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

this new tendency in architecture, with structures based on many creatures, from sea sponges to dinosaurs. The archetypal figure is the Spanish engineer and architect Santiago Calatrava, creator of the Athens Olympic Stadium. Calatrava’s buildings and bridges exhibit creaturely gestures rather than mimicking specific creatures: there are moth-like antennae, forest canopy train-shed roofs, reptilian snouts, a whale’s tail (or bird of prey’s wings). After the turbulent history of architectural styles since the early 20th-century modernist revolution, organic architecture seems an attractive option. It uses the same materials as hi-tech architecture, and both organic and hi-tech architectures have their roots in geometry. Indeed, the key to all bio-inspiration is that nature and human artefacts are acted upon by the same forces and they occupy the same three-dimensional world. And this is why similar solutions are possible in each.

      Alongside the architecture, in cars such as the Vauxhall Tigra, Ford Ka, Volkswagen New Beetle and the latest Nissan Micra, recent car design has also shown itself leaning towards organicism. The idea behind these cars is to be expressive: they sit unusually on the road, with the tail up, and the headlights styled as eyes, giving the impression of a face. These are cars whose moods you can read. In the case of the Vauxhall Tigra, the first of the breed, there is a resemblance to the warning display of an eyed hawkmoth – which is appropriate, because the hawkmoth displays large eye patterns on its wings, trying to look like a much larger and fiercer creature; similarly, the Tigra is a tame little Corsa dressed up to be racy. Whether or not there is a functional reason for such large-scale organic structures (and often there is not) they belong to the new worldview that bio-inspiration has ushered in.

      While writing this book, I have found myself watching insects in the garden far more closely. In fact, I wonder if I ever really noticed them before, other than on the increasingly rare occasions that a butterfly flew in. A sudden flurry in the corner of my eye and a garden spider is binding an already unrecognizable insect. Hoverflies punctuate the air around the Coreopsis. Two cabbage whites lurch across the garden in a mating dance. I realize that one of the reasons I used to be impervious to this micro-choreography is that it all seemed so impenetrable. How on earth did they do it? But, increasingly, we know, or if not, we know how we are going to know in a few years’ time. Welcome to an Aladdin’s cave of bio-inspired materials and devices.

       CHAPTER TWO The Great Sacred Lotus Cleans Up

      Though buried deep

      In the slime of the pool,

      Unstained and untouched

      You come forth to the world

      Glorious in beauty,

      Pure and serene:

      Yet in your innocence

      Oft you deceive us

      Transforming the dew

      On your life-giving leaves Into sparkling gems!

      GONNOSKé KOMAI, ‘To the Lotus-Bloom’

      ‘Nooks and crannies harbour dirt,’ we have always been told: a piece of folk wisdom scientists would not have bothered to dispute until some 15 years ago. But the self-cleaning powers of the sacred lotus plant – recognized and sanctified thousands of years ago in the East – have turned this on its head. The lotus’s secret is that its surface is rough at the micro- and nanolevels. It is almost embarrassing that such an elemental discovery should have waited so long to be made, but it has opened up for human use a new field of self-cleaning surfaces, utilizing the Lotus-Effect^®.

      Water skitters off a lotus leaf like drops of mercury – it doesn’t spread and the globules it forms are highly spherical. So water doesn’t last long on a lotus leaf. As for dirt, it seems to have a greater affinity for water than for the leaf so when it rains it is simply washed off.

      There is a school of thought that science has still to rediscover the greater wisdom of the Ancients. In the case of the lotus, they are right. In ancient Eastern cultures, the lotus’s immaculate emergence from muddy water was more than noticed: the plant became a symbol of the triumph of enlightenment over the dross of earthly life. So deeply does the lotus pervade Indian, Chinese and Japanese consciousness that the name is a byword for, and a guarantor of, purity. The most famous Buddhist chant, Om mani padme hum, translates as ‘Behold! The jewel in the lotus’, and the classic Buddhist texts are known collectively as the Threefold Lotus Sutra. The quest for spiritual cleanliness that runs through Buddhism derives from the lotus’s example, so much so that images of cleaning recur in the texts:

      The Law is like water that washes off dirt. As a well, a pond, a stream, a river, a valley stream, a ditch, or a great sea, each alike effectively washes off all kinds of dirt, so the law-water effectively washes off the dirt of all delusions of living beings.

       Innumerable Meaning Sutra

      While researching this book, I experienced my own lotus epiphany. I had flown from San Francisco to Seattle, and was en route from the airport to the University of Washington campus. It was a long day, my trip was almost at an end and I was tired and anxious. I had to change buses in the middle of Seattle’s downtown subway system. I emerged in the middle of Chinatown and walked into the nearest café for a bite to eat. In the middle of the counter, staring up at me, were lotus cakes. I ate one – it tasted rather like chestnut – and a Proustian madeleine feeling came over me, although this was not for the recollection of time past but a kind of blessing on the future of my enterprise. I had risen from the underworld of the subway system, in which the route to enlightenment – Washington University campus – was temporarily lost. The notion of sweetness

      arising from dross is such a powerful one that once you know of the lotus you cannot help but refer to it: hence its omnipresence in East and South Asian cultures.

      In the West, appreciation of the lotus is more aesthetic than spiritual: ‘No more stately plant adorns our gardens than lotuses,’ is a typical statement from an early 20th-century horticultural book on the water lilies.^* Concerning the flowers, the book goes on: ‘These great blossoms are among the noblest products of the vegetable world. They fairly glow in the morning sunlight.’ With flowers 20–30 cm across, some of the leaves sit on the water, as water lily leaves do, and some stand 1 m from the surface. The water that collects on them is tossed back into the lake by the wind. In size they are dwarfed by the largest water lily, the Victoria regia from the Amazon, which was first brought to flower in England by Joseph Paxton in 1849, but the grace conferred by the lotus’s exceptional purity more than compensates for that. (Incidentally, Victoria regia also has a role in the development of bio-inspiration; Paxton, as the engineer of the Crystal Palace in 1851, was much influenced by its structure; see Chapter 9.)

      I was not sure whether I had ever seen a lotus before I became interested in the Lotus-Effect: water lilies of course, but had some of these been lotuses? I went to the Botanic Gardens at Kew, London, to find out for myself. Lotus plants die down every year and in cultivation are replanted from the runners that spread from the rhizomes rooted in the mud. At Kew in April they had plants of a variety of the American lotus, ‘Perry’s Giant Sunburst’, growing in tanks next to water lilies. Although it had a name redolent of out-of-town garden centres, nevertheless it was a real lotus: the leaves had that bluish bloom you see on some cabbage leaves. Dropping water on the lotus leaves was like dropping mercury on the table. The water drops gleamed with internal reflection and skittered around like quicksilver (fig. 2.1).

      The Lotus-Effect’s discoverer, Professor Wilhelm Barthlott, Director of the Nees-Institute for Biodiversity at Bonn, Germany, is unusual in pursuing parallel careers as a research botanist and as a patent-holding industrial inventor working closely with many industrial partners. ‘Technology transfer’ is a buzz phrase in universities these days, as governments try to kickstart