Biomimetics to the Rescue of Science
Posted on October 10, 2011.
The booming field of biomimetics (imitating nature’s designs) is fascinating not only for the amazing products it promises, but for the fresh new opportunities it provides for science and engineering. From viruses to mammals, everything in the living world is now being seen in a new light: agents of innovation that humans can learn from. Here are just a few examples in recent news, arranged in order from large to small inspirational creatures.
Giraffe bone: Science Daily’s report on “Bionic Manufacturing” happening now at the Fraunhofer Institute didn’t mention giraffes, but it did mention “long bones” as inspiration for new materials that are lightweight and strong. Giraffes have long bones, so they are an apt example of animals with “the perfected structures found in nature” that the scientists so wish to imitate. “Whereas natural materials have evolved over numerous generations to reach the level of perfection we see today, engineers and product designers have to work much faster,” they said; so rather than working by a blind, unguided, aimless, purposeless process, they began with design requirements and computer models. What can we expect from the design research into how nature achieved perfection? Coming soon to a doctor near you: “medical orthopedic devices or anatomically formed body protectors such as lumbar support belts for skiers.”
Climbing plant: Tarzan made good use of lianas – the long, woody, vine-like plants good for swinging from tree to tree. Scientists at the University of Freiberg are finding inspiration for more sophisticated uses from them: self-healing materials, according to Science Daily. Publishing in the Journal of Bionic Engineering, the “bionics experts” envision boats, tires, and air mattresses that can heal their own leaks. How does the liana repair its lesions? “When the lignified cells of the outer supportive tissues which give the plant its bending stiffness are damaged, the plant administers ‘first aid’ to the wound,” the article explained. “Parenchymal cells from the underlying base tissue expand suddenly and close the lesion from inside. Only in a later phase does the real healing process kick in and the original tissue grows back.” Cool; how can we do that?
Circulatory system repair tech: Animal circulatory systems inspired researchers at the University of Illinois to invent a different kind of self-healing material. Prof. Nancy Sottos and team looked at how blood vessels subdivide down to tiny capillaries; this led them to work on “impregnation of plastics with a fine network of channels, each less than 100 millionths of a metre in diameter, that can be filled with liquid resins,” the BBC News reported. “These ‘micro-vascular’ networks penetrate the material like an animal’s circulation system, supplying healing agent to all areas, ready to be released whenever and wherever a crack appears.”
Slippery slope pitchers: The pitcher plant has such a slippery inner surface, a bug landing on it doesn’t have a chance avoiding the digestive juice at the bottom. What would a super-slick surface be good for in our world? New Scientist reporter Lisa Grossman observed, “Scientists searching for clever materials sometimes borrow ideas from nature.” She interviewed Harvard biologist Joanna Aizenberg who is looking at the pitcher plant as another “one of many strategies that nature created to manage and control the interaction with liquid.” Even insects with sticky feet that allow them to walk up walls can’t escape the pitcher plant’s slippery slope. “Aizenberg realized that with the right choice of lubricating liquid, the pitcher plant’s strategy could be adapted to repel virtually anything.” Non-stick skillets that really work, anyone? How about “self-cleaning windows, friction-free oil and water transport pipes, and safe and efficient blood transfusion devices,” too? Maybe even our own pitchers? Nature talked about this, too (477, 22 September 2011, pp. 412–413, doi:10.1038/477412a). The pitcher plant's trick is to infuse a rough surface with liquid that fills in all the surface pores. Aizenberg’s team did this with Teflon, applying a chemical on top of it that formed a nanometers-thick layer. Other liquids and substances hydroplane right off, they found. The pitcher plant’s slipperiness is even greater than that of the lotus leaf, an earlier darling of biomimetics engineers. Other benefits of this “smart material” – “It’s interesting that it combines self-lubrication, self-healing and self-cleaning, which are different processes.”
