Tag Archives: engineered nanomaterials

Better hair dyes with graphene and a cautionary note

Leave a reply

Beauty products aren’t usually the first applications that come to mind when discussing graphene or any other research and development (R&D) as I learned when teaching a course a few years ago. But research and development  in that field are imperative as every company is scrambling for a short-lived competitive advantage for a truly new products or a perceived competitive advantage in a field where a lot of products are pretty much the same.

This March 15, 2018 news item on ScienceDaily describes graphene as a potential hair dye,

Graphene, a naturally black material, could provide a new strategy for dyeing hair in difficult-to-create dark shades. And because it’s a conductive material, hair dyed with graphene might also be less prone to staticky flyaways. Now, researchers have put it to the test. In an article published March 15 [2018] in the journal Chem, they used sheets of graphene to make a dye that adheres to the surface of hair, forming a coating that is resistant to at least 30 washes without the need for chemicals that open up and damage the hair cuticle.

Courtesy: Northwestern University

A March 15, 2018 Cell Press news release on EurekAlert, which originated the news item, fills in more the of the story,

Most permanent hair dyes used today are harmful to hair. “Your hair is covered in these cuticle scales like the scales of a fish, and people have to use ammonia or organic amines to lift the scales and allow dye molecules to get inside a lot quicker,” says senior author Jiaxing Huang, a materials scientist at Northwestern University. But lifting the cuticle makes the strands of the hair more brittle, and the damage is only exacerbated by the hydrogen peroxide that is used to trigger the reaction that synthesizes the dye once the pigment molecules are inside the hair.

These problems could theoretically be solved by a dye that coats rather than penetrates the hair. “However, the obvious problem of coating-based dyes is that they tend to wash out very easily,” says Huang. But when he and his team coated samples of human hair with a solution of graphene sheets, they were able to turn platinum blond hair black and keep it that way for at least 30 washes–the number necessary for a hair dye to be considered “permanent.”

This effectiveness has to do with the structure of graphene: it’s made of up thin, flexible sheets that can adapt to uneven surfaces. “Imagine a piece of paper. A business card is very rigid and doesn’t flex by itself. But if you take a much bigger sheet of newspaper–if you still can find one nowadays–it can bend easily. This makes graphene sheets a good coating material,” he says. And once the coating is formed, the graphene sheets are particularly good at keeping out water during washes, which keeps the water from eroding both the graphene and the polymer binder that the team also added to the dye solution to help with adhesion.

The graphene dye has additional advantages. Each coated hair is like a little wire in that it is able to conduct heat and electricity. This means that it’s easy for graphene-dyed hair to dissipate static electricity, eliminating the problem of flyaways on dry winter days. The graphene flakes are large enough that they won’t absorb through the skin like other dye molecules. And although graphene is typically black, its precursor, graphene oxide, is light brown. But the color of graphene oxide can be gradually darkened with heat or chemical reactions, meaning that this dye could be used for a variety of shades or even for an ombre effect.

What Huang thinks is particularly striking about this application of graphene is that it takes advantage of graphene’s most obvious property. “In many potential graphene applications, the black color of graphene is somewhat undesirable and something of a sore point,” he says. Here, though, it’s applied to a field where creating dark colors has historically been a problem.

The graphene used for hair dye also doesn’t need to be of the same high quality as it does for other applications. “For hair dye, the most important property is graphene being black. You can have graphene that is too lousy for higher-end electronic applications, but it’s perfectly okay for this. So I think this application can leverage the current graphene product as is, and that’s why I think that this could happen a lot sooner than many of the other proposed applications,” he says.

Making it happen is his next goal. He hopes to get funding to continue the research and make these dyes a reality for the people whose lives they would improve. “This is an idea that was inspired by curiosity. It was very fun to do, but it didn’t sound very big and noble when we started working on it,” he says. “But after we deep-dived into studying hair dyes, we realized that, wow, this is actually not at all a small problem. And it’s one that graphene could really help to solve.”

Northwestern University’s Amanda Morris also wrote a March 15, 2018 news release (it’s repetitive but there are some interesting new details; Note: Links have been removed),

It’s an issue that has plagued the beauty industry for more than a century: Dying hair too often can irreparably damage your silky strands.

Now a Northwestern University team has used materials science to solve this age-old problem. The team has leveraged super material graphene to develop a new hair dye that is less harmful [emphasis mine], non-damaging and lasts through many washes without fading. Graphene’s conductive nature also opens up new opportunities for hair, such as turning it into in situ electrodes or integrating it with wearable electronic devices.

…

Dying hair might seem simple and ordinary, but it’s actually a sophisticated chemical process. Called the cuticle, the outermost layer of a hair is made of cells that overlap in a scale-like pattern. Commercial dyes work by using harsh chemicals, such as ammonia and bleach, to first pry open the cuticle scales to allow colorant molecules inside and then trigger a reaction inside the hair to produce more color. Not only does this process cause hair to become more fragile, some of the small molecules are also quite toxic.

