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ideas Science constantly looks to nature for inspiration in its search for solutions to problems, writes David Tan


n 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.

Nature has developed these concepts over billions of years of evolution PROFESSOR JOHN ROGERS

This camera, with its multitude of tiny, pliable lenses, has a near-infinite depth of field. 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 UrbanaChampaign 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 A bee on a web of camera lenses that mimics its own ocular system. Photos: AFP

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, higherresolution 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.”

Medical advances come naturally ............................................. David Tan • Hypodermic needle Thin, hollow tool to introduce fluids into the body developed by ancient Greeks and Romans. Inspiration: snake fangs and insect stings. Significance: quick method to administer medicines developed over the centuries and widely used today. • Porcupine quill-inspired needle Hypodermic needle with backward facing barbs that act like serrated blades on the way in and hooks that snag on the way back out. Inspiration: quills of the North American porcupine. Significance: needle can be more easily inserted yet stays put once in place. • Mussel glue-inspired teeth treatment Sticky material to aid rebuilding of tooth enamel. Inspiration: adhesive used by mussels to attach to rocks Significance: material that stays sticky in a wet environment allows for the outer layers of teeth to repair, reducing pain from sensitive teeth. • Digital fly’s eye camera Digital camera with 180 degree field of view. Inspiration: compound eyes of flies. Significance: the hemispherical digital ‘fly’s eye’ camera

produces an unmatched field of view and can be used to enhance medical devices for monitoring health and wellness, tools for endoscopy and advanced surgical procedures. • Enhanced X-ray detector Nanoscale X-ray detecting material. Inspiration: anti-reflective moth’s eyes. Significance: lower X-ray radiation doses needed, enhanced X-ray image resolution. • Damage-resistant medical implants Ultrastrong ceramic for medical implants and military body armour. Inspiration: mantis shrimp that has club-like arms that can strike prey with a force hundreds of times the shrimp’s weight. Significance: damage-resistant implants can sustain high impact, reduce bone loss through wear and tear and avoid toxic effects and immune reactions caused by loose fine particles from metal implants. • Microneedle adhesive skin patch Stronger and less damaging covering for skin wounds. Inspiration: Pomphorhynchus laevis a parasitic worm. Significance: superior to current adhesives that can either potentially cause tissue damage or allergic reactions.

LAB REPORT .............................................. Jeanette Wang Iron out pregnancy risks Taking iron daily during pregnancy can be good for you and your baby. A new study in the British Medical Journal’s website found that for every 10mg rise in iron dose per day (up to 66mg per day), risk of maternal anaemia was 12 per cent lower, the baby’s birth weight increased by 15 grams, and risk of low birth weight decreased by 3 per cent. The World Health Organisation recommends a dose of 60mg per day for pregnant women. Ninety grams of braised beef liver has about 6mg of iron, and fortified breakfast cereals have up to 18mg per serving. Feeling peckish? Here’s another gluten-free cereal option for coeliac disease sufferers: canary seeds. According to a study in the Journal of Agricultural and Food Chemistry, a variant of the seed made safe for human consumption is said to have more protein than other cereals. Coeliac disease is a gluten-caused inflammation in the small intestine. Partners in crime Female murder victims in Southeast Asia are more likely to have been killed by intimate partners more than anywhere else in the world – or 59 per cent of half a million homicides from 66 countries over the past 20 years that were analysed in a WHO study published in The Lancet. Globally, intimate partners were responsible for 39 per cent of all female murders compared with just 6 per cent for men. The authors note that these are conservative estimates as at least one-fifth of the cases did not report the victim-offender relationship.

Getting to the root of diabetes treatment ................................................ Elizabeth Snouffer As the blending of alternative and mainstream medicine gains traction worldwide, more studies emerge on the benefits of embracing both Eastern and Western philosophies. A recent one published in the journal PLOS ONE found that a conventional diabetes drug, when taken alongside traditional Chinese medicine herbs, was significantly more effective in treating type 2 diabetes. The study by researchers from Peking University and Australia’s University of Queensland involved 800 mainland patients with poorly controlled type 2 diabetes – which leads to complications including blindness, amputation and early death. Patients were randomly assigned to get either the antidiabetic drug glibenclamide alone or the “xiaoke pill”, a compound of Chinese herbs and glibenclamide. After 48 weeks, patients treated with the pill had a significant reduction in risk for hypoglycaemia (low blood sugar) and similar improvements in blood glucose control compared to patients who took only glibenclamide. Professor Ji Linong, the study’s main author and director of the department of endocrinology and metabolism at Peking University People’s

Hospital, believes the results add clinical support for the product’s effectiveness. “Traditional Chinese medicine [TCM] is used widely in treating type 2 diabetes not only in China, but also in the other parts of the world,” says Ji. “But the role of TCM and other herbal medicines in the management of [the disease] is still not established. The absence of scientific understanding has caused scepticism and criticism about TCM, often because of the low methodological quality of trials.” He hopes the recent evidence on TCM’s effectiveness in managing diabetes will contribute towards “reducing entrenched inequity in access to effective care for poor people”, as more than 80 per cent of people in developing countries depend on herbal medicine for basic health care. Eighty per cent of people with diabetes worldwide live in low- and middle-income countries, according to the International Diabetes

Chinese medicine is used in treating type 2 diabetes not only in China JI LINONG, PROFESSOR

Radix astragali is a component of the xiaoke pill. Photo: Freer

Federation. In Hong Kong, about one in 10 individuals, or 700,000 people, have or will develop type 2 diabetes. That number is set to more than double by 2030. Diabetes is known as xiaoke in TCM, because in chronic cases, patients usually manifest emaciation (xiao in Chinese) and thirst (ke). Other illnesses with these symptoms can be called xiaoke as well. A Xiaoke pill contains 0.25 micrograms of gilbenclamide, along with the herbs Radix puerariae (Pueraria root), Radix astragali (Astragalus root), Radix rehmanniae (Rehmannia root), Radix trichosanthis (Trichosanthis root), cornsilk, dried magnolia vine fruit and Chinese yam. Li believes there is growing evidence that the first two herbs


complex may exert action, Projected number of Hong manner to directly or indirectly, Kong people who may reduce blood in two brain regions glucose with known to be involved develop type 2 diabetes by 2030 fewer side in glucose-sensing. effects”. Type 2 diabetes is But Chan also a largely preventable cautions: “Some of these metabolic condition defined by preparations may have severe insufficient insulin and insulin side effects. Compared to resistance. People who drink alcohol, eat Western medicine, the procedure of registration for sugary or high-fat foods, and TCM or herbal mixtures is less lead an unhealthy or sedentary stringent and, often, exaggerated lifestyle are at greater risk of claims may give patients developing xiaoke. Classic unrealistic expectations.” symptoms include frequent Still, there is a need for urination, extreme thirst or affordable and safe alternative hunger, unusual weight loss, treatment. “The scientific fatigue and irritability. evaluation of TCM may advance Professor Juliana Chan Chung-ngor, director of Chinese our understanding of the disease University’s Institute of Diabetes and lead to [the] discovery of novel pathways which may and Obesity, believes that some address some of the unmet “yet to be identified” traditional needs [of diabetics],” says Chan. herbs may prove to “work in a

20130624 health  
20130624 health