Tag Archives: nano zinc oxide

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.

Nanopollution of marine life

Concerns are being raised about nanosunscreens and nanotechnology-enabled marine paints and their effect on marine life, specifically, sea urchins. From a May 13, 2015 news item on Nanowerk (Note: A link has been removed),

Nanomaterials commonly used in sunscreens and boat-bottom paints are making sea urchin embryos more vulnerable to toxins, according to a study from the University of California, Davis [UC Davis]. The authors said this could pose a risk to coastal, marine and freshwater environments.

The study, published in the journal Environmental Science and Technology (“Copper Oxide and Zinc Oxide Nanomaterials Act as Inhibitors of Multidrug Resistance Transport in Sea Urchin Embryos: Their Role as Chemosensitizers”), is the first to show that the nanomaterials work as chemosensitizers. In cancer treatments, a chemosensitizer makes tumor cells more sensitive to the effects of chemotherapy.

Similarly, nanozinc and nanocopper made developing sea urchin embryos more sensitive to other chemicals, blocking transporters that would otherwise defend them by pumping toxins out of cells.

A May 12, 2015 UC Davis news release, which originated the news item, includes some cautions,

Nanozinc oxide is used as an additive in cosmetics such as sunscreens, toothpastes and beauty products. Nanocopper oxide is often used for electronics and technology, but also for antifouling paints, which prevent things like barnacles and mussels from attaching to boats.

“At low levels, both of these nanomaterials are nontoxic,” said co-author Gary Cherr, professor and interim director of the UC Davis Bodega Marine Laboratory, and an affiliate of the UC Davis Coastal Marine Sciences Institute. “However, for sea urchins in sensitive life stages, they disrupt the main defense mechanism that would otherwise protect them from environmental toxins.”

Science for safe design

Nanomaterials are tiny chemical substances measured in nanometers, which are about 100,000 times smaller than the diameter of a human hair. Nano-sized particles can enter the body through the skin, ingestion, or inhalation. They are being rapidly introduced across the fields of electronics, medicine and technology, where they are being used to make energy efficient batteries, clean up oil spills, and fight cancer, among many other uses. However, relatively little is known about nanomaterials with respect to the environment and health.

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

Copper Oxide and Zinc Oxide Nanomaterials Act as Inhibitors of Multidrug Resistance Transport in Sea Urchin Embryos: Their Role as Chemosensitizers by Bing Wu, Cristina Torres-Duarte, Bryan J. Cole, and Gary N. Cherr. Environ. Sci. Technol., 2015, 49 (9), pp 5760–5770 DOI: 10.1021/acs.est.5b00345 Publication Date (Web): April 7, 2015

Copyright © 2015 American Chemical Society

This paper is behind a paywall.

While this research into nanoparticles as chemosensitizers is, according to UC Davis, the first of its kind, the concern over nanosunscreens and marine waters has been gaining traction over the last few years. For example, there’s  research featured in a June 10, 2013 article by Roberta Kwok for the University of Washington’s ‘Conservation This Week’ magazine,

Sunscreen offers protection from UV rays, reduces the risk of skin cancer, and even slows down signs of aging. Unfortunately, researchers have found that sunscreen also pollutes the ocean.

Although people have been using these products for decades, “the effect of sunscreens, as a source of introduced chemicals to the coastal marine system, has not yet been addressed,” a research team writes in PLOS ONE. Sunscreens contain chemicals not only for UV protection, but also for coloring, fragrance, and texture. And beaches are becoming ever-more-popular vacation spots; for example, nearly 10 million tourists visited Majorca Island in the Mediterranean Sea in 2010.

Here’s a link to the 2013 PLOS ONE paper,

Sunscreen Products as Emerging Pollutants to Coastal Waters by Antonio Tovar-Sánchez, David Sánchez-Quiles, Gotzon Basterretxea, Juan L. Benedé, Alberto Chisvert, Amparo Salvador, Ignacio Moreno-Garrido, and Julián Blasco. PLOS ONE DOI: 10.1371/journal.pone.0065451 Published: June 5, 2013

This is an open access journal.

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.

