition. This assures that NANO‐TEX will continue on a strong growth trajectory. Its expanding market reach and prominence will further enhance the competitiveness of WL Ross’s companies in the consumer and industrial fabrics industries, too; the goal that sparked our initial investment interest in NANO‐TEX eight years ago.”

It seems there was a specific product which attracted the Crypton team’s attention,

“This is a strategic acquisition as we extend our market share with apparel throughout the world. The intellectual properties and latest development, Aquapel®, a non‐fluorinated repellency treatment, is very exciting to our research team,” said Rubin.

There’s more about this product on the NANO-TEX Aquapel® page.

On a completely other note, at least one NANO-TEX product has silver in it according to a 2007 entry on the Consumer Products Inventory (Project on Emerging Nanotechnologies),

They Say:

“Nano-Tex™’s revolutionary technology fundamentally transforms fabric at the nano-level to dramatically improve your favorite everyday clothing.”

Nanomaterials:

Silver

Potential Exposure Pathways:

Dermal

How much we know:

Category 4 (Unsupported claim)

Additional Information:

Generic Product

Crypton too has silver in at least one product (from the INCASE Fabric Protection FAQs),

Q:  How does INCASE™ resist bacterial growth?
A: Silver Ion technology is used in INCASE to inhibit the growth of a broad spectrum of medically relevant microorganisms, including bacteria. Silver is one of nature’s original antimicrobials. Used thousands of years ago by Greeks in vessels to preserve water and wine, the natural benefits of silver have now been tapped to keep fabrics odor-free.

Cyrpton’s INCASE product uses sliver ions, which according to some research at Rice University (based in Texas, US), are more toxic than silver nanoparticles, from my July 13, 2012 posting,

He [Pedro Alvarez, George R. Brown Professor and chair of Rice’s Civil and Environmental Engineering Department] said the finding should shift the debate over the size, shape and coating of silver nanoparticles. [emphasis mine] “Of course they matter,” Alvarez said, “but only indirectly, as far as these variables affect the dissolution rate of the ions. The key determinant of toxicity is the silver ions. So the focus should be on mass-transfer processes and controlled-release mechanisms.”

Crypton’s About page strongly suggests an environmentally friendly and health conscious company (Note: Links have been removed),

Innovation. Industry leadership. A deep commitment to product excellence. These core elements are at the heart of the Crypton DNA – a labor of love that began in 1993 when founders Craig and Randy Rubin set out to create a new generation of stylish fabrics that were moisture-resistant and easy-to-clean, yet soft, comfortable and breathable.

From the basement of their Michigan home, a textile revolution was born.

Now based in West Bloomfield Michigan, with a green manufacturing facility in Kings Mountain, North Carolina, Crypton is the only textile solution in the world offering complete stain, moisture, mildew, bacteria and odor-resistant protection thanks to a patented process developed by some of the leading minds in the textile industry.

Early on, by offering a fabric – not a vinyl or plastic – that was capable of resisting stains, moisture, odors and bacteria, Crypton proved to be the perfect solution for the health care market. Following this initial success, Crypton solutions rapidly expanded into some of the finest restaurants, hotels, cruise ships around the world, as well as government complexes, schools and health care facilities.

Now trusted and relied on by over 90% of contract designers, there are more than 20,000 patterns of Crypton fabric available today. Crypton is the only fabric deemed a non-porous surface and can be disinfected when used in conjunction with our U.S. EPA-approved Crypton Disinfectant & Deodorizer.

From fabric, carpet, leather, wall and mattress to pet beds, home accessories, bags and luggage – our mission is to give customers more ways to live healthy, live beautifully and Live Clean®.

While there is no incontrovertible proof that silver nanoparticles and/or silver ions are a serious threat to the environment, it would be nice to see companies acknowledge some of the concerns.