Tag Archives: zinc oxide nanoparticles

NanoFARM: food, agriculture, and nanoparticles

The research focus for the NanoFARM consortium is on pesticides according to an October 19, 2017 news item on Nanowerk,

The answer to the growing, worldwide food production problem may have a tiny solution—nanoparticles, which are being explored as both fertilizers and fungicides for crops.

NanoFARM – research consortium formed between Carnegie Mellon University [US], the University of Kentucky [US], the University of Vienna [Austria], and Aveiro University in Prague [Czech Republic] – is studying the effects of nanoparticles on agriculture. The four universities received grants from their countries’ respective National Science Foundations to discover how these tiny particles – some just 4 nanometers in diameter – can revolutionize how farmers grow their food.

An October ??, 2017 Carnegie Mellon University news release by Adam Dove, which originated the news item, fills in a few more details,

“What we’re doing is getting a fundamental understanding of nanoparticle-to-plant interactions to enable future applications,” says Civil and Environmental Engineering (CEE) Professor Greg Lowry, the principal investigator for the nanoFARM project. “With pesticides, less than 5% goes into the crop—the rest just goes into the environment and does harmful things. What we’re trying to do is minimize that waste and corresponding environmental damage by doing a better job of targeting the delivery.”

The teams are looking at related questions: How much nanomaterial is needed to help crops when it comes to driving away pests and delivering nutrients, and how much could potentially hurt plants or surrounding ecosystems?

Applied pesticides and fertilizers are vulnerable to washing away—especially if there’s a rainstorm soon after application. But nanoparticles are not so easily washed off, making them extremely efficient for delivering micronutrients like zinc or copper to crops.

“If you put in zinc oxide nanoparticles instead, it might take days or weeks to dissolve, providing a slow, long-term delivery system.”

Gao researches the rate at which nanoparticles dissolve. His most recent finding is that nanoparticles of copper oxide take up to 20-30 days to dissolve in soil, meaning that they can deliver nutrients to plants at a steady rate over that time period.

“In many developing countries, a huge number of people are starving,” says Gao. “This kind of technology can help provide food and save energy.”

But Gao’s research is only one piece of the NanoFARM puzzle. Lowry recently traveled to Australia with Ph.D. student Eleanor Spielman-Sun to explore how differently charged nanoparticles were absorbed into wheat plants.

They learned that negatively charged particles were able to move into the veins of a plant—making them a good fit for a farmer who wanted to apply a fungicide. Neutrally charged particles went into the tissue of the leaves, which would be beneficial for growers who wanted to fortify a food with nutritional value.

Lowry said they are still a long way from signing off on a finished product for all crops—right now they are concentrating on tomato and wheat plants. But with the help of their university partners, they are slowly creating new nano-enabled agrochemicals for more efficient and environmentally friendly agriculture.

For more information, you can find the NanoFARM website here.

OECD (Organization for Economic Cooperation and Development) Dossiers on Nanomaterials Are of “Little to No Value for assessing risk?”

The announcement that a significant portion of the OECD’s (Organization for Economic Cooperation and Development) dossiers on 11 nanomaterials have next to no value for assessing risk seems a harsh judgment from the Center for International Environmental Law (CIEL). From a March 1, 2017 posting by Lynn L. Bergeson on the Nanotechnology Now,

On February 23, 2017, the Center for International Environmental Law (CIEL) issued a press release announcing a new report, commissioned by CIEL, the European Environmental Citizens’ Organization for Standardization (ECOS), and the Oeko-Institute, that “shows that most of the information made available by the Sponsorship Testing Programme of the Organisation for Economic Co-operation and Development (OECD) is of little to no value for the regulatory risk assessment of nanomaterials.”

Here’s more from the Feb. 23, 3017 CIEL press release, which originated the posting,

The study published today [Feb. 23, 2017] was delivered by the Institute of Occupational Medicine (IOM) based in Singapore. IOM screened the 11,500 pages of raw data of the OECD dossiers on 11 nanomaterials, and analysed all characterisation and toxicity data on three specific nanomaterials – fullerenes, single-walled carbon nanotubes, and zinc oxide.

“EU policy makers and industry are using the existence of the data to dispel concerns about the potential health and environmental risks of manufactured nanomaterials,” said David Azoulay, Senior Attorney for CIEL. “When you analyse the data, in most cases, it is impossible to assess what material was actually tested. The fact that data exists about a nanomaterial does not mean that the information is reliable to assess the hazards or risks of the material.”

The dossiers were published in 2015 by the OECD’s Working Party on Manufactured Nanomaterials (WPMN), which has yet to draw conclusions on the data quality. Despite this missing analysis, some stakeholders participating in EU policy-making – notably the European Chemicals Agency (ECHA) and the European Commission’s Joint Research Centre – have presented the dossiers as containing information on nano-specific human health and environmental impacts. Industry federations and individual companies have taken this a step further emphasizing that there is enough information available to discard most concerns about potential health or environmental risks of manufactured nanomaterials.

“Our study shows these claims that there is sufficient data available on nanomaterials are not only false, but dangerously so,” said Doreen Fedrigo, Senior Policy Officer of ECOS. ”The lack of nano-specific information in the dossiers means that the results of the tests cannot be used as evidence of no ‘nano-effect’ of the tested material. This information is crucial for regulators and producers who need to know the hazard profile of these materials. Analysing the dossiers has shown that legislation detailing nano-specific information requirements is crucial for the regulatory risk assessment of nanomaterials.”

The report provides important recommendations on future steps in the governance of nanomaterials. “Based on our analysis, serious gaps in current dossiers must be filled in with characterisation information, preparation protocols, and exposure data,” said Andreas Hermann of the Oeko-Institute. “Using these dossiers as they are and ignoring these recommendations would mean making decisions on the safety of nanomaterials based on faulty and incomplete data. Our health and environment requires more from producers and regulators.”

CIEL has an Analysis of OECD WPMN Dossiers Regarding the Availability of Data to Evaluate and Regulate Risk (Dec 2016) webpage which provides more information about the dossiers and about the research into the dossiers and includes links to the report, the executive summer, and the dataset,

The Sponsorship Testing Programme of the Working Party on Manufactured Nanomaterials (WPMN) of the Organisation for Economic Co-operation and Development (OECD) started in 2007 with the aim to test a selection of 13 representative nanomaterials for many endpoints. The main objectives of the programme were to better understand what information on intrinsic properties of the nanomaterials might be relevant for exposure and hazards assessment and assess the validity of OECD chemicals Test Guidelines for nanomaterials. The testing programme concluded in 2015 with the publication of dossiers on 11 nanomaterials: 11,500 pages of raw data to be analysed and interpreted.

The WPMN has not drawn conclusions on the data quality, but some stakeholders participating in EU policy-making – notably the European Chemicals Agency and the European Commission’s Joint Research Centre – presented the dossiers as containing much scientific information that provided a better understanding of their nano-specific human health and environmental impacts. Industry federations and individual companies echoed the views, highlighting that there was enough information available to discard most concerns about potential health or environmental risks of manufactured nanomaterials.