NanoSustain published four case studies: zinc oxide, titanium dioxide, carbon nanotubes, and nanocellulose

A May 17, 2013 news item on Nanowerk highlight a European Commission-funded project, NanoSustain and its publication of a fact sheet and four case studies,,

NanoSustain, a €2.5 million NMP small collaborative project (2010-2013) funded by the European Union under FP7, has published a fact sheet and four case studies addressing these issues.

How do nanotechnology-based products impact human health and the environment?
Can they be recycled?
Can they be safely disposed of?
How can you find out?

The March 20, 2013 NanoSustain news release, which originated the news item, goes on to explain,

… the EC-funded NanoSustain project has been developing new sustainable solutions through an investigation of the life-cycle of nanotechnology-based products, in particular the physical and chemical characteristics of materials, hazard and exposure aspects, and end-of-life disposal or recycling to determine the fate and impact of nanomaterials.

A summary of the different materials and products tested within NanoSustain:

• Case Study #1: Titanium dioxide for paints
• Case Study #2: Zinc oxide for glazing products
• Case Study #3: Carbon nanotubes epoxy resins for plastics
– for structural or electrical/antistatic applications
• Case Study #4: Nanocellulose for advanced paper applications

Information about the individual experimental approaches

Descriptions of the different techniques developed

How these techniques have been successfully applied in physical-chemical characterisation; life-cycle analysis; final disposal; recycling.

Getting access to the case case studies and the fact sheet requires filling out a form but once you’ve done that you get instant access to the materials.

Here’s some information from EuroSustain’s fact sheet,

Factsheets

Analytical Techniques

Development of sustainable solutions for nanotechnology-based products based on hazard characterization and LCA1 The primary goal of the NanoSustain project is to develop new technical solutions for the sustainable design and use, recycling and final treatment of selected nanotechnology-based products.

To achieve this the project has the following objectives: 1) to assess the hazard of selected nanomaterials based on a comprehensive data survey and generation concerning their physicochemical (PC) and toxicological properties, exposure probabilities, etc., and the adaptation, evaluation, validation and use of existing analytical, testing and life-cycle assessment (LCA) methods; 2) to assess the impact of selected products during their life cycle in relation to material and energy flows (LCA); 3) to assess possible exposure routes and risks associated with the handling of these materials, their transformation and final fate; and 4) to explore the feasibility and sustainability of new technical solutions for end-of=life processes, such as reuse/recycling, final treatment or disposal.

Within NanoSustain an assessment has been made of the PC properties, exposure and toxicity, energy and material inputs and outputs at relevant stages of a material or product’s life-cycle. This means: material production, processing, manufacturing, use, transportation, and end-of-life (recycling/disposal). At each stage potential risks to human health and the environment have also been assessed, through a number of experimental models and test systems using materials that would be expected to be released from products containing nanomaterials.

Four nanomaterials were investigated that either already feature in commercial products or are expected to be commercialized on a large scale: titanium dioxide (TiO2) in paint, zinc oxide (ZnO) as a coating for glass, multi-walled carbon nanotubes (MWCNT) in epoxy resins, and nanocellulose in paper.

Detailed information on the nanomaterials have been summarized in internal project material datasheets (MDS), and will be made available as part of peer-reviewed publications on release studies and toxicological investigations. [emphases mine]

Having looked at the four case studies, each of which is two pages, I would describe them as teasers. There’s not a lot of information in them as to the results of the testing which makes sense when you see that they will be publishing in various publications.

I find the inclusion of titanium dioxide, zinc oxide and carbon nanotubes for life-cycle assessments easily understandable as they  have been integrated into many consumer products. However, it’s my understanding that nanocellulose has not reached that level of product integration. Still, given the number of times I’ve been told this is a ‘safe’ product, it’s interesting to see what NanoSustain has to say about its toxicity (from the NanoSustain’s nanocellulose case study),

Work in NanoSustain has provided new data and information on the physicochemical properties, potential human and environmental hazard and risk associated with relevant stages of the life-cycle of nanocellulose based products as well as on the overall energy and material input/output that may happen during manufacturing, use and disposal. Initial results indicate that the nanocellulose degrades efficiently under standard composting conditions, but does not in aquatic environments. Furthermore nanocellulose does not demonstrate any ecotoxicity. Unfortunately nanocellulose forms a gel when suspended in media for inhalation studies, and so no toxicology experiments could be performed (as for the other engineered nanomaterials studied in NanoSustain). Final results will be made available once published in peer-reviewed journals.

