Category Archives: environment

Sunscreens: 2018 update

I don’t usually concern myself with SPF numbers on sunscreens as my primary focus has been on the inclusion of nanoscale metal particles (these are still considered safe). However, a recent conversation with a dental hygienist and coincidentally tripping across a June 19, 2018 posting on the blog shortly after the convo. has me reassessing my take on SPF numbers (Note: Links have been removed),

So, what’s the deal with SPF? A recent interview of Dr Steven Q Wang, M.D., chair of The Skin Cancer Foundation Photobiology Committee, finally will give us some clarity. Apparently, the SPF number, be it 15, 30, or 50, refers to the amount of UVB protection that that sunscreen provides. Rather than comparing the SPFs to each other, like we all do at the store, SPF is a reflection of the length of time it would take for the Sun’s UVB radiation to redden your skin (used exactly as directed), versus if you didn’t apply any sunscreen at all. In ideal situations (in lab settings), if you wore SPF 30, it would take 30 times longer for you to get a sunburn than if you didn’t wear any sunscreen.

What’s more, SPF 30 is not nearly half the strength of SPF 50. Rather, SPF 30 allows 3% of UVB rays to hit your skin, and SPF 50 allows about 2% of UVB rays to hit your skin. Now before you say that that is just one measly percent, it actually is much more. According to Dr Steven Q. Wang, SPF 30 allows around 1.5 times more UV radiation onto your skin than SPF 50. That’s an actual 150% difference [according to Wang’s article “… SPF 30 is allowing 50 percent more UV radiation onto your skin.”] in protection.

(author of the ‘eponymous’ blog) offers a good overview of the topic in a friendly, informative fashion albeit I found the ‘percentage’ to be a bit confusing. (S)he also provides a link to a previous posting about the ingredients in sunscreens (I do have one point of disagreement with regarding oxybenzone) as well as links to Dr. Steven Q. Wang’s May 24, 2018 Ask the Expert article about sunscreens and SPF numbers on skincancer.org. You can find the percentage under the ‘What Does the SPF Number Mean?’ subsection, in the second paragraph.

Ingredients: metallic nanoparticles and oxybenzone

The use of metallic nanoparticles  (usually zinc oxide and/or (titanium dioxide) in sunscreens was loathed by civil society groups, in particular Friends of the Earth (FOE) who campaigned relentlessly against their use in sunscreens. The nadir for FOE was in February 2012 when the Australian government published a survey showing that 13% of the respondents were not using any sunscreens due to their fear of nanoparticles. For those who don’t know, Australia has the highest rate of skin cancer in the world. (You can read about the debacle in my Feb. 9, 2012 posting.)

At the time, the only civil society group which supported the use of metallic nanoparticles in sunscreens was the Environmental Working Group (EWG).  After an examination of the research they, to their own surprise, came out in favour (grudgingly) of metallic nanoparticles. (The EWG were more concerned about the use of oxybenzone in sunscreens.)

Over time, the EWG’s perspective has been adopted by other groups to the point where sunscreens with metallic nanoparticles are commonplace in ‘natural’ or ‘organic’ sunscreens.

As for oxybenzones, in a May 23, 2018 posting about sunscreen ingredients notes this (Note: Links have been removed),

Oxybenzone – Chemical sunscreen, protects from UV damage. Oxybenzone belongs to the chemical family Benzophenone, which are persistent (difficult to get rid of), bioaccumulative (builds up in your body over time), and toxic, or PBT [or: Persistent, bioaccumulative and toxic substances (PBTs)]. They are a possible carcinogen (cancer-causing agent), endocrine disrupter; however, this is debatable. Also could cause developmental and reproductive toxicity, could cause organ system toxicity, as well as could cause irritation and potentially toxic to the environment.

It seems that the tide is turning against the use of oxybenzones (from a July 3, 2018 article by Adam Bluestein for Fast Company; Note: Links have been removed),

On July 3 [2018], Hawaii’s Governor, David Ig, will sign into law the first statewide ban on the sale of sunscreens containing chemicals that scientists say are damaging the Earth’s coral reefs. Passed by state legislators on May 1 [2018], the bill targets two chemicals, oxybenzone and octinoxate, which are found in thousands of sunscreens and other skincare products. Studies published over the past 10 years have found that these UV-filtering chemicals–called benzophenones–are highly toxic to juvenile corals and other marine life and contribute to the fatal bleaching of coral reefs (along with global warming and runoff pollutants from land). (A 2008 study by European researchers estimated that 4,000 to 6,000 tons of sunblock accumulates in coral reefs every year.) Also, though both substances are FDA-approved for use in sunscreens, the nonprofit Environmental Working Group notes numerous studies linking oxybenzone to hormone disruption and cell damage that may lead to skin cancer. In its 2018 annual sunscreen guide, the EWG found oxybenzone in two-thirds of the 650 products it reviewed.

The Hawaii ban won’t take effect until January 2021, but it’s already causing a wave of disruption that’s affecting sunscreen manufacturers, retailers, and the medical community.

