Tag Archives: nanosunscreens

Safer sunblock and bioadhesive nanoparticles from Yale University

The skin has a lot of protective barriers but it’s always possible to make something better so a sunblock that doesn’t penetrate teh skin at all seems like it might be a good thing. Interestingly, this new sunblock or sunscreen is enabled by nanoparticles but not the metallic nanoparticles found in what are sometimes called nanosunscreens. From a Sept. 29, 2015 news item on Nanowerk,

Researchers at Yale have developed a sunscreen that doesn’t penetrate the skin, eliminating serious health concerns associated with commercial sunscreens.

Most commercial sunblocks are good at preventing sunburn, but they can go below the skin’s surface and enter the bloodstream. As a result, they pose possible hormonal side effects and could even be promoting the kind of skin cancers they’re designed to prevent.

But researchers at Yale have developed a new sunblock, made with bioadhesive nanoparticles, that stays on the surface of the skin.

A Sept. 28, 2015 Yale University news release by William Weir, whch originated the news item, describes the research in more detail,

“We found that when we apply the sunblock to the skin, it doesn’t come off, and more importantly, it doesn’t penetrate any further into the skin,” said the paper’s senior author, Mark Saltzman, the Goizueta Foundation Professor of Biomedical Engineering. “Nanoparticles are large enough to keep from going through the skin’s surface, and our nanoparticles are so adhesive that they don’t even go into hair follicles, which are relatively open.”

Using mouse models, the researchers tested their sunblock against direct ultraviolet rays and their ability to cause sunburn. In this regard, even though it used a significantly smaller amount of the active ingredient than commercial sunscreens, the researchers’ formulation protected equally well against sunburn.

They also looked at an indirect — and much less studied — effect of UV light. When the active ingredients of sunscreen absorb UV light, a chemical change triggers the generation of oxygen-carrying molecules known as reactive oxygen species (ROS). If a sunscreen’s agents penetrate the skin, this chemical change could cause cellular damage, and potentially facilitate skin cancer.

“Commercial chemical sunblock is protective against the direct hazards of ultraviolet damage of DNA, but might not be against the indirect ones,” said co-author Michael Girardi, a professor of dermatology at Yale Medical School. “In fact, the indirect damage was worse when we used the commercial sunblock.”

Girardi, who specializes in skin cancer development and progression, said little research has been done on the ultimate effects of sunblock usage and the generation of ROS, “but obviously, there’s concern there.”

Previous studies have found traces of commercial sunscreen chemicals in users’ bloodstreams, urine, and breast milk. There is evidence that these chemicals cause disruptions with the endocrine system, such as blocking sex hormone receptors.

To test penetration levels, the researchers applied strips of adhesive tape to skin previously treated with sunscreen. The tape was then removed rapidly, along with a thin layer of skin. Repeating this procedure allowed the researchers to remove the majority of the outer skin layer, and measure how deep the chemicals had penetrated into the skin. Traces of the sunscreen chemical administered in a conventional way were found to have soaked deep within the skin. The Yale team’s sunblock came off entirely with the initial tape strips.

Tests also showed that a substantial amount of the Yale team’s sunscreen remained on the skin’s surface for days, even after exposure to water. When wiped repeatedly with a towel, the new sunblock was entirely removed. [emphasis mine]

To make the sunblock, the researchers developed a nanoparticle with a surface coating rich in aldehyde groups, which stick tenaciously to the outer skin layer. The nanoparticle’s hydrophilic layer essentially locks in the active ingredient, a hydrophobic chemical called padimate O.

Some sunscreen solutions that use larger particles of inorganic compounds, such as titanium dioxide or zinc oxide, also don’t penetrate the skin. For aesthetic reasons, though, these opaque sunscreen products aren’t very popular. By using a nanoparticle to encase padimate O, an organic chemical used in many commercial sunscreens, the Yale team’s sunblock is both transparent and stays out of the skin cells and bloodstream.

This seems a little confusing to me and I think clarification may be helpful. My understanding is that the metallic nanoparticles (nano titanium dioxide and nano zinc oxide) engineered for use in commercial sunscreens are also (in addition to the macroscale titanium dioxide and zinc oxide referred to in the Yale news release) too large to pass through the skin. At least that was the understanding in 2010 and I haven’t stumbled across any information that is contradictory. Here’s an excerpt from a July 20, 2010 posting where I featured portions of a debate between Georgia Miller (at that time representing Friends of the Earth) and Dr. Andrew Maynard (at that time director of the University of Michigan Risk Science Center and a longtime participant in the nanotechnology risk discussions),

Three of the scientists whose work was cited by FoE as proof that nanosunscreens are dangerous either posted directly or asked Andrew to post comments which clarified the situation with exquisite care,