As for the OECD, it concluded, even before the publication of the dossiers, that “many of the existing guidelines are also suitable for the safety assessment of nanomaterials” and “the outcomes (of the sponsorship programme) will provide useful information on the ‘intrinsic properties’ of nanomaterials.”

The Center for International Environmental Law (CIEL), the European Citizens’ Organisation for Standardisation (ECOS) and the Öko-Institut commissioned scientific analysis of these dossiers to assess the relevance of the data for regulatory risk assessment.

The resulting report: Analysis of OECD WPMN dossiers regarding the availability of data to evaluate and regulate risk, provides insights illustratating how most of the information made available by the sponsorship programme is of little to no value in identifying hazards or in assessing risks due to nanomaterials.

The analysis shows that:

  • Most studies and documents in the dossiers contain insufficient characterisation data about the specific nanomaterial addressed (size, particle distribution, surface shape, etc.), making it impossible to assess what material was actually tested.
  • This makes it impossible to make any firm statements regarding the nano-specificity of the hazard data published, or the relationship between observed effects and specific nano-scale properties.
  • Less than 2% of the study records provide detail on the size of the nanomaterial tested. Most studies use mass rather than number or size distribution (so not following scientifically recommended reporting practice).
  • The absence of details on the method used to prepare the nanomaterial makes it virtually impossible to correlate an identified hazard with specific nanomaterial characteristic. Since the studies do not indicate dispersion protocols used, it is impossible to assess whether the final dispersion contained the intended mass concentration (or even the actual presence of nanomaterials in the test system), how much agglomeration may have occurred, and how the preparation protocols may have influenced the size distribution.
  • There is not enough nano-specific information in the dossiers to inform about nano-characteristics of the raw material that influence their toxicology. This information is important for regulators and its absence makes information in the dossier irrelevant to develop read-across guidelines.
  • Only about half of the endpoint study records using OECD Test Guideliness (TGs) were delivered using unaltered OECD TGs, thereby respecting the Guidelines’ requirements. The reasons for modifications of the TGs used in the tests are not clear from the documentation. This includes whether the study record was modified to account for challenges related to specific nanomaterial properties or for other, non-nano-specific reasons.
  • The studies do not contain systematic testing of the influence of nano-specific characteristics on the study outcome, and they do not provide the data needed to assess the effect of nano-scale features on the Test Guidelines. Given the absence of fundamental information on nanomaterial characteristics, the dossiers do not provide evidence of the applicability of existing OECD Test Guidelines to nanomaterials.

The analysis therefore dispels several myths created by some stakeholders following publication of the dossiers and provides important perspective for the governance of nanomaterials. In particular, the analysis makes recommendations to:

  • Systematically assess the validity of existing Test Guidelines for relevance to nanomaterials
  • Develop Test Guidelines for dispersion and other test preparations
  • Define the minimum characteristics of nanomaterials that need to be reported
  • Support the build-up of exposure database
  • Fill the gaps in current dossiers with characterisation information, preparation protocols and exposure data

Read full report.
Read executive summary.
Download full dataset.

This is not my area of expertise and while I find the language a bit inflammatory, it’s my understanding that there are great gaps in our understanding of nanomaterials and testing for risk assessment has been criticized for many of the reasons pointed out by CIEL, ECOS, and the Oeko-Institute.

You can find out more about CIEL here; ECOS here; and the Oeko-Institute (also known as Öko-Institute) here.

June 2016: time for a post on nanosunscreens—risks and perceptions

In the years since this blog began (2006), there’ve been pretty regular postings about nanosunscreens. While there are always concerns about nanoparticles and health, there has been no evidence to support a ban (personal or governmental) on nanosunscreens. A June 2016 report  by Paul FA Wright (full reference information to follow) in an Australian medical journal provides the latest insights on safety and nanosunscreens. Wright first offers a general introduction to risks and nanomaterials (Note: Links have been removed),

In reality, a one-size-fits-all approach to evaluating the potential risks and benefits of nanotechnology for human health is not possible because it is both impractical and would be misguided. There are many types of engineered nanomaterials, and not all are alike or potential hazards. Many factors should be considered when evaluating the potential risks associated with an engineered nanomaterial: the likelihood of being exposed to nanoparticles (ranging in size from 1 to 100 nanometres, about one-thousandth of the width of a human hair) that may be shed by the nanomaterial; whether there are any hotspots of potential exposure to shed nanoparticles over the whole of the nanomaterial’s life cycle; identifying who or what may be exposed; the eventual fate of the shed nanoparticles; and whether there is a likelihood of adverse biological effects arising from these exposure scenarios.1

The intrinsic toxic properties of compounds contained in the nanoparticle are also important, as well as particle size, shape, surface charge and physico-chemical characteristics, as these greatly influence their uptake by cells and the potential for subsequent biological effects. In summary, nanoparticles are more likely to have higher toxicity than bulk material if they are insoluble, penetrate biological membranes, persist in the body, or (where exposure is by inhalation) are long and fibre-like.1 Ideally, nanomaterial development should incorporate a safety-by-design approach, as there is a marketing edge for nano-enabled products with a reduced potential impact on health and the environment.1

Wright also covers some of nanotechnology’s hoped for benefits but it’s the nanosunscreen which is the main focus of this paper (Note: Links have been removed),

Public perception of the potential risks posed by nanotechnology is very different in certain regions. In Asia, where there is a very positive perception of nanotechnology, some products have been marketed as being nano-enabled to justify charging a premium price. This has resulted in at least four Asian economies adopting state-operated, user-financed product testing schemes to verify nano-related marketing claims, such as the original “nanoMark” certification system in Taiwan.4

In contrast, the negative perception of nanotechnology in some other regions may result in questionable marketing decisions; for example, reducing the levels of zinc oxide nanoparticles included as the active ingredient in sunscreens. This is despite their use in sunscreens having been extensively and repeatedly assessed for safety by regulatory authorities around the world, leading to their being widely accepted as safe to use in sunscreens and lip products.5

Wright goes on to describe the situation in Australia (Note: Links have been removed),

Weighing the potential risks and benefits of using sunscreens with UV-filtering nanoparticles is an important issue for public health in Australia, which has the highest rate of skin cancer in the world as the result of excessive UV exposure. Some consumers are concerned about using these nano-sunscreens,6 despite their many advantages over conventional organic chemical UV filters, which can cause skin irritation and allergies, need to be re-applied more frequently, and are absorbed by the skin to a much greater extent (including some with potentially endocrine-disrupting activity). Zinc oxide nanoparticles are highly suitable for use in sunscreens as a physical broad spectrum UV filter because of their UV stability, non-irritating nature, hypo-allergenicity and visible transparency, while also having a greater UV-attenuating capacity than bulk material (particles larger than 100 nm in diameter) on a per weight basis.7

