Nature’s Nanotech – Brian Clegg

Invisible technology, visible results

When we think of nanotechnology, it’s easy to jump to the conclusion that we are dealing with the ultimate in artificial manufacturing, the diametric opposite of something that’s natural. Yet in practice, nature is built on nanotechnology. From the day-to-day workings of the components of every single biological cell to the subtle optics of a peacock feather, what we see is nanotechnology at work.

Not only are the very building blocks of nature nanoscale, but natural nanotechnology is a magnificent inspiration for ways to make use of the microscopic to change our lives and environment for the better. By studying how very small things work in the natural world we can invent remarkable new products – and this feature is the first in a series that will explore just how much we can learn and gain from nature’s nanotech.

As I described in The Nanotechnology Myth the term ‘nanotechnology’ originates from the prefix nano- which is simply a billionth. Nanotechnology makes use of objects on the scale of a few nanometres, where a nanometre is a millionth of a millimetre. For comparison, a human hair is around 50,000 nanometres across. Nanotechnology encompasses objects that vary in size from a large molecule to a virus. A bacterium, typically around 1,000 nanometres in size, is around the upper limit of nanoscale items.

A first essential is to understand that although nanotechnology, like chemistry, is involved in the interaction of very small components of matter, it is entirely different from a chemical reaction. Chemistry is about the way those components join together and break apart. Nanotechnology is primarily about their physics – how the components interact. If we think of the analogy of making a bicycle, the ‘chemistry’ of the bicycle is how the individual components bolt together, the ‘nanotechnology’ is how, for example, the gear interacts with the chain or pushing the pedals makes the bike go.

This distinction is necessary to get over the concern some people raise about nature and nanotechnology. A while ago, when I wrote my book on environmental truth and lies, Ecologic, I had a strange argument with a representative of the Soil Association, the UK’s primary organic body. In 2008 the Soil Association banned nanoparticles from their products. But it only banned man-made nanoparticles, claiming that natural ones, like soot, are fine ‘because life has evolved with these.

This is a total misunderstanding of the science. If there are any issues with nanotechnology they are about the physics, not the chemistry of the substance – and there is no sensible physical distinction between a natural nanoparticle and an artificial one. In the case of the Soil Association, the reasoning was revealed when they admitted that they take ‘a principles-based regulatory approach, rather than a case-by-case approach based on scientific information.’ In other words their opposition was a knee-jerk one to words like ‘natural’ and ‘artificial’ rather than based on substance.

Of themselves, like anything else, nanoparticles and nanotechnology in general can be used for bad or for good. Whether natural or artificial they have benefits and disadvantages. A virus, for example, is a purely natural nanotechnology that can be devastatingly destructive to living things. And as we will see, there are plenty of artificial nanotechnologies that bring huge benefits.

In nature, nanotechnology is constructed from large molecules. A molecule is nothing more than a collection of atoms, bonded together to form a structure, which can be as simple as a sodium chloride molecule – one atom each of the elements sodium and chlorine – or as complex as the dual helix of DNA. We don’t always appreciate how significant individual molecules are.

I had a good example of this a few days ago when I helped judge a competition run by the University of the West of England for school teams producing science videos. The topic they were given was the human genome – and the result was a set of very varied videos, some showing a surprising amount of talent. At the awards event I was giving a quick talk to the participants, looking at the essentials of a good science video. I pointed out that they had used a lot of jargon without explaining it – a common enough fault even in mainstream TV science.

Just to highlight this, I picked out a term most of them had used, but none had explained – chromosomes. What, I asked them was a chromosome? They told me what it did, but didn’t know what it was, except that it was a chunk of DNA and each human had 46 of them in most of their cells. This is true, but misses the big point. A chromosome is simply a single molecule of DNA. Nothing more, nothing less. One molecule.

Admittedly a chromosome is a very large molecule. Human chromosome 1 is the biggest molecule we know of, with around 10 billion atoms. Makes salt look a bit feeble. But it is still a molecule. The basic components of the biological mechanisms of everything living, up to an including human beings are molecules. Chromosomes provide one example, effectively information storage molecules with genes as chunks of information strung along a strip of DNA. Then there are proteins, the workhorses of the body. There are neurotransmitters and enzymes, and a whole host of molecules that are the equivalent of gears to the body’s magnificent clockwork. These are the building blocks of natural nanotechnology.

So with a picture of what we’re dealing with we can set out to see nature’s nanotech in action and the first example, in the next feature in this series, will show how nanotechnology on the surface of a leaf has inspired both self-cleaning glass and water resistant trainers.