I have written many times about nanocellulose, a topic featuring some interesting and confusing nomenclature and taking this opportunity to highlight a couple of responses from folks who took the time to clarify things for me (from my Aug. 2, 2012 posting),

KarenS says:

Hi Maryse!

From my understanding, nanocrystaline cellulose (NCC), cellulose nanocrystals (CNC), cellulose whiskers (CW) and cellulose nanowhiskers (CNW) are all the same stuff: cylindrical rods of crystalline cellulose (diameter: 5-10 nm; length: 20-1000 nm). Cellulose nanofibers or nanofibrils (CNF), on the contrary, are less crystalline and are in the form of long fibers (diameter: 20-50 nm; length: up to several micrometers).

There is still a lot of confusion on the nomenclature of cellulose nanoparticles, but nice explanations (and pictures!) are given here (and also in other papers from the same conference):

http://www.tappi.org/Downloads/Conference-Papers/2012/12NANO/12NANO49.aspx

and there’s this from my Sept. 26, 2012 posting,

Gary Chinga Carrasco says:

The definition of cellulose nanofibrils as “diameter: 20-50 nm; length: up to several micrometers)” is somewhat simplified. For terminology on MFC terms you may want to take a look at: http://www.nanoscalereslett.com/content/6/1/417

Bringing this piece back to where I started, I look forward to seeing the NanoSustain case studies published with more details in the future.

Note: Since the folks at NanoSustain are likely using their form to collect data, I’m not linking back to the factsheet or nanocellulose case study as I would usually. So, if you want to look at the material, you do need to register via the form.

Soybeans and nanoparticles redux

If you read the Feb. 6, 2013 news release on EurekAlert too quickly you might not realize that only one of the two types of the tested nanoparticles adversely affects soybean plants,

Two of the most widely used nanoparticles (NPs) accumulate in soybeans — second only to corn as a key food crop in the United States — in ways previously shown to have the potential to adversely affect the crop yields and nutritional quality, a new study has found. It appears in the journal ACS Nano. [emphasis mine]

Jorge L. Gardea-Torresdey and colleagues cite rapid increases in commercial and industrial uses of NPs, the building blocks of a nanotechnology industry projected to put $1 trillion worth of products on the market by 2015. Zinc oxide and cerium dioxide are among today’s most widely used NPs. Both are used in cosmetics, lotions, sunscreens and other products. They eventually go down the drain, through municipal sewage treatment plants, and wind up in the sewage sludge that some farmers apply to crops as fertilizer. Gardea-Torresdey’s team previously showed that soybean plants grown in hydroponic solutions accumulated zinc and cerium dioxide in ways that alter plant growth and could have health implications.

The question remained, however, as to whether such accumulation would occur in the real-world conditions in which farmers grow soybeans in soil, rather than nutrient solution. Other important questions included the relationship of soybean plants and NPs, the determination of their entrance into the food chain, their biotransformation and toxicity and the possible persistence of these products into the next plant generation. Their new study, performed at two world-class synchrotron facilities — the SLAC National Accelerator Laboratory in California and the European Synchrotron Radiation Facility in Grenoble, France, addressed those questions. “To our knowledge, this is the first report on the presence of cerium dioxide and zinc compounds in the reproductive/edible portions of the soybean plant grown in farm soil with cerium dioxide and zinc oxide nanoparticles. In addition, our results have shown that cerium dioxide NPs in soil can be taken up by food crops and are not biotransformed in soybeans. [emphasis mine] This suggests that cerium dioxide NPs can reach the food chain and the next soybean plant generation, with potential health implications,” the study notes.

The University of Texas El Paso Feb. 6, 2013 news release provides more detail and more clarity about the results of the research ,

Experiments led by Jorge Gardea-Torresdey, Ph.D., of The University of Texas at El Paso (UTEP) have shown that certain man-made nanoparticles that land in soil can be transferred from the roots of plants to the grains, thus entering the food supply via crops grown for human consumption.