Concerns about nano-sunscreens began in 2008 with a report that nanoparticles in some could bleach the painted surfaces of coated steel.8 This is a completely different exposure situation to the actual use of nano-sunscreen by people; here they are formulated to remain on the skin’s surface, which is constantly shedding its outer layer of dead cells (the stratum corneum). Many studies have shown that metal oxide nanoparticles do not readily penetrate the stratum corneum of human skin, including a hallmark Australian investigation by Gulson and co-workers of sunscreens containing only a less abundant stable isotope of zinc that allowed precise tracking of the fate of sunscreen zinc.9 The researchers found that there was little difference between nanoparticle and bulk zinc oxide sunscreens in the amount of zinc absorbed into the body after repeated skin application during beach trials. The amount absorbed was also extremely small when compared with the normal levels of zinc required as an essential mineral for human nutrition, and the rate of skin absorption was much lower than that of the more commonly used chemical UV filters.9 Animal studies generally find much higher skin absorption of zinc from dermal application of zinc oxide sunscreens than do human studies, including the meticulous studies in hairless mice conducted by the Commonwealth Scientific and Industrial Research Organisation (CSIRO) using both nanoparticle and bulk zinc oxide sunscreens that contained the less abundant stable zinc isotope.10 These researchers reported that the zinc absorbed from sunscreen was distributed throughout several major organs, but it did not alter their total zinc concentrations, and that overall zinc homeostasis was maintained.10

He then discusses titanium dioxide nanoparticles (also used in nanosunscreens, Note: Links have been removed),

The other metal oxide UV filter is titanium dioxide. Two distinct crystalline forms have been used: the photo-active anatase form and the much less photo-active rutile form,7 which is preferable for sunscreen formulations. While these insoluble nanoparticles may penetrate deeper into the stratum corneum than zinc oxide, they are also widely accepted as being safe to use in non-sprayable sunscreens.11

Investigation of their direct effects on human skin and immune cells have shown that sunscreen nanoparticles of zinc oxide and rutile titanium dioxide are as well tolerated as zinc ions and conventional organic chemical UV filters in human cell test systems.12 Synchrotron X-ray fluorescence imaging has also shown that human immune cells break down zinc oxide nanoparticles similar to those in nano-sunscreens, indicating that immune cells can handle such particles.13 Cytotoxicity occurred only at very high concentrations of zinc oxide nanoparticles, after cellular uptake and intracellular dissolution,14 and further modification of the nanoparticle surface can be used to reduce both uptake by cells and consequent cytotoxicity.15

The ongoing debate about the safety of nanoparticles in sunscreens raised concerns that they may potentially increase free radical levels in human skin during co-exposure to UV light.6 On the contrary, we have seen that zinc oxide and rutile titanium dioxide nanoparticles directly reduce the quantity of damaging free radicals in human immune cells in vitro when they are co-exposed to the more penetrating UV-A wavelengths of sunlight.16 We also identified zinc-containing nanoparticles that form immediately when dissolved zinc ions are added to cell culture media and pure serum, which suggests that they may even play a role in natural zinc transport.17

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

Potential risks and benefits of nanotechnology: perceptions of risk in sunscreens by Paul FA Wright. Med J Aust 2016; 204 (10): 369-370. doi:10.5694/mja15.01128 Published June 6, 2016

This paper appears to be open access.

The situation regarding perceptions of nanosunscreens in Australia was rather unfortunate as I noted in my Feb. 9, 2012 posting about a then recent government study which showed that some Australians were avoiding all sunscreens due to fears about nanoparticles. Since then Friends of the Earth seems to have moderated its stance on nanosunscreens but there is a July 20, 2010 posting (includes links to a back-and-forth exchange between Dr. Andrew Maynard and Friends of the Earth representatives) which provides insight into the ‘debate’ prior to the 2012 ‘debacle’. For a briefer overview of the situation you could check out my Oct. 4, 2012 posting.

Nanoparticles for sustainable ways to grow crops

An April 29, 2016 news item on Nanowerk celebrates research into food production,

Scientists are working diligently to prepare for the expected increase in global population — and therefore an increased need for food production— in the coming decades. A team of engineers at Washington University in St. Louis has found a sustainable way to boost the growth of a protein-rich bean by improving the way it absorbs much-needed nutrients.

Ramesh Raliya, a research scientist, and Pratim Biswas, the Lucy & Stanley Lopata Professor and chair of the Department of Energy, Environmental & Chemical Engineering, both in the School of Engineering & Applied Science, discovered a way to reduce the use of fertilizer made from rock phosphorus and still see improvements in the growth of food crops by using zinc oxide nanoparticles.

The food under investigation is the mung bean,

Researchers at Washington University in St. Louis hope that nanoparticle technology can help reduce the need for fertilizer, creating a more sustainable way to grow crops such as mung beans. Courtesy: Washington University in St. Louis

Researchers at Washington University in St. Louis hope that nanoparticle technology can help reduce the need for fertilizer, creating a more sustainable way to grow crops such as mung beans. Courtesy: Washington University in St. Louis

An April 28, 2016 Washington University in St. Louis  news release (also on EurekAlert) by Beth Miller, which originated the news item, provides more detail,

The research was published April 7 [2016] in the Journal of Agricultural and Food Chemistry. Raliya said this is the first study to show how to mobilize native phosphorus in the soil using zinc oxide nanoparticles over the life cycle of the plant, from seed to harvest.

Food crops need phosphorus to grow, and farmers are using more and more phosphorus-based fertilizer as they increase crops to feed a growing world population. However, the plants can only use about 42 percent of the phosphorus applied to the soil, so the rest runs off into the water streams, where it grows algae that pollutes our water sources. In addition, nearly 82 percent of the world’s phosphorus is used as fertilizer, but it is a limited supply, Raliya says.

“If farmers use the same amount of phosphorus as they’re using now, the world’s supply will be depleted in about 80 years,” Raliya said. “Now is the time for the world to learn how to use phosphorus in a more sustainable manner.”

Raliya and his collaborators, including Jagadish Chandra Tarafdar at the Central Arid Zone Research Institute in Jodhpur, India, created zinc oxide nanoparticles from a fungus around the plant’s root that helps the plant mobilize and take up the nutrients in the soil. Zinc also is an essential nutrient for plants because it interacts with three enzymes that mobilize the complex form of phosphorus in the soil into a form that plants can absorb.

“Due to climate change, the daily temperature and rainfall amounts have changed,” Raliya said. “When they changed, the microflora in the soil are also changed, and once those are depleted, the soil phosphorus can’t mobilize the phosphorus, so the farmer applies more. Our goal is to increase the activity of the enzymes by several-fold, so we can mobilize the native phosphorus several-fold.”