Despite FoE’s implications that nanoparticles in sunscreens might cause cancer because they are photoactive, Peter Dobson points out that there are nanomaterials used in sunscreens that are designed not to be photoactive. Brian Gulson, who’s work on zinc skin penetration was cited by FoE, points out that his studies only show conclusively that zinc atoms or ions can pass through the skin, not that nanoparticles can pass through. He also notes that the amount of zinc penetration from zinc-based sunscreens is very much lower than the level of zinc people have in their body in the first place. Tilman Butz, who led one of the largest projects on nanoparticle penetration through skin to date, points out that – based on current understanding – the nanoparticles used in sunscreens are too large to penetrate through the skin.

However, there may be other ingredients which do pass through into the bloodstream and are concerning.

One other thing I’d like to note. Not being able to remove the sunscreen easily ( “When wiped repeatedly with a towel, the new sunblock was entirely removed.”) may prove to be a problem as we need Vitamin D, which is for the most part obtainable by sun exposure.

In any event, here’s a link to and a citation for the paper,

A sunblock based on bioadhesive nanoparticles by Yang Deng, Asiri Ediriwickrema, Fan Yang, Julia Lewis, Michael Girardi, & W. Mark Saltzman. Nature Materials (2015) doi:10.1038/nmat4422 Published online 28 September 2015

This paper is behind a paywall.

Risk assessments not the only path to nanotechnology regulation

Nanowerk has republished an essay about nanotechnology regulation from Australia’s The Conversation in an Aug. 25, 2015 news item (Note: A link has been removed),

When it comes to nanotechnology, Australians have shown strong support for regulation and safety testing.

One common way of deciding whether and how nanomaterials should be regulated is to conduct a risk assessment. This involves calculating the risk a substance or activity poses based on the associated hazards or dangers and the level of exposure to people or the environment.

However, our recent review (“Risk Analysis of Nanomaterials: Exposing Nanotechnology’s Naked Emperor”) found some serious shortcomings of the risk assessment process for determining the safety of nanomaterials.

We have argued that these shortcomings are so significant that risk assessment is effectively a naked emperor [reference to a children’s story “The Emperor’s New Clothes“].

The original Aug. 24, 2015 article written by Fern Wickson (Scientist/Program Coordinator at GenØk – Centre for Biosafety in Norway) and Georgia Miller (PhD candidate at UNSW [University of New South Wales], Australia) points out an oft ignored issue with regard to nanotechnology regulation,

Risk assessment has been the dominant decision-aiding tool used by regulators of new technologies for decades, despite it excluding key questions that the community cares about. [emphasis mine] For example: do we need this technology; what are the alternatives; how will it affect social relations, and; who should be involved in decision making?

Wickson and Miller also note more frequently discussed issues,

A fundamental problem is a lack of nano-specific regulation. Most sector-based regulation does not include a “trigger” for nanomaterials to face specific risk assessment. Where a substance has been approved for use in its macro form, it requires no new assessment.

Even if such a trigger were present, there is also currently no cross-sectoral or international agreement on the definition of what constitutes a nanomaterial.

Another barrier is the lack of measurement capability and validated methods for safety testing. We still do not have the means to conduct routine identification of nanomaterials in the complex “matrix” of finished products or the environment.

This makes supply chain tracking and safety testing under real-world conditions very difficult. Despite ongoing investment in safety research, the lack of validated test methods and different methods yielding diverse results allows scientific uncertainty to persist.

With regard to the first problem, the assumption that if a material at the macroscale is safe, then the same is true at the nanoscale informs regulation in Canada and, as far as I’m aware, every other constituency that has any type of nanomaterial regulation. I’ve had mixed feelings about this. On the one hand, we haven’t seen any serious problems associated with the use of nanomaterials but on the other hand, these problems can be slow to emerge.

The second issue mentioned, the lack of a consistent definition internationally, seems to be a relatively common problem in a lot of areas. As far as I’m aware, there aren’t that many international agreements for safety measures. Nuclear weapons and endangered animals and plants (CITES) being two of the few that come to mind.

The lack of protocols for safety testing of nanomaterials mentioned in the last paragraph of the excerpt is of rising concern. For example, there’s my July 7, 2015 posting featuring two efforts: Nanotechnology research protocols for Environment, Health and Safety Studies in US and a nanomedicine characterization laboratory in the European Union. Despite this and other efforts, I do think more can and should be done to standardize tests and protocols (without killing new types of research and results which don’t fit the models).