For starters, several other municipalities have already or could soon join Hawaii’s effort. In May [2018], the Caribbean island of Bonaire announced a ban on chemicals sunscreens, and nonprofits such as the Sierra Club and Surfrider Foundation, along with dive industry and certain resort groups, are urging legislation to stop sunscreen pollution in California, Colorado, Florida, and the U.S. Virgin Islands. Marine nature reserves in Mexico already prohibit oxybenzone-containing sunscreens, and the U.S. National Park Service website for South Florida, Hawaii, U.S. Virgin Islands, and American Samoa recommends the use of “reef safe” sunscreens, which use natural mineral ingredients–zinc oxide or titanium oxide–to protect skin.

Makers of “eco,” “organic,” and “natural” sunscreens that already meet the new standards are seizing on the news from Hawaii to boost their visibility among the islands’ tourists–and to expand their footprint on the shelves of mainland retailers. This past spring, for example, Miami-based Raw Elements partnered with Hawaiian Airlines, Honolulu’s Waikiki Aquarium, the Aqua-Aston hotel group (Hawaii’s largest), and the Sheraton Maui Resort & Spa to get samples of its reef-safe zinc-oxide-based sunscreens to their guests. “These partnerships have had a tremendous impact raising awareness about this issue,” says founder and CEO Brian Guadagno, who notes that inquiries and sales have increased this year.

As Bluestein notes there are some concerns about this and other potential bans,

“Eliminating the use of sunscreen ingredients considered to be safe and effective by the FDA with a long history of use not only restricts consumer choice, but is also at odds with skin cancer prevention efforts […],” says Bayer, owner of the Coppertone brand, in a statement to Fast Company. Bayer disputes the validity of studies used to support the ban, which were published by scientists from U.S. National Oceanic & Atmospheric Administration, the nonprofit Haereticus Environmental Laboratory, Tel Aviv University, the University of Hawaii, and elsewhere. “Oxybenzone in sunscreen has not been scientifically proven to have an effect on the environment. We take this issue seriously and, along with the industry, have supported additional research to confirm that there is no effect.”

Johnson & Johnson, which markets Neutrogena sunscreens, is taking a similar stance, worrying that “the recent efforts in Hawaii to ban sunscreens that contain oxybenzone may actually adversely affect public health,” according to a company spokesperson. “Science shows that sunscreens are a key factor in preventing skin cancer, and our scientific assessment of the lab studies done to date in Hawaii show the methods were questionable and the data insufficient to draw factual conclusions about any impact on coral reefs.”

Terrified (and rightly so) about anything scaring people away from using sunblock, The American Academy of Dermatology, also opposes Hawaii’s ban. Suzanne M. Olbricht, president of the AADA, has issued a statement that the organization “is concerned that the public’s risk of developing skin cancer could increase due to potential new restrictions in Hawaii that impact access to sunscreens with ingredients necessary for broad-spectrum protection, as well as the potential stigma around sunscreen use that could develop as a result of these restrictions.”

The fact is that there are currently a large number of widely available reef-safe products on the market that provide “full spectrum” protection up to SPF50–meaning they protect against both UVB rays that cause sunburns as well as UVA radiation, which causes deeper skin damage. SPFs higher than 50 are largely a marketing gimmick, say advocates of chemical-free products: According to the Environmental Working Group, properly applied SPF 50 sunscreen blocks 98% of UVB rays; SPF 100 blocks 99%. And a sunscreen lotion’s SPF rating has little to do with its ability to shield skin from UVA rays.

I notice neither Bayer nor Johnson & Johnson nor the American Academy of Dermatology make mention of oxybenzone’s possible role as a hormone disruptor.

Given the importance that coral reefs have to the environment we all share, I’m inclined to support the oxybenzone ban based on that alone. Of course, it’s conceivable that metallic nanoparticles may also have a deleterious effect on coral reefs as their use increases. It’s to be hoped that’s not the case but if it is, then I’ll make my decisions accordingly and hope we have a viable alternative.

As for your sunscreen questions and needs, the Environment Working Group (EWG) has extensive information including a product guide on this page (scroll down to EWG’s Sunscreen Guide) and a discussion of ‘high’ SPF numbers I found useful for my decision-making.

Café Scientifique Vancouver (Canada) talk on May 29th, 2018: Insects in the City: Shrinking Beetles and Disappearing Bees. How Bugs Help Us Learn About the Ecological Effects of Urbanization and Climate Change

I received this Café Scientifique April 30, 2018 notice (received via email),

Our next café will happen on TUESDAY, MAY 29TH at 7:30PM in the back
room at YAGGER'S DOWNTOWN (433 W Pender). Our speaker for the
evening will be DR. MICHELLE TSENG, Assistant Professor in the Zoology
department at UBC. Her topic will be:

INSECTS IN THE CITY: SHRINKING BEETLES AND DISAPPEARING BEES. HOW BUGS
HELP US LEARN ABOUT THE ECOLOGICAL EFFECTS OF URBANIZATION AND CLIMATE
CHANGE

Living in the city, we don’t always see the good bugs amongst the
pesky ones. In this presentation, I’ll take you on a trip down insect
lane and share with you the incredible diversity of insects that have
lived in Vancouver over the last 100 years. Many of these bugs have been
collected and preserved in museums and these collections provide us with
a historical snapshot of insect communities from the past. My students
and I have made some remarkable discoveries using museum insect
collections, and these findings help us understand how these fascinating
creatures are changing in response to warming climates and increased
development.

Michelle Tseng is a professor of insect ecology at the UBC Biodiversity
Research Centre. She and her students study the impacts of habitat and
climate change on plankton and insects. Her group’s work has been
featured in national and international media, and on CBC’s Quirks and
Quarks. Michelle is also the zoologist on the award-winning CBC kids
show Scout and the Gumboot Kids.

