A guest blog by John Dorr, Vice President of Business Development Nanocomp Technologies Inc.

Despite all the fuss over nanotechnology, it’s surprisingly difficult to get a clear sense of how the technology is contributing to new products.  So when the company Nanocomp Technologies Inc. approached me with an idea of writing a guest blog about what they are doing with carbon nanotubes, I jumped at the chance.  I’ve been aware of Nanocomp’s business for some time now and know the company’s President and CEO Peter Antionette, and have been both impressed and intrigued by their use of carbon nanotube sheets and yarns.  At the same time, I didn’t want 2020 Science turning into an industry PR conduit.  So I agreed to the guest blog with one condition – that it stick to science and technology, and not turn into a corporate publicity piece.  As it turns out, John Dorr’s piece is about as far from the hype that often accompanies nanotech stories as you can get. At the same time, this is clearly a significant and potentially important technology – one to watch I think.  Andrew Maynard

In the early 1990’s, a new form of carbon was discovered with highly unusual properties – it was strong, light, and conducted electricity and heat exceptionally well. Because the material was formed from incredibly thin tubes of carbon atoms, it rapidly became know as carbon nanotubes – or CNT for short.

Since their discovery, researchers and businesses have been working hard to exploit the unusual properties of carbon nanotubes – not as easy a task as many people initially thought. However, new and commercially viable uses for the material are now beginning to emerge.

Because of their shape and format, carbon nanotubes can be used in ways similar to other fibers.  As a result, carbon nanotube sheets, yarns and their derivative products are beginning to be introduced into the marketplace. The most productive and scalable manufacturing method in play today employs a gas phase pyrolysis  process for making very large format CNT non-woven textile sheets directly from the reactor without post processing.  As the process grows, a mesh of interconnected, millimeter length CNTs emerges as opposed to a loose powder of micron-scale CNTs. The result is a product that is fundamentally different from Bucky papers, which are made from short tubes that have been dispersed in solvent and subsequently membrane-filtered into film-like structures. They are similar in appearance only.

Figure 1. A 25-foot roll of double wall CNT material is shown being prepared for a customer.

One example of this difference is in mechanical performance. The mechanical strength of the raw, large format sheets is up to 1 GigaPascal (GPa) — five to twenty times better than buckypaper and in the class of m

etals and alloys. Moreover, their electrical conductivity–typically greater than 2 x 10⁶ Si/m–makes them ideal for replacing copper shielding in weight sensitive applications such as for aerospace.

It is also possible to impregnate rolls of these CNT sheets using commercial equipment with a wide variety of thermoset resins such as bismaleimide toughened epoxy (BMI). Figure 1 shows an example of a roll of these sheets.

In addition to sheet material, in a serendipitous blend of traditional and future industry, CNT yarns can be produced by harvesting carbon nanotubes from the reactor onto spools of finished spun material, much like traditional textile-like threads. These yarns can then be braided on commercial wire braiding machines to produce CNT wires of various gauge sizes, as is seen here:

Although the base CNT material is conductive, it can be post-processed to further increase conductivity using a very basic chemistry. This is particularly useful for applications requiring particularly high conductivity – including for application as a high performance, light weight electromagnetic interference (EMI) shield.

Figure 2. An example of four CNT panels seamed together. The people are shown for scale only!

Today, Nanocomp can fabricate sheets that are about four by eight feet long. The sheets can be easily seamed together into panels (see figure 2) or into rolls of any length desired. Such rolls are the standard form factor needed for pre-pregging or other types of resin infiltration, so the material can be easily integrated into such processes.

There are many applications for these materials generally focused on exploiting the unique electrical, thermal and mechanical properties of carbon nanotube sheets and yarns:

Electrical—applications include lightweight conductors, EMI shielding, ground planes and lightning protection, among others. The excellent shielding quality allows CNT material to be used as a substitute for copper braid in single- or multiple-conductor shielded cable. Weight savings from this step alone may range from 30 to 50 percent as compared to conventional materials. Another application is to replace copper conductors at very high frequencies, where the conductivity of CNT yarns can outperform copper.

Thermal—applications include heat straps, thermal interfaces for Integrated Circuit (IC) cooling and thermal interface materials. The thermal conductivity of individual carbon nanotubes can be very high, exceeding 40,000 Watts per Kelvin per meter (W/m-°K) at the nanoscale. Thermal conductivity at the macroscale, as seen in CNT sheets, is generally around 60 W/m-°K). As a comparison, copper has a thermal conductivity of around 400 W/m-°K. However, CNT sheets have a density of 0.5 g/cc while copper has a density of almost 9. On a weight-for-weight basis the CNT sheets have 3.5 times better thermal conductivity than the metal. The material also acts like a black body at wavelengths in the near-UV to the long IR, meaning that strips of the material can be used very effectively as Joule heaters at very high specific power.

Mechanical—potential applications include hybridized vehicular and body armor solutions as well as structural composites for a wide range of applications.  The lightness and strength of carbon nanotubes makes them particularly attractive for forming lightweight yet strong materials, and the carbon nanotube sheets produced by Nanocomp are particularly versatile in this respect.  Preliminary work in armor has focused on the use of the Company’s CNT sheets in thin, lightweight composites capable of stopping civilian handgun threats while maintaining durability and flexibility. While Nanocomp continues to improve the mechanical properties of our materials, we have achieved tensile strength values ranging from 1.1 – 3.5 GPa with CNT yarn, which compares favorably with Kevlar® and its published value of 2.9 GPa whether in sheet format or as yarn that can be subsequently woven into a hybrid fabric.

As with any advanced material, safety is an obvious concern when creating carbon nanotubes.  As mentioned previously, most CNT manufacturers develop products as a powder of short tubes. They can become easily airborne and pose an inhalation hazard.  Nanocomp does not produce material in this form, in fact it does not produce short CNTs at all.  Instead, its reactors produce sheet and yarn articles into which the company’s long CNTs have been inexorably bound, a property that has been borne out by rigorous testing done in partnership with leading government and academic labs. The sheets and yarn articles do not release nanomaterial under typical industrial processing, handling, and storage, and it is the conclusion of outside authorities that the company’s CNTs are simply too big to become airborne or be respirable.

John Dorr is Vice President of Business Development at Nanocomp Technologies, a manufacturer of CNT sheet and yarn materials and value-added products. Nanocomp is one of the only companies to efficiently manufacture and fill customer-ready orders for such carbon nanotube products, and widescale adoption of the material is really quite feasible. The company is set to expand its manufacturing capabilities within the coming year, in response to growing government and commercial market demand. To learn more see: http://www.nanocomptech.com/

[2020 Science has no commercial involvement with Nanocomp, and did not receive any form of financial support for this guest blog.  And as you would expect, the views expressed here are Nanocomp's, and not necessarily mine - just wanted to make that clear   Andrew Maynard]

Ten years ago at the close of the 20th century, people the world over were obsessing about the millennium bug – an unanticipated glitch arising from an earlier technology.  I wonder how clear it was then that, despite this storm in what turned out to be a rather small teacup, the following decade would see unprecedented advances in technology – the mapping of the human genome, social media, nanotechnology, space-tourism, face transplants, hybrid cars, global communications, digital storage, and more.  Looking back, it’s clear that despite a few hiccups, emerging technologies are on a roll – one that’s showing no sign of slowing down.

So what can we expect as we enter the second decade of the twenty first century?  What are the emerging technology trends that are going to be hitting the headlines over the next ten years?

Here’s my list of the top ten technologies I think are worth watching. I’m afraid that, as with all crystal ball gazing, it’s bound to be flawed. Yet as I work on the opportunities and challenges of emerging technologies, these do seem to be areas that are ripe for prime time.

Geoengineering

2009 was the year that geoengineering moved from the fringe to the mainstream.  The idea of engineering the climate on a global scale has been around for a while. But as the penny has dropped that we may be unable – or unwilling – to curb carbon dioxide emissions sufficiently to manage global warming, geoengineering has risen up the political agenda.  My guess is that the next decade will see the debate over geoengineering intensify.  Research will lead to increasingly plausible and economically feasible ways to tinker with the environment.  At the same time, political and social pressure will grow – both to put plans into action (whether multi- or unilaterally), and to limit the use of geoengineering.  The big question is whether globally-coordinated efforts to develop and use the technology in a socially and politically responsible way emerge, or whether we end up with an ugly – and potentially disastrous – free for all.

Smart grids

It may not be that apparent to the average consumer, but the way that electricity is generated, stored and transmitted is under immense strain.  As demand for electrical power grows, a radical rethink of the power grid is needed if we are to get electricity to where it is needed, when it is needed.  And the solution most likely to emerge as the way forward over the next ten years is the Smart Grid.  Smart grids connect producers of electricity to users through an interconnected “intelligent” network.  They allow centralized power stations to be augmented with – and even replaced by – distributed sources such as small-scale wind farms and domestic solar panels.  They route power from where there is excess being generated to where there is excess demand.  And they allow individuals to become providers as well as consumers – feeding power into the grid from home-installed generators, while drawing from the grid when they can’t meet their own demands.  The result is a vastly more efficient, responsive and resilient way of generating and supplying electricity.  As energy demands and limits on greenhouse gas emissions hit conventional electricity grids over the next decade, expect to see smart grids get increasing attention.

