Photo from KQED-QUEST short film, "The Great White Shark: Meet the Man in the Grey Suit" [CC BY-NC 2.0)], via Flickr
Author: Annabel Chen
Sharks are known to hunt everything from mollusks to sea lions, but they are now pursuing a shocking new prey: bacteria. Or rather, their skin is. Sharkskin is inspiring a revolution in bacterial control and sanitation that is spearheaded by University of Florida’s Professor of Engineering, Dr. Anthony Brennan. When Dr. Brennan was hired by the US Office of Naval Research to engineer a surface material that would reduce drag on navy ships by preventing algae and barnacles from growing on ship hulls, he turned to nature for inspiration. The process he used was a young but blossoming process of engineering called biomimicry, which imitates naturally occurring biological models to solve human problems.
In regards to sharkskin, Dr. Brennan noted that, despite being slow-moving marine animals and thus not being able to rely on water movement to dislodge hitchhikers, sharks have a remarkable ability to prevent algae colonies from growing on their skin. The secret to their success lays in the tiny, ridged, diamond-shaped denticles (toothlike scales) on their skin. These denticles, each roughly 1/50 the width of a human hair, are perfectly proportioned to be too rough for algae to take root easily, yet smooth enough as to not inhibit the shark’s movement or create drag underwater. The design of sharkskin allows the shark to do everything Dr. Brennan wanted navy ships to do - go faster and avoid algae growth – and was eventually used to coat entire fleets of ships.
As it turns out, algae isn’t the only microorganism that can’t grow on sharkskin. Years later, Dr. Brennan and his team stumbled upon a breakthrough discovery: bacteria didn’t grow in sharkskin-patterned petri dishes. Intrigued, they then designed a variety of materials micro-patterned with the sharkskin denticle design, and found that they reduced growth of bacteria such as MRSA and e. coli by as much as 99%. Sharklet Technologies then patented the design, and now manufactures sharkskin patterned material that is less than 3 millionths of a meter thick. Sharklet products can be used to coat a variety of surfaces in hospitals, childcare centers, public bathrooms, fitness facilities, and any other place that experiences high touch traffic.
In these places, Sharklet helps kill bacteria and prevents them from spreading without the use of antimicrobial chemicals. This is important because biocides create resistant strains of bacteria that are extremely dangerous to humans and nearly impossible to kill. In the future, Sharklet plans on expanding its products to medical instruments such as scalpels and catheters, as well non-medical applications like keyboards and desk surfaces. The remarkable success of Sharklet's material and its vast array of applications, from ships to scalpels, are true testaments to the ingenuity and creativity behind its designers, as well as the ultimate engineer: nature.