We hope to see you there!

It says Dr. Tseng is in the zoology department but I also found a profile page for her in the botany department and that one had a little more information,

The Tseng lab investigates ecological and evolutionary responses of populations and communities to novel environments.  We test and refine theory related to predator-prey dynamics, body size variation, intra- and interspecific competition, and the maintenance of genetic variation, using laboratory and field experiments with freshwater plant and animal communities.  We also use museum collections to investigate long term patterns in organism phenotype.

Enjoy!

Cloaking devices made from DNA and gold nanoparticles using top-down lithography

This new technique seems promising but there’ve been a lot of ‘cloaking’ devices announced in the years I’ve been blogging and, in all likelihood, I was late to the party so I’m exercising a little caution before getting too excited. For the latest development in cloaking devices, there’s a January 18, 2018 news item on Nanowerk,

Northwestern University researchers have developed a first-of-its-kind technique for creating entirely new classes of optical materials and devices that could lead to light bending and cloaking devices — news to make the ears of Star Trek’s Spock perk up.

Using DNA [deoxyribonucleic acid] as a key tool, the interdisciplinary team took gold nanoparticles of different sizes and shapes and arranged them in two and three dimensions to form optically active superlattices. Structures with specific configurations could be programmed through choice of particle type and both DNA-pattern and sequence to exhibit almost any color across the visible spectrum, the scientists report.

A January 18, 2018 Northwestern University news release (also on EurekAlert) by Megan Fellman, which originated the news item, delves into more detail (Note: Links have been removed),

“Architecture is everything when designing new materials, and we now have a new way to precisely control particle architectures over large areas,” said Chad A. Mirkin, the George B. Rathmann Professor of Chemistry in the Weinberg College of Arts and Sciences at Northwestern. “Chemists and physicists will be able to build an almost infinite number of new structures with all sorts of interesting properties. These structures cannot be made by any known technique.”

The technique combines an old fabrication method — top-down lithography, the same method used to make computer chips — with a new one — programmable self-assembly driven by DNA. The Northwestern team is the first to combine the two to achieve individual particle control in three dimensions.

The study was published online by the journal Science today (Jan. 18). Mirkin and Vinayak P. Dravid and Koray Aydin, both professors in Northwestern’s McCormick School of Engineering, are co-corresponding authors.

Scientists will be able to use the powerful and flexible technique to build metamaterials — materials not found in nature — for a range of applications including sensors for medical and environmental uses.

The researchers used a combination of numerical simulations and optical spectroscopy techniques to identify particular nanoparticle superlattices that absorb specific wavelengths of visible light. The DNA-modified nanoparticles — gold in this case — are positioned on a pre-patterned template made of complementary DNA. Stacks of structures can be made by introducing a second and then a third DNA-modified particle with DNA that is complementary to the subsequent layers.

In addition to being unusual architectures, these materials are stimuli-responsive: the DNA strands that hold them together change in length when exposed to new environments, such as solutions of ethanol that vary in concentration. The change in DNA length, the researchers found, resulted in a change of color from black to red to green, providing extreme tunability of optical properties.

“Tuning the optical properties of metamaterials is a significant challenge, and our study achieves one of the highest tunability ranges achieved to date in optical metamaterials,” said Aydin, assistant professor of electrical engineering and computer science at McCormick.

“Our novel metamaterial platform — enabled by precise and extreme control of gold nanoparticle shape, size and spacing — holds significant promise for next-generation optical metamaterials and metasurfaces,” Aydin said.

The study describes a new way to organize nanoparticles in two and three dimensions. The researchers used lithography methods to drill tiny holes — only one nanoparticle wide — in a polymer resist, creating “landing pads” for nanoparticle components modified with strands of DNA. The landing pads are essential, Mirkin said, since they keep the structures that are grown vertical.

The nanoscopic landing pads are modified with one sequence of DNA, and the gold nanoparticles are modified with complementary DNA. By alternating nanoparticles with complementary DNA, the researchers built nanoparticle stacks with tremendous positional control and over a large area. The particles can be different sizes and shapes (spheres, cubes and disks, for example).

“This approach can be used to build periodic lattices from optically active particles, such as gold, silver and any other material that can be modified with DNA, with extraordinary nanoscale precision,” said Mirkin, director of Northwestern’s International Institute for Nanotechnology.

Mirkin also is a professor of medicine at Northwestern University Feinberg School of Medicine and professor of chemical and biological engineering, biomedical engineering and materials science and engineering in the McCormick School.

The success of the reported DNA programmable assembly required expertise with hybrid (soft-hard) materials and exquisite nanopatterning and lithographic capabilities to achieve the requisite spatial resolution, definition and fidelity across large substrate areas. The project team turned to Dravid, a longtime collaborator of Mirkin’s who specializes in nanopatterning, advanced microscopy and characterization of soft, hard and hybrid nanostructures.

Dravid contributed his expertise and assisted in designing the nanopatterning and lithography strategy and the associated characterization of the new exotic structures. He is the Abraham Harris Professor of Materials Science and Engineering in McCormick and the founding director of the NUANCE center, which houses the advanced patterning, lithography and characterization used in the DNA-programmed structures.