Huang and his team bypassed harmful chemicals altogether by leveraging the natural geometry of graphene sheets. While current hair dyes use a cocktail of small molecules that work by chemically altering the hair, graphene sheets are soft and flexible, so they wrap around each hair for an even coat. Huang’s ink formula also incorporates edible, non-toxic polymer binders to ensure that the graphene sticks — and lasts through at least 30 washes, which is the commercial requirement for permanent hair dye. An added bonus: graphene is anti-static, so it keeps winter-weather flyaways to a minimum.

“It’s similar to the difference between a wet paper towel and a tennis ball,” Huang explained, comparing the geometry of graphene to that of other black pigment particles, such as carbon black or iron oxide, which can only be used in temporary hair dyes. “The paper towel is going to wrap and stick much better. The ball-like particles are much more easily removed with shampoo.”

This geometry also contributes to why graphene is a safer alternative. Whereas small molecules can easily be inhaled or pass through the skin barrier, graphene is too big to enter the body. “Compared to those small molecules used in current hair dyes, graphene flakes are humongous,” said Huang, who is a member of Northwestern’s International Institute of Nanotechnology.

Ever since graphene — the two-dimensional network of carbon atoms — burst onto the science scene in 2004, the possibilities for the promising material have seemed nearly endless. With its ultra-strong and lightweight structure, graphene has potential for many applications in high-performance electronics, high-strength materials and energy devices. But development of those applications often require graphene materials to be as structurally perfect as possible in order to achieve extraordinary electrical, mechanical or thermal properties.

The most important graphene property for Huang’s hair dye, however, is simply its color: black. So Huang’s team used graphene oxide, an imperfect version of graphene that is a cheaper, more available oxidized derivative.

“Our hair dye solves a real-world problem without relying on very high-quality graphene, which is not easy to make,” Huang said. “Obviously more work needs to be done, but I feel optimistic about this application.”

Still, future versions of the dye could someday potentially leverage graphene’s notable properties, including its highly conductive nature.

“People could apply this dye to make hair conductive on the surface,” Huang said. “It could then be integrated with wearable electronics or become a conductive probe. We are only limited by our imagination.”

So far, Huang has developed graphene-based hair dyes in multiple shades of brown and black. Next, he plans to experiment with more colors.

Interestingly, the tiny note of caution”less harmful” doesn’t appear in the Cell Press news release. Never fear, Dr. Andrew Maynard (Director Risk Innovation Lab at Arizona State University) has written a March 20, 2018 essay on The Conversation suggesting a little further investigation (Note: Links have been removed),

Northwestern University’s press release proudly announced, “Graphene finds new application as nontoxic, anti-static hair dye.” The announcement spawned headlines like “Enough with the toxic hair dyes. We could use graphene instead,” and “’Miracle material’ graphene used to create the ultimate hair dye.”

From these headlines, you might be forgiven for getting the idea that the safety of graphene-based hair dyes is a done deal. Yet having studied the potential health and environmental impacts of engineered nanomaterials for more years than I care to remember, I find such overly optimistic pronouncements worrying – especially when they’re not backed up by clear evidence.

Tiny materials, potentially bigger problems

Engineered nanomaterials like graphene and graphene oxide (the particular form used in the dye experiments) aren’t necessarily harmful. But nanomaterials can behave in unusual ways that depend on particle size, shape, chemistry and application. Because of this, researchers have long been cautious about giving them a clean bill of health without first testing them extensively. And while a large body of research to date doesn’t indicate graphene is particularly dangerous, neither does it suggest it’s completely safe.

A quick search of scientific papers over the past few years shows that, since 2004, over 2,000 studies have been published that mention graphene toxicity; nearly 500 were published in 2017 alone.

This growing body of research suggests that if graphene gets into your body or the environment in sufficient quantities, it could cause harm. A 2016 review, for instance, indicated that graphene oxide particles could result in lung damage at high doses (equivalent to around 0.7 grams of inhaled material). Another review published in 2017 suggested that these materials could affect the biology of some plants and algae, as well as invertebrates and vertebrates toward the lower end of the ecological pyramid. The authors of the 2017 study concluded that research “unequivocally confirms that graphene in any of its numerous forms and derivatives must be approached as a potentially hazardous material.”

These studies need to be approached with care, as the precise risks of graphene exposure will depend on how the material is used, how exposure occurs and how much of it is encountered. Yet there’s sufficient evidence to suggest that this substance should be used with caution – especially where there’s a high chance of exposure or that it could be released into the environment.

Unfortunately, graphene-based hair dyes tick both of these boxes. Used in this way, the substance is potentially inhalable (especially with spray-on products) and ingestible through careless use. It’s also almost guaranteed that excess graphene-containing dye will wash down the drain and into the environment.

…

Undermining other efforts?

I was alerted to just how counterproductive such headlines can be by my colleague Tim Harper, founder of G2O Water Technologies – a company that uses graphene oxide-coated membranes to treat wastewater. Like many companies in this area, G2O has been working to use graphene responsibly by minimizing the amount of graphene that ends up released to the environment.

