Sharkskin Surface Topography Inhibits Bacterial Growth

A new way to control infections on artificial surfaces, based on the physical properties of a shark's skin, is able to inhibit the growth of microorganisms and bacteria, including Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli.

The Sharklet surface technology antibacterial properties do not derive from a chemical characteristic, but rather from the shape and microscopic pattern alone. The surface technology is comprised of billions of tiny, raised, microscopic sections that mimic the height, width, length, and curvature of natural sharkskin surface. Each diamond shaped section measures 25 microns across, or about a fifth of the thickness of a human hair, and contains seven raised ribs of varying length that various microorganisms find inhospitable. The sharkskin patterns are etched using a technique called deep ion lithography, and can be embedded onto the surfaces of medical devices such as catheters or artificial hips, as well as medical care equipment such as hospital beds, and even door knobs, and are capable of controlling bacterial growth for up to 21 days.

The Sharklet pattern has been tested and proven effective against plant, animal, and bacterial organisms, and can it be tuned to evoke a specific bioresponse from organisms. While not discernable to the naked eye or easily felt to the touch, the surface technology has demonstrated in laboratory tests to be inhospitable to bacterial growth and biofilm formation, when compared to smooth surfaces. Sharklet surface technology was developed by Sharklet Technologies (Alachua, FL, USA).

"It's the first nontoxic, long lasting, and no-kill surface to control the growth of harmful microorganisms,” said Mark Spiecker, vice president of operations at Sharklet.

A general rule of the ocean is that slow moving marine animals, like whales, are host to organisms such as barnacles and algae, while fast moving animals are generally clean. Certain species of slow-moving sharks seem to violate this rule, however, staying relatively clean due in part to their unique skin pattern. Sharkskin is made of a matrix of tiny, hard, tooth-like structures called dermal denticles or placoid scales. These structures are shaped like curved, grooved teeth and they make the skin a very tough armor with a texture like sandpaper. They have the same structure as a tooth with an outer layer of enamel, dentine, and a central pulp cavity. These scales also help the shark swim more quickly because their streamlined shapes helps decrease the friction of the water flowing along the shark's body by channeling it through grooves.

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