Debating nanotechnologies

To the newcomer, the nanotechnology debate must be very confusing. The idea of a debate implies two sides, but there are many actors debating nanotechnology, and they don’t even share a common understanding of what the word means. The following extended post summarises my view of this many-faceted discussion. Regular readers of Soft Machines will recognise all the themes, but I hope that newcomers will find it helpful to find them all in one place.

Nanotechnology has become associated with some very far-reaching claims. Its more enthusiastic adherents believe that it will be utterly transformational in its effects on the economy and society, making material goods of all sorts so abundant as to be essentially free, restoring the environment to a pristine condition, and revolutionising medicine to the point where death can be abolished. Nanotechnology has been embraced by governments all over the world as a source of new wealth, with the potential to take the place of information technology as a driver for rapid economic growth. Breathless extrapolations of a new, trillion-dollar nanotechnology industry arising from nowhere are commonplace. These optimistic visions have led to new funding being lavished on scientists working on nanotechnology, with the total amount being spent a subject for competition between governments across the developed world. As an antidote to all this optimism, NGOs and environmental groups have begun to mobilise against what they see as another example of excessive scientific technological hubris, which falls clearly in the tradition of nuclear energy and genetic modification, as a technology which promised great things but delivered, in their view, more environmental degradation and social injustice.

And yet, despite this superficial agreement on the transformational power of nanotechnology, whether for good or bad, there are profound disagreements not just about what the technology can deliver, but about what it actually is. The most radical visions originate from the writings of K. Eric Drexler, who wrote an influential and widely read book called “Engines of Creation”. This popularised the term “nanotechnology”, developing the idea that mechanical engineering principles could be applied on a molecular scale to create nano-machines which could build up any desired material or artefact with ultimate precision, atom by atom. It is this vision of nanotechnology, subsequently developed by Drexler in his more technical book Nanosystems, that has entered popular culture through films and science fiction books, perhaps most notably in Neal Stephenson’s novel “The Diamond Age”.

To many scientists, science fiction novels are where Drexler’s visions of nanotechnology should stay. In a falling out which has become personally vituperative, leading scientific establishment figures, notably the Nobel Laureate Richard Smalley, have publically ridiculed the Drexlerian project of shrinking mechanical engineering to molecular dimensions. What is dominating the scientific research agenda is not the single Drexlerian vision, but instead a rather heterogenous collection of technologies, whose common factor is simply a question of scale. These evolutionary nanotechnologies typically involve the shrinking down of existing technologies, notably in information technology, to smaller and smaller scales. Some of the products of these developments are already in the shops. The very small, high density hard disk drives that are now found not just in computers, but in consumer electronics like MP3 players and digital video recorders, rely on the ability to create nanoscale multilayer structures which have entirely new physical properties like giant magnetoresistance. Not yet escaped from the laboratory are new technologies like molecular electronics, in which individual molecules play the role of electronic components. Formidable obstacles remain before these technologies can be integrated to form practical devices that can be commercialised, but the promise is yet another dramatic increase in computing power. Medicine should also benefit from the development of more sophisticated drug delivery devices; this kind of nanotechnology will also play a major role in the development of tissue engineering.

What of the products that are already on shop shelves, boasting of their nanotechnological antecedents? There are two very well publicised examples. The active ingredient in some sunscreens consists of titanium dioxide crystals whose sizes are in the nanoscale range. In this size range, the crystals, and thus the sunscreen, are transparent to visible light, rather than having the intense white characteristic of the larger titanium dioxide crystals familiar in white emulsion paint. Another widely reported applications of nanotechnology are in fabric treatments, which by coating textile fibres with molecular size layers give them properties such as stain resistance. These applications, although mundane, result from the principle that matter when divided on this very fine scale, can have different properties to bulk matter. However, it has to be said that these kinds of products represent the further development of trends in materials science, colloid science and polymer science that have been in train for many years. This kind of incremental nanotechnology, then, does involve new and innovative science, but it isn’t different in character to other applications of materials science that may not have the nano- label. To this extent, the decision to refer to these applications as nanotechnology involves marketing as much as science. But what we will see in the future are more and more of this kind of application making their way to the marketplace, offering real, if not revolutionary, advances over the products that have gone before. These developments won’t be introduced in a single “nanotechnology industry”; rather these innovations will find their way into the products of all kinds of existing industries, often in rather an unobtrusive way.

The idea of a radical nanotechnology, along the lines mapped out by Drexler and his followers, has thus been marginalised on two fronts. Those interested in developing the immediate business applications of nanotechnology have concentrated on the incremental developments that are close to bringing products to market now, and are keen to downplay the radical visions because they detract from the immediate business credibility of their short-term offerings. Meanwhile the nano-science community is energetically pursuing a different evolutionary agenda. Is it possible that both scientists and the nanobusiness community are too eagerly dismissing Drexler’s ideas – could there be, after all, something in the idea of a radical nanotechnology?

My personal view is that while some of Smalley’s specific objections don’t hold up in detail, and it is difficult to dismiss the Drexlerian proposals out of hand as being contrary to the laws of nature, the practical obstacles they face are very large. To quote Philip Moriarty, an academic nanoscientist with a great deal of experience of manipulating single molecules, “the devil is in the details”, and as soon as one starts thinking through how one might experimentally implement the Drexlerian program a host of practical problems emerge.