Radical materials

Good as they are, most of the materials we use these days are flawed – they don’t work as well as they could.  And usually, the fault lies in how the materials are structured at the atomic and molecular scale.  The past decade has seen some amazing advances in our ability to engineer materials with increasing precision at this scale.  The result is radical materials – materials that far outperform conventional materials in their strength, lightness, conductivity, ability to transmit heat, and a whole host of other characteristics.  Many of these are still at the research stage.  But as demands for high performance materials continue to increase everywhere from medical devices to advanced microprocessors and safe, efficient cars to space flight, radical materials will become increasingly common.  In particular, watch out for products based on carbon nanotubes.  Commercial use of this unique material has had it’s fair share of challenges over the past decade.  But I’m anticipating many of these will be overcome over the next ten years, allowing the material to achieve at least some of it’s long-anticipated promise.

Synthetic biology

Ten years ago, few people had heard of the term “synthetic biology.”  Now, scientists are able to synthesize the genome of a new organism from scratch, and are on the brink of using it to create a living bacteria.  Synthetic biology is about taking control of DNA – the genetic code of life – and engineering it, much in the same way a computer programmer engineers digital code.  It’s arisen in part as the cost of reading and synthesizing DNA sequences has plummeted.  But it is also being driven by scientists and engineers  who believe that living systems can be engineered in the same way as other systems.  In many ways, synthetic biology represents the digitization of biology.  We can now “upload” genetic sequences into a computer, where they can be manipulated like any other digital data.  But we can also “download” them back into reality when we have finished playing with them – creating new genetic code to be inserted into existing – or entirely new – organisms.  This is still expensive, and not as simple as many people would like to believe – we’re really just scratching the surface of the rules that govern how genetic code works.  But as the cost of DNA sequencing and synthesis continues to fall, expect to see the field advance in huge leaps and bounds over the next decade.  I’m not that optimistic about us cracking how the genetic code works in great detail by 2020 – the more we learn at the moment, the more we realize we don’t know.  However, I have no doubt that what we do learn will be enough to ensure synthetic biology is a hot topic over the next decade.  In particular, look out for synthesis of the first artificial organism, the development and use of “BioBricks” – the biological equivalent of electronic components – and the rise of DIY-biotechnology.

Personal genomics

Closely related to the developments underpinning synthetic biology, personal genomics relies on rapid sequencing and interpretation of an individual’s genetic sequence.  The Human Genome Project – completed in 2001 – cost taxpayers around $2.7 billion dollars, and took 13 years to complete.  In 2007, James Watson’s genome was sequenced in 2 months, at a cost of $2 million.  In 2009, Complete Genomics were sequencing personal genomes at less than $5000 a shot.  $1000 personal genomes are now on the cards for the near future – with the possibility of substantially faster/cheaper services by the end of the decade.  What exactly people are going to do with all these data is anyone’s guess at this point – especially as we still have a long way to go before we can make sense of huge sections of the human genome.  Add to this the complication of epigenetics, where external factors lead to changes in how genetic information is decoded which can pass from generation to generation, and and it’s uncertain how far personal genomics will progress over the next decade.  What aren’t in doubt though are the personal, social and economic driving forces behind generating and using this information. These are likely to underpin a growing market for personal genetic information over the next decade – and a growing number of businesses looking to capitalize on the data.

Bio-interfaces

Blurring the boundaries between individuals and machines has long held our fascination. Whether it’s building human-machine hybrids, engineering high performance body parts or interfacing directly with computers, bio-interfaces are the stuff of our wildest dreams and worst nightmares.  Fortunately, we’re still a world away from some of the more extreme imaginings of science fiction – we won’t be constructing the prototype of Star Trek Voyager’s Seven of Nine anytime soon.  But the sophistication with which we can interface with the human body is fast reaching the point where rapid developments should be anticipated.  As a hint of things to come, check out the Luke Arm from Deka (founded by Dean Kamen).  Or Honda’s work on Brain Machine Interfaces.  Over the next decade, the convergence of technologies like Information Technology, nanoscale engineering, biotechnology and neurotechnology are likely to lead to highly sophisticated bio-interfaces.  Expect to see advances in sensors that plug into the brain, prosthetic limbs that are controlled from the brain, and even implants that directly interface with the brain.  My guess is that some of the more radical developments in bio-interfaces will probably occur after 2020.  But a lot of the groundwork will be laid over the next ten years.

Data interfaces

The amount of information available through the internet has exploded over the past decade.  Advances in data storage, transmission and processing have transformed the internet from a geek’s paradise to a supporting pillar of 21st century society.  But while the last ten years have been about access to information, I suspect that the next ten will be dominated by how to make sense of it all.  Without the means to find what we want in this vast sea of information, we are quite literally drowning in data.  And useful as search engines like Google are, they still struggle to separate the meaningful from the meaningless.  As a result, my sense is that over the next decade we will see some significant changes in how we interact with the internet.  We’re already seeing the beginnings of this in websites like Wolfram Alpha that “computes” answers to queries rather than simply returning search hits,  or Microsoft’s Bing, which helps take some of the guesswork out of searches.  Then we have ideas like The Sixth Sense project at the MIT Media Lab, which uses an interactive interface to tap into context-relevant web information.  As devices like phones, cameras, projectors, TV’s, computers, cars, shopping trolleys, you name it, become increasingly integrated and connected, be prepared to see rapid and radical changes in how we interface with and make sense of the web.

Solar power

Is the next decade going to be the one where solar power fulfills its promise?  Quite possibly.  Apart from increased political and social pressure to move towards sustainable energy sources, there are a couple of solar technologies that could well deliver over the next few years.  The first of these is printable solar cells.  They won’t be significantly more efficient than conventional solar cells.  But if the technology can be scaled up and some teething difficulties resolved, they could lead to the cost of solar power plummeting.  The technology is simple in concept – using relatively conventional printing processes and special inks, solar cells could be printed onto cheap, flexible substrates; roll to roll solar panels at a fraction of the cost of conventional silicon-based units.  And this opens the door to widespread use.  The second technology to watch is solar-assisted reactors.  Combining mirror-concentrated solar radiation with some nifty catalysts, it is becoming increasingly feasible to convert sunlight into other forms of energy at extremely high efficiencies.  Imagine being able to split water into hydrogen and oxygen using sunlight and an appropriate catalyst for instance, then recombine them to reclaim the energy on-demand – all at minimal energy loss.  Both of these solar technologies are poised to make a big impact over the next decade.

Nootropics

Drugs that enhance mental ability – increasingly referred to as nootropics – are not new.  But their use patterns are.  Drugs like ritalin, donepezil and modafinil are increasingly being used by students, academics and others to give them a mental edge.  What is startling though is a general sense that this is acceptable practice.  Back in June I ran a straw poll on 2020 Science to gauge attitudes to using nootropics.  Out of 207 respondents, 153 people (74%) either used nootropics, or would consider using them on a regular or occasional basis.  In April 2009, an article in the New Yorker reported on the growing use of “neuroenhancing drugs” to enhance performance. And in an informal poll run by Nature in April 2008, 1 in 5 respondents claimed “they had used drugs for non-medical reasons to stimulate their focus, concentration or memory.” Unlike physical performance-enhancing drugs, it seems that the social rules for nootropics are different.  There are even some who suggest that it is perhaps unethical not to take them – that operating to the best of our mental ability is a personal social obligation.  Of course this leads to a potentially explosive social/technological mix, that won’t be diffused easily.  Over the next ten years, I expect the issue of nootropics will become huge.  There will be questions on whether people should be free to take these drugs, whether the social advantages outweigh the personal advantages, and whether they confer an unfair advantage to users by leading to higher grades, better jobs, more money.  But there’s also the issue of drugs development.  If a strong market for nootropics emerges, there is every chance that new, more effective drugs will follow.  Then the question arises – who gets the “good” stuff, and who suffers as a result?  Whichever way you look at it, the 2010′s are set to be an interesting decade for mind-enhancing substances.

Cosmeceuticals

Cosmetics and pharmaceuticals inhabit very different worlds at the moment.  Pharmaceuticals typically treat or prevent disease, while cosmetics simply make you look better.  But why keep the two separate?  Why not develop products that make you look good by working with your body, rather than simply covering it?  The answer is largely due to regulation – drugs have to be put through a far more stringent set of checks and balances that cosmetics before entering the market, and rightly so.  But beyond this, there is enormous commercial potential in combining the two, especially as new science is paving the way for externally applied substances to do more than just beautify.  Products that blur the line are already available – in the US for instance, sunscreens and anti dandruff shampoos are considered drugs.  And the cosmetics industry regularly use the term “cosmeceutical” to describe products with medicinal or drug-like properties.  Yet with advances in synthetic chemistry and nanoscale engineering, it’s becoming increasingly possible to develop products that do more than just lead to “cosmetic” changes.  Imagine products that make you look younger, fresher, more beautiful, by changing your body rather than just covering up flaws and imperfections.  It’s a cosmetics company’s dream – one shared by many of their customers I suspect.  The dam that’s preventing many such products at the moment is regulation.  But if the pressure becomes too great – and there’s a fair chance it will over the next ten years – this dam is likely to burst.  And when it does, cosmeceuticals are going to hit the scene big-time.

So those are my ten emerging technology trends to watch over the next decade.  But what happened to nanotechnology, and what other technologies were on my shortlist?

Nanotech has been a dominant emerging technology over the past ten years.  But in many ways, it’s a fake.  Advances in the science of understanding and manipulating matter at the nanoscale are indisputable, as are the early technology outcomes of this science.  But nanotechnology is really just a convenient shorthand for a whole raft of emerging technologies that span semiconductors to sunscreens, and often share nothing more than an engineered structure that is somewhere between 1 – 100 nanometers in scale.  So rather than focus on nanotech, I decided to look at specific technologies which I think will make a significant impact over the next decade.  Perhaps not surprisingly though, many of them depend in some way on working with matter at nanometer scales.

