Biomimetic architecture has been making waves for some time. The latest stunning addition to the ranks is the One Ocean Pavilion at EXPO 2012 in Yeosu, South Korea, designed by the Austrian architects Soma. The pavilion is a homage to the ocean and marine life and its most dramatic feature is the gill-like array along the facade. These are flexible elements that buckle under compression to create the gill-effect. They are not merely decorative: they open or close to regulate both ventilation and light. The buckling mechanism is a classic out of the D’Arcy Thompson bioinspirational handbook. Forms created under such physical forces take up beautiful “graded forms” as D’Arcy Thompson called them. As the degree of flexure varies along the facade a pleasing serried cascade effect is achieved. I guess the facade could do a Mexican wave if you so programmed it. The pavilion opens today if you’re in striking distance of it.
_ This week’s BBC2 Horizon programme ‘Playing God’, on synthetic biology, had a long item on obtaining spider silk form transgenic goats. We saw a healthy herd of goats at Utah State University’s experimental farm; we saw spider silk being spun. What we weren’t told is that spider silk from transgenic goats was a headline news story almost 10 years ago. Nexia, a Canadian biotech firm, was commercializing spider silk from similar transgenic goats. But the venture failed soon after because the spider silk was way below the quality of natural silk.
Randy Lewis, the researcher at Utah is the world’s expert on synthetic spider silk. He said after Nexia’s failure that he was sure that synthetic spider silk would eventually succeed. So perhaps, 10 years on the tricks have finally been learned? The puzzle is though that earlier this month Randy Lewis published a paper in the US Proceedings of the National Academy of Sciences on producing spider silk from transgenic silkworms. The paper commented: “standard recombinant protein production platforms have provided limited progress due to their inability to assemble spider silk proteins into fibers”. That means goats. So, which is it going to be: goats or silkworms? And can spider silk, after decades of study, make the grade? A straw in the wind may be the forthcoming exhibition at the V&A Museum in London of a spectacularly gorgeous cape made laboriously from natural spider silk. It took 4 years and 1.2 million spiders to produce (which is why we need a synthetic process). What might spur researchers on are the remarkable properties of the garment. The cape is a shimmering gold and this is the natural colour of the silk. It also reputedly has a quite special feel, unlike that of normal silk. Perhaps 2012 is going to be the year of spider silk after all this time. _ When I began researching The Gecko’s Foot, around a decade ago now, spider silk was the hottest material in the bioinspired armoury. But after the high-profile attempts to produce spider silk from genetically engineered goats failed, the subject was back-burnered. The spider silk genes are so large and repetitive and the processing of the gel in the spinnerets so subtle that the spider kept its secret.
But now scientists at the University of Wyoming have done what might have seemed a good idea form the start: insert the spider silk genes into the silkworm. Silkworms have been commercial silk-producing organisms for millennia so this is promising at last. The research is reported in the US Proceedings of the National Academy of Sciences. The fact that the silk comes out of Laramie prompts the thought that spider-silk lariats might be a good idea. Rein in that steer with spider power! _ In Dazzled and Deceived, a key theme was the search for effective ships’ camouflage. It began with the eccentric American artist Abbott Thayer at the turn of the 20th century. Thayer had discovered the law of concealing coloration in nature in 1896 (ie animals are dark on top and pale below to counter glare and shadow and make the outline harder to pick out) and became obsessive in his attempts to convince the military to camouflage ships in the same way. He failed and died in despair in 1922
But in my research I discovered that the naturalist Peter Scott, a naval commander in WW2, had introduced a Thayer-like system of camouflage. He’d read Thayer as a boy, camouflaged his own ship in a freelance manner, and then convinced the Admiralty to adopt it as the Western Approaches colour scheme. The documentation was thin and I sought official confirmation in the National Archive and The Imperial War Museum archives. Nothing could be found. Then I found a reference to a naval document – CB3098 – in David Williams’ Naval Camouflage 1914-1945. It seemed that the Admiralty had posthumously acknowledged Thayer after all. I had to get that report. But although the National Archives had the CB series, 3098 was missing. As so often, the net came to the rescue. Bizarrely, it turned out that a Shropshire modellers’ cottage industry sold a facsimile of CB 3098 – The Camouflage of Ships at Sea – to enable modellers to paint their model ships in authentic colours. The report did indeed vindicate Thayer. Given the crushing rejection he had received, the report’s conclusions are astonishing. How Thayer – long dead – would love to have heard these words: “…during the early part of the 1914-1918 war, a number of schemes for reducing the visibility of ships at sea were submitted to the Admiralty. …The soundest of these proposals, whose best points are incorporated in present-day camouflage practice, came from an American artist, Abbott H. Thayer, and from a British biologist, Professor (now Sir John) Graham Kerr; both based their arguments primarily on their observations of the concealing colouration of wild animals and the two sets of proposals were to some extent complementary.” What could have caused this amazing volute face? The report goes on to say that Thayer and Kerr’s argument that “white is the tone for concealment on an evenly overcast grey day – has been thoroughly vindicated in the present war by the Western Approaches, the scheme of camouflage designed by Lt-Cdr. Peter Scott, MOB’S.., R.N.V.R.” The suggestion is that Scott’s inside knowledge of naval operations helped him to carry conviction where the outsiders had failed. The report notes of Thayer and Scott: “it is interesting that the two men who arrived independently of each other, and at an interval of 25 years, at this same unorthodox conclusion should both have brought to the solution of the problem the imagination of an artist and the eye of a practised observer of nature”. Thayer’s odyssey was convoluted in the extreme, as was the research trail in his wake. _ You start to write a book because a subject has grown till it fills a book-sized space in your mind. Fine, but once you start you’re aware that there are many gaps in your knowledge. A book is forever, you hope, so you’d better fill those gaps.