The authors do seem to be presenting a circular argument with this (from their Aug. 24, 2015 article; Note: A link has been removed),

Indeed, scientific uncertainty about nanomaterials’ risk profiles is a key barrier to their reliable assessment. A review funded by the European Commission concluded that:

[…] there is still insufficient data available to conduct the in depth risk assessments required to inform the regulatory decision making process on the safety of NMs [nanomaterials].

Reliable assessment of any chemical or drug is a major problem. We do have some good risk profiles but how many times have pharmaceutical companies developed a drug that passed successfully through human clinical trials only to present a serious risk when released to the general population? Assessing risk is a very complex problem. even with risk profiles and extensive testing.

Unmentioned throughout the article are naturally occurring nanoparticles (nanomaterials) and those created inadvertently through some manufacturing or other process. In fact, we have been ingesting nanomaterials throughout time. That said, I do agree we need to carefully consider the impact that engineered nanomaterials could have on us and the environment as ever more are being added.

To that end, the authors make some suggestions (Note: Links have been removed),

There are well-developed alternate decision-aiding tools available. One is multicriteria mapping, which seeks to evaluate various perspectives on an issue. Another is problem formulation and options assessment, which expands science-based risk assessment to engage a broader range of individuals and perspectives.

There is also pedigree assessment, which explores the framing and choices taking place at each step of an assessment process so as to better understand the ambiguity of scientific inputs into political processes.

Another, though less well developed, approach popular in Europe involves a shift from risk to innovation governance, with emphasis on developing “responsible research and innovation”.

I have some hesitation about recommending this read due to Georgia Miller’s involvement and the fact that I don’t have the time to check all the references. Miller was a spokesperson for Friends of the Earth (FoE) Australia, a group which led a substantive campaign against ‘nanosunscreens’. Here’s a July 20, 2010 posting where I featured some cherrypicking/misrepresentation of data by FoE in the persons of Georgia Miller and Ian Illuminato.

My Feb. 9, 2012 posting highlights the unintended consequences (avoidance of all sunscreens by some participants in a survey) of the FoE’s campaign in Australia (Note [1]: The percentage of people likely to avoid all sunscreens due to their concerns with nanoparticles in their sunscreens was originally reported to be 17%; Note [2]: Australia has the highest incidence of skin cancer in the world),

Feb.21.12 correction: According to the information in the Feb. 20, 2012 posting on 2020 Science, the percentage of Australians likely to avoid using sunscreens is 13%,

This has just landed in my email in box from Craig Cormick at the Department of Industry, Innovation, Science, Research and Tertiary Education in Australia, and I thought I would pass it on given the string of posts on nanoparticles in sunscreens on 2020 Science over the past few years:

“An online poll of 1,000 people, conducted in January this year, shows that one in three Australians had heard or read stories about the risks of using sunscreens with nanoparticles in them,” Dr Cormick said.

“Thirteen percent of this group were concerned or confused enough that they would be less likely to use any sunscreen, whether or not it contained nanoparticles, putting them selves at increased risk of developing potentially deadly skin cancers.

“The study also found that while one in five respondents stated they would go out of their way to avoid using sunscreens with nanoparticles in them, over three in five would need to know more information before deciding.”

This article with Fern Wickson (with whom I don’t always agree perfectly but hasn’t played any games with research that I’m know of) helps somewhat but it’s going to take more than this before I feel comfortable recommending Ms. Miller’s work for further reading.

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.

Nanotechnology Policy and Regulation in Canada, Australia, the European Union, the UK, and the US: a timeline for us all

The Timeline: Nanotechnology Policy and Regulation in Canada, Australia, the European Union, the United Kingdom, and the United States (PDF; h/t July 10, 2014 news item on Nanowerk) issued by the University of Ottawa’s Institute for Science, Society and Policy (ISSP) takes as its starting point the invention of the field emission microscope in 1936 by Erwin Wilhelm Müller.

This fascinating 40 pp document seems comprehensive to me. While the title suggests otherwise, there are a few mentions of events involving Asian countries and they also include the Berkeley bylaw governing nanotechnology manufacture in the city. From the Timeline, p. 16 (Note: The formatting has been changed significantly),

The City of Berkeley (US)
December 2006

The Berkeley Municipal Code is amended to introduce new measures regarding manufactured nanomaterial health and safety

These amendments require facilities that manufacture or use nanomaterials to disclose in writing which nanomaterials are being used as well as the current toxicology of the materials reported (to the extent known) and to further describe how the facility will safely handle, monitor, contain, dispose, track inventory, prevent releases and mitigate such materials.

Berkeley is currently the only municipal government in the United States to regulate nanotechnology

While searching a month ago (June 2014), I was having difficulty finding information online about the Berkeley bylaw, so this was a delightful surprise.