When Raliya and the team applied the zinc nanoparticles to the leaves of the mung bean plant, it increased the uptake of the phosphorus by nearly 11 percent and the activity of the three enzymes by 84 percent to 108 percent. That leads to a lesser need to add phosphorus on the soil, Raliya said.

“When the enzyme activity increases, you don’t need to apply the external phosphorus, because it’s already in the soil, but not in an available form for the plant to uptake,” he said. “When we apply these nanoparticles, it mobilizes the complex form of phosphorus to an available form.”

The mung bean is a legume grown mainly in China, southeast Asia and India, where 60 percent of the population is vegetarian and relies on plant-based protein sources. The bean is adaptable to a variety of climate conditions and is very affordable for people to grow.

Raliya said 45 percent of the worldwide phosphorus use for agriculture takes place in India and China. Much of the phosphorus supply in developing countries is imported from the United States and Morocco-based rock phosphate mines.

“We hope that this method of using zinc oxide nanoparticles can be deployed in developing countries where farmers are using a lot of phosphorus,” Raliya said.

“These countries are dependent on the U.S. to export phosphorus to them, but in the future, the U.S. may have to help supply food, as well. If this crop can grow in a more sustainable manner, it will be helpful for everyone.”

“This is a broader effort under way at the nexus of food, energy and water,” Biswas said. “Nanoparticle technology enabled by aerosol science helps develop innovative solutions to address this global challenge problem that we face today.”

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

Enhancing the Mobilization of Native Phosphorus in the Mung Bean Rhizosphere Using ZnO Nanoparticles Synthesized by Soil Fungi by Ramesh Raliya, Jagadish Chandra Tarafdar, and Pratim Biswas. J. Agric. Food Chem., 2016, 64 (16), pp 3111–3118 DOI: 10.1021/acs.jafc.5b05224 Publication Date (Web): April 07, 2016

Copyright © 2016 American Chemical Society

This paper is behind a paywall.

Possible nanoparticle-based vaccine/microbiocide for herpes simplex virus-2

An April 27, 2016 news item on ScienceDaily describes a new therapeutic and preventative technology for herpes,

An effective vaccine against the virus that causes genital herpes has evaded researchers for decades. But now, researchers from the University of Illinois at Chicago [UIC] working with scientists from Germany have shown that zinc-oxide nanoparticles shaped like jacks can prevent the virus from entering cells, and help natural immunity to develop.

“We call the virus-trapping nanoparticle a microbivac, because it possesses both microbicidal and vaccine-like properties,” says corresponding author Deepak Shukla, professor of ophthalmology and microbiology & immunology in the UIC College of Medicine. “It is a totally novel approach to developing a vaccine against herpes, and it could potentially also work for HIV and other viruses,” he said.

The particles could serve as a powerful active ingredient in a topically-applied vaginal cream that provides immediate protection against herpes virus infection while simultaneously helping stimulate immunity to the virus for long-term protection, explained Shukla.

An April 27, 2016 UIC news release (also on EurekAlert), which originated the news item, provides more context for the work,

Herpes simplex virus-2, which causes serious eye infections in newborns and immunocompromised patients as well as genital herpes, is one of the most common human viruses. According to the Centers for Disease Control and Prevention, about 15 percent of people from ages 14-49 carry HSV-2, which can hide out for long periods of time in the nervous system. The genital lesions caused by the virus increase the risk for acquiring human immunodeficiency virus, or HIV.

“Your chances of getting HIV are three to four times higher if you already have genital herpes, which is a very strong motivation for developing new ways of preventing herpes infection,” Shukla said.

Treatments for HSV-2 include daily topical medications to suppress the virus and shorten the duration of outbreaks, when the virus is active and genital lesions are present. However, drug resistance is common, and little protection is provided against further infections. Efforts to develop a vaccine have been unsuccessful because the virus does not spend much time in the bloodstream, where most traditional vaccines do their work.

The news release goes on to provide technical details,

The tetrapod-shaped zinc-oxide nanoparticles, called ZOTEN, have negatively charged surfaces that attract the HSV-2 virus, which has positively charged proteins on its outer envelope. ZOTEN nanoparticles were synthesized using technology developed by material scientists at Germany’s Kiel University and protected under a joint patent with UIC.

When bound to the nanoparticles, HSV-2 cannot infect cells. But the bound virus remains susceptible to processing by immune cells called dendritic cells that patrol the vaginal lining. The dendritic cells “present” the virus to other immune cells that produce antibodies. The antibodies cripple the virus and trigger the production of customized killer cells that identify infected cells and destroy them before the virus can take over and spread.

The researchers showed that female mice swabbed with HSV-2 and an ointment containing ZOTEN had significantly fewer genital lesions than mice treated with a cream lacking ZOTEN. Mice treated with ZOTEN also had less inflammation in the central nervous system, where the virus can hide out.

The researchers were able to watch immune cells pry the virus off the nanoparticles for immune processing, using high-resolution fluorescence microscopy.

“It’s very clear that ZOTEN facilitates the development of immunity by holding the virus and letting the dendritic cells get to it,” Shukla said.

If found safe and effective in humans, a ZOTEN-containing cream ideally would be applied vaginally just prior to intercourse, Shukla said. But if a woman who had been using it regularly missed an application, he said, she may have already developed some immunity and still have some protection. Shukla hopes to further develop the nanoparticles to work against HIV, which like HSV-2 also has positively charged proteins embedded in its outer envelope.

ZOTEN particles are uniform in size and shape, making them attractive for use in other biomedical applications. The novel flame transport synthesis technology used to make them allows large-scale production, said Rainer Adelung, professor of nanomaterials at Kiel University. And, because no chemicals are used, the production process is green.

Adelung hopes to begin commercial production of ZOTEN through a startup company that will be run jointly with his colleagues at UIC.

Here’s an image of the particles, courtesy of UIC,

Zinc oxide tetrapod nanoparticles. Credit: Deepak Shukla

Zinc oxide tetrapod nanoparticles. Credit: Deepak Shukla

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

Intravaginal Zinc Oxide Tetrapod Nanoparticles as Novel Immunoprotective Agents against Genital Herpes by Thessicar E. Antoine, Satvik R. Hadigal, Abraam M. Yakoub, Yogendra Kumar Mishra, Palash Bhattacharya, Christine Haddad, Tibor Valyi-Nagy, Rainer Adelung, Bellur S. Prabhakar, and Deepak Shukla. The Journal of Immunology April 27, 2016 1502373  doi: 10.4049/jimmunol.1502373 Published online before print April 27, 2016

This paper is behind a paywall.

One final comment, it’s a long from a mouse vagina in this study to a human one.