In terms of the emerging technologies shortlist, it was tough to whittle this down to ten trends. My initial list included batteries, decentralized computing, biofuels, stem cells, cloning, artificial intelligence, robotics, low earth orbit flights, clean tech, neuroscience and memristors – there are many others that no doubt could and should have been on it.  Some of these I felt were likely to reach their prime sometime after the next decade.  Others I felt didn’t have as much potential to shake things up and make headlines as the ones I chose.  But this was a highly subjective and personal process.  I’m sure if someone else were writing this, the top ten list would be different.

And one final word.  Many of the technologies I’ve highlighted reflect an overarching trend: convergence.  Although not a technology in itself, synergistic convergence between different areas of knowledge and expertise will likely dominate emerging technology trends over the next decade.  Which means that confident as I am in my predictions, the chances of something completely different, unusual and amazing happening are…  pretty high!

Update, 12/27/09  Something’s been bugging me, and I’ve just realized what it is – in my original list of ten, I had smart drugs, but in the editing process they somehow got left by the wayside!  As I don’t want to go back and change the ten emerging technology trends I ended up posting, they will have to be a bonus.  As it is, drug delivery timelines are so long that I’m not sure how many smart drugs will hit the market before 2020.  But when they do, they will surely mark a turning point in therapeutics.  These are drugs that are programmed to behave in various ways.  The simplest are designed to accumulate around disease sites, then destroy the disease on command – gold shell nanoparticles fit the bill here, preferentially accumulating around tumors then destroying them by heating up when irradiated with infrared radiation.  More sophisticated smart drugs are in the pipeline though that are designed to seek out diseased cells, provide local diagnostics, then release therapeutic agents on demand.  The result is targeted disease treatment that leads to significantly greater efficacy at substantially lower doses.  Whether or not these make a significant impact over the next decade, they are definitely a technology to watch.

Update 12/29/09  Which emerging technologies do you thing will trend over the next decade?  Join the discussion on the 2020 Science Facebook page.

Just a quick post (at least, as far as the text goes). Last week, I had the pleasure of appearing on Twit TV’s Dr. Kiki’s Science Hour with Kristen Sanford and Leo Laporte. The conversation covered nanotechnology from every conceivable angle. I should have known with Leo’s opening question – asking what I thought of Eric Drexler’s ideas – that we were in for a fun ride!

As Kiki and Leo managed to get in a whole bunch of questions about what nanotech is (and isn’t), where and how it’s being used, what’s so great about it, and what some of the possible barriers to it’s development are, I thought it worth posting the show here.

I should warn you, it’s long, running just shy of 70 minutes. The full show can be streamed below. But for anyone who wants to fast forward through the boring bits or watch it at their leisure, it can also be downloaded here. [Quicktime, 199 MB]

The show was recorded by the folks at On Demand Twit Video, and is reproduced here under the Attribution-Noncommercial-Share Alike 2.5 Canada Creatives Commons license:

Back in April, the folks at the PBS station THIRTEEN asked me to answer 13 questions on nanotechnology and the environment for their website feature Green Thirteen.   The questions ended up covering most of nanotechnology – what it is, what it’s good for, what the downsides might be, and how we might overcome potential problems to use it effectively.  With this in mind, I thought it worth posting the Q&A here as a brief nanotechnology primer…

1. What is nanotechnology?

The chemist and Nobel prize winner Richard Smalley described nanotechnology as “the art and science of making stuff that does stuff at the nanometer scale.”

Nanotechnology involves working with materials at an incredibly fine scale—around the size of the atoms and molecules that they are made of.  But the aim is to achieve something new and useful by working at this scale.

Working at the nanometer scale—where one nanometer is a mere one billionth of a meter long—it becomes possible to tap into some unique properties of matter.  Many of these properties only become apparent when small clumps of atoms and molecules are carefully constructed and used as the building blocks of larger structures.  For instance, some materials can be used in new ways when they are engineered at the nanoscale, simply because they are more versatile than non-nanoscale materials.  Other materials behave in strange new ways that enable innovative uses.  Gold, for example, becomes a highly reactive, red-colored metal when formed into nanometer-size particles.  And working at the nanoscale allows highly sophisticated new materials to be engineered that would be impossible to produce using conventional technologies—everything from super-strong materials to the next generation of computer chips to targeted drugs.

2. What are the benefits of nanotech?

The benefits of nanotechnology are incredibly broad, but generally involve making existing technologies work better, or enabling the development of  new technologies.

Many people see nanotechnology as a tool kit that allows scientists and engineers to do new things, whether they are chemists, physicists, biologists, or working in a hundred and one other fields.  In many cases, the things we use everyday don’t work as well as they could because we haven’t been able to control their structure precisely at the finest level.  But nanotechnology is changing this.  For instance, a growing number of consumer products are being improved through the use of simple nanotechnology-based applications:  Sunscreens that go on clear, but protect against harmful UV radiation; clothing that repels stains; socks that prevent the buildup of odor-causing bacteria; tennis racquets that are stronger and lighter; MP3 players that are smaller while holding more songs; even foods that are supposedly better because they have been engineered at the nanometer scale.

But these consumer products are only the tip of the nanotechnology iceberg.  Because the technology enables other technologies to work better, it has the potential to help address some of the biggest challenges facing us.  These include combating climate change, generating renewable energy, controlling pollution, ensuring access to clean water, and developing highly effective medical treatments.

As nanotechnology is used to make better products and address serious challenges, it is expected to generate jobs and money.  Some estimates put the possible market value of products that depend in some way on nanotechnology as being worth over $3 trillion dollars within the next five years.  While the significance estimates like these are sometimes hard to evaluate, there is little doubt that the “nanotechnology tool kit” will play a major role in underpinning future technological and economic development.

3. How does nanotech improve existing technologies?

Sophisticated as they might seem, many existing technologies are akin to trying to make fine jewelry while wearing boxing gloves.  Nanotechnology is the equivalent of removing the gloves—it gives us the ability to fine tune how materials and products are put together at the finest level.  For example, consider the integrated circuits at the heart of modern computers.  The power of these circuits is limited by how many components can be squeezed onto a single chip.  But it is also limited by how fast the heat generated by the electrons coursing through the components can be removed.  Nanotechnology is enabling components—individual transistors and connectors—to be shrunk to the nanoscale, allowing many more of them to be packed onto single chips.  But it is also improving the materials used to transmit heat away from these components, ensuring they don’t over-heat and stop working.

Sunscreens are another example of where nanotechnology improves an existing technology.  Ten to fifteen years go there were two options to making a sunscreen.  You could either use chemicals that are absorbed into the skin, and protect against harmful UV radiation from the sun.  Or you could use particles of materials like titanium dioxide—the same material used to make paint and some foods a brilliant white—to coat the skin and reflect the harmful radiation.  The particles were generally more effective at protecting the user and had the advantage that they lay on top of the skin rather than being absorbed into it—but they left a pasty white residue on the skin that was cosmetically unattractive.  Nanotechnology has since removed this disadvantage.  But using nanometer-scale particles of materials like titanium dioxide and zinc oxide, manufacturers have developed sunscreens that are transparent to visible light while still reflecting UV radiation—and that don’t rely on chemicals that are absorbed into the skin.  The result is highly effective products that are also cosmetically acceptable.

Almost any technology that can be thought of which relies on physical materials can be improved using nanotechnology—simply because nanotechnology provides increased control over the atoms and molecules that make up any material and determine its properties.  However, the economic, social and personal advantages of the improvements will not always outweigh the time, effort and resources needed to make them happen.

4. What kinds of industries are involved? How and where are nanomaterials made?

There are many types of industries involved in nanotechnology, ranging from small startup companies to major multinational corporations.  The types of materials being made are also very diverse.  The NanoMetro map published by the Project on Emerging Nanotechnologies gives a feel for the range and location of nanotech businesses in the US, although it probably doesn’t capture everything that is happening.  The map identifies industries using nanotechnology in the broad areas of electronics, energy and environmental applications, imaging and microscopy, tools and instruments, medicine and health, and materials.  One important point here is that nanotechnology is as much about the tools needed to see and manipulate matter at the nanometer scale—electron microscopes and scanning force microscopes for instance—as it is about creating and using new materials.

Many nanotechnology applications rely on nanomaterials—materials that have been engineered with nanometer-scale structures.  A lot of the nanomaterials currently in use are simply nanometer-scale forms of materials that have been used for many years—such as the titanium dioxide nanoparticles used in sunscreens and elsewhere.  As a result, it is common to find companies with experience developing chemicals and materials using more traditional methods beginning to develop nanomaterials.  At the same time, there are a number of smaller companies that are developing increasingly sophisticated and unique nanomaterials.  In many cases, these are being spun out of University-based nanotechnology research.

Approached to making nanomaterials are as diverse as the materials themselves.  Some of the simplest nanomaterials are made by reacting chemicals together, either in a liquid—to produce suspensions of nanoparticles—or in a gas, essentially burning materials in a controlled manner to produce nanometer-scale particles.  These are then collected, purified, and further processed before being added to products.  At the other end of the spectrum, researchers are modifying viruses, and re-programming them to build nanomaterials.  Recent research has led to new batteries that are based on virus-constructed electrodes.  In between, there are many different ways of engineering matter to form nanostructured materials that can be used to add value to products.

