The Gecko’s Foot: How Scientists are Taking a Leaf from Nature's Book. Peter Forbes

system and we generally assume that anything will belong to just one of these categories. One of the most dramatic discoveries of bio-inspiration is that technical components can be incorporated into natural systems.

      Although cells never meet silicon chips or other electronics materials (which have only existed for 30–40 years) in nature, natural proteins can stick to silicon and other electronics materials and in doing so create structures on a much finer scale than would be possible for the technical materials alone.

      Engineers make things by heating, beating and hacking them into shape; chemists make things by cooking up the ingredients; nature makes things through the DNA in the genes. The plan of every creature that exists is at some stage just a coded blueprint strung out along the double helix of DNA. Nature’s way is by far the most subtle, accurate and fine scaled. It can be seen as a combination of engineering and chemistry. DNA is a chemical but it also has architecture – the double helix – and the substances DNA makes – proteins – also have architecture. They are both chemicals and pieces of nanoengineering.

      To exploit DNA’s design potential, bio-inspirationists use hybrid techniques of genetic engineering and silicon-chip fabrication. This may trouble some people – but nature does not recognize the division between organic and inorganic: gorgeous inorganic mineral shell structures are produced under organic control. The rigid organic/inorganic divide is a product of the human mind, more specifically that of chemists who have put the labels ‘Organic’ and ‘Inorganic’ over the doors of departments which used to have very little to do with each other.

      When I put it to Mehmet Sarikaya, the passionate advocate of this new hybrid technology, that some would see a Frankenstein element in it, he said: ‘There will be more good happening than bad because human beings are fundamentally good people. What’s at the back of this scientist’s mind is: Can I have an impact on the early detection of cancer? Can I have an impact on assembling nanofibres for new nano-molecular devices? That’s what we have in mind, that’s why we work.’

      Although bio-inspiration is still largely unfamiliar to a wide public, nanotechnology has already attained a certain notoriety. The idea is abroad that there is something inherently dangerous in the nanorealm. Michael Crichton’s bestseller Prey (2002) imagines self-replicating nanorobots escaping from human control, learning rapidly and becoming ruthless predators. What lies behind this fantasy and does it have any credibility?

      We have always lived in a nanoworld – our bodies and those of all living things are composed of biological nanomachines, and the dust in the air, pollen grains, smoke from all forms of combustion, contain nanoparticles – but like M. Jourdain in Molière’s Le Bourgeois Gentilhomme, who was astonished to discover that he had been speaking prose all his life, we have only just woken up to the fact. And this has caused panic in some quarters. The idea behind Prey came from Eric Drexler’s Engines of Creation (1986), which first put nanotechnology into the public arena. Drexler suggested that nano-technology would spawn self-replicating systems that might get out of control, thus swamping the world with a ‘grey goo’ of synthetic nanomaterial.

       The idea of ‘grey goo’ took on a life of its own; it was resurrected in 2003 by Prince Charles in a speech warning of the dangers of nano-technology. But, in 2004, Drexler set the record straight, in an article co-written with Chris Phoenix of the Centre for Responsible Nanotechnology, saying:

      Nanotechnology-based fabrication systems can be thoroughly non-biological and safe: such systems need have no ability to move about, use natural resources, or undergo incremental mutation. Moreover, self-replication is unnecessary; the development and use of highly productive systems of nanomachinery (nanofactories) need not involve the construction of autonomous self-replicating nanomachines.

      Of course, the nanotechniques of bio-inspiration are biological but, when you look at what these techniques are, you will see that there is no way that their products could reproduce themselves and get out of control.

      Even if nanotechnology is not going to swamp the world, many people remain concerned about some aspects of it. In 2004, the Royal Society and the Royal Academy of Engineering published a report on its benefits and possible dangers. The report stressed that while it would be wise to be wary of ingesting nanoparticles and releasing them to the environment without tests to ascertain what effects these substances can have, nanostructures are a different matter. Nanoparticles are potentially dangerous on two counts: being so small they can enter cells by routes forbidden to larger particles and because they have such a large surface area relative to their volume their chemical and electrical properties are enhanced, which raises the possibility that they could trigger damaging reactions within the cell. There is no reason to fear solid objects structured at the nanolevel: the world is full of solid nanostructures. All living things, including us, are necessarily nanostructured – made from atoms which have to be assembled into nanostructures before they can make up anything large enough to be seen.

      The possibility of a hysterical reaction to things nano really came home to me when I visited the glassmakers Pilkington in St Helens, Merseyside, to discuss Activ™, their new self-cleaning glass, described in Chapter 2. Activ glass has a very thin coating on the surface that gives it self-cleaning properties. This coating is less than 20 nm thick. Kevin Sanderson, one of Activ’s inventors, told me that they had received worried telephone calls asking, ‘Are these nanoparticles on my Activ glass window going to fly off the surface and do me harm?’ In fact, the nanolayer is bonded very strongly to the glass underneath, it is harder than glass and will last as long as the window does.

      As for nanoparticles, there have always been and always will be nanoparticles in the environment: they are called dust. All forms of combustion produce huge clouds of them. The air in the London Underground is full of nanoparticles and some of them may even be carbon nanotubes, the most famous nanoparticle, created by the action of electric sparks from the live rails. It seems likely that the concern about nanoparticles being added to sunscreens and cosmetics will lead to new research on our total exposure to nanoparticles – from car exhausts and the Underground, to bonfires and barbecues.

      Every new technology creates fear and resistance, but as far as it is known at all, bio-inspiration has had a good press to date. It has an eco-friendly feel to it, unlike the more hard-edged nanotechnology; but once its connection to nanotechnology becomes known – that bio-inspiration is mostly nanoscale technology – it will be damned by some through association. So it is important to stress that there is nothing wrong with nanotechnology per se.

      But if nanotechnology induces fear in some people, in science it is also a buzzword: play the nanocard and you unlock the funders’ purse strings. As a result, a lot of people have suddenly discovered that, in reality, they are doing nanotechnology. Physicist Andre Geim tells of engineers ‘who never make anything smaller than 1 metre in diameter and now they’re doing nanotechnology because they can position their things to within 1 nanometre accuracy!’ As Geim says, ‘Adam and Eve were nanotechnologists, they created everything from sperm, from DNA!’

      Bio-inspiration arrives at a time when there is organicism in the air, especially with regard to architecture and design. The theme of Expo 2005, held in Aichi, Japan, from March to September 2005, was ‘Nature’s Wisdom’. Organicism is abroad in both the Zeitgeist of general culture and in materials science and there are connections between large-scale bio-inspired architecture and bio-inspired materials. Many architects want to design smart buildings and to use the new bio-inspired materials. The first really commercial application of bio-inspiration is in paint for the exteriors of buildings, using the Lotus-Effect, closely followed by Pilkington’s self-cleaning Activ™ glass. And if other bio-inspired materials are not yet ready, there is no law against including organic curves in the shape of a building.

      In September 2003, the