Omega-shaped inchworms // Oxygen-deprived sharks // Dried-up water bears // And other critters that have yielded surprising human medical applications.
I n humankind’s quest to fly, countless inventors copied the experts—birds. And the special stick-to-itiveness of burrs inspired Velcro. Yet despite nature’s long history of inspiring solutions to human problems, we’ve always supposed we could do nature one better. But the advent of nanotechnology and sophisticated computer modeling has enabled scientists to examine exactly how nature works—and to find that, often, our materials and processes don’t measure up to those that have existed for millions of years.
Researchers have studied how an abalone assembles calcium carbonate crystals gathered from seawater and then layers them on a soft polymer of its own making to construct a nontoxic shell more durable than the strongest ceramics—a process that could improve implant materials and prosthetics. And how algae use chemicals called furanones to jam the signaling systems that allow bacteria to communicate, a possible model for antibacterial coatings for medical devices.
Biomimetics, a term coined in the 1950s, involves adapting natural structures and processes for human use, and these days the field is burgeoning. In medicine, scientists across many specialties are studying creatures’ means of locomotion, protection and survival, then devising surprising ways to mimic those ingenious natural accomplishments. The more secrets we decode, the more likely it becomes that the next medical miracle might literally be found under a rock.
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Sea anemones, along with other members of the phylum Cnidaria, which includes corals and jellyfish, have evolved highly efficient means to capture prey and deter predators. Their feeding tentacles have specialized stinging cells called nematocytes that contain microcapsules called nematocysts. When they detect the presence of food or foe, the nematocysts fire harpoonlike hollow threads through which the anemone pumps a cocktail of deadly toxins.
NanoCyte, a biotech startup in Zemach, Israel, is extracting microcapsules from the cells of sea anemones (which are nontoxic to humans) to create a topical-drug delivery device. Each microcapsule is dehydrated into a sterile powder and immersed in a gel, but remains intact. A patient must first apply the gel, then the drug itself in liquid form. The drug rehydrates the microcapsules, then the pressure of osmosis forces the hollow, barbed thread coiled in the microcapsule through the skin. Once the drug has been pumped into the patient, the threads degrade in the skin. And because only minuscule quantities of an active pharmaceutical ingredient penetrate the skin, the risk of side effects is low.
NanoCyte says the technology could be used to treat a range of ailments, including psoriasis, skin cancer and diabetes (by delivering insulin). The company will soon launch creams for treating acne and wrinkles, and a U.S. pharmaceutical company is developing a fast-acting local anesthetic cream.
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SEEING WITH SOUND
At dusk, bats navigate through twilight, zeroing in on prey they can’t see by using pulses of ultrasound (beyond the range of human hearing) that they generate in their larynx and send out through their nose or mouth. The bats’ highly sensitive ears then catch echoes of waves bouncing back from objects in their path, and the bats use the timing and shape of the returning waves to calculate the objects’ positions as well as their shape and texture. This remarkable adaptation, which enables bats to detect objects as fine as a human hair, allows them to thrive at night, when there is less competition for insects and other food.
Modeling an invention on the bats’ echolocation sonar, researchers at the University of Leeds recently introduced a carbon-graphite collapsible walking cane to aid the visually impaired. The UltraCane’s handle emits ultrasonic waves that bounce off objects as far as four meters away and send signals to the user through two vibrating buttons on the handle. The strength of the buttons’ pulses indicates the direction, height and distance of the objects. The same part of the brain that a bat uses to orient its movements—the superior colliculus—helps a human process the buttons’ pulses to build a spatial map in her mind’s eye of how the obstacles are arranged, allowing her to walk more quickly and confidently than she could with an ordinary white cane.