Metal nanoparticles and gut microbiomes

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

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

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

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

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

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

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

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

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

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

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

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

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

Here’s some of what they discovered,

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

Here’s the concluding sentence from the abstract,

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

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

Inhibiting pathogens in meat with edible antimicrobial films

Food poisoning is, at best, unpleasant and, at worst, lethal, so anything which helps people and other animals to avoid that condition is to be lauded, assuming there are no significant shortcomings with the solution to avoiding bad meat. According to a May 4, 2014 news item on Nanowerk a team at Penn (Pennsylvania) State University has developed an antimicrobial, edible film which may help solve the problem,

Antimicrobial agents incorporated into edible films applied to foods to seal in flavor, freshness and color can improve the microbiological safety of meats, according to researchers in Penn State’s College of Agricultural Sciences.

Using films made of pullulan — an edible, mostly tasteless, transparent polymer produced by the fungus Aureobasidium pulluns — researchers evaluated the effectiveness of films containing essential oils derived from rosemary, oregano and nanoparticles against foodborne pathogens associated with meat and poultry.

A May 1, 2014 Penn State University news release by Jeff Mulhollem, which originated the news item, describes the research in further detail,

In the study, which was published online in the April issue of the Journal of Food Science, researchers determined survivability of bacterial pathogens after treatment with 2 percent oregano essential oil, 2 percent rosemary essential oil, zinc oxide nanoparticles or silver nanoparticles.

The compounds then were incorporated into edible films made from pullulan, and the researchers determined the antimicrobial activity of these films against bacterial pathogens inoculated onto petri dishes.

Finally, the researchers experimentally inoculated fresh and ready-to-eat meat and poultry products with bacterial pathogens, treated them with the pullulan films containing the essential oils and nanoparticles, vacuum packaged, and then evaluated for bacterial growth following refrigerated storage for up to three weeks.

“The results from this study demonstrated that edible films made frompullulan and incorporated with essential oils or nanoparticles have the potential to improve the safety of refrigerated, fresh or further-processed meat and poultry products,” said Cutter. “The research shows that we can apply these food-grade films and have them do double duty — releasing antimicrobials and imparting characteristics to protect and improve food we eat.”

The edible films are a novelbut effective way to deliver antimicrobial agents to meats, Cutter explained, because the bacteria-killing action is longer lasting. Liquid applications run off the surface, are not absorbed and are less effective. The pullulan films adhere to the meat, allowing the incorporated antimicrobials to slowly dissolve, providing immediate and sustained kill of bacteria. In addition, the microorganisms do not have the opportunity to regrow.

There’s at least one problem with the pullulan films and its not, as far as the researcher is concerned, the silver or zinc oxide nanoparticles (from the news release),

Cutter conceded that pullulan films are not as oxygen-impermeable as plastic packaging now used to package meats, so the edible films are not likely to replace that material.

“The meat industry likes the properties of the polyethylene vacuum packaging materials that they are using now,” she said. “However, the one thing I really want to be able to do in the next few years is to figure out a way to co-extrude antimicrobial, edible films with the polyethylene so we have the true oxygen barrier properties of the plastic with the antimicrobial properties of the edible film.”

Knowing that edible films can release antimicrobials slowly over time and keep bacteria in meat at bay, further research will be aimed at creating what Cutter referred to as “active packaging” — polyethylene film with antimicrobial properties.

“Right now, we have two different packaging materials that are not necessarily compatible, leading to a two-step process. I keep thinking there’s a way to extrude edible, antimicrobial film in one layer with polyethylene, creating all-in-one packaging.

“The chemistry of binding the two together is the challenge, but we need to find a way to do it because marrying the two materials together in packaging would make foods — especially meat and poultry — safer to eat.”

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

Incorporation of Essential Oils and Nanoparticles in Pullulan Films to Control Foodborne Pathogens on Meat and Poultry Products by Mohamed K. Morsy, Hassan H. Khalaf, Ashraf M. Sharoba, Hassan H. El-Tanahi and Catherine N. Cutter. Journal of Food Science, April 2014, Volume 79, Issue 4, pages M675–M684. DOI: 10.1111/1750-3841.12400 Article first published online: 12 MAR 2014

© 2014 Institute of Food Technologists®

This is behind a paywall.

Food and nanotechnology (as per Popular Mechanics) and zinc oxide nanoparticles in soil (as per North Dakota State University)

I wouldn’t expect to find an article about food in a magazine titled Popular Mechanics but there it is, a Feb. 19,2014 article by Christina Ortiz (Note: A link has been removed),

For a little more than a decade, the food industry has been using nanotechnology to change the way we grow and maintain our food. The grocery chain Albertsons currently has a list of nanotech-touched foods in its home brand, ranging from cookies to cheese blends.

Nanotechnology use in food has real advantages: The technology gives producers the power to control how food looks, tastes, and even how long it lasts.

Looks Good and Good for You?

The most commonly used nanoparticle in foods is titanium dioxide. It’s used to make foods such as yogurt and coconut flakes look as white as possible, provide opacity to other food colorings, and prevent ingredients from caking up. Nanotech isn’t just about aesthetics, however. The biggest potential use for this method involves improving the nutritional value of foods.

Nano additives can enhance or prevent the absorption of certain nutrients. In an email interview with Popular Mechanics, Jonathan Brown, a research fellow at the University of Minnesota, says this method could be used to make mayonnaise less fattening by replacing fat molecules with water droplets.

I did check out US grocer, Albertson’s list of ‘nanofoods’, which they provide and discovered that it’s an undated listing on the Project of Emerging Nanotechnologies’ Consumer Products Inventory (CPI). The inventory has been revived recently after lying moribund for a few years (my Oct. 28, 2013 posting describes the fall and rise) and I believe that this 2013 CPI incarnation includes some oversight and analysis of the claims made, which the earlier version did not include. Given that the Albertson’s list is undated it’s difficult to assess the accuracy of the claims regarding the foodstuffs.

If you haven’t read about nanotechnology and food before, the Ortiz article provides a relatively even-handed primer although it does end on a cautionary note. In any event, it was interesting to get a bit of information about the process of ‘nanofood’ regulation in the US and other jurisdictions (from the Ortiz article),

Aside from requiring manufacturers to provide proof that nanotechnology foods are safe, the FDA has yet to implement specific testing of its own. But many countries are researching ways to balance innovation and regulation in this market. In 2012 the European Food Safety Authority (EFSA) released an annual risk assessment report outlining how the European Union is addressing the issue of nanotech in food. In Canada the Food Directorate “is taking a case-by-case approach to the safety assessment of food products containing or using nanomaterials.”

I featured the FDA’s efforts regarding regulation and ‘nanofood’ in an April 23, 2012 posting,

It looks to me like this [FDA’s draft guidance for ‘nanofoods’] is an attempt to develop a relationship where the industry players in the food industry to police their nanotechnology initiatives with the onus being on industry to communicate with the regulators in a continuous process, if not at the research stage certainly at the production stage.

At least one of the primary issues with any emerging technology revolves around the question of risk. Do we stop all manufacturing and development of nanotechnology-enabled food products until we’ve done the research? That question assumes that taking any risks is not worth the currently perceived benefits. The corresponding question, do we move forward and hope for the best? does get expressed perhaps not quite so baldly; I have seen material which suggests that research into risks needlessly hampers progress.