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

Building superlattices from individual nanoparticles via template-confined DNA-mediated assembly by Qing-Yuan Lin, Jarad A. Mason, Zhongyang, Wenjie Zhou, Matthew N. O’Brien, Keith A. Brown, Matthew R. Jones, Serkan Butun, Byeongdu Lee, Vinayak P. Dravid, Koray Aydin, Chad A. Mirkin. Science 18 Jan 2018: eaaq0591 DOI: 10.1126/science.aaq0591

This paper is behind a paywall.

As noted earlier, it could be a while before cloaking devices are made available. In the meantime, you may find this image inspiring,

Caption: Northwestern University researchers have developed a new method to precisely arrange nanoparticles of different sizes and shapes in two and three dimensions, resulting in optically active superlattices. Credit: Northwestern University

Cleaning up disasters with Hokusai’s blue and cellulose nanofibers to clean up contaminated soil and water in Fukushima

The Great Wave off Kanagawa (Under a wave off Kanagawa”), also known as The Great Wave or simply The Wave, by Katsushika Hokusai – Metropolitan Museum of Art, online database: entry 45434, Public Domain, https://commons.wikimedia.org/w/index.php?curid=2798407

I thought it might be a good idea to embed a copy of Hokusai’s Great Wave and the blue these scientists in Japan have used as their inspiration. (By the way, it seems these scientists collaborated with Mildred Dresselhaus who died at the age of 86, a few months after their paper was published. In honour of he and before the latest, here’s my Feb. 23, 2017 posting about the ‘Queen of Carbon’.)

Now onto more current news, from an Oct. 13, 2017 news item on Nanowerk (Note: A link has been removed),

By combining the same Prussian blue pigment used in the works of popular Edo-period artist Hokusai and cellulose nanofiber, a raw material of paper, a University of Tokyo research team succeeded in synthesizing compound nanoparticles, comprising organic and inorganic substances (Scientific Reports, “Cellulose nanofiber backboned Prussian blue nanoparticles as powerful adsorbents for the selective elimination of radioactive cesium”). This new class of organic/inorganic composite nanoparticles is able to selectively adsorb, or collect on the surface, radioactive cesium.

The team subsequently developed sponges from these nanoparticles that proved highly effective in decontaminating the water and soil in Fukushima Prefecture exposed to radioactivity following the nuclear accident there in March 2011.

I think these are the actual sponges not an artist’s impression,

Decontamination sponge spawned from current study
Cellulose nanofiber-Prussian blue compounds are permanently anchored in spongiform chambers (cells) in this decontamination sponge. It can thus be used as a powerful adsorbent for selectively eliminating radioactive cesium. © 2017 Sakata & Mori Laboratory.

An Oct. 13, 2017 University of Tokyo press release, which originated the news item, provides more detail about the sponges and the difficulties of remediating radioactive air and soil,

Removing radioactive materials such as cesium-134 and -137 from contaminated seawater or soil is not an easy job. First of all, a huge amount of similar substances with competing functions has to be removed from the area, an extremely difficult task. Prussian blue (ferric hexacyanoferrate) has a jungle gym-like colloidal structure, and the size of its single cubic orifice, or opening, is a near-perfect match to the size of cesium ions; therefore, it is prescribed as medication for patients exposed to radiation for selectively adsorbing cesium. However, as Prussian blue is highly attracted to water, recovering it becomes highly difficult once it is dissolved into the environment; for this reason, its use in the field for decontamination has been limited.

Taking a hint from the Prussian blue in Hokusai’s woodblock prints not losing their color even when getting wet from rain, the team led by Professor Ichiro Sakata and Project Professor Bunshi Fugetsu at the University of Tokyo’s Nanotechnology Innovation Research Unit at the Policy Alternatives Research Institute, and Project Researcher Adavan Kiliyankil Vipin at the Graduate School of Engineering developed an insoluble nanoparticle obtained from combining cellulose and Prussian blue—Hokusai had in fact formed a chemical bond in his handling of Prussian blue and paper (cellulose).

The scientists created this cellulose-Prussian blue combined nanoparticle by first preparing cellulose nanofibers using a process called TEMPO oxidization and securing ferric ions (III) onto them, then introduced a certain amount of hexacyanoferrate, which adhered to Prussian blue nanoparticles with a diameter ranging from 5–10 nanometers. The nanoparticles obtained in this way were highly resistant to water, and moreover, were capable of adsorbing 139 mg of radioactive cesium ion per gram.

Field studies on soil decontamination in Fukushima have been underway since last year. A highly effective approach has been to sow and allow plant seeds to germinate inside the sponge made from the nanoparticles, then getting the plants’ roots to take up cesium ions from the soil to the sponge. Water can significantly shorten decontamination times compared to soil, which usually requires extracting cesium from it with a solvent.

It has been more than six years since the radioactive fallout from a series of accidents at the Fukushima Daiichi nuclear power plant following the giant earthquake and tsunami in northeastern Japan. Decontamination with the cellulose nanofiber-Prussian blue compound can lead to new solutions for contamination in disaster-stricken areas.

“I was pondering about how Prussian blue immediately gets dissolved in water when I happened upon a Hokusai woodblock print, and how the indigo color remained firmly set in the paper, without bleeding, even after all these years,” reflects Fugetsu. He continues, “That revelation provided a clue for a solution.”

