New York Times December 11, 2001

Engineers Ask Nature for Design Advice

by Jim Robbins

What does a flower known as the sacred white lotus have to do with house paint?

In the world of biomimicry, everything.

The white lotus is a symbol of purity, yet it grows in swamps around the world. The secret of how the flower rises above its dismal environment was discovered by a German botanist, Dr. Wilhelm Barthlott at the University of Bonn, who spent 20 years studying the microscopic architecture of thousands of plant surfaces with a scanning electron microscope. Dr. Barthlott noticed that the leaves that needed the least amount of cleaning before they were scanned had the roughest surfaces.

And the cleanest leaf of all — the white lotus — turned out to have tiny points on it, like a bed of nails, Dr. Barthlott found. When a speck of dust or dirt falls on the leaf, it teeters precariously on those points. When a drop of water rolls across the tiny points, it picks up the poorly attached dirt and carries it away.

The lotus, in other words, has a self- cleaning leaf.

The lotus effect, as it is called, has been applied to a house paint made in Germany called Lotusan. The paint, on the market in Europe and Asia, is guaranteed to stay clean for five years without detergents or sandblasting. Now the lotus effect is being developed for other products, including roof shingles and auto paint.

The lotus effect is an example of biomimicry, an engineering approach that has been gaining momentum in recent years as manufacturers look to nature to solve some engineering problems. By looking at the way plants and animals handle similar kinds of problems, the engineers hope to make products that are less polluting, use fewer materials and even cut costs.

"Businesses should work like a living system," said Janine M. Benyus, a science writer who wrote "Biomimicry," published in 1997, and is now a consultant on the subject. "They should find a way to create conditions conducive to life, not toxic to life."

Nature has inspired engineers for a long time, for things like hypodermic needle tips shaped like rattlesnake fangs and Velcro, which is based on the same principle as those cockleburs that stick to socks in a walk through a field. But the search for biological designs with commercial potential has become more sophisticated and more widespread.

The examples are legion. Dr. Robert J. Full, a biologist at the University of California at Berkeley, has discovered that the attractive force between molecules allows the gecko, a small lizard, to scamper across ceilings and up walls at three feet per second.

Microscopic tips of hair on the gecko's feet actually get close enough to interact with the molecules of the surface it is crossing. To take another step, the gecko peels each foot from the wall. The charge is so powerful that, theoretically, a 90-pound weight could be suspended from a gecko.

A novel approach to hearing comes from the parasitic Ormia fly, which is being studied at the State University of New York at Binghamton and at Cornell. Crickets, able to disguise their location by how they chirp, cannot fool the Ormia, which lays its eggs on the cricket and has an ear that has evolved to find them. Researchers have discovered that the fly has the biological equivalent of directional microphones in its ears; they hope that their studies will lead to a better hearing aid for people.

The idea of biomimicry has become Ms. Benyus's stock in trade. She travels extensively explaining the concept to businesses like Interface Carpets and Nike.

She recently returned from a snorkeling trip to the Galápagos Islands with a group of wastewater treatment engineers from Carollo Engineering, a California firm. The engineers went to see organisms that had evolved to solve their own water treatment problems, like mangrove trees that turn salt water to fresh water, and filter feeders, like barnacles, that eat by straining water.

The engineers returned home with food for thought. Pipes at wastewater plants build up mineral deposits that impede the flow of water. How, the engineers wondered, do filter feeders deposit minerals to build a shell and then turn off the mineralization when it is big enough. If the engineers can understand that process, they thought, they may be able to stop the calcium carbonate deposits at treatment plants and avoid using toxic chemicals to dissolve the deposits.

It is an example of thinking about manufacturing in a different way. "The question we ask is, How would nature solve this problem?" said David Oakey of David Oakey Designs, a company in LaGrange, Ga., that designs commercial carpeting and other textiles using nature as a model. "When you ask that question, you move in directions you never would have thought about."

One such project near the end of development at a Department of Energy laboratory is a water-resistant glue made from mussels. Mussels are bivalves that fasten themselves firmly to ships, piers and other objects in salt water. The foot of the mussel is equipped with a tiny organ that excretes something called byssal threads, four proteins that combine, in the presence of a catalytic fifth protein, to create the glue. The glue is especially powerful, adhering even in salt water and working in a many environmental conditions.

