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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MICRO
STINGS
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.
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