Biomimicry pushes science forward
Science constantly looks to nature for inspiration in its search for solutions to problems, writes David Tan
In 1941, Georges de Mestral was in a Swiss forest walking his dog when he noticed his socks were dotted with small burrs. Looking under the microscope, he saw the barbed covering of the seeds had hooked onto the looped fibres in his clothes.
Here was a blueprint to reversibly bind two materials together. Velcro, thus, was born and the hook-and-loop fasteners were patented in 1955.
This story is probably the best known example of biomimicry, or how nature inspires solutions to everyday problems. But humans have been learning nature's secrets for millennia.
Prehistoric man survived by copying the hunting and shelter behaviour of animals.
In the legend of Icarus, his father Daedalus, inspired by birds, made wings from feathers and wax for them to escape from prison. Icarus, however, plunged to a watery grave when his wings melted because he flew too close to the sun.
In the real world, Leonardo da Vinci in the 15th century dreamed up fabulous flying machines based on birds, although it was not until the 20th century that the Wright brothers successfully created a prototype that led to the sleek aircraft of today.
In medicine, examples of nature-inspired inventions abound, from the classic hypodermic needle to a tooth treatment glue similar to the adhesive that attaches mussels to rocks (see sidebar).
In May, researchers from University of Illinois at Urbana-Champaign revealed how the eyes of flies served as inspiration for a new digital camera for medical imaging.
Currently, most camera technologies are made on flat material, such as silicon wafers that are not flexible, which limits imaging capabilities. To create a hemispherical camera, the researchers used rubbery optics bonded to electronics in a flexible mesh layout.
With large arrays of tiny lenses and miniaturised detectors on a hemisphere, this new camera displays exceptional imaging properties far beyond existing cameras.
"This type of hemispherical design provides unmatched field of view and other powerful capabilities in imaging. Nature has developed and refined these concepts over the course of billions of years of evolution," says lead researcher Professor John Rogers.
The eyes of another insect - moths - last year inspired another team of scientists led by Professor Yi Yasha from the City University of New York to develop a new material to improve medical X-ray imaging.
X-ray machines contain "scintillators", a material that absorbs X-rays and re-emits them as light to create an image. To increase the resolution of these images, the scientists designed a new nanomaterial that comprises thousands of pyramid-shaped bumps, modelled after the surface of a moth's eye that is remarkably anti-reflective.
"The moth eye has been considered one of the most exciting bio structures because of its unique nano-optical properties. Our work improved on this fascinating structure and demonstrated its use in medical imaging materials, where it promises to achieve lower patient radiation doses, higher-resolution imaging of human organs, and even smaller-scale medical imaging," says Yi.
In Singapore, Dr Ali Miserez from Nanyang Technological University has developed an ultra-strong ceramic based on the arm of the mantis shrimp, an animal known to shatter aquarium glass and crab shells.
"The highly damage-resistant property of the mantis shrimp could be most useful in medical products, such as hip and joint implants, as they sustain impacts during activities such as walking.
"Damaged hip implants are a real problem, and cost billions of dollars to health care systems worldwide. They also involve painful operations when they need to be replaced."
Another aquatic creature, a parasitic worm that lives in fish, has inspired improved skin grafting adhesive patches. The spiny-headed worm attaches itself to the intestinal lining of fish by plunging its cactus-like head into the intestinal wall and swelling its head up, which acts as an anchor.
Dr Jeffrey Karp, of Harvard Medical School, created an adhesive patch covered in microneedles with tips that swell up, like the worm's head. The patch forms a seamless contact with tissue to close wounds.
"The adhesion strength of the tips of the microneedle is more than three times stronger than conventional staples used for skin-graft fixation," says Dr Seung Yun Yang, who is part of Karp's research team.
While refinements are still needed, including bringing the down the cost, it won't be long before some of these inventions appear in a clinic near you.
Janine Benyus, author of the book Biomimicry: Innovation Inspired by Nature, says: "It's about looking to nature for inspiration for new inventions.
"It's learning to live gracefully on this planet by consciously emulating life's genius. It's not really technology or biology; it's the technology of biology."