5. What kinds of nanomaterials are appearing in consumer goods?

Most nanotechnology-enabled consumer products currently available rely on relatively simple nanomaterials.  A survey by the Project on Emerging Nanotechnologies indicates that silver nanoparticles are one of the most the dominant nanomaterials currently in use, appearing as an antimicrobial agent in everything from clothing to cooking utensils.  Carbon nanotubes—a unique form of carbon with unusual mechanical and electrical properties—is also appearing in a number of products, predominantly in sporting goods as a way to make them stronger and lighter.  Nanoparticles of zinc oxide and titanium dioxide are widely used in sunscreens and cosmetics, while silica nanoparticles are also being used in a number of products.  In addition there are a number of products using “soft” nanomaterials, which rapidly fall apart when they have done their job.  For instance, some cosmetics use nanometer scale liposomes—very small capsules containing specific materials—to deliver nutrients and other ingredients to the outer layers of the skin.  These disintegrate when they reach their destination, delivering the encapsulated material to where it is needed.

With the exception of carbon nanotubes, these and other nanomaterials being used in consumer products tend to be nanostructured versions of materials that have been used for some time.  However, over the next few years it is likely that increasingly sophisticated and complex nanomaterials will find uses in consumer products.

6. What are the negatives of nanotech?

Like any technology, nanotechnology has its plusses and minuses.  These will generally be specific to different uses of nanotechnology.  For instance, the potential downsides of a nanotechnology-enabled memory chip in an MP3 player will be very different from using nanoparticles in food.

Because of the new and unusual behavior of many engineered nanomaterials, questions have been raised about their safety.  If something can be used in new ways, get to new places, or has new and unusual physical and chemical properties, it is reasonable to ask whether these might also lead to new ways of causing harm—either to humans or the environment.  Evidence to date is sketchy, but it does suggest that some nanomaterials might cause harm in unexpected ways if exposure occurs.  For some nanomaterials, their potential to cause harm will be negligible.  In other situations, more care will need to be taken to ensure safe use—a lot depends on whether exposure is likely, and how toxic the material is.  Common sense and current knowledge go a long way to reducing possible risks.  But more work is still needed to determine the best ways of using these new materials as safely as possible.

Other concerns about nanotechnology are more social and ethical in nature.  Will nanotechnology lead to personal rights being infringed—perhaps through ubiquitous surveillance?  Who will benefit from these emerging technologies, and who will pay the price?  At what point should the use of nanotechnology in enhancing human abilities be questioned?  These and similar questions are not unique to nanotechnology.  But they are an important component of the debate surrounding its development and use.

7. Are there any health side-effects associate with nanotechnology? (e.g. carbon nanotubes causing lung cancer, unexpected in-vivo reactions)

Nanotechnology in and of itself does not lead to health impacts, simply because it is a toolbox of different techniques rather than one specific technology.  However, some uses of nanotechnology could affect people’s health if used inappropriately.

For a material to cause harm to humans, it must first get into the body.  Once there, it’s toxicity will determine how severe any response is.  A high exposure to a low toxicity material (and many nanomaterials will have a low toxicity) may result in a negligible impact.  On the other hand, a low exposure to a highly toxic material could cause a lot of damage.

Two materials that have been researched quite a bit are titanium dioxide nanoparticles, and carbon nanotubes.  In both cases, the materials have been studied in cell cultures and in animals but not humans, and so estimating the toxicity of the materials to people is a little difficult.

Research has shown that inhaled titanium dioxide nanoparticles are more toxic than larger particles of the same substance.  In this case, size makes a difference it seems.  However, as titanium dioxide has a very low toxicity to begin with, the nanoparticles—even though they appear to be more toxic—still seem to be reasonably safe.

Carbon nanotubes appear to be harmful if inhaled, but the harm seems to depend on the type of nanotubes—and there are many types of carbon nanotubes.  Recent research has indicated that long, straight, stiff carbon nanotubes that look like asbestos fibers under the microscope, could be as harmful as asbestos if inhaled.  However, many types of carbon nanotubes don’t have the right shape for this to be a serious concern.  Other research has shown that tangled clumps of carbon nanotubes could also harm the lungs if inhaled, although it unclear how much material is needed for harm to occur.

In both these cases, the critical factor is exposure.  If exposures are low—either while making the materials or using products containing them—risks of health effects will also be low.  The good news is that it seems exposure to carbon nanotubes probably will be low—this is a material that doesn’t readily become airborne as fine fibers.  However, more research is needed to work out how low an exposure is low enough.

8. What kinds of threats to the environment might nanotech pose? (e.g.metal oxide nanoparticle toxicity to fish and frogs)

It’s not clear how harmful different nanomaterials will be if they get out into the environment, although it is clear that some nanomaterials will be more harmful than others.  Important questions that still needs answers include how much material is likely to be release, and from where; whether this material is in the form of nanoparticles, or whether it clumps up into larger particles; how far it is transported, and whether it changes as it moves through the environment; where it accumulates, how long it lasts in the environment, which plants and animals will become exposed, and what the impacts might be.

The good news is that nanoparticles from sources like fires and volcanic eruptions have been ubiquitous in the environment as long as living organisms have been around, and so they have evolved over time to deal with them.  That said, no-one is quite sure how the environment will respond to novel engineered nanomaterials—especially precisely engineered nanoparticles.

One particular potential threat that has already been raised concerns the use of nano-silver in products.  Silver is very effective at killing microbes, which is why it is being used in an increasing number of products.  But it is also highly toxic to a number of organisms as well as microbes.  What is not clear at present is what the impact of silver nanoparticles washed out of products and into the environment might be.  The amounts used may be low enough for the impact to be negligible—or they may not.  It’s a question that can’t be answered well without more information on how much nano-silver is being used, where it is being used, and the likely impacts on the environment if it is released.

9. Who regulates nanotechnology products?

There is no one agency or organization that regulates nanotechnology products.  Rather, they are regulated according to the type of product.  For instance, the US Food and Drug Administration (FDA) is responsible for drugs, food additives and cosmetics that contain engineered nanomaterials.  The US Consumer Protection Safety Commission covers consumer product safety.  The US Department of Agriculture covers food safety—except where FDA has jurisdiction.  And the US Environmental Protection Agency is responsible for chemicals and pesticides.  Each part of this patchwork of regulations and regulatory agencies has different levels of regulatory authority when it comes to nanotechnology products.

10. How much is still not known about the safety of nanotech products, and what needs to be done to fill in the gaps?

From a scientific perspective, there is still a tremendous amount that we don’t know about how to develop and use nanotechnology products safely.  Specific research question that need answers have been raised by a number of organizations, including the Project on Emerging Nanotechnologies and the US government National Nanotechnology Initiative.  There is broad agreement that if nanotechnology is to succeed—and succeed safely—there needs to be a major strategic research program that identifies and fills the outstanding research gaps.  This will require a clear set of goals and objectives, additional research funding, and greater coordination between the organizations that fund research, and those that use the information to ensure material and product safety.

That said, we are not starting out with a blank slate when it comes to using nanotechnology products safely.  Knowledge from other materials can be used to reduce potential risks in many cases, and existing regulations can be applied to nanomaterials—although their implementation may be less than perfect.  However, strategic research will be essential to underpin the long-term safety of increasingly sophisticated nanotechnology-based materials and products.

11. What kinds of recycling challenges are there for nanotech materials? What about nanolitter?

Recycling nanotechnology products presents a number of challenges.  First, there is the problem of stuff that isn’t recycled, either because no-one thinks about it, or because including nanomaterials in a product makes recycling difficult.  This leads to the possibility of nanomaterials being released into the environment as products are disposed of in landfills and slowly degrade, or are incinerated.

Where nanotechnology products are recycled there are two challenges:  Is it worth attempting to extract and reuse the nanotechnology components of the products, and how might this be done; and does the inclusion of a nanomaterial in a product make conventional recycling harder?  To illustrate this second point, imagine nanoparticles of some substance were added to plastic bottles to make them perform better, but that these nanoparticles interfered with the quality of material recycled from conventional plastic bottles.  Would it be better to separate out the nano and non-nano bottles, and how would that be achieved in practice.  The first challenge is perhaps a little easier to address, as it is unlikely that nanomaterials could be recycled from nanotechnology products in a useable state.  Rather, it is more likely that the substances forming the nanomaterials—the silver in nano-silver socks for example—would be reclaimed and used to form new nanomaterials.

12. What are some of the future uses for nanotechnology? How likely is a nano-fabricator?

The next few decades will most likely see some tremendous advances that are based in part on controlling matter at the nanometer scale.  These could well include new forms of generating and storing energy; lighter stronger materials; targeted cancer treatments; treatments for degenerative diseases; efficient ways to purify water; faster more powerful computers; computers that run on light, not electricity; biological organisms that are programmed to make new materials and devices; metamaterials that channel light in highly unusual ways.  We will definitely see a shift from the rather simple nanomaterials being used today to increasingly complex multifunctional nanomaterials.  And associated with this will be an increasingly sophisticated suite of instruments for observing and manipulating the world at the nanoscale.

Based on current research, there will further advances in developing new molecules and nanoscale systems that mimic or reflect what happens in biology (biology, after all, operates very effectively at the nanoscale).  These will move us closer to building new materials and devices molecule by molecule.  But the end result will be much closer to conventional chemistry or biology than the “nano-fabricator”—a speculative machine that can construct complex products out of their constituent atoms, much like the replicators of Star Trek.

13. How can we prevent future problems with nanotechnology? (e.g. grey goo)

Nanotechnology will come with its own set of problems—just as every technology preceding it has.  The trick here will be to have the foresight to spot the problems before they get too large and to navigate a course around them.  This is a tough task.  It will require strategic research to address plausible issues, and ways of translating the results of this research into proactive action.

Even with such an approach, there will be mis-steps.  But hopefully, with the right strategies in place, corrective action will be able to taken fast enough to prevent either major human health or environmental impacts, or the hopes of nanotechnology to address critical challenges being dashed.

