Sharkskin inspired surfaces – In the news

Britney P, Presbyterian Ladies' College

Everyone imagines a hospital as seemingly clean and white on the outside, but teeming with microscopic germs and pathogens on the inside. Although we often conceptualise rigorous sterilising procedures involving chemicals and cleaning agents, microorganisms continue to be scattered about from bed to sink in hospitals. In fact, 1.7 million nosocomial infections occur in U.S. hospitals every year alone. These 99,000 deaths and the loss of $20 billion in healthcare costs are caused by fatal bacterium such as Staphylococcus aureus that preside on shared hospital surfaces.

Devoid of human interference, the natural world is a harmony between bacteria and other mammalian creatures. Examples of these symbiotic relationships are gastrointestinal microbes in cows and algae on whales. In 2002, Dr Anthony Brennan had been investigating how to keep algae from coating the hulls of submarines and ships, on the request of the US Office of Naval Research. Discovering sharks to be the sole “slow moving marine animal that did not foul”, Dr Brennan was inspired to replicate their dermal denticles. In doing so, he managed to create a textured surface with a micropattern approximately 3 microns tall and 2 microns wide. On sharks, these denticles are arranged in a distinct diamond pattern with tiny riblets, that discourage microorganisms from settling on their skin. Likewise, this material repels bacterium without the use of antimicrobials or chemicals.

The bony, microscopic scales in shark skin (left) and a representation of the microscopic diamond-shaped patterns in Sharklet ™ surfaces (https://www.sharklet.com/, right).

Originally, antibiotics and disinfectants were the solutions to pathogen control. However, they soon became the cause of ‘superbugs’ which adapted to resist these killing methods. Sharklet™, founded by Dr Brennan, manufactures products using his bacteria inhibiting material, including Foley urinary catheters, endotracheal tubes, sharkskin wound dressings, central venous catheters and adhesive-backed films. In particular, the pattern has been tested by Sharklet™ laboratories and United States government agency facilities, yielding highly positive results - preventing more than 90% of bacterial attachment. The dentical impressions were tested against many gram negative and positive strains of bacteria including Methicillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and Vancomycin-resistant Enterococcus.

Other than its use to impede bacterial growth in hospitals, sharkskin technology has also been used by Uniroyal for tyre tread patterns to prevent liquid turbulence and expel water from underneath wheels; improving car safety. Sharkskin is also changing the properties of flight, specifically being adopted by Germany’s biggest airline Lufthansa, for two of its Airbus A340/300 jets. The fuselage and wing edges of their aircraft have been coated with these tiny riblets, reducing turbulent vortices and “diminishing surface resistance” when travelling at high speeds. The phenomenon of streamlined sharkskin is now used in an endless range of fields: the military, aerospace, aeronautics, naval construction, wind technology…

Personally, I have no doubt that Sharklet™ will continue to transform the future of materials and surfaces. As an innovation that wards off hospital bugs and yet does not contribute towards the growth of resistant bacterial strains, Sharklet™ is an incredible breakthrough that will counter the thousands of preventable deaths that occur each and every year.

Bibliography

Ask Nature 2016, Sharklet Surface Texture , accessed 30 April 2018, https://asknature.org/idea/sharklet-surface-texture/#.WwjtoFOFPOQ

BioMed Central 2014, Surface micropattern limits bacterial contamination , accessed 29 April 2018, https://aricjournal.biomedcentral.com/articles/10.1186/2047-2994-3-28

Bloomberg 2015, 14 Smart Inventions Inspired by Nature: Biomimicry , accessed 20 April 2018, https://www.bloomberg.com/news/photo-essays/2015-02-23/14-smart-inventions-inspired-by-nature-biomimicry

Live Science 2014, Shark Skin-Like Surfaces May Ward Off Hospital Superbugs , accessed 2 May 2018, https://www.livescience.com/47870-shark-skin-hospital-superbugs.html

Lufthansa Technik n.d., A shark learns to fly , accessed 26 April 2018, https://www.lufthansa-technik.com/famos

Sharklet Technologies n.d., Sharklet , accessed 20 April 2018, https://www.sharklet.com/

UniRoyal n.d., Sharklet Skin Technology , accessed 23 April 2018, https://www.uniroyal-tyres.com/car/why-uniroyal-tyres/shark-skin-technology

The article above is one of the winning entries of GTAC's Biomimicry Blog competition. The competition challenged Victorian students to submit a blog article detailing an example of scientific and mathematical advances that were inspired by nature. Click here for more information.