“The amount of research on cesium decontamination increased after the Chernobyl nuclear power plant accident, but a lot of the studies were limited to being academic and insufficient for practical application in Fukushima,” says Vipin. He adds, “Our research offers practical applications and has high potential for decontamination on an industrial scale not only in Fukushima but also in other cesium-contaminated areas.”

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

Cellulose nanofiber backboned Prussian blue nanoparticles as powerful adsorbents for the selective elimination of radioactive cesium by Adavan Kiliyankil Vipin, Bunshi Fugetsu, Ichiro Sakata, Akira Isogai, Morinobu Endo, Mingda Li, & Mildred S. Dresselhaus. Scientific Reports 6, Article number: 37009 (2016) doi:10.1038/srep37009 Published online: 15 November 2016

This is open access.

The Organization for Economic and Cooperative Development’s (OECD) test guidelines for nanomaterials

An Oct. 13, 2017 news item on Nanowerk announced news test guidelines from the Organization for Cooperation and Economic Development (OECD),

The OECD has released a first set of Test Guidelines developed specifically for nanomaterials, in response to their increased production and usage. The guidelines will help standardise the way countries test the safety of manufactured nanomaterials, whose near atomic-sized particles mean they may require more than regular chemical testing to understand their impact on health and the environment.

An Oct. 13, 2017 OECD press release (received via email), which originated the news item, provides more detail,

Test Guideline 318: Dispersion Stability of Nanomaterials in Simulated Environmental Media will help to assess how a particular nanomaterial would behave in contact with water or other liquids, making it applicable for testing nanomaterials likely to enter the natural environment, agriculture and food production, or to be in everyday skin contact with people through clothing or toiletries.

Additionally, updates to two existing Test Guidelines for inhalation toxicity studies (Guideline 412 and Guideline 413) mean they can now be used to determine the toxicity of inhaled nanomaterials.

The use of nanomaterials has skyrocketed of late, with manufacturers using them to improve performance in everything from tennis rackets to deodorant, yet nanoparticles can more easily penetrate skin, cells and the environment than larger compounds, and the increased likelihood of them entering the environment and human and animal bodies has raised concerns over their safety.

Working for 45 years to standardise methodologies for hazard testing and assessment, the OECD has produced over 160 harmonised test methods for determining physical and chemical properties, the effects of chemicals on health, wildlife and the environment, the efficacy of biocides and the chemistry of pesticide residues.

OECD Test Guidelines are used on a daily basis to test and assess the safety of industrial chemicals, pesticides and personal care products. They are part of the OECD’s Mutual Acceptance of Data programme, which saves over 150 million euros a year for its 42 signatory countries by avoiding duplication, as test data generated in one country is accepted by others having the same data requirement.

Journalists can download the new Test Guidelines for free on the OECD iLibrary at the links below using the OECD’s media log-in and password (available to media on request) or by email on request.

Test Guideline 318

Test Guideline 412

Test Guideline 413

OECD work on safety of manufactured nanomaterials www.oecd.org/chemicalsafety/nanosafety/

OECD work on chemical testing: www.oecd.org/chemicalsafety/testing/

For anyone who’s unaware of just how pervasive nanotechnology-enabled products have become, this brief OECD video illustrates the point nicely,

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.

Popping (nano)bubbles!

Who doesn’t love to pop bubbles? Well, there’s probably someone out there but it does seem to be a near universal delight (especially with the advent of bubble wrap which I’ve seen more than one person happily popping). Scientists are no more immune to that impulse than the rest of us although they approach the whole endeavour from a more technical perspective where popping bubbles becomes destabilization and bubble rupture. From a Sept. 28, 2017 American Institute of Physics (AIP) news release (also on EurekAlert),

Nanobubbles have recently gained popularity for their unique properties and expansive applications. Their large surface area and high stability in saturated liquids make nanobubbles ideal candidates for food science, medicine and environmental advancements. Nanobubbles also have long lifetimes of hours or days, and greater applicability than traditional macrobubbles, which typically only last for seconds.

The stability of nanobubbles is well understood, but the mechanisms causing their eventual destabilization are still in question. Using molecular dynamics simulations (MDS), researchers from the Beijing University of Chemical Technology explored the effect of surfactants — components that lower surface tension — on the stabilization of nanobubbles. They report their findings on the surprising mechanisms of destabilization [emphasis mine] for both soluble and insoluble surfactants this week [Sept. 25-29, 2017] in Applied Physics Letters, from AIP Publishing.

Researchers investigated the differences between soluble and insoluble surfactants and their varying influence on nanobubble stability using MDS software. They created a controled model system where the only variables that could be manipulated were the number of surfactants and the interaction between the surfactant and the substrate, the base of the model where the bubble is formed, to measure the direct influence of surfactants on nanobubble stability.

Analyzing both soluble and insoluble surfactants, the group focused on two possible mechanisms of destabilization: contact line depinning, where the surfactant flexibility reduces the forces responsible for stabilizing the bubble shape, causing it to rupture from lack of inner surface force; and surface tension reduction, causing a liquid to vapor phase transition.

The found soluble surfactants initiated nanobubble depinning when a large amount, roughly 80 percent, of the surfactant was adsorbed by the substrate, eventually causing the nanobubbles to burst.

“However, when small concentrations of soluble surfactant were introduced it remained dissolved, and adsorption onto the substrate was insignificant, generating a negligible effect on nanobubble stability,” said Xianren Zhang at Beijing University of Chemical Technology.