Do like the sundew: Need a better adhesive for that hip replacement or artificial knee? Live Science says the sundew, a carnivorous plant, is providing inspiration. The University of Tennessee has a Nano Bio-systems and Biomimetics Lab whose mission is “to learn from biological principles and apply engineering along the way to develop an end product that uses these compounds and principles to advance technology.” Here’s the sundew wow factor:
The sundew’s adhesive has Spiderman qualities. For example, it can stretch to one million times its normal size. Most rubber bands can stretch to only about six times their original length. This remarkable elasticity makes the adhesive dew secreted from the plant a potentially effective choice for coating replacement body parts, regenerating dying tissues, healing wounds and improving synthetic adhesives. It is so sticky and elastic that it’s also economical — less than a microliter (0.0002 teaspoons) would cover 25 square millimeters (about 0.04 square inches).
In addition, the lab is looking at nanoparticles in English ivy. Why? “These particles can scatter light, and may possibly be an alternative to the metal-based nanoparticles presently used in sunscreen,” a spokesman said. Applications range from medical devices to cosmetics. “The hope is to replace the many synthetic products we use daily with naturally occurring substances.” Isn’t it cool to let surgeons suture up wounds with materials that will “biodegrade as your tissues heal around it, making what is left your material”? Naturally. Authors Pelagie Favi and Samantha Tracht of the University of Tennessee ended their article, “Don’t be surprised if one day soon you can buy band-aids made from sundew.”
Seaweed battery: You feel bad throwing toxic batteries into the trash. Maybe with future batteries you can feel good. Kovalenko et al., reporting in Science, announced an environmentally-friendly battery material that uses brown algae: “We show that mixing Si nanopowder with alginate, a natural polysaccharide extracted from brown algae, yields a stable battery anode possessing reversible capacity eight times higher than that of the state-of-the-art graphitic anodes.” (Science 7 October 2011: Vol. 334 no. 6052 pp. 75-79, DOI: 10.1126/science.1209150).
Orange you glad for biodegradable plastic: One branch of biomimetics is using organic materials for new engineering purposes. PhysOrg, reporting on work at the University of York, asked, “what if we could make plastic from a recycled, natural, biodegradable source?” That source is orange peels. By zapping it with microwaves and converting into a gas, inventors have made a biodegradable plastic. Orange peels are typically thrown into landfills after the fruits are harvested for orange juice. Why not replace the toxic plastic in landfills with an all-natural substitute?
Leaf power: PhysOrg reported that MIT prof Daniel Nocera is making progress with his “artificial leaf.” It can split water into hydrogen and oxygen, like leaves do in photosynthesis, but his device is made of silicon, cobalt, and nickel. Like leaves, though, his invention doesn’t need batteries, wires, or control circuits. But it’s still nowhere close to what plants can do. Read another article on PhysOrg to learn why Berkeley scientists are stumped by photosynthesis:
Scientists have been studying how nature has mastered the efficient capture and near instantaneous transfer of the sun’s energy for more than a century, and while important lessons have been learned that can aid the design of optimal synthetic systems, Fleming and his co-authors say that some of nature’s design principles are not easily applied using current chemical synthesis procedures. For example, the way in which light harvesting is optimized through the organization of chromophores and the tuning of their excitation energy is not easily replicated. Also, the discovery by [Graham] Fleming [Vice Chancellor for Research at UC Berkeley] and his research group that the phenomenon of quantum coherence is involved in the transport of electronic excitation energy presents what the authors say is a “challenge to our understanding of chemical dynamics.”
Dragonfly aircraft: Live Science posted a Science Nation video about dragonflies, the “flying aces of the insect world.” Harvard biologist Stacey Combes is shown filming them in high speed to see how they accomplish their “high speed aerial feats” such as hunting and even reproducing in mid-air. In a mere half-second, a dragonfly can take off, snatch its prey, flip over, and return to its starting point. “Interestingly, they’re one of the most ancient groups of insects,” Combes claimed. “They’ve had a long time to evolve their skills as predators” – interpreted by the narrator as 300 million years. What she didn’t say is that the most ancient fossil dragonflies look identical to modern ones, showing no evolution at all, and had wingspans of over two feet. It would seem coordinating four large wings and having near all-around vision hardly represents a primitive insect. The narrator ended by saying, “engineers are looking to the dragonfly for inspiration in small-scale aircraft design.”