There is (arguably) an omission and that is the Yale Law School Cultural Cognition Project. The Yale researchers have done some influential work about emerging technologies, including a special nanotechnology project devised in the aftermath of the Berkeley bylaw. Their focus then and now has been on public perceptions and attitudes as they affect policy.

Given how many public perception projects there have been and the timeline’s specific focus on regulation and policy, it’s understandable that not many have been included in the timeline.

Still, I was curious to see if the 2012 nanosunscreen debacle in Australia would be included in the timeline. It was not and, given that this incident didn’t directly involve policy or regulation, it’s understandable. Still, I would like to suggest its inclusion in future iterations. (For the curious, my Feb. 9, 2012 posting titled: Unintended consequences: Australians not using sunscreens to avoid nanoparticles? offers a summary and links to this story about an Australian government survey and some unexpected and dismaying results.)

The timeline appears to have a publication date of April 2014 and was compiled by Alin Charrière and Beth Dunning. It is a ‘living’ document so it will be updated in the future. If you have any comments, issp@uottawa.ca. (I will be sending mine soon.)

It is one of a series which includes two other technologies, Synthetic biology and Bioenergy, at this point (July 10, 2014). You can go here for more about the ISSP.

Finally, bravo and bravo to Charrière and Dunning for a job well done.

Nanoscale metal oxides and lung cells

Bear in mind while reading further that all of this research has not taken place in any situation resembling real life conditions: researchers at the Missouri University of Science and Technology (Missouri S&T; located in the US) have found that metal oxides at the nanoscale can be highly toxic to human lung cells according to a Jan. 28, 2014 news item on Nanowerk (Note: A link has been removed),

Nanoparticles are used in all kinds of applications — electronics, medicine, cosmetics, even environmental clean-ups. More than 2,800 commercially available applications are now based on nanoparticles, and by 2017, the field is expected to bring in nearly $50 billion worldwide.

But this influx of nanotechnology is not without risks, say researchers at Missouri University of Science and Technology.

“There is an urgent need to investigate the potential impact of nanoparticles on health and the environment,” says Yue-Wern Huang, professor of biological sciences at Missouri S&T.

Huang and his colleagues have been systematically studying the effects of transition metal oxide nanoparticles on human lung cells (“Cytotoxicity in the age of nano: The role of fourth period transition metal oxide nanoparticle physicochemical properties”). These nanoparticles are used extensively in optical and recording devices, water purification systems, cosmetics and skin care products, and targeted drug delivery, among other applications.

The Jan. 27, 2014 Missouri S&T news release by Linda Fulps, which originated the news item, describes the research in more detail,

“In their typical coarse powder form, the toxicity of these substances is not dramatic,” says Huang. “But as nanoparticles with diameters of only 16-80 nanometers, the situation changes significantly.”

The researchers exposed both healthy and cancerous human lung cells to nanoparticles composed of titanium, chromium, manganese, iron, nickel, copper and zinc compounds — transition metal oxides that are on the fourth row of the periodic table. The researchers discovered that the nanoparticles’ toxicity to the cells, or cytotoxicity, increased as they moved right on the periodic table.

“About 80 percent of the cells died in the presence of nanoparticles of copper oxide and zinc oxide,” says Huang. “These nanoparticles penetrated the cells and destroyed their membranes. The toxic effects are related to the nanoparticles’ surface electrical charge and available docking sites.”

Huang says that certain nanoparticles released metal ions — called ion dissolution — which also played a significant role in cell death.

Huang is now working on new research that may help reduce nanoparticles’ toxicity and shed light on how nanoparticles interact with cells.

“We are coating toxic zinc oxide nanoparticles with non-toxic nanoparticles to see if zinc oxide’s toxicity can be reduced,” Huang says. “We hope this can mitigate toxicity without compromising zinc oxide’s intended applications. We’re also investigating whether nanoparticles inhibit cell division and influence cell cycle.”

Concerning results? Yes. But, before determining how alarmed you should be, there are a few questions you might want to ask while reading the news release and/or the research paper :

  1. How were these cells exposed to the metal nanoparticles? ‘Breathing’ or were they sitting in a solution?
  2. What was the concentration of metal nanoparticles? (even good things can be bad for you at high concentrations)

This isn’t an attempt to dismiss the findings but rather to point out how much painstaking research has to take place before conclusions of any kind can be drawn. It’s why scientists tend to quite careful in their comments.

In looking at this work, I was reminded of the research into ‘nanosunscreens’ and concerns about the metal oxide nanoparticles (zinc oxides and/or titanium dioxide) penetrating the skin barrier and building up to toxic levels in the body.  In an Oct. 4, 2012 posting about zinc oxide nanoparticles and penetrating the skin barrier, I mentioned this in the context of some then recent research at Bath University (UK),

I missed the fact that this study was an in vitro test, which is always less convincing than in vivo testing. In my Nov. 29, 2011 posting about some research into nano zinc oxide I mentioned in vitro vs. in vivo testing and Brian Gulson’s research,

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.

