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5.2.2 Selfcleaning of Fish Scales and Biomimetic Applications
The ribbed texture of the scales of a shark provided the inspiration for the design of
multifunctional coatings with not only drag-reducing, but also self-cleaning
functions. Self-cleaning surfaces are of scientifi c interest especially for antifouling
coatings (see for review Liu and Jiang 2012 ). Numerous marine invertebrates are
responsible for biofouling on underwater surfaces of both commercial and naval
vessels. Correspondingly, modern surface-active and non-toxic antifouling technologies using biomimetic approaches are in trend today (Salta et al. 2010 ; Callow
and Callow 2011 ; Banerjee et al. 2011 ). Surface roughness can affect the hydrodynamic performance of antifouling coatings and infl uence the settlement behaviour
of fouling larvae, which makes it an important parameter in the evaluation of novel
coatings. Surface roughness is a parameter that originates from marine engineering,
but has been used extensively by marine scientists to characterise novel coatings
and to investigate microtopographies that might inhibit settlement behaviour
(Howell and Behrends 2006 ).
Recently, mimicking the surface structures of shark skin, hierarchical engineered
anti-fouling microtopographies on the polymer basis surfaces were patented
(Brennan et al. 2006 ) and fabricated (Genzer and Marmur 2008 ). For example, a
polydimethyl siloxane elastomer (PDMSe) material termed as Sharklet AF™ was
inspired by surface microtopography based on the skin of sharks. As reported by
Chung et al. ( 2007 ):
“The Sharklet AF™ PDMSe was tested against smooth PDMSe for biofi lm formation of Staphylococcus aureus over the course of 21 days. The smooth surface
exhibited early-stage biofi lm colonies at 7 days and mature biofi lms at 14 days,
while the topographical surface did not show evidence of early biofi lm colonization
until day 21. At 14 days, the mean value of percent area coverage of S. aureus on the
smooth surface was 54 % compared to 7 % for the Sharklet AF™ surface (p < 0.01).
These results suggest that surface modifi cation of indwelling medical devices and
exposed sterile surfaces with the Sharklet AF™ engineered topography may be an
effective solution in disrupting biofi lm formation of S. aureus ,” (Chung et al. 2007 ).
Sharklet Technologies are patented and include antifouling surfaces against the
settlement of zoospores of the ship fouling alga Ulva (Schumacher et al. 2007 ) as
well as several medical tools and devices including a Sharklet Urinary Catheter to
help reduce hospital-acquired infections (see for review http://www.sharklet.com/
technology/ ).
The fabrication of the bionic shark-skin coatings with life-sized scale-like microstructure is the trend today. The shark skin structure has inspired the Speedo
company to develop technology called FAST SKIN®. This technology is used in
the manufacturing of swimwear in order to minimise the water resistance ( http://
www.speedo.de/de/swimwear_products/performance/fastskinfsii/index.html ).
According to the website of Sym Tech Company (USA), “Sharkskin Surface
Protection is the next generation protection coating for automotive surfaces. Once
applied, Sharkskin’s nano-sized silicon dioxide molecules re-assemble themselves
5.2 Fish Swimming and the Surface Shape of Fish Scale
5.2.2 Selfcleaning of Fish Scales and Biomimetic Applications
The ribbed texture of the scales of a shark provided the inspiration for the design of
multifunctional coatings with not only drag-reducing, but also self-cleaning
functions. Self-cleaning surfaces are of scientifi c interest especially for antifouling
coatings (see for review Liu and Jiang 2012 ). Numerous marine invertebrates are
responsible for biofouling on underwater surfaces of both commercial and naval
vessels. Correspondingly, modern surface-active and non-toxic antifouling technologies using biomimetic approaches are in trend today (Salta et al. 2010 ; Callow
and Callow 2011 ; Banerjee et al. 2011 ). Surface roughness can affect the hydrodynamic performance of antifouling coatings and infl uence the settlement behaviour
of fouling larvae, which makes it an important parameter in the evaluation of novel
coatings. Surface roughness is a parameter that originates from marine engineering,
but has been used extensively by marine scientists to characterise novel coatings
and to investigate microtopographies that might inhibit settlement behaviour
(Howell and Behrends 2006 ).
Recently, mimicking the surface structures of shark skin, hierarchical engineered
anti-fouling microtopographies on the polymer basis surfaces were patented
(Brennan et al. 2006 ) and fabricated (Genzer and Marmur 2008 ). For example, a
polydimethyl siloxane elastomer (PDMSe) material termed as Sharklet AF™ was
inspired by surface microtopography based on the skin of sharks. As reported by
Chung et al. ( 2007 ):
“The Sharklet AF™ PDMSe was tested against smooth PDMSe for biofi lm formation of Staphylococcus aureus over the course of 21 days. The smooth surface
exhibited early-stage biofi lm colonies at 7 days and mature biofi lms at 14 days,
while the topographical surface did not show evidence of early biofi lm colonization
until day 21. At 14 days, the mean value of percent area coverage of S. aureus on the
smooth surface was 54 % compared to 7 % for the Sharklet AF™ surface (p < 0.01).
These results suggest that surface modifi cation of indwelling medical devices and
exposed sterile surfaces with the Sharklet AF™ engineered topography may be an
effective solution in disrupting biofi lm formation of S. aureus ,” (Chung et al. 2007 ).
Sharklet Technologies are patented and include antifouling surfaces against the
settlement of zoospores of the ship fouling alga Ulva (Schumacher et al. 2007 ) as
well as several medical tools and devices including a Sharklet Urinary Catheter to
help reduce hospital-acquired infections (see for review http://www.sharklet.com/
technology/ ).
The fabrication of the bionic shark-skin coatings with life-sized scale-like microstructure is the trend today. The shark skin structure has inspired the Speedo
company to develop technology called FAST SKIN®. This technology is used in
the manufacturing of swimwear in order to minimise the water resistance ( http://
www.speedo.de/de/swimwear_products/performance/fastskinfsii/index.html ).
According to the website of Sym Tech Company (USA), “Sharkskin Surface
Protection is the next generation protection coating for automotive surfaces. Once
applied, Sharkskin’s nano-sized silicon dioxide molecules re-assemble themselves
5.2 Fish Swimming and the Surface Shape of Fish Scale