In the long term, there may be challenges that are outside our current ability to comprehend the potential dangers, and how to avoid them.  Not self-replicating nanobots perhaps—the so-called “grey goo” that is more science fantasy than science fact—but other technological breakthroughs that take us places unimaginable a few years ago.  The only way to deal with such challenges is to develop institutions that are sufficiently fleet footed and forward-looking to respond to the challenges as they come over the horizon.

The one thing we cannot afford to do is to stick our heads in the sand and ignore potential of nanotechnology to do great good and possibly great harm.

These questions and answers first appeared in their original form at THIRTEEN.ORG on April 28 2009

Reading yesterday’s New York Times, it seems China could well be poised to leapfrog the West in advanced battery technology (China Vies to Be World’s Leader in Electric Cars). According to the article, Chinese leaders have adopted a plan aimed at turning the country into one of the leading producers of hybrid and all-electric vehicles within three years, and making it the world leader in electric cars and buses after that.

If they deliver the goods, the economic ramifications will be significant.  But then so will the resulting breakthroughs in battery technology.

Despite our ever-increasing addiction to battery-powered gizmos, current technologies are seriously limited.  My laptop and cell-phone (and this morning, my e-book) constantly seem to die at most inopportune moments.  And remembering to recharge the 1001 things in my life that depend on batteries (while working out which recharger goes with which device) is a time-suck I could easily live without.

No question, personal electronics are desperately in need of a major battery upgrade.

But that’s small fry compared to the challenges of developing usable batteries for power-hungry cars.

The problem is, it’s hard to get electricity into batteries fast; hard to get it out again; and once you’ve got a lot of it in there, hard to prevent the battery having a melt-down—remember the stories of igniting/exploding PC batteries?  These are tractable problems for the small stuff—cell phones and the like—but they present enormous obstacles to scaling up batteries large enough to power cars.

Yet developing battery-powered cars makes a lot of sense… It reduces reliance on highly-refined fossil fuels.  It has the potential to even out electricity demands—essentially using batteries as an energy-buffer.  It enables Prius-like energy-recovery while driving. And it relocates a harmful source of pollution (tailpipe emissions) to where it can be better managed—at the power station.

The good news is that emerging technologies like nanotechnology are providing solutions to at least some of the challenges being faced in developing advanced batteries.  Lithium ion batteries in particular are benefiting from electrodes engineered with nanometer-scale structures, which decrease charging time and increase power output, while improving battery safety.  Companies like A123 and Altairnano are already exploiting nanotechnology-based developments in advanced batteries.  And anecdotally, experts suspect that the performance of most high-end laptop batteries already depend on the use of carbon nanotubes in the electrodes.

There’s still some way to go before this technology matures to the point where electric cars make sense on a grand scale.  But that day is coming.  And by all accounts China will be in the lead when it does.  China is already a major player in the field of nanotechnology (see last week’s piece by Tom Mackenzie in The Guardian for instance), and has the capacity to focus research and development resources where they are most likely to deliver the goods.

The end result probably doesn’t bode well for an ailing US car industry which is still struggling to readjust to a world where smaller, lighter, greener are the order of the day (even the much-touted Chevy Volt still looks like old ideas dressed in new technology).  But a push by China to develop technologically and economically viable electric cars could stimulate world-wide development of battery technologies that leads to a reduced dependence on fossil fuels, and a smaller overall environmental footprint.

That would certainly be good news.

And as a spin-off, there’s a chance that we might finally get batteries for our laptops, cell phones and e-books that don’t die when we need the most.  Now that would be progress indeed!

Footnotes

While writing this, there was some discussion on the NYT article and batteries in general on Twitter.  I particularly wanted to acknowledge helpful comments and links from @joergheber (esp. on wireless power transfer), @quantum_tunnel (re-engineering batteries) and @crc2008 (for the link to the Lightning Car Company) – thanks guys.

I’m looking at an electron microscope image of a carbon nanotube – as I cannot show it here, you’ll have to imagine it.  It shows a long, straight, multi-walled carbon nanotube, around 100 nanometers wide and 10 micrometers long.  There is nothing particularly unusual about this.  What is unusual is that the image also shows a section of the lining of a mouse’s lung.  And the nanotube is sticking right through the lining, like a needle through a swatch of felt.

The image was shown at the annual Society of Toxicology meeting in Baltimore last week, and comes from a new study by researchers at the National Institute for Occupational Safety and Health (NIOSH) on the impact of inhaled multi-walled carbon nanotubes on mice.

It’s highly significant because it takes scientists a step closer to understanding whether carbon nanotubes that look like harmful asbestos fibers, could cause asbestos-like disease…

Questions were raised about carbon nanotubes and their superficial similarity to asbestos fibers as far back as 1992.  Yet it wasn’t until last year that research was published suggesting carbon nanotubes that look like harmful asbestos fibers could possibly also cause asbestos-like diseases—specifically the disease of the lungs’ lining mesothelioma.

The Poland study, published in the journal Nature Nanotechnology, indicated that development of the disease mesothelioma was theoretically possible following inhalation exposure.  But it didn’t establish whether exposure could occur to asbestos-like carbon nanotubes in practice or, if they were inhaled, whether the nanotubes could move to and penetrate the sensitive outer layer of the lungs.

Both steps would have to occur for there to be a chance of mesothelioma developing.

The current study from NIOSH seems to close the loop on one of those steps.  Some caution is needed here as the research has yet to be peer reviewed (see Richard Denison’s comments for instance).  Yet the findings are so significant that NIOSH thought it important to keep people abreast of developments before the work is finally reviewed and published.

In the study, a suspension of carbon nanotubes was introduced into the mice lungs using the pharyngeal aspiration technique, and the movement of the nanotubes through the lungs subsequently tracked.  The researchers found that some of the nanotubes migrated from the alveoli in the lungs (the tiny sacs where oxygen passes form the air to the blood) to the pleura—the delicate membrane surrounding the lungs.  As seen in the image described above, there was direct evidence that some of these needle-like fibers physically penetrated through the lung lining, into the region where mesothelioma can develop.

The researchers are at pains to point out that these data are preliminary, and are not conclusive.  The results could have been influenced by the way the nanotubes were delivered to the lungs, the amount of material applied, or the types of animals used.  Nevertheless, they demonstrate that, in principle, some forms of carbon nanotubes have the potential to migrate to the outer layer of the lungs.  And this, combined with the data from Poland et al., raises the stakes considerably regarding potential health impacts.

The data from this study will be peer-reviewed and published shortly, allowing a more critical evaluation.  But given the significance of the preliminary findings, it seems  there is an urgent need for a more extensive strategic research program to establish how harmful different types of carbon nanotubes are, and how they can be handled safely.

Without this, it’s hard to see how manufacturers will be able to make informed choices on good practices that don’t either endanger workers and users, or place an overwhelming burden on production processes.

In the meantime, the best advice seems to be: Take great care to avoid airborne exposures when working with carbon nanotubes that bear a physical resemblance to asbestos.

So you want to make or use carbon nanotubes, but you are worried about handling then safely.  What do you do?  The good news is that the UK Health and Safety Executive has just published an information sheet that addresses just this question.  Risk management of carbon nanotubes is (according to the blurb) “specifically about the manufacture and manipulation of carbon nanotubes, and has been prepared in response to emerging evidence about the toxicology of these materials.”

But is it any good?  Here’s my initial take:

HSE recommends a precautionary approach for managing the risks of all carbon nanotubes. This is a good move.  The evidence so far—which admittedly is sparse—points towards all forms of carbon nanotubes being more harmful in the lungs than non-nanotube forms of carbon.  Of course, it depends on how you define “precautionary,” but “looking before you leap” seems a reasonable translation in this case.

No mention is made of possible exposure when working with carbon nanotube-containing products. HSE’s information sheet is clear that exposure to nanotubes can occur when making the stuff, when using it, and when researching its properties.  But there is no mention of what could occur when machining, grinding or cutting a product containing carbon nanotubes.  To be fair, research so far indicates that in most cases, once carbon nanotubes are embedded in a product they are unlikely to come out.  But if a precautionary approach is to be taken, it seems sensible to at least ask whether there is a chance that exposure to the material will occur while working with carbon nanotube-containing products.

The review of new evidence neglects particle-like effects in the lungs. The information sheet revolves around concerns over asbestos-like behavior and certain types of carbon nanotubes, which is understandable given the unpleasantness and latency period of diseases like mesothelioma.  But current research suggests that even clumps of carbon nanotubes that don’t look like asbestos fibers are more toxic if inhaled than might be imagined.  Last July, Anna Shvedova and colleagues published research showing that inhaling non asbestos-like single walled carbon nanotubes at concentrations currently recommended as safe by many manufacturers could be harmful.

In other words, it isn’t just asbestos-like behavior that we need to be concerned with here.

Use of carbon nanotubes appears to be discouraged in the absence of information on inhalation hazards. The information sheet states:

“HSE views CNT’s [carbon nanotubes] as being substances of very high concern.  Although the recent findings only apply to some CNTs we think a precautionary approach should be taken to the risk management of all CNTs, unless sound documented evidence is available on the hazards from breathing in CNTs.  If their use cannot be avoided, HSE expects a high level of control to be used.”

I may be reading this section wrong, but the message seems to be: If you don’t have a good handle on how harmful the substance you are using might be, don’t use it. But if you absolutely must, do everything possible to reduce exposures to a minimum. As there are no definitive data on carbon nanotube toxicity yet, this advice seems to boil down to the use of carbon nanotubes being discouraged.

Given the economic potential here, I’m interested in how this will play with industry.

