Biomimetics of fish scales: value and prospects

Abstract

The body of an ideal fish is covered by scales which are either thin or thick. These scales arise as external growths from the epidermis of the skin. Fish scales are known to contain pigmentation that gives colour to the scales for example, the Minytrema melanops is greyish brown in colour because of the grey colour from the scales while its close relative the small mouth buffalo Ictiobus bubalus is Olive-bronze in colour. Fish scales in general contain a variety of pigments that give the fish a variety of colors. Fish scales constitute about 2% of the total body weight, but said to be rich in nutritive components just as the flesh of the fish. The scale of fish is similar to the structure of a typical bone. Fish scales comprise of 40% -55%collagen type 1, hydroxyapatite and calcium carbonate fat, lecithin and scleroprotein. The mechanical testing of fish scales was reported to show that the unique design of the strength of scales is significant for mechanical characteristics. Again, the mechanical strength and toughness displayed by fish scale composition (external ganoine layer and internal layer) with enforced mineral properties enable the protective nature of the scales. Fish skin can be used like any other leather for various wear-resistant items such as shoes bags and purses. With the use of various tanning processes and chemicals, fish skin is successfully used for shoes and clothing.