The six panels come from a 21-day study that monitored the growth of Staphylococcus aureus on a smooth surface (left column of Dow Corning Silastic T-2 elastomer) and a Sharklet surface. Top row shows bacterial growth after seven days, the middle row after 14, and bottom row after 21. The bacteria have been highlighted with color.

A surface made of micro-scale features shaped, arranged, and spaced in a particular pattern provides a nontoxic and nonbiocidal way to control microorganism growth on a surface. University of Florida researcher Anthony Brennan invented the surface after studying shark skin. Sharks are generally slow swimmers yet are rarely seen with skin growths, such as barnacles.

The engineered surface, called Sharklet, is the first licensed and patented topography that will be commercialized by Sharklet Technologies LLC, Alachua, Fla. (sharklet.com). The company says other topographies are being evaluated for their bioadhesion and cell growth characteristics. The annual U.S. cost for controlling hospital acquired infections reaches some $4.5 billion and annually affects about 2 million people.

Sharklet Technologies intends to initially target medical environments and devices, items such as catheters and places where controlling bacteria growth is critical in preventing infections.

“The Sharklet surface has proven effective at inhibiting biofilm formation for up to 21 days, an improvement over existing smooth biomaterial surfaces,” says Sharklet VP Mark Spiecker. “One theory for the surface's effectiveness is that it's inhospitable for microorganisms. Tests in sea water showed an 85% reduction in algal-spore settlement and 97% fewer in barnacle larvae settling on it compared to smooth control surfaces.” Spiecker points out that the surface does not kill bacteria, but rather inhibits its growth and ability to form a biofilm.

Brennan has been looking for factors that let microorganisms attach to surfaces, colonize, and complete their productive or destructive cycles. He found that microorganisms settling on a surface respond in a controlled way to chemical and physical surface modifications and hypothesized that these surfaces might be engineered to either encourage or discourage microorganism growth and biofilm formation.

Brennan and team used these concepts to develop an engineered topography, a surface with characteristics that can be tuned for a specific bioresponse between a microorganism and surface. Spiecker says applications could involve any surface that people touch.