Posted 15 August 2011, by Staff, MedStar Institute for Innovation, mi2.org
Sometimes, in order to find the best solutions, we need to look no further than nature itself. Researchers from a variety of disciplines have tapped into this idea and are busy at work studying sharks.
Mimicking sharks seems only natural when you consider the marvel of their design. With a hydrodynamic shape, water moves smoothly over the surface of the shark’s skin, despite the fact that the skin is anything but smooth. Dermal denticles cover the skin in series of ribbed individual scales with longitudinal grooves. Bearing these “little skin teeth,” sharks are able to move quickly and seamlessly through the water. While some might think the roughness of their skin would cause them to slow down a bit, the exact opposite is true.
When a smooth-surfaced object passes through water, water coming at the object is moving slower than that which is flowing away from it. Turbulence results as the waters merge, thus slowing down the object. However, because sharkskin is not smooth, the scales channel the flow of water, speeding up the slower water and attracting the faster water toward the shark. The result is less of a speed discrepancy and less turbulence. The shark is able to glide effortlessly through the water with greater speed which would only be impeded by smooth skin.
How can this knowledge aid in manmade inventions? Who would benefit from this design?
The Speedo company for one. Incorporating this unique design into their swimwear prior to the 2000 Olympic games, the goal of faster swimmers was realized when eighty percent of the metals won in the swimming competitions were awarded to those wearing Speedo’s Fastskin suits. Plus, of the fifteen swimming world records, thirteen of them were broken by swimmers donning the “shark skin” suits.
Boat manufacturers have long been studying sharkskin as well, hoping to come up with surfaces that will glide more efficiently through bodies of water. The advantage to boat surfaces modeled after sharkskin evolves from the shark’s incredible ability to stay free of the usual speed hindrances existing in the ocean. Barnacle larvae, bacteria, algae and other ectoparasites cling to most everything passing through the water. ..except sharks. The design of the skin reduces the friction needed for most of these parasites to adhere to it. An additional benefit is the apparent “self-cleaning” properties of the skin, which constantly purges itself of the seemingly tenacious parasites that do manage to grab on. When mimicking this in the exterior design of boats, not only do the boats operate more efficiently due to the reduction (of close to 30%) of organisms sticking to the hull, it also results in far less toxins being used to clean the exterior surfaces of the vessel. Invasive marine species are less apt to be transported from one location to another as well.
And it’s not just the skin boat designers are studying. BioPower Systems is one company trying to incorporate a shark’s tail-like design into their boats, looking to convert wave energy into electrical energy. While the common blade-style generators are apt to injure marine life, the newer design does not.
The most promising and exciting possibilities when it comes to mimicking sharks, however, may be in the pursuit of health innovations. With hospital-acquired infections being a major concern, the development of antimicrobial surfaces of medical devices modeled after shark skin could be an answer to solving this growing problem. Cancer research is also being done to determine if these amazing creatures hold the key to immunity.
Nature has already solved some tough problems… perhaps all we have to do is look.