10 Materials that Emulate Nature: Photos
Scientists emulate nature's wisdom to create innovations in the lab.
Nature has it all figured out. It's smart, efficient and innovative. That's why scientists and engineers all over the world try to copy it in their labs. The field of research concerned with imitating nature is called biomimetics.
"Biomimicry is the conscious emulation of nature's wisdom," says Tim McGee, a senior biologist with the Biomimicry Institute, a nonprofit that brings together scientists, engineers, and architects to create sustainable technologies. "It's looking to nature to understand the patterns of how it works, why it works."
McGee makes a subtle distinction between biomimicry and bioinspired design. Biomimicry, he says, usually works toward sustainability whereas bioinspired design doesn't necessarily. The expansive field of biomimicry includes designing AC-free buildings based on termite mounds and improving transportation systems using slime molds.
For McGee, these 10 examples show how far biomimicry can go.
Implanting electrodes in the brain can help treat neurological problems, but the hard plastic used to make them lessened the positive effects of the treatment. In 2008, scientists at Case Western Reserve University looked to sea cucumber skin for a solution.
"It goes from a soft spongy to hard," McGee says. The scientists, led by professor Christoph Weder, created a new material from fine cellulose fibers in a polymer matrix and published their findings (abstract) in Science.
The fibers become loose or bound together in different conditions. Without water, the adaptable medical material is stiff, but when added it gets soft. "By being more responsive to their environment, these materials can keep us healthier longer," McGee adds.
McGee points to the company Ecovative Design, located near Troy, New York, which uses fungi to grow durable and compostable packaging as an example of making a strategically biodegradable material.
The company uses live filamentous fungi to convert agricultural waste into chitin, a tough fiber that is produced as the fungi digest. McGee thinks this process could be used to create a wider range of products, from furniture and computer cases to more advanced composites.
"I even have a ‘rubber ducky' that they made out of their material for fun," he says. "It is a platform technology that takes waste and turns it into a valuable structure."
The ability of viruses to self-assemble led materials scientist Angela Belcher and her MIT colleagues to genetically engineer them so they would form materials into functioning devices. In a 2009 article in Science (abstract), the team described how they got a harmless type of virus to transform itself into a battery.
"What's cool about that is it's on the nanoscale," McGee says. "They've grown transistors, batteries. She's created a whole technology that's new." He also highlights self-assembly research done by Harvard University materials scientist Joanna Aizenberg, who is working on growing and manipulating nanostructures.
Decomposition on a forest floor and at the edge of rivers inspired one Australian company called Biolytix to develop a wastewater treatment system that relies on organisms including worms and beetles. This living "humus" allowed the system to function far better than a standard septic tank, without requiring chemicals.
"Their tank processes the waste ten times more effectively than a septic tank would," McGee says. Massive flooding in Australia and New Zealand overwhelmed the company, causing it to voluntary liquidate. "Unfortunately in innovation, the smarter or better systems and materials don't always prevail in the marketplace," McGee says.
Austrian architect Thomas Herzig, inspired by the way biological cells form tissue, designed modular "cells" made from either PVC or thermoplastic polyurethane. These patented pneumocells can be combined to form numerous structures, including shelters and canopies.
"You can put them together to make whatever you want," McGee says. "This technology is an example of ephemeral architecture, creating easy to build, highly adaptive structures with low energy input." Each inflatable pneumocell is airtight, fire-retardant, blocks solar radiation, and keeps its shape. Because of the membrane design, if one cell gets damaged, the rest will continue to support the structure.
Inspired by coral's magnesium and calcium ultrastructures, the Los Gatos, California-based Calera Corporation developed a process that turns carbon dioxide from gas or coal plants and seawater into "green cement." By using waste, the technology sequesters CO2 instead of producing more the way traditional Portland cement does.
Each ton of replacement cement Calera's process creates sequesters a ton of CO2, McGee says. "Traditionally, cement is one of the largest emitters of CO2 in the built environment," he adds. "This technology is a game-changer."
Much as plants do, the Waltham, Massachusetts-based green plastics company Novomer views carbon dioxide as a resource. Combining CO2 from ethanol production and a petrochemical material with a catalyst developed at Cornell University, Novomer creates a polymer.
"When we think about CO2 pollution, we see it as a huge waste, a big problem. Plants see it as a huge benefit, more starting material," McGee says. "Instead of drilling for oil, or growing biomass for the carbon we need in plastics, we can use the very CO2 we see as a waste to be the solution."
University of Massachusetts Amherst scientist Alfred Crosby took a closer look at how Venus flytraps function to develop a novel polymer surface. The plant has tiny hairs that, when touched, trigger its leaflets to turn from concave to convex, trapping prey.
In an article published in Advanced Materials (abstract) in 2007, Crosby and his team described how they had mimicked the snapping function to create a polymer covered in tiny lenses that can be triggered to transform from convex to concave. Such material has the potential to be "tunable."
"I'm fascinated by Al Crosby's research because it links together the nanoscale with the microscale," McGee says. "Al and his team look to nature for inspiration on how it performs this task, and then they take these lessons and figure out how we can do this with our technology."
Even "waterproof" bandages are inevitably going to come off. University of California, Santa Barbara organic chemistry professor Herbert Waite set out to figure out a way to make manmade adhesives stick better to wet surfaces. He looked at how marine organisms, including mussels, stay put.
Mussels produce a bunch of leathery threads called the byssus that are strong and can attach to surfaces such as wax, glass, bone, and metal. By studying the byssus, Waite would like to process proteins so that they mimic the mussel functions, creating useful applications.
"Herb has created an entire field of research and a creative approach to seeing the world around us," McGee says. "His insights have inspired many others to basic research or applications -- one of the most famous is PureBond, where the product itself is much safer than the formaldehyde alternative."
Sharks, unlike other marine animals, move relatively slowly but stay free from bacteria. Using research from the University of Florida as to why this happens, the company Sharklet Technologies developed a uniquely patterned film that resists organism growth.
"It is the shape of their skin. More specifically, it is a shape, a pattern, formed by how their denticles (like scales) come together," Sharklet Technologies CEO Joe Bagan told Discovery News in 2008. "It is very specific, not found anywhere else, and we believe has evolved for the specific purpose of keeping the animal clean."
The features in Sharklet's film are only about 3 microns tall, but Bagan called it "Mount Everest" for an organism.
"The real interesting bit is that sharks do this with the surface texture -- no chemicals," McGee says. "This non-lethal resistance strategy is great for hospitals because it means that it is less likely that bacteria will build up resistance."