Yet as Tim pointed out to me, if people are led to believe “that bunging a few grams of graphene down the drain every time you dye your hair is OK, this invalidates all the work we are doing making sure the few nanograms of graphene on our membranes stay put.” Many companies that use nanomaterials are trying to do the right thing, but it’s hard to justify the time and expense of being responsible when someone else’s more cavalier actions undercut your efforts.

…

Overpromising results and overlooking risk

This is where researchers and their institutions need to move beyond an “economy of promises” that spurs on hyperbole and discourages caution, and think more critically about how their statements may ultimately undermine responsible and beneficial development of a technology. They may even want to consider using guidelines, such as the Principles for Responsible Innovation developed by the organization Society Inside, for instance, to guide what they do and say.

…

If you have time, I encourage you to read Andrew’s piece in its entirety.

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

Multifunctional Graphene Hair Dye by Chong Luo, Lingye Zhou, Kevin Chiou, and Jiaxing Huang. Chem DOI: https://doi.org/10.1016/j.chempr.2018.02.02 Publication stage: In Press Corrected Proof

This paper appears to be open access.

*Two paragraphs (repetitions) were deleted from the excerpt of Dr. Andrew Maynard’s essay on August 14, 2018

US National Institute of Occupational Health and Safety (NIOSH) released four new documents for handling nanomaterials

Leave a reply

A March 12, 2018 news item on Nanowerk announced the latest from the US National Institute of Occupational Health and Safety (NIOSH) on the safe handling of nanomaterials in the workplace,

Realizing the promise of any scientific advancement requires understanding of its potential human health effects, and its safe and responsible development, even at the level of engineered nanomaterials, which can be nearly atomic-sized. The National Institute for Occupational Safety and Health (NIOSH) launched four new products this week intended to provide options to companies for controlling possible exposure of their workers to nanomaterials on the job.

A March 12, 2018 NIOSH news release, which originated the news item, fills in some details,

Engineered nanomaterials are intentionally produced to have at least one primary dimension less than 100 nanometers (nm). These very small particles have unique shapes and physical and chemical properties. These materials become desirable for specific product applications in areas including medicine, electronics, biomaterials, and consumer products. Workers in industries that use or make these uniquely engineered nanomaterials may inhale nanoparticles on a daily basis, posing a potential respiratory hazard.

“Researching, developing, and utilizing these nano properties is at the heart of new technology, just as worker safety is at the heart of what we do at NIOSH,” said NIOSH Director John Howard, M.D. “The information contained in these new workplace design solution documents provide employers with strategic steps towards making sure their employees stay safe while handling nanomaterials.”

The four new documents provide helpful recommendations on minimizing exposures during common processes and tasks, including:

Each workplace design solutions document provides key tips on the design, use, and maintenance of exposure controls for nanomaterial production, post processing, and use. The poster poses questions that employers and workers should consider before starting work with a nanomaterial. For each question, the poster provides options to reduce exposures to nanomaterials based on the physical form. The poster can be displayed in a lab or work environment, making it an easily accessible reminder of the important health and safety considerations for working with nanomaterials.

To access the products, and for more information about nanotechnology research at NIOSH, please visit https://www.cdc.gov/niosh/topics/nanotech/pubs.html

NIOSH is the federal institute that conducts research and makes recommendations for preventing work-related injuries and illnesses. More information about NIOSH can be found at www.cdc.gov/niosh.

That’s all folks!

Nanosunscreen in swimming pools

Leave a reply

Thanks to Lynn L. Bergeson’s Sept. 21, 2016 posting for information about the US Environmental Protection Agency’s (EPA) research into what happens to the nanoparticles when your nanosunscreen washes off into a swimming pool. Bergeson’s post points to an Aug. 15, 2016 EPA blog posting by Susanna Blair,

… It’s not surprising that sunscreens are detected in pool water (after all, some is bound to wash off when we take a dip), but certain sunscreens have also been widely detected in our ecosystems and in our wastewater. So how is our sunscreen ending up in our environment and what are the impacts?

Well, EPA researchers are working to better understand this issue, specifically investigating sunscreens that contain engineered nanomaterials and how they might change when exposed to the chemicals in pool water [open access paper but you need to register for free] … But before I delve into that, let’s talk a bit about sunscreen chemistry and nanomaterials….

Blair goes on to provide a good brief description of  nanosunscreens before moving onto her main topic,

Many sunscreens contain titanium dioxide (TiO2) because it absorbs UV radiation, preventing it from damaging our skin. But titanium dioxide decomposes into other molecules when in the presence of water and UV radiation. This is important because one of the new molecules produced is called a singlet oxygen reactive oxygen species. These reactive oxygen species have been shown to cause extensive cell damage and even cell death in plants and animals. To shield skin from reactive oxygen species, titanium dioxide engineered nanomaterials are often coated with other materials such as aluminum hydroxide (Al(OH)3).