… 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?

Here’s a link to and a citation for Yue-Wern Huang and his team’s latest research,

Cytotoxicity in the age of nano: The role of fourth period transition metal oxide nanoparticle physicochemical properties by Charles C. Chusuei, Chi-Heng Wu, Shravan Mallavarapu, Fang Yao Stephen Hou, Chen-Ming Hsu, Jeffrey G. Winiarz, Robert S. Aronstam, Yue-Wern Huang. Chemico-Biological Interactions, Volume 206, Issue 2, 25 November 2013, Pages 319–326.

This paper is behind a paywall.

Anatase and rutile titanium dioxide and nanosunscreens

The American Chemical Society (ACS) features some research into nanoscreens and the anatase form of titanium dioxide in a Sept. 25, 2013 news release,,

Using a particular type of titanium dioxide — a common ingredient in cosmetics, food products, toothpaste and sunscreen — could reduce the potential health risks associated with the widely used compound. The report on the substance, produced by the millions of tons every year for the global market, appears in the ACS journal Chemical Research in Toxicology.
Francesco Turci and colleagues explain that titanium dioxide (TiO2) is generally considered a safe ingredient in commercially available skin products because it doesn’t penetrate healthy skin. But there’s a catch. Research has shown that TiO2 can cause potentially toxic effects when exposed to ultraviolet light, which is in the sun’s rays and is the same kind of light that the compound is supposed to offer protection against. To design a safer TiO2 for human use, the researchers set out to test different forms of the compound, each with its own architecture.

They tested titanium dioxide powders on pig skin (which often substitutes for human skin in these kinds of tests) with indoor lighting, which has very little ultraviolet light in it. They discovered that one of the two most commonly used crystalline forms of TiO2, called rutile, easily washes off and has little effect on skin. Anatase, the other commonly used form, however, was difficult to wash off and damaged the outermost layer of skin — even in low ultraviolet light. It appears to do so via “free radicals,” which are associated with skin aging. “The present findings strongly encourage the use of the less reactive, negatively charged rutile to produce safer TiO2-based cosmetic and pharmaceutical products,” the researchers conclude.

It should be noted that the researchers used pig skin, i.e., the skin was not on a pig and, therefore, not part of a living organism with its various biological systems coming into play. As well, the testing was done indoors not under direct sunlight which is the condition under which most of us use sunscreen. This research points to problems  with using anatase nanoscale titanium dioxide in sunscreens but it doesn’t provide unequivocal proof.

The Danish Environmental Protection Agency report (this Oct. 3, 2013 posting of mine) on the state of the art of research into nanomateial dermal absorption does refer to research in this area, although it does not include Turci’s work (Note: The numbers n the excerpted text are reference numbers for the bibliography)),

When looking at bulk composition and the level of dermal penetration noted in studies using a specific material type, there appears to be very little pattern between bulk composition and penetration depth. Taking for example TiO2 as one of the most widely studied nanoparticles, we see reports of penetration no further than the SC [subcutaneous skin layer] 78, 86, 91 but also several studies suggesting deeper penetration (basal cell layer) and even penetration into the dermis 63, 84 although this is often reported as being a very small fraction/infrequent. Another compositional issue in relation to nanoparticles and in particular TiO2 is the crystalline structure. TiO2 is often used in either its anatase or rutile form or as mixture of both. Within the literature, there are studies using both the anatase form 86, 94, the rutile form 91, 114 or a mixture 84, 114 although we were unable to find any studies which appear to systematically evaluate the role of crystal form in TiO2 absorption into the skin. [emphasis mine] (p. 44 of this report: Dermal Absorption of Nanomaterials Part of the ”Better control of nano” initiative 2012 – 2015 Environmental Project No. 1504, 2013).

For those who would like to read Turci’s research for themselves,

Crystalline Phase Modulates the Potency of Nanometric TiO2 to Adhere to and Perturb the Stratum Corneum of Porcine Skin under Indoor Light by Francesco Turci, Elena Peira, Ingrid Corazzari, Ivana Fenoglio, Michele Trotta, and Bice Fubini. Chem. Res. Toxicol., Article ASAP DOI: 10.1021/tx400285j Publication Date (Web): September 12, 2013
Copyright © 2013 American Chemical Society

This research is behind a paywall.

