I have two items on quantum dots today. The first concerns a toxicity study performed on primates at the University of Buffalo (NY, USA). From the May 22, 2012 news item by Will Soutter for Azonano,

A multi-institute toxicity study on quantum dots in primates has discovered that these nanocrystals are safe for a period of one year.

This finding is encouraging for researchers and physicians looking for novel techniques to treat diseases such as cancer using nanomedicine. The organizations involved in the study included the University at Buffalo, Nanyang Technological University, ChangChun University of Science and Technology, and the Chinese PLA General Hospital.

On digging a little further, I found this information on the University of Buffalo website, from their May 21, 2012 news release,

– Tiny luminescent crystals called quantum dots hold great promise as tools for treating and detecting diseases like cancer.

– A pioneering study to gauge the toxicity of quantum dots in primates has found cadmium-selenide quantum dots to be safe over intervals of time ranging from three months to a year. The study is likely the first to test the safety of quantum dots in primates.

– The authors say more research is needed to determine quantum dots’ long-term effect on health; elevated levels of cadmium from the quantum dots were found in the primates even after 90 days.

The research, which appeared on May 20 in Nature Nanotechnology online , is likely the first to test the safety of quantum dots in primates.

In the study, scientists found that four rhesus monkeys injected with cadmium-selenide quantum dots remained in normal health over 90 days. Blood and biochemical markers stayed in typical ranges, and major organs developed no abnormalities. The animals didn’t lose weight.

Two monkeys observed for an additional year also showed no signs of illness.

The first  results are hopeful but there are some concerns,

The new toxicity study — completed by the University at Buffalo, the Chinese PLA General Hospital, China’s ChangChun University of Science and Technology, and Singapore’s Nanyang Technological University — begins to address the concern of health professionals who worry that quantum dots may be dangerous to humans.

The authors caution, however, that more research is needed to determine the nanocrystals’ long-term effects in primates; most of the potentially toxic cadmium from the quantum dots stayed in the liver, spleen and kidneys of the animals studied over the 90-day period.

…

The cadmium build-up, in particular, is a serious concern that warrants further investigation, said Ken-Tye Yong, a Nanyang Technological University assistant professor who began working with Prasad [Paras N. Prasad] on the study as a postdoctoral researcher at UB.

Unusually, this article seems to be open access at Nature Nanotechnology,

A pilot study in non-human primates shows no adverse response to intravenous injection of quantum dots

Ling Ye, Ken-Tye Yong, Liwei Liu, Indrajit Roy, Rui Hu, Jing Zhu, Hongxing Cai, Wing-Cheung Law, Jianwei Liu, Kai Wang, Jing Liu, Yaqian Liu, Yazhuo Hu, Xihe Zhang, Mark T. Swihart, and Paras N. Prasad

Nature Nanotechnology (2012) doi:10.1038/nnano.2012.74

The acquisition of an Israeli quantum dot company by Merck is my second bit of quantum dot news, from the May 22, 2012 news item on Nanowerk,

Merck announced today that within the scope of a capital increase by the Israeli start-up company QLight Nanotech, it is acquiring an interest in the Jerusalem-based company. QLight Nanotech is a spin-off subsidiary of Yissum, the technology transfer company of the Hebrew University of Jerusalem. QLight Nanotech develops products for use in displays and energy-efficient light sources based on semiconductor nanoparticles known as quantum dots.

I understood that Merck was a pharmaceutical company so I was bit surprised to see this (from the May 22, 2012 news item on the Solid State Technology website)

“I am excited that our basic science discoveries on semiconductor nanocrystals are now being realized in innovative technological applications. The partnership with Merck, a world leader in materials for display applications, is a synergistic one allowing us at Qlight Nanotech to implement advanced chemicals manufacturing and applications’ know-how,” said the scientific founder of  QLight Nanotech, Professor Uri Banin of the Hebrew University of Jerusalem, who will continue to support the company as a shareholder and advisor alongside of Yissum.

In fact, Merck bills itself as a pharmaceuticals and a s chemicals company.

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 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.

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 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.

One of the scientists on a research team at Trent University (Ontario, Canada) is claiming that safety questions about nanomaterials are not being asked and so the team is embarking on a study of silver nanoparticles and their impact on a lake ecosystem. From the May 2, 2012 news item on Nanowerk,

Dr. Chris Metcalfe, professor and director of the Institute for Watershed Science at Trent University, is the principal investigator on the Lake Ecosystem Nanosilver (LENS) project with Trent researchers, Drs. Maggie Xenopoulos, Holger Hintelmann and Paul Frost, and colleagues from Fisheries and Oceans Canada and Environment Canada.

“This is a high profile project that will have the eyes of the scientific community on Trent,” said Professor Metcalfe. “We’re fortunate that we have four world-class researchers on our team.” Over the past decade, tiny substances called nanomaterials have become part of our daily lives.

It’s possible that the clothes you’re wearing, or the sunscreen you just applied, contain nanomaterials. Because of this growing use, there is now concern that nanomaterials may pose threats to the environment.