EPA researchers are testing to see whether swimming pool water degrades the aluminum hydroxide coating, and if the extent of this degradation is enough to allow the production of potentially harmful reactive oxygen species. In this study, the coated titanium dioxide engineered nanomaterials were exposed to pool water for time intervals ranging from 45 minutes to 14 days, followed by imaging using an electron microscope.  Results show that after 3 days, pool water caused the aluminum hydroxide coating to degrade, which can reduce the coating’s protective properties and increase the potential toxicity.  To be clear, even with degraded coating, the toxicity measured from the coated titanium dioxide, was significantly less [emphasis mine] than the uncoated material. So in the short-term – in the amount of time one might wear sunscreen before bathing and washing it off — these sunscreens still provide life-saving protection against UV radiation. However, the sunscreen chemicals will remain in the environment considerably longer, and continue to degrade as they are exposed to other things.

…

Blair finishes by explaining that research is continuing as the EPA researches the whole life cycle of engineered nanomaterials.

Removing titanium dioxide nanoparticles from water may not be that easy

Leave a reply

A March 10, 2015 news item on Nanowerk highlights some research into the removal of nanoscale titanium dioxide particles from water supplies (Note: A link has been removed),

The increased use of engineered nanoparticles (ENMs) in commercial and industrial applications is raising concern over the environmental and health effects of nanoparticles released into the water supply. A timely study that analyzes the ability of typical water pretreatment methods to remove titanium dioxide, the most commonly used ENM, is published in Environmental Engineering Science (“Titanium Dioxide Nanoparticle Removal in Primary Prefiltration Stages of Water Treatment: Role of Coating, Natural Organic Matter, Source Water, and Solution Chemistry”). The article is available free on the Environmental Engineering Science website until April 10, 2015.

A March 10, 2015 Mary Ann Liebert, Inc., publishers news release (also on EurekAlert), which originated the news item, provides more details about the work (Note: A link has been removed),

Nichola Kinsinger, Ryan Honda, Valerie Keene, and Sharon Walker, University of California, Riverside, suggest that current methods of water prefiltration treatment cannot adequately remove titanium dioxide ENMs. They describe the results of scaled-down tests to evaluate the effectiveness of three traditional methods—coagulation, flocculation, and sedimentation—in the article “Titanium Dioxide Nanoparticle Removal in Primary Prefiltration Stages of Water Treatment: Role of Coating, Natural Organic Matter, Source Water, and Solution Chemistry.”

“As nanoscience and engineering allow us to develop new exciting products, we must be ever mindful of associated consequences of these advances,” says Domenico Grasso, PhD, PE, DEE, Editor-in-Chief of Environmental Engineering Science and Provost, University of Delaware. “Professor Walker and her team have presented an excellent report raising concerns that some engineered nanomaterials may find their ways into our water supplies.”

“While further optimization of such treatment processes may allow for improved removal efficiencies, this study illustrates the challenges that we must be prepared to face with the emergence of new engineered nanomaterials,” says Sharon Walker, PhD, Professor of Chemical and Environmental Engineering, University of California, Riverside.

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

Titanium Dioxide Nanoparticle Removal in Primary Prefiltration Stages of Water Treatment: Role of Coating, Natural Organic Matter, Source Water, and Solution Chemistry by Nichola Kinsinger, Ryan Honda, Valerie Keene, and Sharon L. Walker. Environmental Engineering Science. doi:10.1089/ees.2014.0288.

This paper is freely available until April 10, 2015.

Interestingly Sharon Walker and Nichola Kinsinger recently co-authored a paper (mentioned in my March 9, 2015 post) about copper nanoparticles and water treatment which concluded this about copper nanoparticles in water supplies,

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.

Taking these these two paper into account (and the many others I’ve read), there is no simple or universal answer to the question of whether or not ENPs or ENMs are going to pose environmental problems.

Deadline extension (travel grants and poster abstracts) for alternate testing strategies (ATS) of nanomaterials workshop

Leave a reply

It seems there have been a couple of deadline extensions (to August 1, 2014) for the September 15-16, 2014 ‘Workshop to Explore How a Multiple Models Approach can Advance Risk Analysis of Nanoscale Materials’ in Washington, DC (first mentioned in my July 10, 2014 posting featuring a description of the workshop). You can go here to submit a poster abstract (from any country) and you can go here if you’re a student or young professional (from any country) in search of a $500 travel award.

I managed to speak to one of the organizers, Lorraine Sheremeta, (Assistant Director, Ingenuity Lab, University of Alberta and co-author a July 9, 2014 Nanowerk Spotlight article about the workshop). Lorraine (Lori) kindly spoke to me about the upcoming workshop, which she described as an academic conference,.

As I understand what she told me, the hosts for the September 15-16, 2014 Workshop to Explore How a Multiple Models Approach can Advance Risk Analysis of Nanoscale Materials in Washington, DC want to attract a multidisciplinary group of people to grapple with a few questions. First, they want to establish a framework for establishing which are the best test methods for nanomaterials. Second, they are trying to move away from animal testing and want to establish which methods are equal to or better than animal testing. Thirdly, they want to discuss what they are going to do with the toxicological data  that we have  been collecting on nanomaterials for years now.