Recommended qualitative risk management actions will reduce exposures… At the heart of the information sheet is advice on steps to reduce exposure to airborne carbon nanotubes when working with the substance.  These are solid, generic, good occupational hygiene practices—“use appropriate work processes,” “control exposures at source,” “make sure exposures are controlled at all times” etc.  And if followed, they should lead to fewer people being exposed to less material.  But I do wonder how practical some of them are for dealing with certain forms of carbon nanotubes—especially when it comes to working in fume cupboards and keeping material wet where possible.

…But there are few indications of “how much is enough.” Qualitative actions abound in the information sheet: “use appropriate work processes;” “provide suitable work equipment;” maintain “adequate control of exposure at all times.”  But such advice is hard to apply in the absence of any information on what processes are “appropriate,” how suitability is determined, and when “adequate control” is achieved.

I’m sure the point here is that any actions to reduce exposures are better than none.  But without quantitative benchmarks, the chances are that some people will be exposed to worryingly high levels of carbon nanotubes (under the “we tried our best” arguement), while others will struggle to obtain exposure levels that are needlessly low.

On balance, I have to commend the HSE on coming out with the information sheet on the ground that any information is better than no information, and I’m sure that some will find it helpful.  But I do worry that the information provided isn’t specific enough to either protect peoples’ health effectively, or provide nanotech businesses with the help they need to do the right thing without over-doing it.

And unfortunately, the document fails to provide links to other sources of information that may help remove some of the ambiguity (see some of the documents below for instance).

The bottom line here is that the information sheet is great for raising awareness, but seems to falls short of providing much in the way of practical advice.

Of course, I don’t actually have to make hard decisions on what exposures are acceptable for my employees, which controls to put in place, and how to assess their effectiveness.

Maybe if I did, my perspective would be different.

End Notes

I should note that I was asked to informally review a late draft of the information sheet last year.  I suspect I was too late in returning my comments though—the published document isn’t substantially different from my review copy.

For more substantive advice, I would recommend reading the document “Nanotechnologies – Part 2: Guide to safe handling and disposal of manufactured nanomaterials” from BSI Inc.  My review of it can be found here.

More detailed information on working safely with nanomaterials is also published by the US National Institute for Occupational Safety and Health.

Similar advice is available from the standards organizations ISO and ASTM International (see  Alphabet soup hides the secrets of safe nanotech! for further information)

Thoughts on applying Control Banding to working with nanomaterials can be found in this excellent paper by Sam Paik and colleagues.  While not dealing specifically with carbon nanotubes, it does develop a framework for making exposure control decisions:

Application of a Pilot Control Banding Tool for Risk Level Assessment and Control of Nanoparticle Exposures.  Paik et al. (2008) Annals of Occupational Hygiene 2008 52(6):419-428

Paik’s work forms the basis of safe handling guidelines recommended by the Institut de recherche Robert-Sauvé en santé et en sécurité du travail (IRSST), the Commission de la santé et de la sécurité du travail (CSST) and NanoQuébec.

Additional 2020 Science blogs addressing carbon nanotube safety:

• Carbon nanotubes: the new asbestos? Not if we act fast
• Resolving the carbon nanotube identity crisis
• Asbestos-like nanomaterials – should we be concerned?

]]> http://2020science.org/2009/03/17/working-safely-with-carbon-nanotubes/feed/ 1 http://2020science.org/2009/01/23/asbestos-like-nanomaterials-should-we-be-concerned/ http://2020science.org/2009/01/23/asbestos-like-nanomaterials-should-we-be-concerned/#comments Fri, 23 Jan 2009 21:53:33 +0000 Andrew Maynard http://2020science.org/?p=705

I’m afraid the “A” word just won’t go away.  It seems that every time people start thinking about the possible health effects of long, thin, fibrous nanomaterials, the question pops up “is this the next asbestos?”  You’d have thought that the issue would have been resolved by now—after all, nanomaterials like carbon nanotubes have been around for some time.  But as the years go by the question persists, and the answer remains elusive.  I’d like to say that this isn’t for want of trying, but sadly there hasn’t been that much interest in funding the right research so far.

This blog was prompted by the recent publication of a report assessing the state of knowledge on fiber-like nanoparticles and their potential health impacts.  The report, commissioned by the Department for Environment, Food and Rural Affairs (DEFRA) in the UK and prepared/published by the Institute for Occupational Medicine (IOM), addresses whether “High Aspect Ratio Nanoparticles” (aka “HARN”) should raise the same health concerns as asbestos fibres.  Here we go again you might say—and indeed the report covers a lot of old ground.  Yet repetitive as the messages might be, the reality is that this is an issue which remains far from being resolved, and could cost some sectors of the nanotechnology industry dearly if clear information and safe working guidelines aren’t forthcoming soon.

To be honest, the report is not an easy read—it was prepared as a report to a government department, and reads as a report to government department.  In other words, it’s not that accessible to anyone outside the immediate target audience.  Nevertheless, it does contain critical information on how this specific class of engineered nanomaterials should be approached if it is to be used safely and successfully.

I’ll get to the report’s key points in a moment.  But first it is worth sketching out an incomplete but interesting nevertheless timeline for carbon nanotube safety questions—picking on carbon nanotubes as, in certain forms, they are the archetypal HARN…

Carbon nanotubes were observed by a number of researchers between the 1950’s and 1980’s, although the relevance of the observations went largely unnoticed (I hate to say it, but Wikipedia covers this pretty well).  It wasn’t until Sumio Ijima published the paper “Helical microtubules of graphitic carbon” in the journal Nature in 1991 that things began to get interesting.

The following year there was a letter published in the same journal raising a cautious note.  The letter was written in response to an article by Paul Calvert on the potential utility of emerging nanofibers—including carbon nanotubes.  In it, Gerald Coles—an occupational hygienist—writes:

“Sir—Attractive though they are, the technical properties of ultra-thin man-made fibres pointed out by Paul Calvert (Nature 357 365; 1992) should not hide the potential—at least for those fibres resistant to biological degradation in vivo—for related occupational risks to workers.

Fortunately, most reinforcing fibres hitherto produced in quantity have, as Calvert pointed out, been of diameter 10 µm or more; the practical risk from occupational or other exposure to their airborne dusts remains doubtful.  But work on fibres other than asbestos has shown the morphology and biological persistence of fibrous materials to be of greater significance in relation both to pnemoconiosis and, more seriously, to mesothelioma, than their chemical constitution.

A need for stringent precautions in preventing occupational exposure to the dusts of these thinner materials might well result in cost increases in manufacture that would outweigh the “dramatic reduction in production costs” hypothesized by Calvert.”

Nothing much happened then until 1998, when Science reporter Bob Service filed a news piece under the headline “Nanotubes: The Next Asbestos?” Service writes

“The dangers of asbestos first came to light in the early 1960s, when studies linked exposure to these silicate fibers with mesothelioma–a rare cancer of the lining of the chest or abdomen that’s commonly fatal. Asbestos fibers were found to be so small that they could be inhaled into the deep lung, where they could stick around for decades. Once there, metals in the silicate fibers could act as catalysts to create reactive oxygen compounds that go on to damage DNA and other vital cellular components.

Whether nanotubes could reproduce this behavior is unknown: Their toxicity has yet to be tested. But already views on their safety differ sharply. “[Nanotubes] may be wonderful materials,” says Art Langer, an asbestos expert at the City University of New York’s Brooklyn College. “But they reproduce properties [in asbestos] that we consider to be biologically relevant. There is a caution light that goes on.” Most notably, says Langer, nanotubes are the right size to be inhaled, their chemical stability means that they are unlikely to be broken down quickly by cells and so could persist in the body, and their needlelike shape could damage tissue.”

Did these concerns lead to action?  Nope.  A few studies began to emerge a few years later observing unusual effects in the lungs associated with single walled carbon nanotubes (see for instance Lam’s review)—but in the main these weren’t materials that physically resembled asbestos.

The next major milestone was in 2006, when a bunch of us published the commentary “Safe Handling of Nanotechnology” in Nature.  Here we stated

“Fibre-shaped nanomaterials possibly represent a unique inhalation hazard, and their pulmonary toxicity should be evaluated as a matter of urgency. Inhalation of a sufficient dose of asbestos fibres can lead to the malignant disease mesothelioma, the causation of which is related to the length, width and chemistry of the fibres, as well as their ability to persist in the lungs.

Although it is not clear whether fibre-shaped nanoscale particles formed from carbon and other materials will behave like asbestos or not, some materials are sufficiently similar to cause concern: any failure to pick up asbestos-like behaviour as early as possible would be potentially devastating to the health of exposed people and to the future of the nanotechnology industry. We propose that the potential health impact of high-aspect-ratio, biopersistent engineered nanotubes, nanowires and nanofibres is systematically investigated within the next 5 years.”

Since then, there have been a couple of studies exploring the potential of fiber-like carbon nanotubes to cause mesothelioma—most notably the Poland et al. study that appeared in Nature Nanotechnology in 2008.  The study indicated (in a nutshell) that carbon nanotubes that look like harmful asbestos fibers, seem to behave like harmful asbestos fibers.

Looking through this rather roughly sketched out timeline, it is clear that questions over similarities between carbon nanotubes and asbestos have been circulating for some years, yet little has been done to discover the extent of this similarity, and actions that need to be taken as a consequence.

So back to the DEFRA report.  In amongst a whole heap of scientific information, there are some key messages that come through:

The Fiber Paradigm. Over the years, experts have developed a profile for fibers that are more likely to be harmful if inhaled.  According to this profile, for something to show asbestos-like toxicity, it needs to satisfy three criteria:

• Diameter: Fibres must be thin enough reach past the upper  airways and into the sensitive region of the lungs where oxygen diffuses into the bloodstream.  (Penetration into the lungs is not affected that much by fiber length.)
• Length: Fibers must be long enough to initiate harm through mechanisms such as frustrated phagocytosis—where the lung’s natural defenses break down because scavenger cells (macrophages) cannot physically engulf the fibers.
• Biopersistence: Fibers must stick around for a long time in the lungs (tens of years) without dissolving or breaking up.

