Plagiarising the original technologist.

Nature Credits Evolution for Biomimetics Revolution

Evolution News & Views March 27, 2015 11:35 AM | 

If you could just strip out the superfluous evolution-talk in Nature's special Outlook feature on biomimetics, you'd be left with a showcase of intelligent design. The series, "Biomaterials: inspired by the natural world," focuses on amazing traits of various living things that inspire scientists and engineers, but evolution keeps trying to steal the credit. Herb Brody begins the overview:

Millions of years of evolution have made the biological world into a supremely effective materials-development laboratory. This Outlook examines the ways in which substances found in the natural world are inspiring imitations that might eventually endow humans with superhuman powers. [Emphasis added.]

Each of the nine articles except the last mentions evolution at least once, but evolution contributes nothing to the scientific substance. The word is used just as a narrative gloss, as Dr. Philip Skell used to say: such-and-such "has evolved" to do this-or-that.

Setting evolution aside, look at the biomaterials listed in the series that are inspiring imitators, and see what applications are coming from these natural designs. (Brody's lead article contains links to the other articles.) Some of the plants and animals are already the stars in biomimetics, but others are new, providing more inspiration for "practical and durable" materials.

Spider silk is inspiring strong, durable materials. "The silk that these arthropods use to spin webs is extraordinarily tough," Brody says. "Indeed, the scene from Spider Man 2 in which a New York City subway train is stopped by a spiderweb is not far removed from the realms of reality. Scientists are learning how to fabricate synthetic versions of these fibres." Applications: artificial tendons, fighter pilot helmets, Spiderman-like climbing ropes, and anything that needs to be lightweight but strong.

Silkworm silk, though not as tough as spider silk, is simpler and easier to work with. Applications: medical devices and biodegradable sutures; drug-releasing implants, artificial corneas, "silk orthopaedic hardware strong enough to screw into bone and then degrade over time, and squishy scaffolds for growing neurons from the brain's cerebral cortex."

Shark skin is made of V-shaped scales called denticles. Aligned with the local water flow, they reduce drag. Application: swimsuits that allow a swimmer to go 7 percent faster.

Pine cones are made of two layers that respond differently to temperature and humidity (like a bimetallic strip in a thermostat). This allows them to drop their seeds after a fire. Applications: smart clothing fabric that responds by "breathing" with the humidity and temperature.

Lotus leaves are super-waterproof due to two layers that trap air. The layer of papillae traps air under a waxy secretion, such that water rolls off, catching dust on the way. Application: waterproof clothing that is stain resistant.

Hydrogels are common in nature. They are "materials comprising networks of polymer chains that can absorb or release water as conditions change." Applications: high-absorbency diapers, medical devices that avoid rejection and help wounds heal.

Gecko toes are covered with microscopic setae that can cling to almost any surface by atomic forces. "Geckos' feet are so sticky that, in theory, they could support the weight of a 130 kg person hanging from the ceiling." Application: Hand pads that allow a man to walk up glass.

Ivy stems produce "one of nature's strongest adhesives," combining strength with elasticity. Applications: surgical glue, new type of sunscreen, tissue that regenerates. "And the veins onnasturtium leaves have led to the development of a synthetic surface that could prevent rain from freezing on aeroplane wings or keep grimy fingerprints off smartphone screens."

Green tea, cacao and red wine contain polyphenols that resist oxidants and bacteria. Applications: coatings for medical instruments or food-preparation surfaces.

Morpho butterfly wings shine bright blue not from pigment, but from "structural color" made by nanoscopic patterns that intensify reflected light at certain wavelengths. Application: unfading fabric colors.

Squid, cuttlefish, and octopuses rapidly change skin color. Application: the US military is looking into this for more effective camouflage techniques.

Mussel shells create adhesives from protein that fasten underwater and cling tightly in the waves. Similar waterproof adhesives have been found in starfish and barnacles. Applications: marine adhesives, spacecraft glues, filters for wastewater treatment and desalination plants, and new ways to target cancer cells.

Sea cucumber skin is soft and pliable but can stiffen in less than a second when a predator is near. The reaction is reversible. Applications: better microelectrodes for brain implants.

Capadona explains that fine control over the changes in stiffness and degree of swelling is crucial, rather than just a simple issue of changing between soft and stiff states. "This is why we looked to nature for a unique design to inspire ours," he says.

Pitcher plant interior walls are extremely slippery. Application: SLIPS technologies, imitating the pitcher plant's properties, has made stain-resistant lab coats.

Nacre, or mother-of-pearl found in oysters, is "extraordinarily fracture-resistant." So is the dentinin teeth. Application: shatterproof glass.

Armadillo skin's armored plates are "models of materials that are flexible, puncture-proof, and water-resistant." Graphene is an up-and-coming super-material that can substitute for some proteins, but "The difficult part is to first understand nature."

Fish scales offer "tough armour for the animal even as it is flexing, flipping and squirming." Application: protective clothing, body armor for vulnerable joints.

Bone is made up of two weak materials: hydroxyapatite, a chalky substance, and collagen, "very similar to gelatin." Yet "from these weak raw materials, nature produces a strong, flexible, self-healing structure." Applications: bone and joint replacements.

Living cells guide the growth of a complex, rigid frame that houses blood vessels and supports the entire body. Trying to better understand this complex structureand how it works has kept teams of scientists busy for many years.

What Has Evolution Done for You Lately?

Design inspiration comes from all over the animal and plant kingdoms. The focus here is on design-- a word used more often in the articles than evolution. Perhaps the most instructive reference to evolution is in Katherine Bourzac's article, "Spiders: Web of Intrigue." Following six useless references to evolution, we learn that "bioinformatics" is where the action is:

Tara Sutherland, a bioengineer at the Commonwealth Scientific and Industrial Research Organization in Canberra, Australia, is looking to silks that are less well known than those from spiders and silkworms. Sutherland's analysis has uncovered 23 groups of independently evolved types of silk in 100,000 different insect species. [Note the lateral pass to "convergent evolution."] In common with Kaplan, Sutherland has medical applications in mind. She zeroed in on one insect from thousands of options: the honeybee. Honeybees use silk to provide thermal insulation and structural support for their hives.

Sutherland approached the problem of picking the right silk from a bioinformatics point of view, not an evolutionary one. She wanted to make the most of what biopolymers offer. Unlike plastics and other materials, proteins can sense and respond to the environment. Sutherland wants to make tissue-engineering scaffolds that release cell-attracting signals on cue, or silk bandages that release antibiotics when they sense an infection. She has funding from the clothing firm Nike and NASA, among others....

For Sutherland and others, the fibres produced by silk makers in the wild areendlessly fascinating and full of design ideas. "Silk is the best stuff on Earth," says Kaplan. "There's nothing like it."

A narrative gloss to fit the Darwinian worldview inspires no one. "Design ideas": that's what the world needs. What has intelligent design done for you lately? The list above is just a taste of the useful knowledge a focus on design provides.