Amid controversies, Australian government spends big bucks on Australian Institute for Nanoscience

Kim Carr, Australia’s Minister for Innovation, Industry, Science and Research, delivered  an extraordinary speech, by Canadian standard (ours tend to remarkable blandness), at the sod-turning event for the new Australian Institute for Nanoscience (AIN) due to open in May 2015. Before getting to the speech, here’s a bit more about the event from a July 24, 2013 news item on Global Times,

Australian government will deliver a fund for the new Australian Institute for Nanoscience ( AIN) which will open in May 2015 to boost its research of nanotechnology, Minister for Innovation, Industry, Science and Research Kim Carr confirmed in a statement after breaking the ground for the new facility at the University of Sydney on Wednesday.

The AIN project is a major new building combining research laboratories with teaching facilities to drive cross-disciplinary collaboration to develop nanomaterials and devices.

The July 24, 2013 Australian government media release about the AIN sod-turning provides more details about the government’s investment in the institute and its backing of nanoscience/nanotechnology research,

Senator Kim Carr said the Australian Government’s $40 million contribution, through the Education Investment Fund, to assist in the facility’s construction backs in Labor’s commitment to giving our researchers the tools they need to pursue world-leading work.

“Nanotechnology is a transformative force for manufacturing and is predicted to be worth $US3 trillion globally by 2020. Australia needs to stake a claim to our slice of that pie now, by building well-researched prototypes for the market. AIN will help make that happen and keep Australian research internationally competitive.”

Senator Carr said AIN will increase our national research capability by bringing together world-class nanoscience researchers across three main areas:

  • New medical diagnostics and therapies combining quantum technology with imaging and drug delivery and solutions such as a fully implantable bionic eye;
  • Faster, more secure and more efficient communications based on photonics and quantum science technologies; and
  • Revolutionary optical instrumentation to explore the frontiers of our universe, along with faster data processing technologies for the SKA.

I’m not sure where Carr got the “… worth $US3 trillion globally by 2020” number for nanotechnology’s impact on the global economy. More interesting to me, are these comments from Carr’s speech (you can find the entire speech here),

It is a great pleasure to share in the progress of the Australian Institute for Nanoscience here at Sydney University.

Three years have passed since I announced the funding for this facility:

$40 million from the Federal Government;

backed by $71 million from the university;

and a further $20 million from other sources, including the New South Wales government, the Australian National Fabrication Facility; the ARC’s CUDOS; the Australian Astronomical Observatory and Bandwidth Foundry International.

It was one of the many projects made possible by the Education Investment Fund – which, over three rounds, secured a total of $3.5 billion in new research infrastructure for a federal contribution of $1.5 billion.

This is an impressive return on investment.

At that time, this was the sort of research guaranteed to bring out the anti-science crowd.

There were beat-ups in the press, demonstrations in universities, and scare campaigns run on worksites. [emphasis mine]

It was as if the Enlightenment had never happened. It was as if nanoscience was some kind of global conspiracy to kill us all with sunscreen. [emphasis mine]

But I saw this project differently. And I put my views on the record at the time this investment was announced.

As I said back then:

“I don’t begin by saying “this is too strange” or “this is too hard”. I don’t begin by saying “no”.

I begin by asking, “what’s in it for Australia?” – “what’s in it for the people we serve?” – and “how can we make this work?”

The speech continues with a very optimistic view of all the economic benefits to be derived from an investment in nanoscience/nanotechnology.

Given the extreme lack of interest in Canada and its very odd (or perhaps it’s a harbinger of the future?) almost unknown National Institute of Nanotechnology (NINT), which exists on a NINT University of Alberta website and on a NINT National Research Council website, the “beat-ups in the press, etc.” provide a fascinating and contrasting socio-cultural perspective. The difference is perhaps due to a very active, both in Australia and internationally, Friends of the Earth group.

Friends of the Earth Australia campaigned long (years) and hard against nanosunscreens in a leadup to some rather disturbing survey findings in 2012 (my Feb. 9, 2012 posting) where some 13% of Australians, first reported as 17%,  didn’t use any sunscreens whatsoever, due to their fear of ‘nanosunscreens’.

Kim Carr has been mentioned here before in an Aug. 26, 2011 posting which highlighted a study showing  Australians held positive (?) attitudes towards nanotechnology and those attitudes had gotten more positive over time. My guess, not having looked at the study, is that the study focussed on areas where people usually express positive attitudes (e. g. better health care with less invasive medical procedures) and not on environmental issues (e.g. nanosilver in your clothing washing off and ending up in the water supply).

I do love how elected officials, the world over, pick and choose their ‘facts’.

Natural and engineered nanoparticles in an Orion magazine podcast & in a NanoBosc machinima piece

The Jan. 16, 2013 Orion magazine podcast discussion (more about that later) regarding safety and engineered and natural nanoparticles arose from an article (worth reading) by Heather Millar in the magazine’s January/February 2013 issue, Pandora’s Boxes.

