Little Wonders

Mention nanotechnology at a dinner party and most people – except for those who go completely blank – will think of Raquel Welch and Donald Pleasence rocketing about the bloodstream in the 1966 movie Fantastic Voyage. If the guests are a bit more up to date, they’ll mention Eric Drexler and his compelling vision of nanotechnological power in the 1986 book Engines of Creation. The truly with-it will nod knowledgeably and start discussing Michael Crichton’s 2002 science-gone-mad thriller, Prey.

But the world of nanotechnology is already as close as your drugstore, and as undramatic. In fact, the next time you come back from the beach without a sunburn – unless you stayed in the beach bar – it’s because your sunscreen contained tiny particles of titanium dioxide. And that’s not all: tennis rackets now contain carbon nano-tubes to make them more rigid, cosmetics have nano-particles to help them spread evenly, and slacks have nano-whiskers to repel stains.

In labs around the world, researchers are beavering away to find new uses for known nano-science and to extend our understanding of how to make materials and structures that are so small, a thousand of them could fit on the width of a human hair. (The prefix nano is derived from the Latin nanus, which means dwarf. A nanometre is one-billionth of a metre.) The future holds – or might hold – filters that clean water more cheaply and efficiently, lights that use a fraction of the energy of today’s bulbs, or cancer treatments that zero in on tumour cells. While the silicon microchip has dominated innovation over the last 30 years, the next three decades could belong to nanotechnology. The U.S. National Science Foundation predicts that the market for nanotech and its products could reach $1 trillion a year by 2015.

At U of T, about 50 scientists and engineers call themselves nanotechnologists, and dozens more use the tools of nanotech in more traditional fields. The university is the first in the world to offer a four-year nanotechnology degree for undergraduates, and so far about 30 students have graduated from the program. Toronto’s top scientists in the field are sought after, and their work has an inordinate impact considering how few of them there are, says Doug Perovic, chair of the department of materials science and engineering and one of the university’s foremost nanotechnologists.

The challenge for the university, says Perovic, is to overcome a lack of co-ordination among its various departments. Nanotechnology exists on the frontier where physics, chemistry and biology converge. While research is being conducted in each of these disciplines, there is, as yet, no central nanotechnology division. “We’re doing all kinds of great stuff, and the nano [degree] shows the kind of co-ordination that can happen. But so far we don’t have a big nano-flag to wave,” says Perovic.

So what, exactly, is nanotechnology?

The gurus of the very small consider the “nano-scale” to be anything between one and 100 nanometres wide. At that magnitude, the head of a pin is enormous and even the marvellous movie vessel used by the fair Raquel – while remarkably tiny by human standards – is much too big and clumsy to be considered nanotechnology. To understand the nano-scale, you have to think about single living cells – and not the whole cell, either, but the tiny gaps where chemicals enter or leave, or the receptors where proteins dock to carry out the business of life. We’re talking really, really, really small.

At that level, some matter behaves differently – and it’s those different properties that are causing some of the excitement. Consider, for instance, Professor Warren Chan’s work with quantum dots – tiny blobs of cadmium and selenium a few nanometres in diameter. Because of their tiny size, they interact with light to glow very brightly – so brightly that a single one can be seen in an optical microscope. This brightness, which isn’t shared by larger chunks of the same material, may make quantum dots useful, for example, as diagnostic tools. Chan and his team at U of T’s Institute of Biomaterials and Biomedical Engineering are trying to find ways to make quantum dots home in on cancer cells. Most cancers remain undetected until they’re large and hard to eradicate, he says; imagine if you could find cancers when they were only a few hundred cells in size. If each of those cells were lit up, a surgeon would have no trouble cutting them out. Even more impressive: suppose each quantum dot were connected to both a molecule that could find the cancer and a molecule that could kill it. Such powerful nanotech applications could be developed within five to 10 years, says Chan.

Ted Sargent, a professor in electrical engineering who holds the Nortel Networks-Canada Research Chair in Emerging Technologies, is creating small, energy-efficient devices to unite communication and computing. One of the interesting aspects of Sargent’s work involves how these devices will be made.

Already in its brief history, nanotech has spawned two waves, popularly referred to as the “top-down” and “bottom-up” approaches. The top-down vision refers to the creation of nano-structures by machining or etching. It is an extension of existing technologies that focuses on producing smaller, faster, and more energy- and cost-efficient systems and devices. It’s the approach used today by technology giant Intel to make nano-scale microchips. (Intel technicians use enormously powerful lithographic techniques to carefully sculpt a chip from a larger piece of material.)