“We have seen an exponential growth in the use of nanomaterials,” said Professor Xenopoulos, an associate professor in the Biology department at Trent University. “However, questions of safety are not being asked.” [emphasis mine]

Likely the claim is a little overenthusiasm or a lack of clarity on the speaker’s part since there has been more than one study about nanosilver particles and safety, including one at Purdue University mentioned in a March 4, 2010 posting on the Beyond Pesticides blog. The Purdue study (The effects of silver nanoparticles on fathead minnow (Pimephales promelas) embryos) is behind a paywall.

Here’s a bit more about silver nanoparticles and the LENS study,

While the benefits of nanomaterials are recognized, we know little about their risks to health and the environment. Due to their extremely small size, nanomaterials interact with cells and organic molecules, raising questions about their impact on organisms.

Due to their antibacterial properties, nanosilver particles are among the most widely-used nanomaterials in consumer goods. Clothing, home appliances, paint, bandages and food storage containers are a few of the products which may contain nanosilver. As we use and dispose of these products, there is a risk that nanosilvers will travel through our municipal water systems into our lakes and rivers.

The research team is working to understand the effect of nanosilver particles on the aquatic environment. Initial laboratory research conducted at Trent indicates that nanosilver can strongly affect aquatic organisms at the bottom of the food chain, such as bacteria, algae and zooplankton.

To further examine these effects in a real ecosystem, the team is conducting a study at the Experimental Lakes Area, near Kenora, in northwestern Ontario.

The LENS project will monitor changes in a lake’s ecosystem that occur after the addition of nanosilver. It will follow nanosilver as it travels through the lake ecosystem, track effects through the entire food web, and determine how resulting changes alter ecosystem function.

There’s more about the LENS project on the Trent University LENS (Lake Ecosystem Nanosilver) Project page (excerpt),

Our previous laboratory research has shown that nanosilver in the aquatic environment first affect organisms at the bottom of the food chain, including bacteria, algae and zooplankton. These responses may have devastating effects upon aquatic ecosystems by reducing overall productivity and altering the cycling of nutrients, such as carbon, nitrogen and phosphorus. There may be compensatory mechanisms within aquatic ecosystems that can mitigate these responses, but it is impossible to predict these responses using laboratory studies. Through support from the Strategic Grants Program of the Natural Sciences and Engineering Research Council of Canada and Environment Canada, a team of researchers from Trent University, Environment Canada and Fisheries and Oceans Canada will conduct a study at the Experimental Lakes Area (ELA) in northwestern Ontario by adding nanoform silver to a small lake over two summer field seasons ion 2013-14. During nano-silver additions, we will monitor the lake for changes to nutrient cycling and the biological effects within the entire food chain. However, in 2012, before starting the lake additions, we will refine our approach by determining what happens in mesocosms (i.e. plastic tubes) that are deployed in lakes. ELA has been used for over 40 years as a living laboratory to study the effects of pollutants in the environment, including past studies of the impacts of pollution from phosphorus, acid deposition, mercury and endocrine disruptors. These studies have resulted in policies to reduce the impacts of pollution. While we do not take lightly the impact that this study will have upon a lake in ELA, this approach is the only way to determine ecosystem level impacts and to influence regulatory policy regarding the ecological risks of NMs.

This is a three-year project, which starts this year (2012).

Capt. Peter McBride Ottawa (Canada) Fire Services declared that nanotechnology has been proven unsafe at a Fire Dept. Instructors Conference (FDIC)  in Indianapolis (US), which was held April 16-21, 2012. From the April 24, 2012 article by Ed Ballam for Firehouse.com,

Firefighters and responders have known for decades that smoke is harmful to their health, but the latest studies have shown that the microscopic materials that become airborne during fires are far more deadly than ever realized. That’s because of the proliferation of nanotechnology – particles that are one billionth of a meter in size – that are found in today’s consumer products.

Capt. Peter McBride Ottawa (Canada) Fire Services spoke of the dangers of nanotechnologies, which contain known cancer causing materials, at the Fire Department Instructors Conference (FDIC) in Indianapolis. He is a safety officer in Ottawa, responsible for the health and safety of the firefighters in his department.

I’m not sure how McBride determined that these particles were cancer-causing or exactly which particles he’s discussing.  From the article,

He became acutely interested in nanotechnologies when a huge downtown sporting goods store burned and belched acrid black smoke for blocks. Carbon fiber sporting goods, including thousands of skis, burned and emitted microscopic particles that coated everything, particularly his white department-issued SUV. He noticed stubborn black deposits on the SUV that just wouldn’t come off.

…

Realizing smoke was an inherent hazard of firefighting, he set out to see exactly what that black goop was on his SUV and how to best protect his crews from its hazards.

…

And what he found is that when material with nanotechnology burns, it emits dangerous particulates.

