This month’s National Geographic magazine is featuring an article on the exciting field of Biomimetics, or the science of mimicking nature in the development of new materials and products. Of all the industries, medicine will probably be one of the biggest beneficiaries of future discoveries in this field.
For all nature’s sophistication, many of its clever devices are made from simple materials like keratin, calcium carbonate, and silica, which nature manipulates into structures of fantastic complexity, strength, and toughness. The abalone, for example, makes its shell out of calcium carbonate, the same stuff as soft chalk. Yet by coaxing this material into walls of staggered, nanoscale bricks through a subtle play of proteins, it creates an armor as tough as Kevlar —3,000 times harder than chalk. Understanding the microscale and nanoscale structures responsible for a living material’s exceptional properties is critical to re-creating it synthetically. So today Andrew Parker had arranged to view the skin of a thorny devil museum specimen under a scanning electron microscope, hoping to find the hidden structures that allow it to absorb and channel water so effectively.
With a microscopist at the helm, we soared over the surface of the thorny devil’s skin like a deep-space probe orbiting a distant planet, dipping down now and then at Parker’s request to explore some curious feature of the terrain. There seemed to be little of interest in the Matterhornlike macrostructure of an individual thorn, though Parker speculated that it might wick away heat from the lizard’s body or perhaps help capture the morning dew. Halfway down the thorn, however, he noticed a series of nodules set in rows, which seemed to grade down to a larger water-collection structure. Finally we dove into a crevasse at the base of the thorn and encountered a honeycomb-like field of indentations, each 25 microns across.
"Ah-ha!" Parker exclaimed, like Sherlock Holmes alighting upon a clue. "This is clearly a superhydrophobic surface for channeling water between the scales." A subsequent examination of the thorny devil’s skin with an instrument called a micro-CT scanner confirmed his theory, revealing tiny capillaries between the scales evidently designed to guide water toward the lizard’s mouth. "I think we’ve pretty well cracked the thorny devil structure," he said. "We’re ready to make a prototype."
Full article at National Geographic: Biomimetics: Design by Nature…
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