Bottom-up nano-science, on the other hand, is preoccupied with understanding and controlling the chemical and physical properties of atoms and the structure of molecules, both organic and inorganic. It’s something of a grassroots approach to technology. Sargent and his colleagues are combining the best features of the two strategies: the control afforded by top-down programming, and the convenience and simplicity of letting molecules and materials self-assemble through bottom-up nanotechnology. He and U of T chemist Eugenia Kumacheva recently developed a template, for example, that coaxes nano-scale crystals to grow into a desired shape and quality. This work could lead to a new class of “intelligent materials” that unites the traditionally disparate technologies underlying computing (electronics) and ultra-high-speed Internet communications (optics), says Sargent.

Indeed, one of the promises of nanotech is new materials that are self-constructed on the nano-scale but have new, useful properties on the scale we live in. Perovic and U of T chemist Geoffrey Ozin recently found a way to create a whole new class of material, dubbed PMO (for periodic mesoporous organo-silicate), in which organic and inorganic molecules are mixed in precise ways to create new electrical and mechanical properties. From a practical point of view, this material promises to be useful in computer chips. From a theoretical point of view, it represents that rarest of scientific achievements, the breakthrough. “It’s not very often in today’s world that you can create a whole new type of material,” says Perovic.

Some fear that these new materials may pose new dangers, especially to human and environmental health. Chan points out that his quantum dots will need careful testing before they can be used in the human body. The dots are made of metals whose effects on the body aren’t completely understood. As well, because of their small size, they may move through the body in unexpected ways, causing unexpected health effects.

The risks of nanotechnology should not be ignored, even if most practical applications are still several years away, says ethicist Peter Singer, director of the university’s Joint Centre for Bioethics. “Any new wave of technology raises social and ethical considerations,” he says, adding that nanotech is “the third great technological wave” to hit the world in the past 40 years, after information technology and biotechnology.

Already, Singer says, there are signs that nanotech could be hit with the same sort of backlash that slammed into unsuspecting biotechnologists working on genetically modified organisms (GMOs) a few years back. Some of the same players – including Prince Charles and the Winnipeg-based Action Group on Erosion, Technology and Concentration, one of the lobby organizations that spearheaded the global anti-GMO drive – are already calling for a moratorium on nanotech research and applications.

Nanotechnologists, therefore, should get their act together and start engaging the public in discussion before it’s too late, says Singer. In a paper titled “Mind the Gap: Science and Ethics in Nanotechnology,” published in the journal Nanotechnology, Singer and his co-authors argue that bench scientists need to pay attention to the ethical, social and economic implications of their work. Recently, Canada’s National Institute for Nanotechnology, based in Edmonton, added an ethical stream to its research agenda.

The issue may not only be important to researchers in the West. In another paper, Singer and colleagues examine the role of the Third World in nanotech. “We set out to track the nano-divide,” Singer says, fully expecting to find that developing nations were being left out. Instead, they found a very strong and financially important nanotech effort in these countries, which could be short-circuited if the naysayers get their way.

“There’s a great risk of undermining that effort,” Singer says, if people in the developed world focus only on the risks without recognizing the potential benefits for developing countries. The outcry over genetically modified crops provides a useful analogy. The developing world stands to gain the most from the introduction of such crops, but faces the greatest opposition from groups in the developed world, who stand to gain the least.

The model for getting the public onside might be the Human Genome Project, which famously devoted a small percentage of every research dollar to ethical and social factors. If nanotech takes that route, Singer says, “I’m sanguine that the gap between the ethical considerations and the science can be closed, and the benefits of nanotechnology harnessed for development.”

On the other hand, at least part of the impending storm can be blamed on hype, says U of T professor Christopher Yip who, with cross-appointments to three departments, could be a poster boy for the emerging discipline. Yip takes the view that much of nanotechnology is really rebranding. “A lot of the molecular-level science has been going on for a long time,” he says. “New tools exist to probe structures at a new level, but it’s really just physics, chemistry and biology by another name. You can’t really ban nanotech in a blanket way.”

Yip’s work on biological systems involves understanding such mechanisms as how proteins do their work, rather than on coming up with new disease treatments. Using such nano-tools as a scanning probe microscope, Yip and his team are able, for instance, to see directly how anti-microbial drugs dig death-dealing holes in the cell walls of bacteria.

Making new substances has always been fraught with peril – one need think only of the alphabet soup of chemicals blamed for everything from cancer to the decline of the ozone layer. “The whole nano-space is moving so fast,” says Chan, noting that the first applications for his area, quantum dots, only appeared in 1998.

But where there are potential risks, there are also potential benefits. And U of T researchers are working on the leading edge, investigating nano-science and seeking new applications for that science, as well as trying to grasp how the technology will change our world. “A lot of surprises will come,” says Perovic. “Most of the applications that will really change the world for the better … I don’t think we’ve even thought of them yet.”

Michael Smith is a science writer in Toronto.