After reading on this topic for five or so years, my sense is that most people are prepared to combine the two approaches, i.e., move forward while researching possible risks. The actual conflicts seem to centre around these questions, how quickly do we move forward; how much research do we need; and what is an acceptable level of risk?

On the topic of researching the impact that nanoparticles might have on plants (food or otherwise), a January 24, 2013 North Dakota State University (NDSU) news release highlights a student researcher’s work on soil, plants, and zinc oxide nanoparticles,

NDSU senior Hannah Passolt is working on a project that is venturing into a very young field of research. The study about how crops’ roots absorb a microscopic nutrient might be described as being ahead of the cutting-edge.

In a laboratory of NDSU’s Wet Ecosystem Research Group, in collaboration with plant sciences, Passolt is exploring how two varieties of wheat take up extremely tiny pieces of zinc, called nanoparticles, from the soil.

As a point of reference, the particles Passolt is examining are measured at below 30 nanometers. A nanometer is 1 billionth of a meter.

“It’s the mystery of nanoparticles that is fascinating to me,” explained the zoology major from Fargo. “The behavior of nanoparticles in the environment is largely unknown as it is a very new, exciting science. This type of project has never been done before.”

In Passolt’s research project, plants supplied by NDSU wheat breeders are grown in a hydroponic solution, with different amounts of zinc oxide nanoparticles introduced into the solution.

Compared to naturally occurring zinc, engineered zinc nanoparticles can have very different properties. They can be highly reactive, meaning they can injure cells and tissues, and may cause genetic damage. The plants are carefully observed for any changes in growth rate and appearance. When the plants are harvested, researchers will analyze them for actual zinc content.

“Zinc is essential for a plant’s development. However, in excess, it can be harmful,” Passolt said. “In one of my experiments, we are using low and high levels of zinc, and the high concentrations are showing detrimental effects. However, we will have to analyze the plants for zinc concentrations to see if there have been any effects from the zinc nanoparticles.”

Passolt has conducted undergraduate research with the Wet Ecosystem Research Group for the past two years. She said working side-by-side with Donna Jacob, research assistant professor of biological sciences; Marinus Otte; professor of biological sciences; and Mohamed Mergoum, professor of plant sciences, has proven to be challenging, invigorating and rewarding.

“I’ve gained an incredible skill set – my research experience has built upon itself. I’ve gotten to the point where I have a pretty big role in an important study. To me, that is invaluable,” Passolt said. “To put effort into something that goes for the greater good of science is a very important lesson to learn.”

According to Jacob, Passolt volunteered two years ago, and she has since become an important member of the group. She has assisted graduate students and worked on her own small project, the results of which she presented at regional and international scientific conferences. “We offered her this large, complex experiment, and she’s really taken charge,” Jacob said, noting Passolt assisted with the project’s design, handled care of the plants and applied the treatments. When the project is completed, Passolt will publish a peer-reviewed scientific article.

“There is nothing like working on your own experiment to fully understand science,” Jacob said. “Since coming to NDSU in 2006, the Wet Ecosystem Research Group has worked with more than 50 undergraduates, possible only because of significant support from the North Dakota IDeA Networks of Biomedical Research Excellence program, known as INBRE, of the NIH National Center for Research Resources.”

Jacob said seven undergraduate students from the lab have worked on their own research projects and presented their work at conferences. Two articles, so far, have been published by undergraduate co-authors. “I believe the students gain valuable experience and an understanding of what scientists really do during fieldwork and in the laboratory,” Jacob said. “They see it is vastly different from book learning, and that scientists use creativity and ingenuity daily. I hope they come away from their experience with some excitement about research, in addition to a better resume.”

Passolt anticipates the results of her work could be used in a broader view of our ecosystem. She notes zinc nanoparticles are an often-used ingredient in such products as lotions, sunscreens and certain drug delivery systems. “Zinc nanoparticles are being introduced into the environment,” she said. “It gets to plants at some point, so we want to see if zinc nanoparticles have a positive or negative effect, or no effect at all.”

Researching nanoparticles the effects they might have on the environment and on health is a complex process as there are many types of nanoparticles some of which have been engineered and some of which occur naturally, silver nanoparticles being a prime example of both engineered and naturally occurring nanoparticles. (As well, the risks may lie more with interactions between nanomaterials.) For an example of research, which seems similar to the NDSU effort, there’s this open access research article,

Low Concentrations of Silver Nanoparticles in Biosolids Cause Adverse Ecosystem Responses under Realistic Field Scenario by Benjamin P. Colman, Christina L. Arnaout, Sarah Anciaux, Claudia K. Gunsch, Michael F. Hochella Jr, Bojeong Kim, Gregory V. Lowry,  Bonnie M. McGill, Brian C. Reinsch, Curtis J. Richardson, Jason M. Unrine, Justin P. Wright, Liyan Yin, and Emily S. Bernhardt. PLoS ONE 2013; 8 (2): e57189 DOI: 10.1371/journal.pone.0057189

One last comment, the Wet Ecosystem Research Group (WERG) mentioned in the news release about Passolt has an interesting history (from the homepage; Note: Links have been removed),

Marinus Otte and Donna Jacob brought WERG to the Department of Biological Sciences in the Fall of 2006.  Prior to that, the research group had been going strong at University College Dublin, Ireland, since 1992.

The aims for the research group are to train graduate and undergraduate students in scientific research, particularly wetlands, plants, biogeochemistry, watershed ecology and metals in the environment.  WERG research  covers a wide range of scales, from microscopic (e.g. biogeochemical processes in the rhizosphere of plants) to landscape (e.g. chemical and ecological connectivity between prairie potholes across North Dakota).  Regardless of the scale, the central theme is biogeochemistry and the interactions between multiple elements in wet environments.

The group works to collaborate with a variety of researchers, including soil scientists, geologists, environmental engineers, microbiologists, as well as with groups underpinning management of natural resources, such the Minnesota Department of Natural Resources, the Department of Natural Resources of Red Lake Indian Reservation, and the North Dakota Department of Health, Division of Water Quality.

Currently, WERG has several projects, mostly in North Dakota and Minnesota.  Otte and Jacob are also Co-directors of the North Dakota INBRE Metal Analysis Core, providing laboratory facilities and mentoring for researchers in undergraduate colleges throughout the state. Otte and Jacob are also members of the Upper Midwest Aerospace Consortium.