Cerium dioxide, which is commonly used in sunscreens and oil refining, remained intact when it was absorbed by the plant, and was transferred all the way into the edible soybean grains. [emphasis mine]

On the other hand, zinc oxide – commonly used in sunscreens and cosmetics – was transferred to the grain, but had broken down to a nontoxic form. [emphasis mine]

To track the nanoparticles’ route within the plants, the researchers used the intense beams of X-rays from the SLAC National Accelerator Laboratory’s Stanford Synchrotron Radiation Lightsource (SSRL) and the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. The X-rays also helped reveal whether or not the nanoparticles were chemically transformed in the process.

While studies are under way, Gardea-Torresdey says there is currently little information on the potential health implications of nanoparticles.

UTEP has produced a video titled, UTEP Study Shows Engineered Nanoparticles Can Enter Food Supply. This piece, which features Gardea-Torresdey and a student,  seems to be less about the study and more about the benefits of studying at UTEP and the impact of the Latino community in the US,


Here’s a citation and a link to the article (Note: This work bears a remarkable resemblance to the work mentioned in my Aug. 20, 2012 posting about soybeans and nanoparticles, not least because the studies share three or more authors),

In Situ Synchrotron X-ray Fluorescence Mapping and Speciation of CeO2 and ZnO Nanoparticles in Soil Cultivated Soybean (Glycine max) by Jose A. Hernandez-Viezcas, Hiram Castillo-Michel, Joy Cooke Andrews , Marine Cotte , Cyren Rico, Jose R. Peralta-Videa, Yuan Ge, John H. Priester, Patricia Ann Holden, and Jorge L. Gardea-Torresdey. ACS Nano, DOI: 10.1021/nn305196q Publication Date (Web): January 15, 2013

Copyright © 2013 American Chemical Society

The article is behind a paywall.

Caution and nanoscale zinc oxide in sunscreens

While I’ve had my reservations about the anti-nanoscreen campaigning, it is important to remember that safety research into the use of nanoparticles in sunscreens is ongoing. A new piece of research on nanoscale zinc oxide and sunscreens has been performed at the Missouri University of Science and Technology and this is something I would put under the category of interesting, possibly disturbing, and not at all definitive.

From the May 8, 2012 news item on Nanowerk,

… researchers at Missouri University of Science and Technology are discovering that sunscreen may not be so safe after all. Cell toxicity studies by Dr. Yinfa Ma, Curators’ Teaching Professor of chemistry at Missouri S&T, and his graduate student Qingbo Yang, suggest that when exposed to sunlight, zinc oxide, a common ingredient in sunscreens, undergoes a chemical reaction that may release unstable molecules known as free radicals. Free radicals seek to bond with other molecules, but in the process, they can damage cells or the DNA contained within those cells. This in turn could increase the risk of skin cancer.

“Zinc oxide may generate free radicals when exposed to UV (ultraviolet) sunlight,” May [sic] says, “and those free radicals can kill cells.”

Ma studied how human lung cells immersed in a solution containing nano-particles of zinc oxide react when exposed to different types of light over numerous time frames. Using a control group of cells that were not immersed in the zinc oxide solution, Ma compared the results of light exposure on the various groups of cells. He found that zinc oxide-exposed cells deteriorated more rapidly than those not immersed in the chemical compound. Even when exposed to visible light only, the lung cells suspended in zinc oxide deteriorated. But for cells exposed to ultraviolet rays, Ma found that “cell viability decreases dramatically.”

I categorized this research as mildly disturbing for a couple of reasons. (a) It’s never good to hear about lung cells deteriorating. (b) I never slather sunscreen on my lungs. (c) Why didn’t the researcher test skin cells? (d) The cells were immersed in a solution; what concentration of zinc oxide nanoparticles were present in the solution and is that the same concentration found in my sunscreen?

As the researcher notes this work is just part of a longer scientific inquiry (from the May 8, 2012 news item),

Ma’s research on zinc oxide’s effect on cells is still in the early stages, so he cautions people from drawing conclusions about the safety or dangers of sunscreen based on this preliminary research.

“More extensive study is still needed,” May says. “This is just the first step.”

For instance, Ma plans to conduct electron spin resonance tests to see whether zinc oxide truly does generate free radicals, as he suspects. In addition, clinical trials will be needed before any conclusive evidence may be drawn from his studies.

