Regeneration
Antifreeze
Amphibians (Amphibia) are animals which can live both on land and in water, although some salamanders never metamorphisise and so can live in water for the entirity of their life. They are often seen as the ecological link between the early water-dwelling life forms and land-based life on Earth.
The total number of known amphibian species is approximately 7,000, of which nearly 90% are frogs. The smallest amphibian in the world is a frog from New Guinea with a length of just 7.7 mm (0.30 in) while the largest living amphibian is the 1.8 m (5 ft 11 in) Chinese Giant Salamander.
Amphibians
Some amphibians possess the ability to tolerate freezing: the wood frog, grey tree frog, spring peeper, and chorus frog, along with one species of Siberian salamander.
In the autumn these amphibians store glycogen in their liver, they may have up to 10 times as much as normal by the winter. Once temperatures drop below freezing, and water just inside the skin starts to freeze, they rapidly transform this glycogen into glucose, which serves as antifreeze. Blood glucose can increase up to 200-fold in response to freezing. Besides manufacturing antifreeze, freeze-tolerant frogs are able to evacuate water from major organs, thus reducing the formation of ice in these critical areas. One strange twist in the process is that as water turns to ice, heat is given off, and it is this heat that saves the frogs from cooling too rapidly. They can freeze, but they mustn't freeze too fast!
This biologically responsive antifreeze could be used to reduce pollution and chemical waste, as well as protecting vulnerable structures, such as hot water pipes from the grasp of ice and potential cracks.
It is well known that various amphibians have the ability to regrow lost body parts. They can regenerate tails or limbs lost while escaping from predators. At this time, this ability is seldom seen in mammals or people (although infants sometimes display the ability to regenerate). How to artificially induce this process in mammals and people is at the cutting edge of medical research. A possible breakthrough is no longer in the realm of science fiction but is a genuine possibility.
The obvious advantages to amputees, from wounded soldiers to accident victims, will continue to drive the funding of this research.
Poison dart frogs contain a compound which in very small doses works as an anaesthetic but can be deadly. It works by blocking the transmission of nerve impulses to the muscles. Injection of the arrow poison into the bloodstream causes death by respiratory failure because the chest and abdominal muscles became paralysed. However, these molecules are only effective by injection into the bloodstream and cannot be absorbed from the digestive system, demonstrated by the native Indians who used the poisons on arrows and darts (hence the name) to hunt for food.
The safety of many drugs could be greatly increased by developing them into molecules which cannot be absorbed by the digestive system and so must be administered directly into the bloodstream - many accidental overdoses and the dangers of drugs pose to small children would be reduced.
Biomimicry is not a new idea, and the invention of swimming flippers over 200 years ago certainly shows this. Benjamin Franklin is credited with inventing swim flippers. He was looking at frogs, marvelling at how they swam so well compared to people, and decided that some swim flippers that mimicked the webbed feet of the frog flippers would do the trick! His original swimming flippers were made of wood, as back then, they did not have the plastics and silicone compounds we use in modern swim flippers. But the idea has since been developed and is still developing today.
Selective drug molecules
Flippers
Reusable adhesive tape
Pollutant detection
Tree frogs have solved the problem of developing an anhesive tape which doesn't lose its stickiness when it's peeled off.
Researchers studied the toe pads of tree frogs to figure out what makes them stick to surfaces, and copied the idea.
When conventional sticky tape is pulled off of a surface, cracks spread through the adhesive away from the point where the tape is being detached. This makes it possible to peel the tape, but the cracks remain and are part of the reason it loses its stickiness.
The researchers found that a pattern of tiny channels on the frogs' foot pads increased their adhesion to a surface, while the channels prevented the spread of cracks when the feet are pulled from surfaces.
They then designed elastic layers embedded with channels filled with either air or fluids beneath an adhesive layer. The result: stickiness increased by as much as 30 times, and the material could be peeled off and reused.
Amphibians, in all their life stages, lack a protective outer layer, making some adult amphibians appear almost translucent. Their eggs have no shell and, as larvae and as adults, their skin is thin and moist. This makes amphibians very sensitive to any change in their environmental, be it on land or in water, and means they are often referred to as ecological indicators. If this level of sensitivity could be harnessed it could be used by scientists to indicate even the slightest increase in pollution. This could in fact be beneficial to many amphibians which are currently massively under threat from fungal infection and pollution worldwide.
Dialysis
Sunscreen
The pigment melanin is found in the eggs of many amphibians. This proves very effective at protecting the eggs from sunlight and harmful UV rays, while the jelly around the eggs keeps the eggs warm. A synthetic version of the pigment melanin could prove more effective in the manufacture of sun creams and sun lotions than many of the chemicals currently used.
All amphibians have a partially permeable skin instead of a tough barrier layer of skin. In the case of the Spade-foot toad, which lives in the desert of the US and Mexico, this membrane is vital to its survival. It allows the toad to survive in an area with very little water by burrowing to damper, more humid areas and absorbing the water through its skin - liquid water isn't necessary. However, this process of osmosis - water transfer through a partially permeable membrane - is now also used in dialysis machines for patients with kidney disease to filter and clean their blood.
Shock absorbers
On the steep slopes of California's Sierra Nevada mountain range lives the Mount Lyell salamander. When disturbed, or when it needs to descend, the amphibian curls its head under its back legs, wraps its tail along its body, and tucks its legs in. It not only looks like a black tire, it behaves like one. Rolling over and over, it bowls down any slope with ease, its rubbery body absorbing the impact of bounces. The ability of its skeleton to bend and adapt, and then bounce without breaking has inspired new polymers, and a rethink of the structure shock absorbers.
