ABSTRACT
ABSTRACT Shark-skin surfaces show the non-smoothness characteristics due to the presence of riblet structures. In this work, biomimetic shark-skins were prepared by means of different bio-replicated forming techniques. These techniques include the PDMS elastomeric stamping method (e.g., PES method) and the PDMS embedded-elastomeric stamping method (e.g., PEES method). The study characterized the fabricated biomimetic surfaces through the use of scanning electron microscopy (SEM) as well as 3D microscope. The accuracy of the two replication routes were compared, which included measuring the surface integrity and dimensional parameters ( s, h ) of the riblet-groove structure. The results show that fresh shark-skin without chemical treatments should be used as a replication template whenever possible to attain a satisfactory replication accuracy of the riblet structure. The PES and PEES methods proposed here are effective bio-replicated forming routes in simulating the microstructures of a shark-skin surface. Compared with the PES method, the PEES method has greater precision in simulating the microstructures of a shark-skin surface.
ABSTRACT
The variations observed in the mechanical behaviour of shark skin at different locations and direction of test, bring out the influence of the histological characteristics on the mechanical properties of the skin. These differences in histological characteristics also give an idea about the functional significance of different regions of the skin.
ABSTRACT
Objective To investigate the methods of isolating collagen from different shark skins and to study its biochemical properties.Methods The collagen from the Blue shark scalp was extracted and purified by enzymolysis after treatment with diluted caustic alkali,and the collagen from the Spanish mackerel skins was extracted and purified by phosphate buffer method,respectively.Subsequently,the relative molecular mass,thermal denatured temperature and secondary structure of extracted collagen were determined.Results The extracted collagen with a yield of 2.9%～4.1% showed three clear bands by SDS-PAGE,and the relative molecular mass were 205,134 and 118KDa.The collagen from Blue shark and Spanish mackerel skins maximal thermal denatured temperature was 69,47℃,respectively.The secondary structures of their collagen were primary with ?-sheet and the random structure,without ?-alix.Conclusion The purified collagen was also extracted by the method of enzymolysis after treatment with diluted caustic alkali and the method of phosphate buffer.The relative molecular mass and the composition of Blue shark collagen and Spanish mackerel collagen were limited.However,the different extracted conditions could affect the specifically biochemical properties of thermal denatured temperature and secondary structure of collagen.