I became interested in mimicry over 25 years ago when I was editing natural history encyclopedias.There was just something uncanny about the idea of one creature impersonating another, especially when it was an animal trying to look like a plant. There’s a bug, Ityraea, that collects on twigs en masse and looks like a convincing flower spike until they all get up and drop off the twig; the leafy sea dragon has tattered appendages to its fins that exactly mimic the sea-weed it lives among; the Kallima butterfly has gorgeously rich purple and organ wings: when they’re open, that is; closed the underside is dead-leaf brown, complete with mouldy bits and holes and it even mimics the leaf stalk. But I didn’t want the book (now Dazzled and Deceived: Mimicry and Camouflage) to be simply a catalogue of these stupendous creatures, one after another. The bible of the subject was Hugh Cott’s Adaptive Coloration in Animals and I knew that Cott had served as a camouflage officer in World War II, as had some painters. I wanted to see how camouflage and mimicry played out in human affairs as well as nature. Long before Velcro, camouflage was the first great bio-inspired technique. This wartime research took me to the National Archives at Kew and the Imperial War Museum, where I spent many happy hours. The Desert War in North Africa in World War II began to fascinate me. Seeing reports in the archives, written on old typewriters in the desert, the files now slowly rotting in the archives was deeply thrilling. The Imperial War Museum has many accounts lodged by ordinary serving forces personnel and I combed these for accounts of the camouflage operation in North Africa. This of course was totally needle-in-haystack but I struck lucky. Reading the file of Sergeant Bob Thwaites, the camouflage school in the desert suddenly loomed into view. Thwaites had a very pithy take on forces life: Our first acquaintance with our instructor was not encouraging. We had been told he was one of Britain’s most eminent naturalists and appeared to have been dragged protesting from a twitcher’s hide, bundled into a captain’s uniform made by a blind tailor and posted to Maadi. This was vivid writing and, even better, this had to be my man, Hugh Cott, he was writing about: He was middle-aged, balding and with a military bearing suggesting that he could well have thought Sandhurst to be a seaside resort. But, according to Thwaites, Cott won them over with an eye-opening list of camouflage tricks and insights including how to get your bearings from churches, why cowboy jackets are fringed and how many animals don’t just look like something else, they behave like it: such as the bittern which if disturbed sways like the reeds it is trying to emulate. For Thwaites it was an exercise in lateral thinking; for me it was manna from heaven. The patterns we make as we criss-cross each other’s lives are infinite and most of them are hidden. Go seek and you will find treasure. _Having written about James Gordon it seems only right to mention the deep pioneer of biomimetics: D’Arcy Wentworth Thompson (1860-1948). Thompson wasn’t looking for engineering solutions derived from nature but his explorations of mechanical principles in nature created the mindset that allowed biomimetics to flourish. There was a time lag of about three quarters of a century before his influence was felt but that wasn’t his fault.
Thompson saw that nature’s love affair with hexagons (bees’ honeycomb, skeletons of radiations, the Giant’s Causeway etc) was the result of nature following least stress, least material strategies in different contexts. In the case of the radiolarians it all derived from foams, with the minerals that formed the skeleton being deposited in the interstices of the foam. In the hands of scientists such as Geoffrey Ozin, this is now a recognised synthetic technique. D’Arcy Thompson’s most influential passages don’t yet have any biomimetic applications but they are important in the science of biological form, evo devo, and nothing concerning form can be ruled out in biomimetics. Thompson showed how some body forms can be derived from others by systematic grid deformations. He showed for instance how a human skull can be morphed into a chimp’s or vice versa. The discovery of the hox genes in the 1980s provided a mechanism for Thompson’s transformations. There is a strong link with Gordon in that Thomson analysed living structures in terms of stress, showing for instance the connection between the skeletons of large animals such as the bison and bridges. This proved an exciting inspiration for the London Eye architects Marks and Barfield, who in their early days conceived of a dinosaur bridge in which the span required only one anchor point, the bridge’s vertebral elements being held in tension and compression like a stegosaurus’ backbone. Reading D’Arcy Thompson you feel a world of possibility opening up. There is just one book, On Growth and Form, first published in 1917.My copy is the abridged edition, edited by John Tyler Bonner in 1961. _ I’ve been re-reading James Gordon’s two Penguin books The New Science of Strong Materials and Structures: Or Why Things Don’t Fall Down. I can say that I’ve learnt more about the physical world from these two books than from any other source. Gordon was a British engineer and materials scientist who can claim to be the pioneer of biomimetics in Britain.