Or, as she and her colleague from the Society of Risk Analysis (Jo Anne Shatkin) have put in it in their Nanowerk Spotlight article:

… develop a report on the State of the Science for ATS for nanomaterials, catalogue of existing and emerging ATS [alternate testing strategies] methods in a database; and develop a case study to inform workshop deliberations and expert recommendations

The collaborative team behind this event includes, the University of Alberta’s Ingenuity Lab, the Society for Risk Analysis, Environment Canada, Health Canada, and the Organization for Economic Co-operation and Development (OECD) Working Party on Manufactured Nanomaterials (WPMN) .

The speaker lineup isn’t settled at this time although they have confirmed Vicki Stone of Heriot-Watt University in Scotland (from her university bio page),

Vicki Stone, Professor of Toxicology, studies the effects of nanomaterials on humans and environmentally relevant species.  Current research projects investigate the mechanism of toxicity of a range of nanomaterials in cells of the immune system (macrophages and neutrophils), liver (hepatocytes) , gastrointestinal tract, blood vessels (endothelium) and lung.  She is interested in interactions between nanomaterials, proteins and lipids, and how this influences subsequent toxicity.  Current projects also develop in vitro alternatives using microfluidics as well as high resolution imaging of individual nanomaterials in 3D and over time.  In addition Vicki collaborates with ecotoxicologists to investigate the impacts of nanomaterials on aquatic organisms. Vicki coordinated a European project to identify the research priorities to develop an intelligent testing strategy for nanomaterials (www.its-nano.eu).

Vicki is Director of the Nano Safety Research Group at Heriot-Watt University, Edinburgh, and Director of Toxicology for SAFENANO (www.safenano.org). She has acted as the Editor-in-chief of the journal Nanotoxicology (http://informahealthcare.com/nan) for 6 years (2006-2011). Vicki has also published over 130 publications pertaining to particle toxicology over the last 16 years and has provided evidence for the government commissioned reports published by the Royal Society (2003) and the on Environmental Pollution (2008).  Vicki was previously a member of the UK Government Committee on the Medical Effects of Air Pollution (COMEAP) and an advisory board member for the Center for the Environmental Implications of NanoTechnology (CEINT; funded by the US Environmental Protection Agency)).

A representative from PETA (People for the Ethical Treatment of Animals) will also be speaking. I believe that will be Amy Clippinger (from the PETA website’s Regulatory Testing webpage; scroll down about 70% of the way),

Science adviser Amy Clippinger has a Ph.D. in cellular and molecular biology and genetics and several years of research experience at the University of Pennsylvania.

PETA representatives have been to at least one other conference on the topic of nano, toxicology, and animal testing as per my April 24, 2014 posting about NANOTOX 2014 in Turkey,

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.

There is a lot of interest internationally in improving how we test for toxicity of nanomaterials. As well, the drive to eliminate or minimize as much as possible the use of animals in testing seems to be gaining momentum.

Good luck to everyone submitting a poster abstract and/or an application for a travel grant!

In case you don’t want to scroll up, the SRA nano workshop website is here.

An upcoming alternate testing strategies (ATS) for nanomaterials workshop and the quest to reduce animal testing

Leave a reply

It’s too late to announce a call for poster abstracts or travel awards but that still leaves the possibility of attending a September 15-16, 2014 Workshop to Explore How a Multiple Models Approach can Advance Risk Analysis of Nanoscale Materials in Washington, DC. In a July 9, 2014 Nanowerk Spotlight article,, Jo Anne Shatkin (President, Vireo Advisors) and Lorraine Sheremeta (Assistant Director, Ingenuity Lab, University of Alberta) tout the workshop in the context of describing new approaches to nanotoxicology research (Note: A link has been removed),

Engineered nanoscale materials (ENM or ‘nanomaterials’) offer the potential to create safer and more effective products through the use of smaller quantities of improved performance materials. Currently nanomaterials are used to improve the performance of life-saving drugs and medical technologies, to make renewable energy more efficient, to make value added products from industrial waste streams, to improve food, packaging, to lightweight materials used in transportation systems, and to improve many of the personal care products that we use every day. Nanomaterial manufacture and use is expected to increase over the coming years and despite the widespread use of nanomaterials in a variety of consumer products, we are only beginning to understand the impacts of these emerging materials on our health and the environment. To this end, the University of Alberta’s Ingenuity Lab is collaborating with the Society for Risk Analysis to evaluate the potential to use alternative test strategies (ATS) to improve our ability to assess nanomaterial toxicity and environmental impact.

