High Resolution Scanning Electron Microscope Examination of the Fish Scale: Inspiration for Novel Biomaterials

Abstract

A Scanning Electron Microscopic study on the fish scale of Cyprinus carpio communis (freshwater carp), depicts remarkable structural and compositional characteristics which may be used as inspiration for novel biomaterial design. The fracture surface structure and sintered fish scale reveals an osseous layer on its dorsal side. It has a compact heterogeneous crystalloid-like structure of assorted shapes and sizes. The ventral side is made of orthogonally arranged mineralized needle like crystalloids template embedded in a fibrillary plate. Frozen scales revealed that this dorsal layer may contain high atomic number elements as it appeared bright with back scattered electron signals. The ventral side consists of collagen plates and a matrix, which are arranged orthogonally in a double-twisted, plywood-like structure. There are alternate crystalloid and matrix which are arranged orthogonally and forming 15-17 layers in between these two sides. This provides useful information of scale composition. Design features from the structure of the fish scale may be useful in the development of functional biomaterials, in various different fields including nano-composites, biopolymers and natural source of hydroxyapatite, used in applied therapeutic, pharmaceutical industries and semiconductor technology. The tolerance of the fish scale to high temperature and very low temperature cooling revealed unique characteristics for biomaterial fabrication. The orthogonally arranged ventral side plates of collagen embedded in proteoglycans may also prove to be a good source of scaffold material for cell culturing for tissue engineering.