September 18, 2009 | David F. Coppedge

Nature’s Designs Are Engineers’ Finds

Nature is a treasure trove of technology.  Though engineers have garnered inspiration from nature since the Wright brothers and before, it seems that in recent years there has been a gold rush to follow nature’s lead.

  1. Wet glue:  Worms may not be very inspiring to most people, but Science News reported that scientists at the University of Utah in Salt Lake City are developing “worm-inspired superglue.”  By watching how the sandcastle worm glues pieces of sand, minerals and shell pieces into its shell, the scientists imitated the technique and invented a glue that works underwater.  The secret is in proteins possessing strong positive and negative charges.  The new glue may help doctors repair bone in the wet environment of the body during surgery.  After the bone regrows, the non-toxic glue would simply break down in the body.
  2. Super velcro:  Velcro became one of the early triumphs of modern biomimetics when in 1941 George de Mestral became intrigued by the cockleburs that stuck to his dog’s fur.  The famous “hook and loop” fabric he developed has become as indispensable in our lives as adhesive tape.  Science News reported that researchers at the Technical University of Munich have developed “velcro on steroids” – a metallic version that can hold 35 metric tons per square meter.  The article said the connectors are “patterned on the burrs that some plants have evolved to adhere to the coats of animals for seed dispersal.”
  3. Wing wonders:  Did you know that locusts are the long-distance champs of the insect world?  They can fly for hundreds of miles.  Science News, Live Science and Science Daily reported on work at Oxford to understand the wing design of “nature’s most efficient flyers.”  (Science News likened the dragonfly to fighter jets and the locust to 747s.)  The researchers are finding that the flexibility in the wing is crucial to the efficiency.  Dr. John Young of the University of New South Wales (Australia) said, “The message for engineers working to build insect-like micro-air vehicles is that the high lift of insect wings may be relatively easy to achieve, but that if the aim is to achieve efficiency of the sort that enables inter-continental flight in locusts, then the details of deforming wing design are critical.”
        Dr. Young said that until recently it has been impossible to study insect wings in detail because they flap so fast and their shape is so complicated.  Now, with wind tunnels and computer models, the problems are becoming tractable.  Incidentally, he pointed out, the “bumblebee paradox” (the claim that insects defy the laws of aerodynamics) is dead.  He affirmed, “Modern aerodynamics really can accurately model insect flight.”  That doesn’t mean it is simple.
  4. Pearl of great price:  “Nature’s ability to generate with ease amazingly complex and functional inorganic structures is the envy of materials engineers,” wrote Nils Kroger in Science last week.1  He was talking about nacre – the mother-of-pearl material found in oysters.  It’s hard enough to predict a material from the genes that form it, he said: “An additional level of complexity exists for organisms that form body parts composed of mineralized structures such as sea shells, bone, and teeth.”  Why is that?  “These organisms must also carefully control the interfaces between the soft body parts and the growing mineral.”  And that is what oysters do that is the envy of materials engineers.  “These highly organized aragonite layers, termed nacre, are unique to mollusks and endow the material with extraordinary toughness and a characteristic luster,” he said.
        Nacre’s secret is in careful control of minerals by protein layers in the growing material.  It appears now that proteins high in the amino acid aspartate are key to growing mineralized structures.  “Indeed, aspartate-rich proteins appear to be a common tool of biomineral-forming organisms, irrespective of the chemistry of the mineral phase,” he said.  “They are involved in the formation of calcium phosphate biominerals of bone and teeth and the amorphous silica cell walls of diatoms.”  It may be a challenge for evolutionary biologists to explain this convergent technology among such diverse organisms, but aside from that, “Knowledge of the molecular details of biomineralization processes is key to enable biomimetic syntheses of new high-performance composite materials.”

Graphic designers should have ample opportunities to design cartoon logos of plants and animals for the suite of new products that are coming out of biomimetic engineering.  How to make locusts and worms look attractive in advertising could be a challenge, though.  According to The Guardian, artists are up to the challenge.  The London Zoo had a 3-day “Pestival” to “celebrate insects in art, and the art of being an insect.”  One of the displays is a human-size “termite pavilion” that shows termites are not just home destroyers – they might just be the inspiration for future energy-efficient homes.

1.  Nils Kroger, “The Molecular Basis of Nacre Formation,” Science, 11 September 2009: Vol. 325. no. 5946, pp. 1351-1352, DOI: 10.1126/science.1177055.

Evolution cannot rightly claim credit for any of this.  Silly phrases in the form, “technical achievements that plants or animals have evolved to do such and such” are useless distractions.  The focus is on design, design, design.

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