Shatkin and Sheremeta describe toxicology tests and explain the importance of refining and improving these tests (from the article),

Standard in vivo toxicology test methods that depend heavily on the use of animals have long been used to assess chemical safety. [emphasis mine*] Existing and novel in vitro and in silico test methods provide important alternatives to in vivo animal testing for chemicals and potentially for ENM. Genotoxicity tests, for example, are used to assess the mutagenic potential of chemicals or nanomaterials in the replication of DNA in cells. Driven in part by increasing market and regulatory requirements for safer and more sustainable products, large international infrastructure has developed for creating, testing and validating in vitro test methods, and its use is expanding to chemical and nanomaterial assessment (NSF, 2007). The goals of reducing, refining and replacing animal testing (the commonly cited ‘three Rs’) – resonate with key and diverse stakeholders including animal rights groups, the bioethics community, the pharmaceutical industry, regulatory agencies and the broader public. [emphasis mine*]

Despite nearly a decade of effort in the conduct toxicology and exposure research to inform the assessment of health and environmental risks of nanomaterials, major gaps remain in the ability to understand and quantify risks. While there is now a large body of published data on carbon nanotubes and metal oxide nanoparticles, concern has been raised that speculation about nanomaterial risk has hardened into an assumption that there are ‘as-yet-to-be-discovered risks’ that we must identify and manage (Maynard, 2014) that demands extensive testing.

The authors describe ATS (alternative test strategies) in greater detail,

ATS approaches are regarded by many to have the potential for rapid screening of large numbers and types of materials. They can include a breadth of techniques including high throughput screening methods (HTS), high content screening, computational approaches, toxicogenomics, cell-based methods, in vitro assays and non-mammalian whole animal models. The emergence of ATS raises questions about how the results of these methods may be used for assessing the potential risks of ENM. For instance, ATS could be used in combination in a multiple models approach to evaluate new ENM in a number of rapid assays and compare with well-studied substances using in vivo testing; thereby identifying ENM for additional testing in a more strategic fashion than is possible through conventional testing approaches.

They also describe the current state of affairs with ATS,

In the United States, the U.S. ToxCast program has, as part of their 21st century toxicity screening program (NRC, 2007), tested 29 NMs with 62 in vitro test methods (Wang et al. 2013). Many researchers, including several from the University of Alberta, have proposed and developed ATS to include a variety of methods, some which are standardized for chemicals, and others which take advantage of developments including advanced biological mechanistic understanding, genomics, metabolomics, automation and informatics. However, these existing as well as emerging ATS have a short history with nanomaterials, and have not yet proven to be reliable for quantitative estimation of ENM risk. Still, several international efforts have developed ATS that have potential to be used for screening purposes, and to guide further testing priorities for regulatory decision making. The goal of the September [2014] workshop by the Society for Risk Analysis is to explore ways in which distinct ATS may be used for screening and prioritizing the need for more extensive testing of novel ENM.

The parties (including the authors of the article) involved in developing this risk workshop are listed, also mentioned are members of the international testing scene,

Lori Sheremeta, the Assistant Director of Ingenuity Lab in Edmonton Alberta and past Chair of the Society for Risk Analysis (SRA) Emerging Nanoscale Materials Specialty Group (ENMSG), is collaborating with U.S.-based nanomaterials risk expert Jo Anne Shatkin (an SRA Councilor and co-founder of the SRA ENMSG), Environment Canada, Health Canada, the SRA ENMSG and others on a Pilot Project with the Organization for Economic Co-operation and Development (OECD) Working Party on Manufactured Nanomaterials (WPMN) to develop a report on the State of the Science for ATS for nanomaterials, catalogue of existing and emerging ATS methods in a database; and develop a case study to inform workshop deliberations and expert recommendations.

…

There are many international efforts to develop, as well as to validate and standardize, these methods for chemicals, including organizations such as the US National Toxicology Program Interagency Center for the Evaluation of Alternative Toxicological Methods (ICCVAM), the European Union Reference Laboratory European Centre for the Validation of Alternative Methods (EURL ECVAM), the Japanese Center for the Validation of Alternative Methods (JacVAM), the Korean Centre for the Validation of Alternative Methods (KoCVAM) and the OECD. There is wide recognition that the diversity of NMs renders it impractical to use traditional animal testing to evaluate safety, hence there is significant interest in assessing the performance of both existing and emerging alternative testing strategies for NMs. Further, the EU directive REACH (Directive 2006/121/EC) requires replacing in vivo testing, and there is widespread popular agreement about the desire to limit animal testing. Finally, there is a need for more biologically informative toxicology methods (Hartung, 2010; Silbergeld et al, 2011; Landsiedel et al, 2009).

A list of the workshop objectives is offered  in the article,

The main objectives of the workshop are to:

assess the state of the science on HTS and ATS from a ‘multiple models’ perspective to identify areas of common findings from differing approaches, areas of greatest uncertainty, and priorities for follow up in applied research toward risk assessment of ENM;
evaluate the ability to use data from ATS/HTS methods for screening purposes – combining suites of assays and comparing well-studied substances to novel ones;

assess the ability to use a suite of ATS methods to amplify the Weight of Evidence;

characterize uncertainty associated with predictive relationships and propose strategies to address uncertainties;

elicit the perspectives of diverse stakeholders about the use of HTS/ATS for screening purposes in risk analysis of ENM; and

develop a set of recommendations for these alternative approaches to become more widely adopted for environmental, health and safety decision making about ENM across the product life cycle. The output of the workshop holds potential for transformation through risk screening approaches that promote safer and more sustainable material and technology development.