Simulations with insoluble surfactants showed comparable results to soluble surfactants when interacting heavily with substrates, but a new mechanism was discovered demonstrating a liquid-to-vapor transition model of bubble rupture [emphasis mine].

The transition is similar to how we traditionally envision bubbles popping, occurring when a surfactant significantly reduces the surface tension on the outside of the nanobubble. Nanobubbles destabilize in this fashion when a large amount of surfactant is present, but little — around 40 percent — surfactant-substrate interaction occurs.

These findings are critical to understanding nanobubble stability and have implications for nanobubble interaction with other molecules, including proteins and contaminants. Nanobubble applications could revolutionize aspects of modern medicine such as ultrasound techniques, expand functions in food science, and improve waste water treatment. But better characterizing basic properties like instability is essential to fully utilizing their potential in these applications.

There researchers have made this image illustrating their work available,

Several typical snapshots for nanobubbles losing their stability with various concentrations of surfactants and levels of interaction with substrates. In each picture, top panel shows evolution of the system with all involved particles, while in the bottom panel, solvent molecules are not shown to clarify the effect of surfactants. CREDIT: Qianxiang Xiao, Yawei Liu, Zhenjiang Guo, Zhiping Liu, and Xianren Zhang

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

How nanobubbles lose stability: Effects of surfactants featured by Qianxiang Xiao, Yawei Liu, Zhenjiang Guo, Zhiping Liua, and Xianren Zhang. Appl. Phys. Lett. 111, 131601 (2017); doi: http://dx.doi.org/10.1063/1.5000831

This paper is open access.

Plastic nanoparticles and brain damage in fish

Researchers in Sweden suggest plastic nanoparticles may cause brain damage in fish according to a Sept. 25, 2017 news item on phys.org,

Calculations have shown that 10 per cent of all plastic produced around the world ultimately ends up in the oceans. As a result, a large majority of global marine debris is in fact plastic waste. Human production of plastics is a well-known environmental concern, but few studies have studied the effects of tiny plastic particles, known as nanoplastic particles.

“Our study is the first to show that nanosized plastic particles can accumulate in fish brains”, says Tommy Cedervall, a chemistry researcher at Lund University.

A Sept. 25, 2017 Lund University press release, which originated the news item, provides more detail about the research,

The Lund University researchers studied how nanoplastics may be transported through different organisms in the aquatic ecosystem, i.e. via algae and animal plankton to larger fish. Tiny plastic particles in the water are eaten by animal plankton, which in turn are eaten by fish.

According to Cedervall, the study includes several interesting results on how plastic of different sizes affects aquatic organisms. Most importantly, it provides evidence that nanoplastic particles can indeed cross the blood-brain barrier in fish and thus accumulate inside fish’s brain tissue.

In addition, the researchers involved in the present study have demonstrated the occurrence of behavioural disorders in fish that are affected by nanoplastics. They eat slower and explore their surroundings less. The researchers believe that these behavioural changes may be linked to brain damage caused by the presence of nanoplastics in the brain.

Another result of the study is that animal plankton die when exposed to nanosized plastic particles, while larger plastic particles do not affect them. Overall, these different effects of nanoplastics may have an impact on the ecosystem as a whole.

“It is important to study how plastics affect ecosystems and that nanoplastic particles likely have a more dangerous impact on aquatic ecosystems than larger pieces of plastics”, says Tommy Cedervall.

However, he does not dare to draw the conclusion that plastic nanoparticles could accumulate in other tissues in fish and thus potentially be transmitted to humans through consumption.

“No, we are not aware of any such studies and are therefore very cautious about commenting on it”, says Tommy Cedervall.

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

Brain damage and behavioural disorders in fish induced by plastic nanoparticles delivered through the food chain by Karin Mattsson, Elyse V. Johnson, Anders Malmendal, Sara Linse, Lars-Anders Hansson & Tommy Cedervall. Scientific Reports 7, Article number: 11452 (2017) doi:10.1038/s41598-017-10813-0 Published online: 13 September 2017

This paper is open access.

A jellyfish chat on November 28, 2017 at Café Scientifique Vancouver get together

Café Scientifique Vancouver sent me an announcement (via email) about their upcoming event,

We are pleased to announce our next café which will happen on TUESDAY,
NOVEMBER 28TH at 7:30PM in the back room of YAGGER'S DOWNTOWN (433 W
Pender).

JELLYFISH – FRIEND, FOE, OR FOOD?

Did you know that in addition to stinging swimmers, jellyfish also cause
extensive damage to fisheries and coastal power plants? As threats such
as overfishing, pollution, and climate change alter the marine
environment, recent media reports are proclaiming that jellyfish are
taking over the oceans. Should we hail to our new jellyfish overlords or
do we need to examine the evidence behind these claims? Join Café
Scientifique on Nov. 28, 2017 to learn everything you ever wanted to
know about jellyfish, and find out if jelly burgers are coming soon to a
menu near you.

