Microstructural Analysis of in vitro Nacre Formation on Shell Bead and Titanium by Cultured Mantle Tissue of Pearl Oyster, Pinctada fucata

Abstract

Nacre, the inner iridescent layer of molluscan shells is an organic-inorganic composite material. The layered arrangement of platelet-shaped CaCO3 crystals and organic matrix in a brick-and-mortar structure makes it a strong, resilient, and iridescent material. In-vitro nacre formation on shell bead by the mantle tissue of the pearl oyster, Pinctada fucata has already been reported. The current study details a microstructural investigation and comparison of in vitro nacre deposition by the mantle tissue of pearl oyster, P. fucata on shell bead and titanium plates. Nacre platelets were observed by Scanning Electron Microscopy (SEM) and its CaCO3 composition was determined by Energy Dispersive X-Ray Spectroscopy (EDS) analysis on both shell bead and titanium plate. Nacre deposits displayed the typical lamellar brick and mortar” arrangement composed of aragonite platelets which form the “bricks” and organic matrix that forms the “mortar”. Details of the microstructure of in vitro nacre formed by the mantle tissue of pearl oyster were elucidated for the first time by Atomic Force Microscopy (AFM). Further, the deposition of nacre on titanium proves its potential application as a suitable biomaterial in dental and bone implants, due to its biocompatibility towards regeneration.