You can find more about the September 15-16, 2014 Workshop to Explore How a Multiple Models Approach can Advance Risk Analysis of Nanoscale Materials in Washington, DC here.

The text in the article is a bit rough. Some of the ideas and topics don’t follow each other logically. So, be prepared to spend a little time reading, Happily, there are references included with the article.

I last mentioned Jo Anne Shatkin here in the context of a 2013 paper on alternative test strategies (ATS) in an Aug. 22, 2013 posting. I think the most recent mention of Lorraine Sheremeta here is in a Jan. 11, 2010 posting about Canada, nanotechnology, and food.

Final note, I am hoping to get some more information about the workshop and ATS scene from Lorraine Sheremeta to be published in a subsequent posting.

* I added the emphases at 0830 hours PDT July 10, 2014.

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

Leave a reply

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.

US multicenter (Nano GO Consortium) study of engineered nanomaterial toxicology

1 Reply

Nano Go Consortium is the name they gave a multicenter toxicology study of engineered nanomaterials which has pioneered a new approach  in the US to toxicology research. From the May 6, 2013 news item on Azonano,

For the first time, researchers from institutions around the country have conducted an identical series of toxicology tests evaluating lung-related health impacts associated with widely used engineered nanomaterials (ENMs).

The study [on rodents] provides comparable health risk data from multiple labs, which should help regulators develop policies to protect workers and consumers who come into contact with ENMs.

The May 6, 2013 North Carolina State University news release, which originated the news item, describes the results from one of two studies that were recently published by the Nano GO Consortium in Environmental Health Perspectives,

The researchers found that carbon nanotubes, which are used in everything from bicycle frames to high performance electronics, produced inflammation and inflammatory lesions in the lower portions of the lung. However, the researchers found that the nanotubes could be made less hazardous if treated to remove excess metal catalysts used in the manufacturing process or modified by adding carboxyl groups to the outer shell of the tubes to make them more easily dispersed in biological fluids.

The researchers also found that titanium dioxide nanoparticles also caused inflammation in the lower regions of the lung. Belt-shaped titanium nanoparticles caused more cellular damage in the lungs, and more pronounced lesions, than spherical nanoparticles.

Here’s a link to and a citation for this study on rodents,

Interlaboratory Evaluation of Rodent Pulmonary Responses to Engineered Nanomaterials: The NIEHS NanoGo Consortium by James C. Bonner, Rona M. Silva, Alexia J. Taylor, Jared M. Brown, Susana C. Hilderbrand, Vincent Castranova, Dale Porter, Alison Elder, Günter Oberdörster, Jack R. Harkema, Lori A. Bramble, Terrance J. Kavanagh, Dianne Botta, Andre Nel, and Kent E. Pinkerton. Environ Health Perspect (): .doi:10.1289/ehp.1205693  Published: May 06, 2013

And the information for the other study which this consortium has published,

Interlaboratory Evaluation of in Vitro Cytotoxicity and Inflammatory Responses to Engineered Nanomaterials: The NIEHS NanoGo Consortium by Tian Xia, Raymond F. Hamilton Jr, James C. Bonner, Edward D. Crandall, Alison Elder, Farnoosh Fazlollahi, Teri A. Girtsman, Kwang Kim, Somenath Mitra, Susana A. Ntim, Galya Orr, Mani Tagmount8, Alexia J. Taylor, Donatello Telesca, Ana Tolic, Christopher D. Vulpe, Andrea J. Walker, Xiang Wang, Frank A. Witzmann, Nianqiang Wu, Yumei Xie, Jeffery I. Zink, Andre Nel, and Andrij Holian. Environ Health Perspect (): .doi:10.1289/ehp.1306561 Published: May 06, 2013

Environmental Health Perspectives is an open access journal and the two studies are being offered as ‘early’ publication efforts and will be updated with the full studies at a later date.

Most interesting for me is the editorial offered by four of the researchers involved in the Nano GO Consortium, from the editorial,

Determining the health effects of ENMs presents some unique challenges. The thousands of ENMs in use today are made from an enormous range of substances, vary considerably in size, and take a diversity of shapes, including spheres, cubes, cones, tubes, and other forms. They are also produced in different laboratories across the world using a variety of methods. In the scientific literature, findings on the properties and toxicity of these materials are mixed and often difficult to compare across studies. To improve the reliability and reproducibility of data in this area, there is a need for uniform research protocols and methods, handling guidelines, procurement systems, and models.

…

Although there is still much to learn about the toxicity of ENMs, we are fortunate to start with a clean slate: There are as yet no documented incidences of human disease due to ENM exposure (Xia et al. 2009). Because ENMs are manmade rather than natural substances, we have an opportunity to design, manufacture, and use these materials in ways that allow us to reap the maximum benefits—and minimal risk—to humans.

