Sharklet, manufactured by Sharklet Technologies, is a bio-inspired plastic sheet product structured to impede

microorganism A microorganism, or microbe,, ''mikros'', "small") and ''organism'' from the el, ὀργανισμός, ''organismós'', "organism"). It is usually written as a single word but is sometimes hyphenated (''micro-organism''), especially in olde ...

growth, particularly

bacterial growth 250px, Growth is shown as ''L'' = log(numbers) where numbers is the number of colony forming units per ml, versus ''T'' (time.) Bacterial growth is proliferation of bacterium into two daughter cells, in a process called binary fission. Providing ...

. It is marketed for use in hospitals and other places with a relatively high potential for

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of prokaryotic microorganisms. Typically a few micrometr ...

to spread and cause infections. Coating surfaces with Sharklet work due to the nano-scale texture of the product's surface. The inspiration for Sharklet's texture came through analysis of the texture of

shark skin Shagreen is a type of rawhide (textile) , rawhide consisting of rough untanned skin, historically from a horse's or onager's back, or from shark or sting ray, ray. Etymology The word derives from the French language, French ''chagrin'' and is ...

, which does not attract

barnacles A barnacle is a type of arthropod constituting the subclass Cirripedia in the subphylum Crustacea, and is hence related to crabs and lobsters. Barnacles are exclusively marine, and tend to live in shallow and tidal waters, typically in eros ...

or other

biofouling Biofouling or biological fouling is the accumulation of microorganisms, plants, algae, or small animals where it is not wanted on surfaces such as ship and submarine hulls, devices such as water inlets, pipework, grates, ponds, and rivers that ...

, unlike ship hulls and other smooth surfaces. The texture was later found to also repel microbial activity.

History

Sharklet material is bio-inspired and was developed by Dr. Anthony Brennan, materials science and engineering professor at

University of Florida The University of Florida (Florida or UF) is a public land-grant research university in Gainesville, Florida. It is a senior member of the State University System of Florida, traces its origins to 1853, and has operated continuously on its ...

, while trying to improve antifouling technology for ships and submarines at Pearl Harbor. Brennan realized that sharks do not experience fouling. He observed that shark's skin denticles are arranged at the micrometre scale in a distinct

diamond Diamond is a solid form of the element carbon with its atoms arranged in a crystal structure called diamond cubic. Another solid form of carbon known as graphite is the chemically stable form of carbon at room temperature and pressure, ...

repeating micro-pattern with millions of tiny ribs. The width-to-height ratio of shark denticle riblets corresponded to his mathematical model for the texture of a material that would discourage

s from settling. The first test performed showed an 85% reduction in green algae settlement compared to smooth surfaces.

Texture

Sharklet's texture is a combination of “ridge” and “ravine” at a micrometer scale.

Resistance to bacterial attachment

Adherence prevention and translocation restriction have been demonstrated, and are believed to contribute significantly to restrict the risk of device-associated infections. Sharklet's topography creates mechanical stress on settling bacteria, a phenomenon known as

mechanotransduction In cellular biology, mechanotransduction ('' mechano'' + '' transduction'') is any of various mechanisms by which cells convert mechanical stimulus into electrochemical activity. This form of sensory transduction is responsible for a number of ...

. Nanoforce gradients caused by surface variations induces stress gradients within the lateral plane of the surface membrane of a settling microorganism during initial contact. This stress gradient disrupts normal cell functions, forcing the microorganism to provide energy to adjust its contact area on each topographical feature to equalize the stresses. This expenditure of energy is thermodynamically unfavorable for the settler, inducing it to search for a different surface to attach to. Sharklet is made, however, with the same material as other plastics. The physical arrangement enhances the

hydrophobicity In chemistry, hydrophobicity is the physical property of a molecule that is seemingly repelled from a mass of water (known as a hydrophobe). In contrast, hydrophiles are attracted to water. Hydrophobic molecules tend to be nonpolar and, t ...

of the device surface such that the bacteria attachment energy is insufficient for adherence and/or colonization. Environmental surface contamination provides a potential reservoir for pathogens to persist and cause infection in susceptible patients. Microorganisms colonize biomedical implants by developing biofilms, structured communities of microbial cells embedded in an extracellular polymeric matrix that are adherent to the implant and/or the host tissues. Biofilms are an important threat to human health as they may harbor large numbers of pathogenic bacteria. Up to 80% of bacterial infections in humans involve microorganisms from biofilms, and biofilm formation on medical devices can lead to nosocomial infections and potentially higher mortality rate. Indwelling of medical devices is associated with high risk of infection, given the abundance of bacterial flora on human skin and the risk of contamination from other sources, The fact that many of the pathogens responsible for these infections are multi-drug-resistant, or even panresistant, has become particularly problematic, with few treatment options being available to Healthcare workers and the industry are seeking safe and effective means to prevent device-associated infections. Sharklet micro-patterns can be incorporated onto the surfaces of a variety of medical devices during the manufacturing process. This micro-pattern is effective against bio-fouling and microbial attachment and is non-toxic. It therefore has potential to help infection control on medical devices such as per-cutaneous devices. Sharklet micro-patterns have been shown to control the bio-adhesion of a wide range of marine microorganisms, pathogenic bacteria and eukaryotic cells. They reduce '' S. aureus'' and ''

S. epidermidis ''Staphylococcus epidermidis'' is a Gram-positive bacterium, and one of over 40 species belonging to the genus ''Staphylococcus''. It is part of the normal human microbiota, typically the skin microbiota, and less commonly the mucosal microbiot ...

'' colonization after exposure to a simulated vascular environment by 70% or greater when compared to smooth controls. This micro-pattern similarly reduces platelet adhesion and fibrin sheath formation by approximately 80%. An in vitro study demonstrated that it reduced the colonization of ''S. aureus'' and '' P. aeruginosa'' bacterial pathogens effectively. Importantly, this infection control was achieved without the aid of

antimicrobial An antimicrobial is an agent that kills microorganisms or stops their growth. Antimicrobial medicines can be grouped according to the microorganisms they act primarily against. For example, antibiotics are used against bacteria, and antifungals ar ...

agents.

References

External links

Technologies Inspired by Sharks
*{{Cite news, url = https://www.pbs.org/newshour/bb/armor-like-shark-skin-may-offer-blueprint-defense-superbugs/, title = Armor-like shark skin may offer blueprint for defense against superbugs, last = Srinivasan, first = Hari, date = March 26, 2015, work = PBS Newhour, access-date = March 29, 2015 Antimicrobials Products introduced in 2004 Biomimetics

History

Texture

Resistance to bacterial attachment

See also

References

External links