In vitro growth of flat aragonite crystals between the layers of the insoluble organic matrix of the abalone Haliotis laevigata

Nacre of abalone shells consists of aragonite platelets and organic material, the so-called organic matrix. During the growth process of the shell the aragonite platelets grow into a scaffold formed by the organic matrix. In this work we tried to mimic this growth process by placing a piece of the insoluble organic matrix (which is a part of the organic matrix) of the abalone Haliotis laevigata in a crystallization device which was flowed through by CaCl2 and NaHCO3 solutions. Using this setup amongst others flat aragonite crystals grow on the insoluble organic matrix. When investigating these crystals in a transmission electron microscope it is possible to recognize similarities to the structure of nacre, like the formation of mineral bridges and growth between layers of the insoluble organic matrix. These similarities are presented in this paper.

► Flat aragonite crystals were grown in vitro on the insoluble matrix of H. laevigata.
► (S)TEM and EDX investigations were performed on these crystals.
► Two main similarities to the growth process of nacre occur.
► The flat aragonite crystals have grown between the layers of the insoluble matrix.
► The crystals separated by the insoluble matrix are connected via mineral bridges.