With $13 million from the American Recovery and Reinvestment Act (2009), the National Institute of Environmental Health Sciences (NIEHS) awarded 13 2-year grants to advance research on the health impacts of ENMs (NIEHS 2013). [emphasis mine] Ten grants were awarded through the National Institutes of Health (NIH) Grand Opportunities program and three were funded through the NIH Challenge Grants program. One goal of this investment was to develop reliable, reproducible methods to assess exposure and biological response to nanomaterials.

…

Within the framework of the consortium, grantees designed and conducted a series of “round-robin” experiments in which similar or identical methods were used to perform in vitro and in vivo tests on the toxicity of selected nanomaterials concurrently at 13 different laboratories.

…

Conducting experiments in a round-robin format within a consortium structure is an unfamiliar approach for most researchers. Although some researchers acknowledged that working collaboratively with such a large and diverse group at times stretched the limits of their comfort zones, the consortium ultimately proved to be “greater than the sum of its parts,” resulting in reliable, standardized protocols that would have been difficult for researchers to achieve by working independently. Indeed, many participants reflected that participating in the consortium not only benefitted their shared goals but also enhanced their individual research efforts. The round-robin approach and the overall consortium structure may be valuable models for other emerging areas of science.

Here’s a link to and a citation for the Consortium’s editorial, which is available in full,

Nano GO Consortium—A Team Science Approach to Assess Engineered Nanomaterials: Reliable Assays and Methods by Thaddeus T. Schug, Srikanth S. Nadadur, and Anne F. Johnson. Environ Health Perspect 121(2013). http://dx.doi.org/10.1289/ehp.1306866 [online 06 May 2013]

I like the idea of researchers working together across institutional and geographical boundaries as that can be a very powerful approach. I hope that won’t devolve into a form of institutionalized oppression where individual researchers are forced out or ignored. In general, it’s the outlier research that often proves to be truly groundbreaking, which often generates extraordinary and informal (and sometimes formal) resistance. For an example of groundbreaking work that was rejected by other researchers who banded together informally, there’s Dan Shechtman, 2011 Nobel Laureate in Chemistry, famously faced hostility from his colleagues for years over his discovery of quasicrystals.

OECD (Organization for Economic Cooperation and Development) and six years of nanomaterials safety work

Leave a reply

Thank to Carla Caprioli (@carlacap)for pointing out this OCED (Organization for Economic Cooperation and Development overview document of their health and safety activities regarding nanomaterials, which was announced on Sept. 13, 2012 according SafeNano,

The Organisation for Economic Co-operation and Development Working Party on Manufactured Nanomaterials (OECD WPMN) has released an announcement regarding “Six Years of OECD Work on the Safety of Manufactured Nanomaterials: Achievements and Future Opportunities“.

…

As nanomaterials started to be used in commercial applications, OECD launched a programme of work in 2006 to ensure that the approaches for hazard, exposure and risk assessment for manufactured nanomaterials are of a high quality, science-based and internationally harmonised.

Based on this, the OECD and its member countries have come to the conclusion that the approaches for the testing and assessment of traditional chemicals are in general appropriate for assessing the safety of nanomaterials, but may have to be adapted to the specificities of nanomaterials. As with other chemicals, it is clear that each nanomaterial may pose specific challenges, but in most instances, they can be addressed with existing test methods and assessment approaches. In some cases, it might be necessary to adapt methods of sample preparation and dosimetry for safety testing. Similarly, adaptations may be needed for certain Test Guidelines but it will not be necessary to develop completely new approaches for nanomaterials. OECD continues to review all existing methodologies to identify and implement the necessary changes needed for their application to nanomaterials.

The four-page document won’t provide any new information or insights for long time observers but for new observers it does offer a listing of the OECD-published documents on safety and engineered nanomaterials. This excerpt from p. 4 of the document describes the OECD’s future plans,

There is still much to learn before our understanding of the safely [sic] use of manufactured nanomaterials is sufficient. However, the work achieved so far allows a better understanding of remaining “unknowns”. Knowing that the general approaches for the testing and assessment of traditional chemicals are in general appropriate for assessing the safety of nanomaterials, OECD will now focus on those specific aspects of manufactured nanomaterials, which require the adaptation and/or development of specific testing methods used for assessing human health and environmental safety as well as on developing guidance documents for assessing manufactured nanomaterials adapted to their specifities. This will  include guidance on estimating exposure (including fate and transport) on how to use results on physicochemicals [sic] endpoints in exposure assessment and mitigation measures to reduce exposure to safe levels (defining appropriate exposure metrics). At the same time, as R&D on manufactured nanomaterials/nanotechnologies is increasing, OECD remains vigilant in order to address emerging issues in a timely and resource efficient way.

It’s a good to find compilations either to point you in the right direction for your document or to confirm that you’ve found everything on the subject and on very rare occasions you may realize you found something everyone else missed.