Insect wall climber: Berkeley scientists have created a robot that can climb up cloth. It looks so much like a living insect, it would scare a homemaker. PhysOrg included a video clip of it in action. “Berkeley, the Biomimetic Millisystems Lab is at the forefront of mimicking nature,” the article said. “Its lab mission is ‘to harness features of animal manipulation, locomotion, sensing, actuation, mechanics, dynamics, and control strategies,’ in its work with small lightweight millirobots.”
Abalones, diatoms, and viruses: Professor Angela Blecher at MIT is a genius at the pinnacle of her scientific career. What does she do? Look to nature for engineering ideas. Inspired by abalones, whose shells are 3,000 times stronger than chalk (98% the same calcium carbonate but 2% added protein), and diatoms – both of which take elements from sea water and construct fantastically strong materials from them, she is applying a kind of directed evolution to see if she can mimic the feat. She takes common raw materials and submits them to viruses programmed to create randomly-varying proteins, looking for the ones that will generate non-toxic, novel, environmentally-safe materials. “Instead of waiting 50 million years, she's speeding up the evolutionary process by running 1 billion experiments at a time,” the BBC News reporter said, apparently oblivious that Blecher is applying intelligent design. Biomimetics is such a promising field, she said this: “I think 50 years from now, we'll look back on biology as an important part of the toolkit in manufacturing... we’ll look back and say this is one of the fundamental tools we developed in this century.”
Rethinking old tech: A related field to biomimetics is re-engineering old natural technologies. We tend to think, for instance, that burning wood for energy is unsustainable because it would deplete the forests, and polluting because of the smoke. Actually, Mason Inman at National Geographic reported, wood burning can actually be superior to “cleaner” energy sources. “Burning trees for power may seem backward, dirty, and environmentally hostile,” he wrote, “But a high-tech new way of wood burning holds great potential to save energy, cut costs, and even fight global warming, a new study says.” In fact, advanced wood combustion technologies could supply more energy than hydroelectric dams without running out of trees. And did you know that wood burning is carbon neutral? All the carbon absorbed by wood is released back, with no net increase in atmospheric carbon. If coal and oil is reduced, there is a net reduction in carbon emissions.
Joensuu, Finland, is an example of a city supporting its population of 58,000 with efficient, sustainable wood burning. Forget fireplaces and old-fashioned wood-burning stoves, though. “In advanced wood combustion power plants, intense heat and carefully controlled conditions ensure that nearly all the carbon in the wood is broken down into flammable gases,” Inman explained. “Then the gases are ignited, burning much more cleanly than a typical smoky home fireplace.” In addition, special filters keep small particulates out of the atmosphere. Tree material that is already being cut down from lumbering and trimming could supply a sustainable amount of material. The energy is already there in the wood; it just needs to be released. For a fascinating article on the nature of wood, see Brian Thomas’s article on ICR, “Thank God for wood.”
Cow power: Roasting cow patties seems as low-tech as cooking by campfire next to a covered wagon. But some farmers have found that roasting dried cow dung, under the appropriate conditions, is a great way to save money. Maggie Koerth-Baker on National Geographic News highlighted a farm in Minnesota that converts cow manure, kept free of oxygen and digested by bacteria, into clean energy that not only provides high-quality fertilizer but energy independence. “Electricity from the digester powers their dairy, plus 70 other households.” No fossil fuels; living off the land; that sounds both ancient and modern.
There are treasures all around us to inspire a whole century of new technologies and innovations. What a great time for young people to enter science. Biomimetics burst on the scene without any obligation to Charles Darwin. The references to evolution in just a couple of the entries above were stupid and useless. Evolution has nothing to do with this (someone please explain to Prof Blecher, a very smart woman, that what she is doing is the opposite of Darwinian evolution). A new age of useful, beneficial science is blossoming, where young minds with a keen eye for design can leverage insights from nature into successful careers, and entrepreneurs can take what they learn and make tons of money with useful products that will create jobs and launch careers, while simultaneously being good stewards of the planet. We need to remove Charlie’s icons like the Russians removed Lenin at the fall of Soviet communism, like the Iraqis removed Saddam Hussein, and get on with the new age of nature’s enlightenment. It’s all about design – intelligent, wise design.