There are other factors that may be important in determining toxicity, but these are the big three.

High Aspect Ratio Nanoparticles and the Fiber Paradigm. The review concluded that there are some HARN that satisfy the profile of the fiber paradigm—certain forms of carbon nanotubes in particular—and that these should be approached with caution.  Quoting from the document:

“This review has identified many similarities between HARN and asbestos with regard to their physico-chemical properties and toxicological effects and has concluded that there is sufficient evidence to suggest that HARN which have the same characteristics (diameter, length and biopersitence) as pathogenic fibres are likely to have similar pathology.”

Identifying potentially harmful asbestos-like substances. The review’s authors put together a handy flow-chart for identifying nanomaterials which might be more likely to cause harm in a similar way to asbestos.  It’s just a suggestion, but I thought it was a useful one:

Research priorities: Finally, the report’s authors highlight areas requiring further research if progress is to be made:

• Hazard Identification: The characterisation of the physico-chemical properties
  of HARN especially the length of the fibres and their biopersistence
• Dose-Response Assessment: Acute and chronics adverse effects of HARN;
  Cellular and molecular mechanisms of HARN toxicity investigated with in vitro
  and in vivo models
• Exposure Assessment: Identification and quantification of the routes (e.g.
  inhalation, dermal); the pattern and the  intensity of exposure
• The Risk Assessment of HARN: Combining exposure and Hazard to
  calculate the health risks from exposure to HARN.

To me, this seems a no-brainer.  Carbon nanotubes in particular are such an important material that we cannot afford not to commercialize them.  But at the same time, it would be morally reprehensible to plow ahead without heeding the warning signs that this material—in some forms at least—needs to be handled with care.  It still amazes me that 17 years after health and safety questions were first raised, we are still framing the questions rather than finding the answers.

Hopefully though this will change and the DEFRA report will be the precursor to some solid research.  It’s certainly needed.

A nanotechnology fix for high-end audio addicts?

I’m sitting at my computer watching a surreal balletic movie—a sheet of highly aligned carbon nanotubes is being slowly stretched, then allowed to slowly contract.  In the background is a soundtrack of traditional-sounding Chinese music.

At least I think the soundtrack is over-dubbed, until I realize that the music is coming directly from the nanotube sheet itself, which has been attached to a small amplifier.

And it suddenly dawns on me that I am watching something rather special—perhaps the biggest breakthrough in loudspeaker technology in decades…

The movie comes out of the lab of Kaili Jiang at Tsinghua University in Beijing, and accompanies a paper recently published on-line in the journal Nano Letters (Flexible, Stretchable, Transparent Carbon Nanotube Thin Film Loudspeakers, Xiao et al. DOI: 10.1021/nl802750z).

Jiang’s team has been perfecting a technique for growing “forests” of uniform carbon nanotubes on silicon wafers, and “drawing” them out into films just a few tens of nanometres thick.  These self-supporting films of closely aligned nanotubes have plenty of commercial potential, from transparent conducting surfaces to strong materials.  So it’s hard to imagine what prompted the research team hook one of their films up to an audio amplifier.

Yet at some point, some enterprising researcher took the initiative, and the music flowed…

Since the paper was posted on the Nano Letters website it has attracted a flood of web-chatter (for example, check out Michael Berger’s excellent coverage at Nanowerk, or the recent article in the Economist).  And much of it has focused on meshing the new technology with consumer electronics—phones, TV’s, laptop computers, even clothing that quite literally speaks volumes about the wearer (the nanotube films continue to work as an audio transducer when attached to fabric, and even when bent, stretched or otherwise manipulated).

But what caught my attention was the possibility here for high-end audio—not the aural mediocrity that consumers seem more than willing to put up with, but the drive to make sound production as real as… well, reality itself.

Surprisingly perhaps, nanotechnology hasn’t had much of a presence in the field of high-end audio so far—a sector that often adopts new technologies early on in the push to make ever-more exclusive, unique and audibly superior products.  The closest manufacturers have got to using nanotechnology (to my knowledge) are the rather superb 800D loudspeakers from Bowers and Wilkerson, that use micrometer-thin Chemical Vapour Deposition-formed diamond tweeters to produce some of the purest high notes possible (or so I’m told—the 800D’s are a tad above my pay grade!).

But the nanotube loudspeaker may change all that.  And here’s why:

Current loudspeaker technologies are the weak link in the audio chain—even the best loudspeakers distort the sound and add their own character to it to some degree.  And much of the problem lies in converting an electrical signal into a mechanical signal (an oscillating cone for instance), and thence into an acoustic signal.  Along the way, the purity of the sound is always compromised in some way.  And as a result, even a $20,000 pair of speakers will still have an audible influence on music heard through them.

The carbon nanotube film in contrast cuts out the mechanical stage, and makes it possible to convert an electrical signal directly into an audio signal.  Unlike any conventional loudspeaker I can think of, in a nanotube loudspeaker, there will be no moving parts.  This in itself would be a major leap forward in sound reproduction.  But there’s more.

In theory, the radiating surface of a nanotube loudspeaker could be made pretty large—meters square even—with every part of the surface generating sound in perfect coherence with every other part. This is a huge deal. It means having power and purity at the same time—something that is near-impossible with cheaper conventional loudspeakers, and barely possible with megabucks high-end models.

Add to this the electrical simplicity of the nanotube film (it presents a predominantly resistive load) and an ability to work over a very large frequency range, and you have a package this is looking very attractive, and might even have what it takes to make high quality digital speakers a practical reality—loudspeakers that take a digital signal from CD’s, DVD’s or computer audio files, and convert that signal directly into sound (without having to convert it into an analogue signal first—another weak link in the audio chain).

Even if these carbon nanotube films live up to just a fraction of their promise, this is a technology that should have any self-respecting audiophile addict in an ecstasy of anticipation.

Of course there are hurdles to overcome.  It’s unclear how quality control will affect sound quality, or how delicate the resulting transducers will be.  Some nifty electronics will also be needed to drive the nanotube loudspeakers to their maximum capability.

And then there is the question of safety.  It’s not clear whether the carbon nanotubes being used in Jiang’s lab match those that could cause health problems if inhaled, or whether there is any possibility of the films shedding potentially harmful carbon nanotubes.  But some judicious investigations on this front would seem in order—if only to assure people that listening to the finest quality high-end audio systems in the future will not end up being a terminally exhilarating experience.

There is also the cost of the carbon nanotubes themselves—which is still on the high end of expensive.

Actually, I’m not sure this is such a barrier, judging by what people will pay for the last word in high-end audio equipment.  Take the pinnacle of the Bowers and Wilkerson loudspeaker range for example—the Nautilus loudspeaker.  A result of five years’ development with the goal being perfection—or as close as is humanly possible—a pair will set you back in excess of $60,000.  Yet people still buy them!

In this business, people aren’t going to be phased by paying a few thousand dollars extra in the quest for audio nirvana.  Which is why I think that high-end loudspeaker manufacturers will be taking this new technology seriously—and most likely will be paving the way for more accessible carbon nanotube audio products that really do rock—figuratively as well as literally.

And as a last word, if you are one of the millions who couldn’t care a jot about high-end audio, check out Jiang’s nanotube-enabled musical flag below. What it lacks in quality, it certainly makes up for in novelty!

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Technical stuff (added Nov 27 2008)

For the technically minded, Jiang’s team aren’t entirely certain how the nanotube film works as a loudspeaker, but they are pretty sure it is due to the thermoacoustic effect, where the audio signal leads to rapid heating ad cooling of the nanotubes, leading to the formation of soundwaves (Michael Berger’s Nanowerk article includes useful background on the effect, and an animation of what is most likely going on in the nanotube speaker can be found in the Jiang paper supplemental material).  The result is that electrical signals are converted directly into soundwaves, simultaneously at each point on the film, and without any moving parts.  And it is this that makes the nanotube film so robust, versatile, and potentially high quality.

One downside of the thermoacoustic effect is that the frequency in a normal alternating current signal  is doubled when converted into sound, leading to a rather disconcerting shift in pitch in what is heard.  The nanotubes are heated just as much when the incoming signal goes negative as when it goes positive, leading to the doubling.  The trick Jiang and colleagues used to overcome this was to bias the electrical signal, so it was always positive (essentially making this a “class A” speaker).

Intriguingly, this tendency to double the incoming frequency shouldn’t be a problem if the nanotube film is used as a digital speaker.  The idea here is that a stream of digital pulses is fed directly into the loudspeaker, and the conversion of the signal from digital to analogue starts as the electrcal input is transformed into an acoustic output.  Because the pulses in a digital stream are all of the same polarity (the signal is either on or off, rather than varying from positive to negaitive), there will be no frequency doubling.  And the frequency response of the nanotube film is wide enough to convert the pulses of a digitally sampled audio track into sound waves that will be interpreted as music or speech by the human ear.

Just one niggling question – will feeding a digital signal directly into the nanotube film cause a melt-down through excessive heating?  It’s a possibility, but it would be a great experiment to try!

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Twelve months ago today I held a bag of multi-walled carbon nanotubes up before a hearing of the U.S. House Science Committee.  I wanted to emphasize the discrepancy between the current state of the science on carbon nanotubes, and a tendency to classify this substance as the relatively benign material graphite from a safety perspective.  So it is perhaps fitting that on the anniversary of that congressional hearing, the US Environmental Protection Agency is making it clear that carbon nanotubes are in fact, a new substance—and should be regulated as such.

