Sharklet: The Antimicrobial Properties of Sharkskin

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Last post we learned that the unique pattern of sharkskin allows the animals to reduce drag and move more efficiently through  the water. But that's not the only advantage to the small scales covering sharks. It turns out that the fish's scales also prevent microorganisms from attaching and growing. 

This was discovered when material scientist and engineering professor at the University of Florida, Dr. Anthony Brennan, was at Pearl Harbor while trying to create new anti-fouling technology for US Navy ships and submarines. He observed an algae covered submarine pull into the harbor and likened it to a whale covered in barnacles. He wondered why sharks, who are also large slow moving animals, are never covered in barnacles or algae?

The reason is due to way algae take root. The algae colonize in small groups in order to establish large colonies or biofilms. The organism follows the path of least resistance and takes root wherever it takes the least amount of energy to do so. The structure and roughness of sharkskin increases the energy needed to attach and thus discourages the microorganisms from growing. An accidental application, the antimicrobial property of sharkskin, was discovered when a student attempted to grow a bacterial culture on a sharkskin patterned petri dish.

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Using architecture of sharkskin, Brennan created a coating known as Sharklet. It mimics the roughness, and thus the antimicrobial properties of sharkskin, by using small bumps arranged in a diamond pattern. Each diamond is approximately 22 microns wide, 16 microns tall, and each riblet about 3 microns in height. This products main use is the creation of antimicrobial surfaces that could be placed in hospitals and medical devices where there is a risk of spreading microbes and infections. The revolutionary new coating reduces that amount of bacteria on a surface by between 90% and 99%, depending on the type of bacteria.

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Since the discovery of bacteria, the conventional approach to fighting it has been antibiotics and other kill strategies. While a good temporary measure, this practice has bred superbugs that are resistant to the disinfectants that we have today. Sharklet is a simple answer to a complex problem. Since it prevents microorganisms from growing using geometry alone, it requires no special disinfectants or treatments. This allows for not only a bacteria free surface, but a chemical free one as well, which would translate to a healthier, more natural environment.