Our speaker for the evening will be DR. LUCAS BROTZ, a Postdoctoral
Research Fellow with the Sea Around Us at UBC’s Institute for the
Oceans and Fisheries. Lucas has been studying jellyfish for more than a
decade, and has been called “Canada’s foremost jellyfish
researcher” by CBC Nature of Things host Dr. David Suzuki. Lucas has
participated in numerous international scientific collaborations, and
his research has been featured in more than 100 media outlets including
Nature News, The Washington Post, and The New York Times. He recently
received the Michael A. Bigg award for highly significant student
research as part of the Coastal Ocean Awards at the Vancouver Aquarium.

We hope to see you there!

You can find out more about Lucas Brotz here and about Sea Around Us here.

For anyone who’s curious about the jellyfish ‘issue’, there’s a November 8, 2017 Norwegian University of Science and Technology press release on AlphaGallileo or on EurekAlert, which provides insight into the problems and the possibilities,

Jellyfish could be a resource in producing microplastic filters, fertilizer or fish feed. A new 6 million euro project called GoJelly, funded by the EU and coordinated by the GEOMAR Helmholtz Centre for Ocean Research, Germany and including partners at the Norwegian University of Science and Technology (NTNNU) and SINTEF [headquartered in Trondheim, Norway, is the largest independent research organisation in Scandinavia; more about SINTEF in its Wikipedia entry], hopes to turn jellyfish from a nuisance into a useful product.

Global climate change and the human impact on marine ecosystems has led to dramatic decreases in the number of fish in the ocean. It has also had an unforseen side effect: because overfishing decreases the numbers of jellyfish competitors, their blooms are on the rise.

The GoJelly project, coordinated by the GEOMAR Helmholtz Centre for Ocean Research, Germany, would like to transform problematic jellyfish into a resource that can be used to produce microplastic filter, fertilizer or fish feed. The EU has just approved funding of EUR 6 million over 4 years to support the project through its Horizon 2020 programme.

Rising water temperatures, ocean acidification and overfishing seem to favour jellyfish blooms. More and more often, they appear in huge numbers that have already destroyed entire fish farms on European coasts and blocked cooling systems of power stations near the coast. A number of jellyfish species are poisonous, while some tropical species are even among the most toxic animals on earth.

“In Europe alone, the imported American comb jelly has a biomass of one billion tons. While we tend to ignore the jellyfish there must be other solutions,” says Jamileh Javidpour of GEOMAR, initiator and coordinator of the GoJelly project, which is a consortium of 15 scientific institutions from eight countries led by the GEOMAR Helmholtz Centre for Ocean Research in Kiel.

The project will first entail exploring the life cycle of a number of jellyfish species. A lack of knowledge about life cycles makes it is almost impossible to predict when and why a large jellyfish bloom will occur. “This is what we want to change so that large jellyfish swarms can be caught before they reach the coasts,” says Javidpour.

At the same time, the project partners will also try to answer the question of what to do with jellyfish once they have been caught. One idea is to use the jellyfish to battle another, man-made threat.

“Studies have shown that mucus of jellyfish can bind microplastic. Therefore, we want to test whether biofilters can be produced from jellyfish. These biofilters could then be used in sewage treatment plants or in factories where microplastic is produced,” the GoJelly researchers say.

Jellyfish can also be used as fertilizers for agriculture or as aquaculture feed. “Fish in fish farms are currently fed with captured wild fish, which does not reduce the problem of overfishing, but increases it. Jellyfish as feed would be much more sustainable and would protect natural fish stocks,” says the GoJelly team.

Another option is using jellyfish as food for humans. “In some cultures, jellyfish are already on the menu. As long as the end product is no longer slimy, it could also gain greater general acceptance,” said Javidpour. Finally yet importantly, jellyfish contain collagen, a substance very much sought after in the cosmetics industry.

Project partners from the Norwegian University of Science and Technology, led by Nicole Aberle-Malzahn, and SINTEF Ocean, led by Rachel Tiller, will analyse how abiotic (hydrography, temperature), biotic (abundance, biomass, ecology, reproduction) and biochemical parameters (stoichiometry, food quality) affect the initiation of jellyfish blooms.

Based on a comprehensive analysis of triggering mechanisms, origin of seed populations and ecological modelling, the researchers hope to be able to make more reliable predictions on jellyfish bloom formation of specific taxa in the GoJelly target areas. This knowledge will allow sustainable harvesting of jellyfish communities from various Northern and Southern European populations.

This harvest will provide a marine biomass of unknown potential that will be explored by researchers at SINTEF Ocean, among others, to explore the possible ways to use the material.

A team from SINTEF Ocean’s strategic program Clean Ocean will also work with European colleagues on developing a filter from the mucus of the jellyfish that will catch microplastics from household products (which have their source in fleece sweaters, breakdown of plastic products or from cosmetics, for example) and prevent these from entering the marine ecosystem.

Finally, SINTEF Ocean will examine the socio-ecological system and games, where they will explore the potentials of an emerging international management regime for a global effort to mitigate the negative effects of microplastics in the oceans.

“Jellyfish can be used for many purposes. We see this as an opportunity to use the potential of the huge biomass drifting right in front of our front door,” Javidpour said.

You can find out more about GoJelly on their Twitter account.

Cellulose- and chitin-based biomaterial to replace plastics?

Although the term is not actually used in the news release, one of the materials used to create a new biomaterial could safely be described as nanocellulose. From a Sept. 20, 2017 Pennsylvania State University (Penn State) news release (also on EurekAlert) by Jeff Mulhollem,

An inexpensive biomaterial that can be used to sustainably replace plastic barrier coatings in packaging and many other applications has been developed by Penn State researchers, who predict its adoption would greatly reduce pollution.