Carbon nanotubes are often described as sheets of graphite—the stuff that makes pencil lead black—wrapped into a tube; leading to nanometre-thin “fibres” that are incredibly strong for their weight, and highly conducting—thermally as well as electrically.  But perhaps because of this simple imagery, they are often handled as if they are graphite—especially when it comes to using them safely.

Given the amount of time and money researchers and industry are pouring into producing and using carbon nanotubes, you would think that they are at least marginally different from their flat-sheeted cousins.  In fact the differences are anything but marginal: Wrapping the sheets associated with graphite into tubes radically changes the physical chemical and biological properties of these carbon-based materials—just like re-arranging the carbon atoms that make up soot into diamonds leads to the formation of a fundamentally different material.

Yet many companies continue to persist in claiming “it’s just graphite” when questions arise over the possible health impacts of being exposed to carbon nanotubes.

But all that is about to change.  Hot on the heels of clarification from the European Commission that carbon nanotubes (and other novel forms of carbon) need to be registered under the new REACH chemicals regulations, the US EPA has clarified their position on the material.  According to a just-released notice in the Federal Register, the EPA

“generally considers [carbon nanotubes] to be chemical substances distinct from graphite or other allotropes of carbon listed on the TSCA Inventory.”

In effect, this means that any company wanting to manufacture or import carbon nanotubes in the United States needs to submit a Pre Manufacturing Notice (PMN) to the EPA—unless the material can be shown to be on the Toxic Substances Control Act (TSCA) Chemical Substances Inventory. And the chances of that are pretty slim—at present.

EPA actually established their position on carbon nanotubes back in 2007, in a document clarifying how the agency saw TSCA applying to engineered nanomaterials [available here].  But the agency’s stance was so unclear that the Federal Register notice clarifying the situation was felt necessary.  In the words of the notice just published:

“current pre-notice inquiries to the Agency and questions in public forums still indicate a lack of clarity on this issue.”

This is a significant step forward for the US EPA, and a very welcome one.  Research is continuing to show that some forms of carbon nanotubes are potentially dangerous if inhaled in sufficient quantities.  Earlier this year, Craig Poland and colleagues showed that long thin multiwalled carbon nanotubes are potentially able to cause the disease mesothelioma if inhaled.  And more recently Anna Shvedova and co-researchers confirmed that inhaled single walled carbon nanotubes can have a unique impact on the lungs of mice.

Neither of these studies suggests that carbon nanotubes behave anything like graphite if they get into the lungs.  Yet companies persist with treating this material like graphite.

I’ve previously noted that carbon nanotube distribution companies like CheapTubes Inc. consider all forms of the material as being like graphite for health and safety purposes.  In fact, as of October 31, the Materials Safety Data Sheet posted on the CheapTubes website noted of carbon nanotubes:

“This material is listed on the US Toxic Substances Control Act (TSCA) Inventory”

There is little doubt now that this is, in fact, not the case.

The EPA’s clarification will certainly help ensure that this innovative material is used safely, and its full potential is realized without causing undue harm.  There are though, perhaps inevitably, still some unresolved issues.   These include various material use and production quantity exemptions that could be used by some companies to justify not applying TSCA to their nanotubes (see for instance the series of articles by Richard Denison on TSCA and nanomaterials).  But smart companies are realizing that compliance is the best way to ensuring safe and sustainable products—which is why a number of PMN’s for carbon nanotubes have already been submitted to EPA (again, Richard Denison’s blog at the Environmental Defense Fund has useful comments on this point).

There are however two rather large flies in the ointment:

The EPA clarification doesn’t add anything to the question of where many other engineered nanomaterials stand on the regulations front.  Carbon nanotubes are chemically distinct from other forms of carbon, and so are easily defined under TSCA as news substances.  But if you take something like titanium dioxide or silver and form it into nanoparticles, current regulations make no distinction between the nano and non-nano forms of the material—even though research suggests the nano-form may be more harmful.

Just as importantly, submitting a PMN for a specific type of carbon nanotube material opens the way for that material being added to the TSCA Chemical Substances Inventory.  And once there, other companies are free to make, use and sell the material.  As Richard Denison writes,

“Once reviewed and placed on the TSCA Inventory, any company can manufacture and use the nanomaterial without even having to notify EPA it is doing so.” (unless EPA simultaneously issue a Significant New Use Rule)

Yet researchers are only just beginning to discover what might make different carbon nanotubes harmful, and how to avoid that harm.  What are the chances therefore of carbon nanotubes being added to the TSCA inventory before we have a good handle on how to use them safely?

The bottom line here is that resolving the regulatory status of carbon nanotubes is an important step forward.  But there is still some way to go before this material is regulated in a way that will encourage innovation while preventing undue harm—whether to people or the environment.

And while carbon nanotubes can perhaps leave the couch feeling a little more confident about themselves, we shouldn’t forget that there are still plenty of other materials out there that are suffering from a nano-induced identity crisis.

Mix carbon nanotubes and asbestos together (metaphorically) and you get an explosive mix—at least if news coverage of the latest publication coming out of Professor Ken Donaldson’s team is anything to go by.  The research—published on-line today in Nature Nanotechnology—is the first to explicitly test the hypothesis that long carbon nanotubes behave like long asbestos fibres in the body.

In brief, the study (which I was a co-author on) used an established method to test whether a fibrous material has the potential to lead to the disease mesothelioma—a cancer of the outer lining of the lungs that can take decades to develop following exposure.  In the method, samples of material are injected into the abdominal space of mice, where inflammation and the formation of granulomas in the lining tissue (the mesothelium) are studied over a seven-day period.  Previous research has established that the combined presence of fibres, inflammation and granulomas is a very strong indicator that mesothelioma will occur in the long-term.  While the method uses lining of the abdominal space, it is highly predictive of what happens in the same tissue surrounding the lungs, if it is exposed to durable fibres.

Five materials were tested in this study: short amosite asbestos fibres, long amosite asbestos fibres, short and/or tangled multi walled carbon nanotubes (two samples), long straight multi walled carbon nanotubes (two samples), and carbon black (compact graphite-based particles.  The results: fibres longer than 15 micrometers to 20 micrometers (whether asbestos or carbon nanotubes) led to a positive response; short/compact particles did not.

This is the first study to demonstrate that carbon nanotubes that physically resemble harmful asbestos fibres, can also behave like harmful asbestos fibres.

What the study does not address is whether exposure to long straight carbon nanotubes will occur or, if it does, whether these fine fibres will reach the mesothelium surrounding the lungs, and go on to cause mesothelioma.

But the results are sufficiently compelling to suggest urgent action is needed if we are to prevent a long lasting legacy of harm from some forms of carbon nanotubes, and ensure the emergence of safe and trusted carbon nanotube applications.

First and foremost, targeted research is needed to validate this study, assess the magnitude and nature of likely carbon nanotube exposures—from material production to product disposal—and evaluate whether inhaled nanotubes can work their way to the outer lining of the lungs.  The current U.S. federal strategy for nanotechnology-related environmental, health and safety research (PDF, 2.2 MB) does not specifically address the health impacts of carbon nanotubes (despite a recommendation from the UK Royal Society and Royal Academy of Engineering in 2004 to carry out exactly this type of research).  Perhaps it’s time to rethink what is important here.

But action is also needed now to ensure carbon nanotube exposures to workers and users are kept as low as possible.  This means developing appropriate exposure measurement methods, applying effective control and containment protocols, and agreeing on benchmark exposure levels to use in the absence of more formal exposure limits.  The recent BSI Guide to safe handling and disposal of manufactured nanomaterials (PD 6699-2:2007, see also“Safe nanotechnology in the workplace: A practical guide”) recommends a benchmark exposure level of 0.01 fibres/ml for carbon nanotubes in the absence of any other information—this would seem to be good advice for long carbon nanotubes, until more is known about their exposure potential and hazardous nature. Long multi-walled carbon nanotubes can currently be purchased from outlets like CheapTubes Incorporated for as little as 40 cents a gram (as long as you by them in kilogramme quantities), yet the health and safety advice still assumes these are as harmless as graphite—this has to change.

And thirdly, action is needed to ensure transparency—making sure regulators, industries and consumers know which types of carbon nanotubes are being used, where they are being used, and what precautions should be taken to ensure safe use.

Carbon nanotubes have great potential as a unique material that can be used in many unique and beneficial ways—from reducing our environmental impact to curing diseases.  But mis-steps now could easily undermine trust in this nascent industry, and prevent the material’s potential from being realized.

The comparison with asbestos is firmly grounded in the physical resemblance between certain forms of the two materials, and this alone should stimulate clear action to ensure safe use.  But the health impacts of asbestos exposure still resonate through society—deaths from asbestos-related disease are not expected to peak for another ten years—and the mere suggestion of similarities between nanotubes and asbestos fibres could cause investors and users to shy away from this new technology unless there are clear assurances that health and safety concerns are being fully addressed.

Widespread pickup in the media of the current study suggests that people care about carbon nanotubes, and whether they are safe.  The good news is that we still have time to ensure they are used safely—but only if we act now and act fast.

Additional Resources

Carbon nanotubes introduced into the abdominal cavity of mice show asbestos-like pathogenicity in a pilot study.  Poland et al. (2008). doi:10.1038/nnano.2008.111

Carbon nanotubes display asbestos-like behaviour – a SAFENANO commentary by Ken Donaldson

Project on Emerging Nanotechnologies

Nanotechnology consumer products inventory

International Council On Nanotechnology backgrounder on multi walled carbon nanotunes and mesothelioma

NIOSH Science Blog

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This post first appeared on the SAFENANO blog in May 2008