In the meantime, Ma advises sunbathers to use sunscreen and to limit their exposure to the sun.

“I still would advise people to wear sunscreen,” he says. “Sunscreen is better than no protection at all.”

I suspect that last comment is an indirect reference to a recent study (mentioned in my Feb. 9, 2012 posting) that found 13% of Australians said they weren’t using any sunscreens due to their fears about nanoparticles in those products.

At this point, nanosunscreens get a very cautious pass given the information at hand.

For anyone who’s interested in how stories about science and risk, specifically concerning nanosunscreens, can get reported, I’d advise a glance at the 2020 Science blog. (Andrew Maynard, Director of the Risk Science Center at the University of Michigan, has been writing on his 2020 blog for years and covered nanosunscreens on more than one occasion.) In his May 3, 2012 posting he recounts his experience trying to refine comments about nanosunscreens and safety as a reporter is getting his story, with quotes from Andrew, to press.

ETA Aug. 17, 2012: I’d forgotten but was recently reminded that lung cells and skin cells are the same base cell until they differentiate themselves at a later stage of development. (I’m sure scientists are silently screaming but that’s my best description of the process.) So, I better appreciate why the researchers used lung cells for their study but my comment remains, I don’t slather sunscreen on my lungs. While the results of the study are interesting, they don’t seem applicable to a real world experience.

Nanosunscreens, zinc oxide, cancer, and the latest research

Researchers in Singapore (Nanyang Technological University and the National University of Singapore) have published a study suggesting that nano zinc oxide, found in some sunscreens, may potentially cause cancer. The Nov. 29, 2011 news item on Nanowerk provides this detail,

The chemical, Zinc Oxide, is used to absorb harmful ultra violet light. But when it is turned into nano-sized particles, they are able to enter human cells and may damage the cells’ DNA. This in turn activates a protein called p53, whose duty is to prevent damaged cells from multiplying and becoming cancerous. However, cells that lack p53 or do not produce enough functional p53 may instead develop into cancerous cells when they come into contact with Zinc Oxide nanoparticles. [emphases mine]

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

A few items I was not able to determine (it’s in the study but I don’t understand the term ‘sonicate’ or others the researchers used),

  • were the concentrations of nano zinc oxide used in the research the standard concentrations one would find in a sunscreen, and
  • were the cells continuously exposed to nano zinc oxide, e.g. sitting in a bath of the chemical, or were the cells exposed in the way cells in a body would be exposed

I ask these questions not to so much to expose my ignorance but to point out how difficult it is draw conclusions from a study when you don’t have the training for it. In fact, if you read the news item on Nanowerk or the study (The role of the tumor suppressor p53 pathway in the cellular DNA damage response to zinc oxide nanoparticles [article behind paywall]), you’ll notice that even the researchers have phrased their findings very carefully.

You’ll also notice that there is another agenda (from the news item on Nanowerk),

The breakthrough also validated efforts by Asst Prof Loo and Asst Prof Ng to pioneer a research group in the emerging field of nanotoxicology, which is still very much in its infancy throughout the world.

The research team would also like to work with the European Union to uncover the risks involving nanomaterials and how these materials should be regulated before they are made commercially available. Asst Prof Joachim Loo, who received his Bachelor and Doctorate degrees from NTU, was the only Singaporean representative in a recent nanotechnology workshop held in Europe. At the workshop, it was agreed that research collaborations in nanotoxicology between EU and South-east Asia should be increased.

Another research study on nano zinc oxide was released last year (it was not cited in the references for the latest Nov. 2011 study). From the Aug. 20, 2010 news item on physorg.com,

A technique developed by Macquarie University has proven for the first time that a tiny amount of zinc from sunscreens is absorbed through the skin into the human body, but is not yet able to discern whether the zinc is in nanoparticle form.

Professor Brian Gulson of Macquarie University conducted the research – published online in the current edition of the journal Toxicological Sciences – with collaborators in CSIRO and the Australian National University and the Australian Photobiology Testing Facility. The research was widely reported on in February 2010 following a presentation by Gulson at a scientific conference.