For anyone familiar with the term ‘Pandora’s box’, Millar’s and the magazine’s bias is made clear immediately, nanoparticles are small and threatening. From the Pandora’s box Wikipedia essay,

Today, the phrase “to open Pandora’s box” means to perform an action that may seem small or innocuous, but that turns out to have severe and far-reaching consequences. [emphases mine]

Millar’s article is well written and offers some excellent explanations. For example, there’s this from Pandora’s Boxes,

So chemistry and physics work differently if you’re a nanoparticle. You’re not as small as an atom or a molecule, but you’re also not even as big as a cell, so you’re definitely not of the macro world either. You exist in an undiscovered country somewhere between the molecular and the macroscopic. Here, the laws of the very small (quantum mechanics) merge quirkily with the laws of the very large (classical physics). Some say nanomaterials bring a third dimension to chemistry’s periodic table, because at the nano scale, long-established rules and groupings don’t necessarily hold up.

Then, she has some dodgier material,

Yet size seems to be a double-edged sword in the nanoverse. Because nanoparticles are so small, they can slip past the body’s various barriers: skin, the blood-brain barrier, the lining of the gut and airways. Once inside, these tiny particles can bind to many things. They seem to build up over time, especially in the brain. Some cause inflammation and cell damage. Preliminary research shows this can harm the organs of lab animals, though the results of some of these studies are a matter of debate.

Some published research has shown that inhaled nanoparticles actually become more toxic as they get smaller. Nano–titanium dioxide, one of the most commonly used nanoparticles (Pop-Tarts, sunblock), has been shown to damage DNA in animals and prematurely corrode metals. Carbon nanotubes seem to penetrate lungs even more deeply than asbestos. [emphases mine]

I think it’s worth ‘unpacking’ these two paragraphs, so here goes.  Slipping past the body’s barriers is a lot more difficult than Millar suggests in the first paragraph. My July 4, 2012 posting on breakthough research  where they penetrated the skin barrier includes this comment from me,

After all the concerns  about nanosunscreens and nanoparticles penetrating the skin raised by civil society groups, the Friends of the Earth in particular, it’s interesting to note that doctors and scientists consider penetration of the skin barrier to be extremely difficult. Of course, they seem to have solved [as of July 2012] that problem which means the chorus of concerns may rise to new heights.

I had a followup in my Oct.3, 2012 posting titled, Can nanoparticles pass through the skin or not?, suggesting there’s still a lot of confusion about this topic even within the scientific community.

Moving on to the other ‘breaches’. As I recall, there was a recent  (Autumn 2012?) nanomedicine research announcement that the blood-brain barrier was breached by nanoparticles. I haven’t yet encountered any mention of breaching the gut and I mention lungs in my next paragraph where I discuss carbon nanotubes.

As for that second paragraph, it’s an example of scaremongering. ‘Inhaled nanoparticles become more toxic as their size decreases’—ok. Why mention nano-titanium oxide in pop tarts and sunblocks, which are not inhaled, in the followup sentence? As for the reference to DNA damage and corroded metals further on, this is straight out of the Friends of the Earth literature which often cites research in a misleading fashion including those two pieces.  There is research supporting part of Millar’s statement about carbon nanotubes—provided they are long and multiwalled. In fact, as they get shorter, the resemblance to asbestos fibers in the lungs or elsewhere seems to disappear as per my Aug 22, 2012 posting and my Jan. 16, 2013 posting.

You don’t need to read the article before listening to the fascinating Jan. 16, 2013 Orion magazine podcast with Millar (reading portions of her article) and expert guests, Mark Wiesner from Duke University and director of their Center for Environmental Implications of Nano Technology (CEINT was first mentioned in my April 15, 2011 posting), Ronald Sandler from Northeastern University and author of Nanotechnology: The Social And Ethical Issues, and Jaydee Hanson, policy director for the International Center for Technology Assessment.

The discussion between Wiesner, Sandler, and Hanson about engineered and natural nanoparticles is why I’ve called the podcast fascinating. Hearing these experts ‘fence’ with each other highlights the complexities and subtleties inherent in discussions about emerging technologies (nano or other) and risk. Millar did not participate in that aspect of the conversation and I imagine that’s due to the fact that she has only been researching this area for six months while the other speakers all have several years worth experience individually and, I suspect, may have debated each other previously.