In a sporting goods store fire, I’d expect carbon nanotubes and silver nanoparticles in the particulate matter as these are commonly used in sporting goods. If there were other nanoparticles created as a consequence of the fire, I’d like to know which ones.

On a more general note, we have been ingesting more nanoparticles than we know. For example, burning diesel gas which we have been inhaling for decades also emits dangerous particulates at the nanoscale as we recently found out (my Oct. 7, 2012 posting on diesel gas honey bees [scroll down 1/2 way]).

Getting back to firefighters and nanotechnology, my concern is that McBride is making a claim without supporting data as he does here in the article,

“I am not against nanotechnologies,” McBride said. “I am against us not doing anything to protect ourselves from the known dangers.” [emphasis mine]

Who knows about these dangers? I haven’t seen a single claim from a researcher about the ‘known dangers’ of nano: particles/materials/technologies. In fact, it’s the uncertainty that’s disturbing.

I’m not the only with issues about this piece, commenters have quickly noted the problems, from the article webpage (I fixed some minor typos),

Bmayo

I’m sorry but Captain Mc Bride is very mistaken In the world of engineering and science there is a huge difference between. .Nano and micro, micro is thousands of time larger than nano-particles. also the idea of keeping and using a the SCBA until the fire is totally out is nothing new. The fire service has been teaching this for over 30 years.

Antimatter

yeah, it’s just the specific mention of carcinogenicity, mentioned twice, that i want evidence for. that’s not a word you toss around casually in this industry.

Adam Sawyer

There are some legitimate health risks with certain types of combustible nanoparticles/nanofibers, but just because a product has “nanotechnology” in it does not necessarily mean it’s dangerous.  The challenge will be for fire safety researchers and toxicologists to collaborate and figure out what’s getting into the air and at what concentration.  Study it the same way plastics were studied decades ago and we’ll figure out which materials cause problems and which don’t.

Chris

Yep,,,,,The joys of Firefighting …

Rseitzsr13

Very Very good article

Antimatter

I’m a safety trainer, and any small particulates can be hazardous, but I’d like information on the “known cancer causing materials.” I’ve never seen anything alleging that before, and if you have references, please list them.

No one could possibly fault McBride for his concerns about safety and it’s certainly true new nanotechnology-enabled products could pose special hazards. If McBride has data that supports his contention, I, like Antimatter, would like to see the references. I’d also appreciate a little more specificity with the terminology.

Another organization advises the precautionary principle when dealing with nanomaterials. This time it’s the Women in Europe for a Common Future (WECF) organization and they’ve just released a position paper. From the March 30, 2012 news item on Nanowerk,

Women in Europe for a Common Future, an international network of over 100 women’s, environmental and health organisations implementing projects in 40 countries and advocating globally for a healthy environment, has released a position paper on nanoparticles and nanotechnology: Nano – The great unknown (pdf).

…

WECF recognizes that nanotechnologies could bring long-term profits and overall societal benefits. However, in order to make an overall judgment, data is needed regarding the hazards, exposure, risks and ethical consequences for humans, the environment and our society as a whole.

Maybe I’m getting grumpy these days but It seems to me that the time for describing ‘nanotechnology as the latest buzzword’ has passed. Here’s the opening sentence from the position paper,

Nanotechnology, the latest buzzword in the global technology revolution, is the science of ‘small things’: the de­signing, manipulating and engineer­ing of materials at nanoscale. (p. 1)

Also on page 1 is a claim as to the number of nanotechnology-enabled products on the market,

The number of consumer products on the world market claiming to contain nanomaterials exceeded 1300 already by 2010, and there are probably more, as the actual presence of nanomaterials is dif­ficult to identify.

The source for the number of nano products is not cited although WECF does list the Project for Emerging Nanotechnologies (PEN) and its product inventory in the bibliography. PEN’s inventory has no oversight (PEN has always been quite frank about this); anyone can register a product and claim there are nanomaterials in it.

Further in the position paper, Canada and California are mentioned,

Other regulatory entities too are work­ing on developing the first laws that can address the concerns on nanomaterials. Canada and the state of California, for example, took the step of imposing mandated disclosure requirements on nanomaterial use and toxicity assess­ment. Canada’s law of January 2009 targets domestic companies and institu­tions that manufacture or buy more than 1 kilogram of nanomaterial per year. According to these new regulations, these entities must now reveal how much nanomaterial they use, how they use it, and what they know about its toxicity. (p. 3)

I’m not familiar enough with the situation in California to comment on it but I am somewhat puzzled by the description of a Canadian law targeting domestic companies and institutions that manufacture or buy more than 1 kilogram of nanomaterials per year. There was a one time only requirement to report on how much nanomaterial was being imported into Canada but, as far as I’m aware, there is no law or regulation which states that this must be done on an ongoing basis. (You can read more about the reporting scheme in my April 12, 2010 posting.) This statement was not cited and I can’t find anything in the bibliography that might be the source for this information.

My problem with this position paper is that I can’t trust any of the information because the little I am familiar with contradicts their statements and they don’t support those statements with sources that I can research.