The team traced the skin absorption of a highly purified and stable isotope which allowed them to distinguish the zinc from the sunscreen from that which is naturally present in the body or environment. Zinc is absolutely essential to bodily functions.

The researchers suggest that follow-up studies from the scientific community with different formulations over longer periods of time are essential, but that until evidence to the contrary is obtained, people spending time outdoors should continue to use sunscreens.

Getting back to that question about the concentration of the nano zinc oxide solution used in the most recent studies in Singapore, here’s what Brian Gulson had to say about nano zinc oxide concentrations in his work and about a shortcoming in his study (from an Australian Broadcasting Corporation [ABC] Feb. 25, 2010 interview with Ashley Hall,

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

ASHLEY HALL: So is it a significant amount?

BRIAN GULSON: No, no it’s really not.

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

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

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

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

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

It seems it’s not yet time to press the panic button since more research is needed for scientists to refine their understanding of nano zinc oxide and possible health effects from its use.

Final note: The researchers listed on the Singapore study are: Kee Woei Ng, Stella P.K. Khoo, Boon Chin Heng, Magdiel I. Setyawati, Eng Chok Tan, Xinxin Zhao, Sijing Xiong, Wanru Fang, David T. Leong, and Joachim S.C. Loo

Misunderstanding the data or a failure to research? Georgia Straight article about nanoparticles

It’s good to see articles about nanotechnology. The recent, Tiny nanoparticles could be a big problem, article written by Alex Roslin for the Georgia Straight (July 21, 2011 online or July 21-28, 2011 paper edition) is the first I’ve seen on that topic in that particular newspaper. Unfortunately, there are  some curious bits of information included in the article, which render it, in my opinion, difficult to trust.

I do agree with Roslin that nanoparticles/nanomaterials could constitute a danger and there are a number of studies which indicate that, at the least, extreme caution in a number of cases should be taken if we choose to proceed with developing nanotechnology-enabled products.

One of my difficulties with the article is the information that has been left out. (Perhaps Roslin didn’t have time to properly research?) At the time (2009) I did read with much concern the reports Roslin mentions about the Chinese workers who were injured and/or died after working with nanomaterials. As Roslin points out,

Nanotech already appears to be affecting people’s health. In 2009, two Chinese factory workers died and another five were seriously injured in a plant that made paint containing nanoparticles.

The seven young female workers developed lung disease and rashes on their face and arms. Nanoparticles were found deep in the workers’ lungs.

“These cases arouse concern that long-term exposure to some nanoparticles without protective measures may be related to serious damage to human lungs,” wrote Chinese medical researchers in a 2009 study on the incident in the European Respiratory Journal.

Left undescribed by Roslin are the working conditions; the affected people were working in an unventilated room. From the European Respiratory Journal article (ERJ September 1, 2009 vol. 34 no. 3 559-567, free access), Exposure to nanoparticles is related to pleural effusion, pulmonary fibrosis and granuloma,

A survey of the patients’ workplace was conducted. It measures ∼70 m2, has one door, no windows and one machine which is used to air spray materials, heat and dry boards. This machine has three atomising spray nozzles and one gas exhauster (a ventilation unit), which broke 5 months before the occurrence of the disease. The paste material used is an ivory white soft coating mixture of polyacrylic ester.

Eight workers (seven female and one male) were divided into two equal groups each working 8–12 h shifts. Using a spoon, the workers took the above coating material (room temperature) to the open-bottom pan of the machine, which automatically air-sprayed the coating material at the pressure of 100–120 Kpa onto polystyrene (PS) boards (organic glass), which can then be used in the printing and decorating industry. The PS board was heated and dried at 75–100°C, and the smoke produced in the process was cleared by the gas exhauster. In total, 6 kg of coating material was typically used each day. The PS board sizes varied from 0.5–1 m2 and ∼5,000 m2 were handled each workday. The workers had several tasks in the process including loading the soft coating material in the machine, as well as clipping, heating and handling the PS board. Each worker participated in all parts of this process.

