March 28, 2018 | David F. Coppedge

Earwig Origami and Maple Seed Rockets

Engineering solutions from unlikely organisms inspire applications for wide-ranging human needs.

Earwig Origami

Those disgusting bugs with rear-end pincers we usually find among the vermin skittering away under rotting logs. Who could love an earwig? There are some 2,000 species of the bugs in the order Dermaptera (skin wing). Despite appearances, earwigs are generally not harmful to humans. The idea they can climb into your ear canals at night and lay their eggs in your brain is an old wive’s tale, Wikipedia says. Still, most people would rather keep them outside the house and spray them dead when found inside. Thank God some scientists are courageous enough to look a little deeper at them. Three scientists found a wonderful thing. Reporting in Science, they noticed that the hindwings, folded under the forewings, reveal a new kind of origami that breaks the rules.

Origami involves folding two-dimensional sheets into complex three-dimensional objects. However, some shapes cannot be created using standard folds. Faber et al. studied the wing of an earwig, which can fold in ways not possible using origami and can alter its shape for flight. The authors replicated this ability by using a membrane that allows for deformations and variable stiffness. Prestretching generated energetically bistable origami patterns that exhibited passive self-folding behavior.

The researchers got excited about this anomalous folding pattern, because they see engineering gold in applications.

In contrast to well-known paper-folded objects, the wing of the earwig has an exquisite natural folding system that cannot be sufficiently described by current origami models. Such an unusual biological system displays incompatible folding patterns, remains open by a bistable locking mechanism during flight, and self-folds rapidly without muscular actuation. We show that these notable functionalities arise from the protein-rich joints of the earwig wing, which work as extensional and rotational springs between facets.Inspired by this biological wing, we establish a spring origami model that broadens the folding design space of traditional origami and allows for the fabrication of precisely tunable, four-dimensional–printed objects with programmable bioinspired morphing functionalities.

What’s required to make this self-actuated rapid morphing possible? “Programmable matter that can self-shape, morph, and actuate through ‘instructions’ embedded into its own material architecture is widespread in nature and has opened exciting possibilities in robotics, biomedical technologies, arts, and design,” they say. Where do the ‘instructions’ come from? In all cases humans have observed come into being, instructions that create functional materials come from design. These authors only mention evolution once, saying without explanation, “the wing has evolved to fully and rapidly self-fold from the open toward the closed state.”

As we have noted before, “evolved to” is an illogical phrase, because Darwinian evolution is blind and aimless by definition. It had no goal to achieve this elegant system in the earwig. “Spring origami” involves not only precise angles and locations of creases, but materials including proteins like resilin with stretchy and springy properties just right for folding and unfolding. Brain software, in addition, must exist to operate the wings. Chance could never achieve such complexity in billions of years. “Programmable matter” requires a programmer. The authors almost say this. Responding to engineering attempts at origami, they say, “Despite these efforts, synthetic origami structures developed so far are still far from reaching the range of functionalities and design freedom observed in nature.” The paper uses the word design 30 times, and evolution just once, indicating where the excitement lies. Recognizing the “design principles of the earwig wing,” they attempt to imitate it, and the applications are promising: biomedical devices, collapsible portable displays, soft robots, or deployable spacecraft modules.

Maple Seed Rockets

Every child knows the fun of throwing handfuls of maple seeds into the air and watching them descend softly like little helicopters. Some kids grow up to be scientists and, remembering that childhood experience, take a deeper look at those drifting seeds, called samaras by biologists. Often, the design principle of nature leads to visions of applications. How about rocket science?

In Phys.org, we find that rocket scientists from the Vienna University of Technology want to launch instruments from rockets or balloons that can drift down slowly, collecting atmospheric data. The “wings” on these instruments act like maple seeds, slowing down the descent to give the instruments more time to collect data while avoiding impact damage.

The basic idea for the innovative measurement device is reminiscent of maple seeds, which fall to the ground very slowly and gently due to their long wings. The tubular probes from Project Daedalus are also provided with wings. A specially developed ejection mechanism is intended to launch three of these probes from the rocket at an altitude of 80 km, at which point their wings fold out and ensure that the devices return to Earth as slowly and as unscathed as possible. GPS modules are then intended to report the landing location, so that the devices can be retrieved as easily as possible.

The project has pulled in interdisciplinary scientists, showing that the humble maple seed has proved to be a motivator for good science.

Biomimetic Skin

What’s new at Harvard’s Wyss Institute for Biologically Inspired Engineering? A research team is “Drawing inspiration from plants and animals to restore tissue,” Phys.org reports. Fetal tissue contains a protein called fibronectin that helps the growing baby grow wound-free skin. By spinning this substance into a cotton-candy-like dressing, researchers at Wyss believe they have found a way to speed the healing of war wounds on the battlefield. Their technique might some day help balding men regrow hair follicles, too.

In in vivo testing, the researchers found that wounds treated with the fibronectin dressing showed 84 percent tissue restoration within 20 days, compared to 55.6 percent restoration in wounds treated with a standard dressing.

The researchers also demonstrated that wounds treated with the fibronectin dressing have close to normal epidermal thickness and dermal architecture, and even regrew hair follicles—often considered one of the biggest challenges in the field of wound healing.

Amazing FactsAnother method, using soy-based fibers, will be inexpensive, they believe. Both dressing types hold promise for wounded warriors and burn victims, thanks to inspiration from plants and animals. Another paper in Nature Communications reports on “A supramolecular biomimetic skin combining a wide spectrum of mechanical properties and multiple sensory capabilities.” Notice how they point to which designer is smart:

Biomimetic skin-like materials, capable of adapting shapes to variable environments and sensing external stimuli, are of great significance in a wide range of applications, including artificial intelligence, soft robotics, and smart wearable devices. However, such highly sophisticated intelligence has been mainly found in natural creatures while rarely realized in artificial materials.

Using hydrogels, the team of Wu and Pei has fabricated artificial skin with some of the properties of real skin, hoping to use “biomimetic skins with sophisticated intelligence similar to natural skins” on soft robots, prosthetic hands and fingers, and for other applications.

God has hidden his intelligence in his creation. Like in an Easter egg hunt, biomimetics science searches out these signs of intelligence in order to consume its bounty, then use the inspiration to create additional signs of intelligence with human engineering. They must never forget where the intelligence came from.

 

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