Completely compostable, the material — a polysaccharide polyelectrolyte complex — is comprised of nearly equal parts of treated cellulose pulp from wood or cotton, and chitosan, which is derived from chitin — the primary ingredient in the exoskeletons of arthropods and crustaceans. The main source of chitin is the mountains of leftover shells from lobsters, crabs and shrimp consumed by humans.

These environmentally friendly barrier coatings have numerous applications ranging from water-resistant paper, to coatings for ceiling tiles and wallboard, to food coatings to seal in freshness, according to lead researcher Jeffrey Catchmark, professor of agricultural and biological engineering, College of Agricultural Sciences.

“The material’s unexpected strong, insoluble adhesive properties are useful for packaging as well as other applications, such as better performing, fully natural wood-fiber composites for construction and even flooring,” he said. “And the technology has the potential to be incorporated into foods to reduce fat uptake during frying and maintain crispness. Since the coating is essentially fiber-based, it is a means of adding fiber to diets.”

The amazingly sturdy and durable bond between carboxymethyl cellulose and chitosan is the key, he explained. The two very inexpensive polysaccharides — already used in the food industry and in other industrial sectors — have different molecular charges and lock together in a complex that provides the foundation for impervious films, coatings, adhesives and more.

The potential reduction of pollution is immense if these barrier coatings replace millions of tons of petroleum-based plastic associated with food packaging used every year in the United States — and much more globally, Catchmark noted.

He pointed out that the global production of plastic is approaching 300 million tons per year. In a recent year, more than 29 million tons of plastic became municipal solid waste in the U.S. and almost half was plastic packaging. It is anticipated that 10 percent of all plastic produced globally will become ocean debris, representing a significant ecological and human health threat.

crab shells

The material is comprised of cellulose pulp from wood or cotton, and chitosan, derived from chitin, the primary ingredient in the exoskeletons of arthropods and crustaceans. The main source of chitin is shells from lobsters, crabs and shrimp. Image: © iStock Photo OKRAD

The polysaccharide polyelectrolyte complex coatings performed well in research, the findings of which were published recently in Green Chemistry. Paperboard coated with the biomaterial, comprised of nanostructured fibrous particles of carboxymethyl cellulose and chitosan, exhibited strong oil and water barrier properties. The coating also resisted toluene, heptane and salt solutions and exhibited improved wet and dry mechanical and water vapor barrier properties.

“These results show that polysaccharide polyelectrolyte complex-based materials may be competitive barrier alternatives to synthetic polymers for many commercial applications,” said Catchmark, who, in concert with Penn State, has applied for a patent on the coatings.

“In addition, this work demonstrates that new, unexpected properties emerge from multi-polysaccharide systems engaged in electrostatic complexation, enabling new high-performance applications.”

Catchmark began experimenting with biomaterials that might be used instead of plastics a decade or so ago out of concerns for sustainability. He became interested in cellulose, the main component in wood, because it is the largest volume sustainable, renewable material on earth. Catchmark studied its nanostructure — how it is assembled at the nanoscale.

He believed he could develop natural materials that are more robust and improve their properties, so that they could compete with synthetic materials that are not sustainable and generate pollution — such as the low-density polyethylene laminate applied to paper board, Styrofoam and solid plastic used in cups and bottles.

“The challenge is, to do that you’ve got to be able to do it in a way that is manufacturable, and it has to be less expensive than plastic,” Catchmark explained. “Because when you make a change to something that is greener or sustainable, you really have to pay for the switch. So it has to be less expensive in order for companies to actually gain something from it. This creates a problem for sustainable materials — an inertia that has to be overcome with a lower cost.”

lab vials

The amazingly sturdy and durable bond between carboxymethyl cellulose and chitosan is the key. The two very inexpensive polysaccharides, already used in the food industry and in other industrial sectors, have different molecular charges and lock together in a complex that provides the foundation for impervious films, coatings, adhesives and more. Image: Penn State

Funded by a Research Applications for Innovation grant from the College of Agricultural Sciences, Catchmark currently is working to develop commercialization partners in different industry sectors for a wide variety of products.

“We are trying to take the last step now and make a real impact on the world, and get industry people to stop using plastics and instead use these natural materials,” he said. “So they (consumers) have a choice — after the biomaterials are used, they can be recycled, buried in the ground or composted, and they will decompose. Or they can continue to use plastics that will end up in the oceans, where they will persist for thousands of years.”

Also involved in the research were Snehasish Basu, post-doctoral scholar, and Adam Plucinski, master’s degree student, now instructor of engineering at Penn State Altoona. Staff in Penn State’s Material Research Institute provided assistance with the project.

The U.S. Department of Agriculture supported this work. Southern Champion Tray, of Chattanooga, Tennessee, provided paperboard and information on its production for experiments.

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

Sustainable barrier materials based on polysaccharide polyelectrolyte complexes by
Snehasish Basu, Adam Plucinski, and Jeffrey M. Catchmark. Green Chemistry 2017, 19, 4080-4092 DOI: 10.1039/C7GC00991G

This paper is behind a paywall. One comment, I found an anomaly on the page when I visited. At the top of the citation page, it states that this is issue 17 of Green Chemistry but the citation in the column on the right is “2017, 19 … “, which would be issue 19.