Accumulated dust particles were found at the intake of the gas exhauster. During the 5 months preceding illness the door of the workspace was kept closed due to cold outdoor temperatures. The workers were all peasants near the factory, and had no knowledge of industrial hygiene and possible toxicity from the materials they worked with. The only personal protective equipment used on an occasional basis was cotton gauze masks. According to the patients, there were often some flocculi produced during air spraying, which caused itching on their faces and arms. It is estimated that the airflow or turnover rates of indoor air would be very slow, or quiescent due to the lack of windows and the closed door. [emphases mine]

Here’s the full text from the researchers’ conclusion,

In conclusion, these cases arouse concern that long-term exposure to some nanoparticles without protective measures may be related to serious damage to human lungs. It is impossible to remove nanoparticles that have penetrated the cell and lodged in the cytoplasm and caryoplasm of pulmonary epithelial cells, or that have aggregated around the red blood cell membrane. Effective protective methods appear to be extremely important in terms of protecting exposed workers from illness caused by nanoparticles.

There is no question that serious issues about occupational health and safety with regards to nanomaterials were raised. But, we work with dangerous and hazardous materials all the time; precautions are necessary whether you’re working with hydrochloric acid or engineered nanoparticles. (There are naturally occurring nanoparticles too.)

Dr. Andrew Maynard (at the time he was the Chief Science Advisor for the Project on Emerging Nanotechnologies, today he is the Director of the University of Michigan’s Risk Science Center) on his 2020 Science blog wrote a number of posts dated Aug. 18, 2009 about this tragic industrial incident, including this one where he culled comments from six other researchers noting some of the difficulties the Chinese researchers experienced running a clinical study after the fact.

The material on silver nanoparticles and concerns about their use in consumer products and possible toxic consequences with their eventual appearance in the water supply seem unexceptionable to me. (Note:  I haven’t drilled down into the material and the writer cites studies unknown to me but they parallel information I’ve seen elsewhere).

The material on titanium dioxide as being asbestos-like was new to me, the only nanomaterial I’d previously heard described as being similar to asbestos is the long carbon nanotube. I am surprised Roslin didn’t mention that occupational health and safety research which is also quite disturbing, it’s especially surprising since Roslin does mention carbon nanotubes later in the article.

There is a Canadian expert, Dr. Claude Ostiguy, who consults internationally on the topic of nanotechnology and occupational health and safety. I wonder why he wasn’t consulted. (Note: He testified before Canada’s House of Commons Standing Committee on Health meeting in June 2010 on this topic. You can find more about this in my June 23, 2011 posting, Nanomaterials, toxicity, and Canada’s House of Commons Standing Committee on Health.)

Quoted quite liberally throughout the article is researcher, Dr.Robert Schiestl (professor of pathology and radiation oncology at the University of California at Los Angeles [UCLA]). This particular passage referencing Schiestl is a little disconcerting,

Schiestl said nanoparticles could also be helping to fuel a rise in the rates of some cancers. He wouldn’t make a link with any specific kind of cancer, but data from the U.S. National Cancer Institute show that kidney and renal-pelvis cancer rates rose 24 percent between 2000 and 2007 in the U.S., while the rates for melanoma of the skin went up 29 percent and thyroid cancer rose 54 percent.

Since Schiestl isn’t linking the nanoparticles to any specific cancers, why mention those statistics? Using that kind of logic I could theorize that the increase in the number and use of cell phones (mobiles) may have something to do with these cancers. Perhaps organic food has caused this increase? You see the problem?

As for the number of nanotechnology-enabled products in use, I’m not sure why Roslin chose to cite the Project on Emerging Nanotechnologies’ inventory which is not scrutinized, i. e., anyone can register any product as nanotechnology-enabled. The writer also mentioned a Canadian inventory listing over 1600 products  cited in an ETC Group report, The Big Downturn? Nanogeopolitics,

Has anyone ever seen this inventory? I’ve been chasing it for years and the only time the Canadian government reports on this inventory is in the Organization for Economic Cooperation and Development (OECD) report (cited by the ETC Group [no. 79 in their list of references] and noted in both my Feb. 1, 2011 posting and my April 12, 2010 posting). Here’s the OECD report, if you’d like to see it for yourself. The top three questions I keep asking myself is where is the report/inventory, how did they determine their terms of reference, and why don’t Canadian taxpayers have easy access to it? I’d best return to my main topic.