Gordon shows, with the confidence of an engineer who’d made materials for WW2 fighter planes but with a disarming irreverence, why it’s almost impossible to destroy a brick arch, why the comet airliner crashed, why ships still break in two, how to create superstore whiskers of glass, and countless others insights into our material world. As the first biomimetician he counters the prejudice many engineers used to have against natural materials, showing how many natural materials exceed conventional engineering materials in their properties. Above all he explains the difference between strength, stiffness, toughness and elsaticity in the most vivid way possible. The great beauty of structural engineering is that that the whole subject can be explained in terms of two opposed concepts: compression and tension. The interrelationship between the two lies behind every structure, from the Parthenon to the London Eye. Once you grasp this, buildings and bridges never look the same again. As a rule of thumb, all buildings until the 19th century used compression only, but architects and engineers now increasingly favour tension structures, being lighter and potentially more elegant, hence those wonderful cable-stayed bridges. Not only do you learn wonderful things from Gordon’s books, he writes so well, with a tone so intimate you feel he is talking just to you. He laces his text with stories from nature, the classical world (a passion of his), and his own rich experience of the triumphs and disasters of a life in engineering. They are books to re-read as you might want to read again any literary classic. They are literary classics. _ In The Gecko’s Foot I went out on a limb for tensegrity. It was mostly a macro-scale architectural technique that derived from the innovative sculptures of Kenneth Snelson. But it does have a biomimetic angle: Donald Ingber, at Harvard, has shown how the cell uses tensegrity to maintain its shape.
Tensegrity structures are held together by tension elements. There are stiff rods but in a classic tensegrity these do not touch. They are quite simple to make and great fun. I couldn’t resist them for The Gecko’s Foot. Tensegrity is now a very live area of nantechonological research thanks to more work at Harvard, developing tensegrity DNA structures. An editorial in Nature Nanotechnology (2010, 5, p. 473) stressed the links that can be made between macro and nano – tensegrity began with large sculptures but is now proving fruitful at the nanoscale. In this it is following the path that led from Buckminster Fuller’s architectural domes to the tiny C60 molecule named buckminsterfullerene in Fuller’s honour. In 1936 the Swiss surrealist artist Meret Oppenheim created an art object, Le Déjeuner en fourrure, consisting of a teacup, saucer and spoon covered with fur from a Chinese gazelle. It is a classic of ambiguity, reminding us that we have a tendency to keep living things and non-living separate. We do not like wild animals in the house – spiders, mice, cockroaches – because indoors is our realm, orderly and hygienic: it is the antithesis of anarchic disease-ridden nature.
But some of the most original work in science is now being done by biomimeticians who happily combine natural structures with technical ones. Angela Belcher at MIT works with bacteriophages. Genetic engineering techniques have enabled scientists to test millions of random peptide sequences (peptides are short sequences of amino acids; effectively mini-proteins), in a process known as bio-panning, to see if any have the ability to interact with inorganic computer components. The test peptide sequences are created on the surface of the phage heads. Belcher has now developed a whole array of electronic components, always using the phage as the template. Sometimes the phage itself is sacrificed, burnt off, leaving the metal and mineral components in place, sometimes there is no need to do this. In a charming graphic twist on the vegetable/mineral interface, Belcher has a schematic depicting the process in which the phage is stylized as a rocket (very like a World War V2). This is the fur-lined teacup in reverse: a living, organic creature tricked out as a technical device. _ In writing The Gecko’s Foot, one technique of biomimetics was so obvious that I missed it altogether. Nature’s nano-structures – whether it be the fine structure of butterfly wing scales or the bumpy surface of self-cleaning lotus leaf or the millions of tiny spatula hairs on a gecko’s foot or the calcite lens of a brittle star – have optical or superhydrophobic or powerful adhesive properties that we would dearly love to replicate. It didn’t occur to me that instead of trying to find synthetic methods of duplicating them, it might be possible to simply use the natural structure as a template, creating a negative of the structure which can then be used to mould the replica. This is now a growing technique. It is often said that we shouldn’t copy nature slavishly – we should be smarter than that – but sometimes it might just be the best bet. Incidentally, the journal in which the following review appears is a valuable source of updates.
Bioinspiration and Biomimetics, 2011, 6 No 3, September, 031001. |
AuthorI'm a writer whose interests include the biological revolution happening now, the relationship between art and science, jazz, and the state of the planet Archives
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