Green chemistry and zinc oxide nanoparticles from Iran (plus some unhappy scoop about Elsevier and access)

It’s been a while since I’ve featured any research from Iran partly due to the fact that I find the information disappointingly scant. While the Dec. 22, 2013 news item on Nanowerk doesn’t provide quite as much detail as I’d like it does shine a light on an aspect of Iranian nanotechnology research that I haven’t previously encountered, green chemistry (Note: A link has been removed),

Researchers used a simple and eco-friendly method to produce homogenous zinc oxide (ZnO) nanoparticles with various applications in medical industries due to their photocatalytic and antibacterial properties (“Sol–gel synthesis, characterization, and neurotoxicity effect of zinc oxide nanoparticles using gum tragacanth”).

Zinc oxide nanoparticles have numerous applications, among which mention can be made of photocatalytic issues, piezoelectric devices, synthesis of pigments, chemical sensors, drug carriers in targeted drug delivery, and the production of cosmetics such as sunscreen lotions.

The Dec. 22, 2013 Iran Nanotechnology Initiative Council (INIC) news release, which originated the news item, provides a bit more detail (Note: Links have been removed),

By using natural materials found in the geography of Iran and through sol-gel technique, the researchers synthesized zinc oxide nanoparticles in various sizes. To this end, they used zinc nitrate hexahydrate and gum tragacanth obtained from the Northern parts of Khorassan Razavi Province as the zinc-providing source and the agent to control the size of particles in aqueous solution, respectively.

Among the most important characteristics of the synthesis method, mention can be made of its simplicity, the use of cost-effective materials, conservation of green chemistry principals to prevent the use of hazardous materials to human safety and environment, production of nanoparticles in homogeneous size and with high efficiency, and most important of all, the use of native materials that are only found in Iran and its introduction to the world.

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

Sol–gel synthesis, characterization, and neurotoxicity effect of zinc oxide nanoparticles using gum tragacanth by Majid Darroudi, Zahra Sabouri, Reza Kazemi Oskuee, Ali Khorsand Zak, Hadi Kargar, and Mohamad Hasnul Naim Abd Hamidf. Ceramics International, Volume 39, Issue 8, December 2013, Pages 9195–9199

There’s a bit more technical information in the paper’s abstract,

The use of plant extract in the synthesis of nanomaterials can be a cost effective and eco-friendly approach. In this work we report the “green” and biosynthesis of zinc oxide nanoparticles (ZnO-NPs) using gum tragacanth. Spherical ZnO-NPs were synthesized at different calcination temperatures. Transmission electron microscopy (TEM) imaging showed the formation most of nanoparticles in the size range of below 50 nm. The powder X-ray diffraction (PXRD) analysis revealed wurtzite hexagonal ZnO with preferential orientation in (101) reflection plane. In vitro cytotoxicity studies on neuro2A cells showed a dose dependent toxicity with non-toxic effect of concentration below 2 µg/mL. The synthesized ZnO-NPs using gum tragacanth were found to be comparable to those obtained from conventional reduction methods using hazardous polymers or surfactants and this method can be an excellent alternative for the synthesis of ZnO-NPs using biomaterials.

I was not able to find the DOI (digital object identifier) and this paper is behind a paywall.

Elsevier and access

On a final note, Elsevier, the company that publishes Ceramics International and many other journals, is arousing some ire with what appears to be its latest policies concerning access according to a Dec. 20, 2013 posting by Mike Masnick for Techdirt Note: Links have been removed),

We just recently wrote about the terrible anti-science/anti-knowledge/anti-learning decision by publishing giant Elsevier to demand that Academia.edu take down copies of journal articles that were submitted directly by the authors, as Elsevier wished to lock all that knowledge (much of it taxpayer funded) in its ridiculously expensive journals. Mike Taylor now alerts us that Elsevier is actually going even further in its war on access to knowledge. Some might argue that Elsevier was okay in going after a “central repository” like Academia.edu, but at least it wasn’t going directly after academics who were posting pdfs of their own research on their own websites. While some more enlightened publishers explicitly allow this, many (including Elsevier) technically do not allow it, but have always looked the other way when authors post their own papers.

That’s now changed. As Taylor highlights, the University of Calgary sent a letter to its staff saying that a company “representing” Elsevier, was demanding that they take down all such articles on the University’s network.

While I do feature the topic of open access and other issues with intellectual property from time to time, you’ll find Masnick’s insights and those of his colleagues are those of people who are more intimately familiar (albeit firmly committed to open access) with the issues should you choose to read his Dec. 20, 2013 posting in its entirely.

Toxicity, nanoparticles, soil, and Europe’s NANO-ECOTOXICITY Project

I have featured pieces on nanoparticles, toxicity, and soil in the past (this Aug. 15, 2011 posting about Duke University’s mesocosm project is probably the most relevant) but this study is the first one I’ve seen focusing on earthworms. From the Sept. 23, 2013 news item on Nanowerk (Note: A link has been removed),

From the clothes and make-up we wear to the electronic devices we use every day, nanotechnology is becoming ubiquitous. But while industry has mastered the production of such materials, little is known about their fate once their service life comes to an end. The NANO-ECOTOXICITY project looked into their impact on soil organisms.

The Sept. 23, 2013 CORDIS (European Commission Community Research and Development Information Service) news release, which originated the new item, offers a Q&A (Question and Answer) with the project research leader,

Dr Maria Diez-Ortiz, research leader of the NANO-ECOTOXICITY project, tells us about her research findings and how she expects them to help increase knowledge and shape tools allowing for standard environmental hazard and risk-assessment methodologies.

What is the background of the NANO-ECOTOXICITY project?

Nanotechnology is based on the idea that, by engineering the size and shape of materials at the scale of atoms, i.e. nanometres (nm), distinct optical, electronic, or magnetic properties can be tuned to produce novel properties of commercial value. However, there is an obvious concern that such novel properties may also lead to novel behaviour when interacting with biological organisms, and thus to potentially novel toxic effects.

Since nanoparticles (NPs) are similar in size to viruses, their uptake by and transport through tissues are based on mechanisms distinct from those of molecular uptake and transport. Therefore, there is concern that standard toxicological tests may not be applicable or reliable in relation to NPs, hence compromising current risk-assessment procedures.

The majority of research on nano-safety in the environment has so far focused on the aquatic environment. Current research on environmental fate, however, indicates that soils will become the biggest environmental sink for nanoparticles. Following their entry into liquid waste streams, nanoparticles will pass through wastewater-treatment. processes, ending up in waste sludge which may accumulate in the agricultural land where this sludge is often applied.

What are the main objectives of the project?

This project deals with the toxicokinetics – that is, the rate at which a chemical enters a body and affects it – of metal nanoparticles coming into contact with soil-dwelling organisms. The aim is to determine NPs’ fate and effects in terrestrial ecosystems by means of case studies with zinc oxide and silver NPs, which represent different fate kinetics.

The project’s main objectives are to assess the toxicity of metal nanoparticles in soils in the short and long term; the main route of exposure for earthworms and whether it differs from those of ionic metals; and, finally, the influence of the exposure media on metal nanoparticle toxicity.

What is new or innovative about the project and the way it is addressing these issues?