"We've measured bond strength, and there's evidence that it can be developed into good adhesive," said Dr. Frank Roberto, a senior scientist at the Department of Energy's Idaho National Engineering and Environmental Laboratory in Idaho Falls. Experts are also looking at using the superglue to fasten the metal oxide platters on computer hard disks, to replace sutures in the human body and to repair ships while they remain in the water.

A major hurdle is that 10,000 shucked and ground-up mussels are needed to distill a single gram of the protein. But nine years after they began, scientists are manufacturing small amounts of glue in a fermenting process. But fermenting will not produce enough glue for commercial use. One possibility, Dr. Roberto said, is to insert a mussel gene into a plant through genetic engineering so the supersticky proteins can be grown as a crop.

Some researchers and entrepreneurs consider splicing genes a legitimate way to enhance biomimicry. A biotechnology company in Montreal called Nexia, for example, says that it has transplanted the gene for making dragline silk from the golden orb weaving spider into a handful of Nigerian goats that can now be milked for silk. Re-creating spider silk is one of the field's major goals because it is five times as strong as steel and much lighter.

Nexia's chief executive and founder, Dr. Jeffrey Turner, said the transgenetic goats excreted protein in their milk that, when isolated, assembled itself into fine strands of spider silk, a product the company calls Biosteel. The strands are woven into larger units.

"We hope to have thousands of goats producing silk for everything from ophthalmic sutures to bulletproof vests," said Dr. Turner, who added that the process did not harm the goats. "A goat has 70,000 genes, and only one of them is from a spider." But transplanting genes between species worries some.

"That's about as far from biomimicry as you can get," Ms. Benyus said. "The movement of genes from a mammal to a plant is not a common natural strategy. It's really scary to me."

Some researchers are looking at natural processes of construction in the hope of finding efficient, less polluting ways to build structures. At Sandia National Laboratory in Albuquerque, such work tries to mimic abalone shells, which are among the hardest, most durable materials in nature. The shells are made up of alternating layers of hard and soft material. When a crack occurs in a hard layer, it is absorbed by the soft layer and does not spread.

While some packaging mimics that layering, it is still manufactured with ordinary methods: the energy- intensive, polluting approach that engineers call "heat, beat and treat." Dr. Jeffrey Brinker, a senior scientist at Sandia, has been working with others on ways to create such materials with self-assembling polymers. That strategy depends on repellent and attractive forces like the ones that let detergent molecules in a solution dissolve the oil in a pan.

Molecules of smart polymers can be herded almost instantly into hard and soft layers with synthesized detergent molecules to create things as diverse as hard, transparent finishes on automobiles and coatings for windshields. The process is now used commercially to make parts for computers, and it may soon find wider application.

"They're more elegant and more efficient than traditional polymers," Dr. Brinker said. "They are very cheap, clean and there is no waste."

Another area where biomimicry may be commercially useful is in carpet manufacturing. One carpet company that is interested in a more natural approach is Interface Carpets, one of the world's largest commercial carpet companies, based in Atlanta. It went in that direction after its chief executive, Ray Anderson, read a book by Paul Hawken, Amory Lovins and L. Hunter Lovins called "Natural Capitalism" (1999). In Mr. Anderson's own book, "Mid- Course Correction: Toward a Sustainable Enterprise" (1998), he called moving toward sustainability the next industrial revolution.

"I am a plunderer," Mr. Anderson was quoted as saying, speaking of his business and manufacturing methods, in an interview in U.S. News & World Report in 1998. "Someday people like me may be put in jail."

Mr. Oakey's company designs products for Interface. A biomimicked carpet now on the designed by Mr. Oakey is called Entropy. When an ordinary commercial carpet wears out, the whole thing needs to be replaced because of differences in dye lots, though just 20 percent of the carpet may be be worn. Entropy, Mr. Oakey said, mimics the randomness of a forest floor with different shades and sizes. Because there are no matching problems, small sections can be replaced, installation is easier, and there is far less waste.

Entropy is just a start, not an end, Mr. Oakey said. Interface is doing research on carpets made from a plastic formed with corn and recycled materials.

Nature continues to lead him to think about carpet in new ways. "Can you do it without dye, but with refraction, like the feather of a bird?" he asked. "Can you make it like a snake skin, where instead of taking out the whole carpet you take a sliver off the top and replace that?"

File Date: 012.12.01