As for the material Roslin offers about nanosunscreens I was surprised given the tenor of the article to see that the Environmental Working Group (EWG) was listed as an information source since they recommend mineral sunscreens containing nanoscale ingredients such as titanium dioxide and/or zinc oxide as preferable to sunscreens containing hormone disruptors.  From the EWG page on sunscreens and nanomaterials,

Sunscreen makers offer mineral and non-mineral formulations, as well as products that combine both mineral and non-mineral active ingredients. Mineral formulations incorporate zinc oxide or titanium dioxide in nano- and micro-sized particles that can be toxic if they penetrate the skin. Most studies show that these ingredients do not penetrate through skin to the bloodstream, but research continues. These constitute one in five sunscreens on the market in 2010 and offer strong UVA protection that is rare in non-mineral sunscreens.

The most common ingredients in non-mineral sunscreens are oxybenzone, octisalate, octinoxate, and avobenzone found in 65, 58, 57, and 56 percent of all non-mineral sunscreens on the market, respectively. The most common, oxybenzone, can trigger allergic reactions, is a potential hormone disruptor and penetrates the skin in relatively large amounts. Some experts caution that it should not be used on children. Three of every five sunscreens rated by EWG are non-mineral, and one in five sunscreens combines both mineral and non-mineral active ingredients.

EWG reviewed the scientific literature on hazards and efficacy (UVB and UVA protection) for all active ingredients approved in the U.S. Though no ingredient is without hazard or perfectly effective, on balance our ratings tend to favor mineral sunscreens because of their low capacity to penetrate the skin and the superior UVA protection they offer. [emphasis mine]

(I did find some information (very little) about Health Canada and sunscreens which I discuss in June 3, 2011 posting [if you’re impatient, scroll down about 1/2 way].)

There was some mention of Health Canada in Roslin’s article but no mention of last year’s public consultation, although to be fair, it seemed a clandestine operation. (My latest update on the Health Canada public consultation about a definition for nanomaterials is May 27, 2011.)

I find some aspects of the article puzzling as Roslin is an award-winning investigative reporter. From the kitco bio page,

Alex Roslin is a leading Canadian investigative journalist and active trader based in Montreal. He has won a Canadian Association of Journalists award for investigative reporting and is a five-time nominee for investigative and writing prizes from the CAJ and the National Magazine Awards. He has worked on major investigations for Canada’s premier investigative television program, the fifth estate, and the CBC’s Disclosure program. His writing has appeared in Technical Analysis of Stocks & Commodities, The Financial Post, Toronto Star and Montreal Gazette. He regularly writes about investing for The Montreal Gazette.

I notice there’s no mention of writing in either science or health matters so I imagine this is an early stage piece in this aspect of Roslin’s career, which may explain some of the leaps in logic and misleading information. Happily, I did learn a few things from reading the article and while I don’t trust much of the information in it, I will investigate further as time permits.

In general, I found the tenor of the article more alarmist than informational and I’m sorry about that as I would like to see more information being shared and, ultimately, public discussion in Canada about nanotechnology and other emerging technologies.

California’s call for information about nanomaterials

A little late but better than never, the US state of California has issued a call for information focused on analytical test methods, i.e., lab procedures for testing, nano silver, nano zero valent iron, nano titanium dioxide, nano zinc oxide, nano cerium oxide, and quantum dots. The deadline for a response is Dec. 21, 2011, one year from the date of the request. From the Dec. 27, 2010 news item on Nanowerk,

DTSC [Department of Toxic Substances Control] has conducted a search of known public sources for analytical test methods for these six nanomaterials. We have compiled our research in this bibliography. DTSC has also contacted and consulted with manufacturers, researchers, environmental laboratory experts, other governments, and stakeholders regarding analytical test methods for these nanomaterials in these matrices. We convened public workshops and symposia on nanotechnology and, in particular, these six nanomaterials.

From our research, consultations, and workshops, we have determined that little or no information on analytical test methods for these nanomaterials in the human body or the environment now exists. To better understand the behavior, fate and transport of the se six nanomaterials, appropriate analytical test methods are needed for manufacturers, for contract and reference laboratories, and for regulatory agencies.

You can get more information about the call from the DTSC site including a list of companies that received the ‘call for information’ letter.