We have been running a long-term study where soils with AgNP [silver nanoparticles] were stored and left to age for up to a year; their toxicity was tested at the start and after three, seven and 12 months of ageing. The results showed that silver toxicity increased over time, meaning that short-term standard toxicity tests may underestimate the environmental risk of silver nanoparticles.

In parallel, we found that organisms exposed to silver nanoparticles in short-term studies accumulated higher silver concentrations than organisms that were exposed to the same mass concentration of ionic silver. However, these NP exposed organisms actually suffered lower toxic effects. This observation contradicts the prevailing assumption in toxicology that the internalised concentration is directly related to chemical concentration at the target site and hence to its toxicity. This observation creates a new paradigm for nano-ecotoxicology.

What is not yet known is whether the accumulated NP metal may in the longer-term ultimately become toxic (e.g. through dissolution and ion release) in cells and tissues where AgNPs may be stored. Should this occur, the high concentrations accumulated may ultimately result in greater long-term toxicity for NPs than for ionic forms. This may reveal these accumulated NPs as internalised ‘time bombs’ relevant to long-term effects and toxicity.

However, it has to be borne in mind that the redicted environmental concentrations resulting from current use of nanoparticles (e.g. results from EU projects like NANOFATE2) are many times smaller than those used in these studies, meaning that such accumulations of nanoparticle-related silver are unlikely to occur in the environment or, ultimately, in humans.

What difficulties did you encounter and how did you solve them?

The main problems encountered relate to the tracking of nanoparticles inside the tissues and soils, as both are complex matrices. The analysis of the particles is a challenge in itself, even when in water, but to get information about their state in these matrices often requires unrealistic exposure concentrations (due to low detection limits of the highly specialised techniques used for analysis) or extraction of the particles from the matrices, which could potentially change the state of the particles.

In this project, I travelled to University of Kentucky to work with Jason Unrine and used gentle water-based extractions of soil samples immediately before analysing them using ‘Field-flow fractionation’ and ‘Inductively coupled plasma mass spectrometry’ to identify the state of nanoparticles in my aged soils.

To look at what form (speciation) of silver and zinc from the nanoparticle exposures could be found inside worms I collaborated with NANOFATE researchers at Cardiff University who fixed and thinly sectioned the worm tissues. I was lucky to be given the time to use specialist facilities like the UK’s Diamond Light Source synchrotron to investigate where and in what form the metals and potential nanoparticles could be found in these tissues.

The main challenge is that as soon as you take nanoparticles out of the manufacturers’ bottle they start changing, particularly when put into environments likes natural soils and waters, or even organisms. Therefore a lot of characterisation is needed during exposure to establish the state of the nanoparticles the organisms have been exposed to and how fast they are changing from pristine particles to dissolved ions, or particles with completely different surfaces.

Technical solutions to characterisation have been found during this short project, but this will remain a logistical challenge for many years to come as the analysis equipment is still very specialised and expensive and therefore not generally available.

What are the concrete results from the research so far?

The project has helped us draw various conclusions regarding the impact of NPs on the environment and how to assess them. First, we now know that soil acidity, or pH, influences the dissolution and toxicity of ZnO nanoparticles [zinc oxide].

Then, we found that toxicity of silver nanoparticles’ increases over time and that the particles’ coating affects their toxicity to soil invertebrates.

As previously mentioned, earthworms exposed to silver nanoparticles for 28 days accumulated higher silver concentrations than earthworms exposed to silver ions, without the excess silver from the nanoparticles having a toxic effect. [emphasis mine] Moreover, soil ingestion was identified as the main route of exposure to AgNP and ZnONP in earthworms.

How can industry and decision-makers ensure that nanomaterials do not impact our environment?

We hope that this project, and the larger EU project NANOFATE to which it is linked, will provide knowledge and tools enabling standard environmental-hazard and risk-assessment methodologies to be applied to engineered nanoparticles (ENPs) with just a few judicious modifications. The current systems and protocols for chemical risk assessment have been developed over decades, and where no novel toxic mechanisms exist, our results tend to say that nano fits in as long as we measure the right things and characterise realistic exposures properly.

Our research aims to determine the minimum methodological tweaks needed. So far everything indicates that the potential benefits from nanotechnology can be realised and managed safely alongside other chemicals. While we are fairly confident at this stage that ENPs impose no greater acute effects on important biological parameters – like reproduction – than their ionic forms, the NANO-ECOTOXICITY results demonstrate that we have some way to go before we can state loud and clear that we do not believe there is any novel low-level or long-term effect.

As for all chemicals, proving such a negative is impossible using short-term tests. We think the final conclusions by industry and regulators on safe use of nanoparticles should and will have to be made according to a ‘weight of evidence’ approach – proving there is a gap between predicted likely exposure levels and those levels seen to cause any effects or accumulations within ecosystem species.

What are the next topics for your research?

This project has finished but the next step for any other funding opportunity would be to address increasingly environmentally relevant exposure scenarios by analysing how nanoparticles modify in the environment and interact with living tissues and organisms at different trophic levels. I would like to investigate nanoparticle transformation and interactions in living tissues. To date, the studies that have identified this ‘excess’ accumulation of non-toxic metal loads in nanoparticleexposed organisms have only been short term.

Apart from the obviously increased food-chain transfer potential, is also not known whether, over the longer term, the accumulated NP-derived metal ultimately becomes toxic when present in tissues and cells. Such transformation and release of metal ions within tissues may ultimately result in greater longterm toxicity for NPs than for ionic forms.

Furthermore, I want to test exposures in a functioning model ecosystem including interspecific interactions and trophic transfer. Since interactions between biota and nanoparticles are relevant in natural soil systems, caution is needed when attempting to predict the ecological consequences of nanoparticles based on laboratory assays conducted with only a single species. In the presence of the full complement of biological components of soil systems, complex NPs may follow a range of pathways in which coatings may be removed and replaced with exudate materials. Studies to quantify the nature of these interactions are therefore needed to identify the fate, bioavailability and toxicity of realistic ‘non-pristine’ forms of NPs present in real soil environments.

New to me was the material about ageing silver nanoparticles and their increased toxicity over time. While this is an interesting piece of information it’s not necessarily all that useful. It seems even with their increased uptake compared to silver ions, silver nanoparticles (Diez-Ortiz doesn’t indicate whether or not * they tested variously aged silver nanoparticles) did not have toxic effects on the earthworms tested.

The NANO-ECOTOXICITY website doesn’t appear to exist anymore but you can find the NANOFATE (Nanoparticle Fate Assessment and Toxicity in the Environment) website here.

* ‘not’ removed to clarify meaning, Oct. 9, 2013. (Note: I had on Oct. 8, 2013 removed ‘not’ in a second place from the sentence in an attempt t o clarify the meaning and ended up not making any sense at all.) Please read Maria Diez-Ortiz in the Comments, as she clarifies matters in a way I could never hope to.