But one aspect of Drexler’s argument is very important, and undoubtedly correct. We know that a radical nanotechnology, with sophisticated nanoscale machines operating on the molecular scale, can exist, because cell biology is full of such machines. This is beautifully illustrated in David Goodsell’s recent book Bionanotechnology: Lessons from Nature. But Drexler goes further. He argues that if nature can make effective nanomachines from soft and floppy materials, with the essentially random design processes of evolution, then the products of a synthetic nanotechnology, using the strongest materials and the insights of engineering, will be very much more effective. My own view (developed my book “Soft Machines”) is that this underestimates the way in which biological nanotechnology exploits and is optimised for the peculiar features of the nanoscale world. To take just one example of a highly efficient biological nanomachine, ATP-synthase is a remarkable rotary motor which life-forms as different as bacteria and elephants all use to synthesise the energy storage molecular ATP. The efficiency with which it converts energy from one form to another is very close to 100%, a remarkable result when one considers that most human-engineered energy conversion devices, such as steam turbines and petrol engines, struggle to exceed 50% efficiency. This is one example, then, of a biological nanomachine that is close to optimal. The reason for this is that biology uses design principles very different to those we learn about in human-scale engineering, that exploit the special features of the nanoworld. There’s no reason in principle why we could not develop a radical nanotechnology that uses the same design principles as biology, but the result will look very different to the miniaturised cogs and gears of the Drexlerian vision. Radical nanotechnologies will be possible, then, but they will owe more to biology than to conventional engineering.

Discussion of the possible impacts of nanotechnology, both positive and negative, has shown signs of becoming polarised along the same lines as the technical discussion. The followers of Drexler promise on the on hand a world of abundance of all material needs, and an end to disease and death. But they’ve also introduced perhaps the most persistent and gripping notion – the idea that artificial, self-replicating nanoscale robots would escape our control and reproduce indefinitely, consuming all the world’s resources, and rendering existing life extinct. The idea of this plague of “grey goo” has become firmly embedded in our cultural consciousness, despite some indications of regret from Drexler, who has more lately emphasised the idea that self-replication is neither a desirable nor a necessary feature of a nanoscale robot. The reaction of nano-scientists and business people to the idea of “grey goo” has been open ridicule. Actually, it is worth taking the idea seriously enough to give it a critical examination. Implicit in the notion of “grey goo” is the assumption that we will be able to engineer what is effectively a new form of life that is more fit, in a Darwinian sense, and better able to prosper in the earth’s environment than existing life-forms. On the other hand, the argument that biology at the cell level is already close to optimal for the environment of the earth means that the idea that synthetic nano-robots will have an effortless superiority over natural lifeforms is much more difficult to sustain.

Meanwhile, mainstream nanobusiness and nanoscience has concentrated on one very short-term danger, the possibility that new nanoparticles may be more toxic than their macroscale analogues and precursors. This fear is very far from groundless; since one of the major selling points of nanoparticles is that their properties may be different from the analogous matter in a less finely divided state, it isn’t at all unreasonable to worry that toxicity may be another property that depends on size. But I can’t help feeling that there is something odd about the way the debate has become so focused on this one issue; it’s an unlikely alliance of convenience between nanobusiness, nanoscience, government and the environmental movement, all of whom have different reasons for finding it a convenient focus. For the environmental movement, it fits a well-established narrative of reckless corporate interests releasing toxic agents into the environment without due care and attention. For nanoscientists, it’s a very contained problem which suggests a well-defined research agenda (and the need for more funding). By tinkering with regulatory frameworks, governments can be seen to be doing something, and nanobusiness can demonstrate their responsibility by their active participation in the process.

The dominance of nanoparticle toxicity in the debate is a vivid illustration of a danger that James Wilsdon has drawn attention to – the tendency for all debates on the impact of science on society to end up exclusively focused on risk assessment. In the words of a pamphlet by Willis and Wilsdon – “See-through Science” – “in the ‘risk society’ perhaps the biggest risk is that we never get around to talking about anything else.” Nanotechnology – even in its evolutionary form – presents us with plenty of very serious things to talk about. How will privacy and civil liberties survive in a world in which every artefact, no matter how cheap, includes a networked computer? How will medical ethics deal with a blurring of the line between the human and the machine, and the line between remedying illness and enhancing human capabilities?

Some people argue that new technologies like nanotechnology are potentially so dehumanising that we should consciously relinquish them. Bill McKibben, for example, makes this case very eloquently in his book “Enough“. Although I have a great deal of sympathy with McKibben’s rejection of the values of the trans-humanists, who consciously seek to transcend humanity, I don’t think the basic premise of McKibben’s thesis is tenable. The technology we have already is not enough. Mankind currently depends for its very existence at current population levels on technology. To take just one example, our agriculture depends on the artificial fixation of nitrogen, which is made possible by the energy we derive from fossil fuels. And yet the shortcomings of our existing technologies are quite obvious, from the eutrophication that excessive use of synthetic fertilisers causes, to the prospect of global climate change as a result of our dependence on fossil fuels. As the population of the world begins to stabilise, we have the challenge of developing new technologies that will allow for the whole population of the world to have decent standards of living on a sustainable basis. Nanotechnology could play an important role, for example by delivering cheap solar cells and the infrastructure for a hydrogen economy, together with cheap ways of providing clean water. But there’ll need to be real debates about how to set priorities so that the technology bring benefits to the poor as well as the rich.