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March 26, 2004 — In the 1940s, Swiss engineer George de Mestral returned from a hike with his dog and discovered that his pants and his pooch’s coat were covered with cockleburs.
Examining the burrs’ hooks under a microscope, de Mestral was struck with an idea for a fabric fastener. Velcro was born.
Velcro is the quintessential example of biomimetics, or biomimicry, literally the study of nature in order to imitate it.
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Mother Nature has an impressive resume as an engineer. In nearly 4 billion years, she’s perfected millions of innovative designs and manufacturing techniques in such diverse fields as biochemistry, materials science and mechanical engineering. It’s no surprise, then, that small tech researchers are looking to nature’s elegance for engineering aid.
For example, take gecko tape, a new adhesive recently developed by British scientists at the University of Manchester’s Centre for Mesoscience and Nanotechnology. Coated with 500-nanometer-diameter polymer fibers that are just 2 microns long, the glueless tape exploits the same small-scale physical phenomena that enable a gecko to walk up a wall.
At a number of other laboratories, researchers are studying how sea mollusks, like abalone, manufacture their self-healing, superhard shells. Mimicking that biological process could someday lead to clear, tough, impermeable coatings or composites.
Materials science professor Angela Belcher at the Massachusetts Institute of Technology has also found inspiration in abalone. As a graduate student, she teased out the biochemical process the mollusk uses to build its shell. Armed with that knowledge, she recently genetically engineered a virus to coat itself in a shell of semiconducting nanoparticles. Burning away the virus “scaffold” causes the nanoparticles to fall together and form a nanowire.
Biomimetics is taking hold in the industrial arena as well. Last summer, Bell Labs scientists published a paper in the journal Nature reporting that a deep-sea sponge known as euplectella produces optical fiber similar to the stuff in telecommunications networks. The natural fibers aren’t transparent enough for real-world applications, but they are far more durable than commercial optical fiber.
“In this case, a relatively simple organism has a solution to a very complex problem in integrated optics and materials design,” said Cherry Murray, senior vice president of physical sciences research at Bell Labs. “While many years away from being applied to commercial use, this understanding could be very important in reducing the cost and improving the reliability of future optical and telecommunications equipment.”
You might call the products of Iridigm Display Corp. “bioMEMicry.” The company claims that their tiny screens for mobile devices replicate the way structures on butterfly wings cause light to bend and reflect, creating shimmering color without pigment.
Iridigm’s iMoD (Interferometric Modulator) display elements are MEMS devices consisting of two conductive plates, 25-60 microns on a side. One plate is stacked on a glass substrate and the other is suspended over it with a slight gap of air. Voltage keeps the plates separated, allowing light to reflect off the substrate. Switching off the voltage closes the gap, turning the iMoD black. The size of the gap between the plates determines the visible color.
While biomimetics is worthy of wonder, a reality check reveals that inspiration comes a lot easier than imitation. Duplicating nature’s designs is no easy task. Perhaps the biggest challenge is that our methods of fabrication are in their infancy compared to what nature has taken billions of years to evolve.
The study of biology has advanced far faster than the engineering needed to imitate biological systems, says California Institute of Technology biologist Michael Dickinson. A MacArthur “Genius” Fellow, Dickinson is reverse engineering a fly’s “flight control system” to bring its principles to robotics. His insights into insect aerodynamics have already informed an effort at UC Berkeley to build a robotic fly.
Today, even the most state-of-the-art microfabrication facilities are no match for biological machines that place proteins, he says.
Still, biomimetics has taken its first baby steps … right into Mother Nature’s arms.