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