At the risk of enthusing too much about naturally occurring nanoparticles, I’m mentioning, again (my Feb. 1, 2013 posting), the recently published book by Nanowiki, Nanoparticles Before Nanotechnology, in the context of the stunning visual images used to illustrate the book. I commented previously about them and Victor Puntes of the Inorganic Nanoparticles Group at the Catalan Institute of Nanotechnology (ICN) and one of the creators of this imagery, kindly directed me to a machinima piece (derived from the NanoBosc Second Life community) which is the source for the imagery. Here it is,

NanoBosc from Per4mance MetaLES ..O.. on Vimeo.

Happy Weekend!

Flesh-eating fungus, ivy and other inspirations from nature

Michael Berger has featured Dr. Mingjun Zhang’s team’s fascinating work on flesh-eating fungus in a Dec. 18, 2012 Spotlight article on Nanowerk,

“Most studies on naturally occurring organic nanoparticles have focused on higher organisms,” Mingjun Zhang, an associate professor of biomedical engineering at the University of Tennessee, Knoxville, tells Nanowerk. “Given the earth’s rich biological diversity, it is reasonable to hypothesize that naturally occurring nanoparticles, of various forms and functions, may be produced by a wide range of organisms from microbes to metazoans.”

In his research, Zhang has focused on looking at nature for inspirations for solutions to challenges in engineering and medicine, especially in small-scale, such as bioinspired nanomaterials, bioinspired energy-efficient propulsive systems, and bioinspired nanobio systems for interfacing with cellular systems.

In new work, Zhang and his research associate Dr. Yongzhong Wang have turned their focus to Arthrobotrys oligospora, a representative flesh eater with a predatory life stage in the fungal kingdom.

The researchers have published their work in Advanced Functional Materials ((early online publication behind a paywall),

Naturally Occurring Nanoparticles from Arthrobotrys oligospora as a Potential Immunostimulatory and Antitumor Agent by Yongzhong Wang, Leming Sun, Sijia Yi, Yujian Huang, Scott C. Lenaghan, and Mingjun Zhang in Advanced Functional Materials

Article first published online: 4 DEC 2012 DOI: 10.1002/adfm.201202619

Here’s the abstract,

Arthrobotrys oligospora, a representative flesh eater in the fungal kingdom, is a potential source for natural-based biomaterials due to the presence of specialized 3D adhesive traps that can capture, penetrate, and digest free-living nematodes in diverse environments. The purpose of this study is to discover novel nanoparticles that occur naturally in A. oligospora and to exploit its potential biomedical applications. A new culture method, fungal sitting drop culture method, is established in order to monitor the growth of A. oligospora in situ, and observe the nanoparticle production without interfering or contamination from the solid media. Abundant spherical nanoparticles secreted from the fungus are first revealed by scanning electron microscopy and atomic force microscopy. They have an average size of 360–370 nm, with a zeta potential of –33 mV at pH 6.0. Further analyses reveal that there is ≈28 μg of glycosaminoglycan and ≈550 μg of protein per mg of nanoparticles. Interestingly, the nanoparticles significantly induce TNF-α secretion in RAW264.7mouse macrophages, indicating a potential immunostimulatory effect. The nanoparticles themselves are also found slightly cytotoxic to mouse melanoma B16BL6 and human lung cancer A549 cells, and show a synergistic cytotoxic effect upon conjugation with doxorubicin against both cells. This study proposes a new approach for producing novel organic nanoparticles secreted from microorganisms under controlled conditions. The findings here also highlight the potential roles of the naturally occurring nanoparticles from A. oligospora as an immunostimulatory and antitumor agent for cancer immunochemotherapy.

In more generalized language (from Berger’s Spotlight article),

“It is really exciting to use a natural microbe system to produce nanoparticles for potential cancer therapy,” says Zhang. “Originally, we were trying to understand how the fungus secretes an adhesive trap that can capture, penetrate, and digest free-living nematodes in diverse environments. By doing that we almost accidentally discovered the nanoparticles produced.”

Zhang’s team investigated the fungal nanoparticles’ potential as a stimulant for the immune system, and found through an in vitro study that the nanoparticles activate secretion of an immune-system stimulant within a white blood cell line. They also investigated the nanoparticles’ potential as an antitumor agent by testing in vitro the toxicity to cells using two tumor cell lines, and discovered nanoparticles do kill cancer cells.

Berger’s article in addition to giving more details about Zhang’s current work and his work with ivy and possible applications for ivy-based nanoparticles in sunscreens also provides some discussion of naturally occurring nanoparticles as opposed to engineered (or man-made)  nanoparticles.

The University of Tennessee’s Dec. 4, 2012 press release is also a good source of information on Zhang’s latest work on flesh-eating fungus. For the indefatiguable who are interested in Zhang’s work on ivy and potential nanosunscreens, there’s also my July 22, 2010 posting.