Characteristics of biogenic calcite in the prismatic layer of a pearl oyster, Pinctada fucata

Okumura, Taiga; Suzuki, Michio; Nagasawa, Hiromichi; Kogure, Toshihiro

doi:10.1016/j.micron.2010.05.004

Cited by 51 publications

(50 citation statements)

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“…They are anisotropic in shape, extending differently along diverse crystallographic directions [11]. These findings are in good agreement with the TEM observations [8,13] of intracrystalline submicrometre partitions with different diffraction contrasts, which were limited by discontinuously aligned biomacromolecules. Up to now, no data on the misorientation between adjacent nanodomains have been provided, although values less than 28 can be inferred from fig.…”

Section: Introductionsupporting

confidence: 89%

“…Up to now, no data on the misorientation between adjacent nanodomains have been provided, although values less than 28 can be inferred from fig. 2 in Okumura et al [8].…”

Section: Introductionmentioning

confidence: 96%

“…The domeshaped crystals of aragonite, which initiate the nacre of Pinctada, have been shown by transmission electron microscopy (TEM) to consist of a complex arrangement of crystalline domains with diverse orientations [5]. The columnar calcitic prismatic units forming the outer layer of Pinctada consist of several subunits [6,7] each, with complex boundaries, which were shown by TEM-EBSD to display a considerable degree of mutual misorientation [8]. These same units were shown to display large variations in the orientations of their c-axes [9], hence being different crystallographic domains.…”

Section: Introductionmentioning

confidence: 99%

“…In order to increase the level of completeness and resolution of the crystallography of such material with respect to previous studies [8,9], a complete EBSD study of the calcitic columnar prisms of the outer shell layer of the black-lipped pearl oyster Pinctada margaritifera has been performed. The crystallographic data obtained with EBSD have been checked with TEM and AFM.…”

Section: Introductionmentioning

confidence: 99%

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Crystallographic orientation inhomogeneity and crystal splitting in biogenic calcite

Checa

Bonarski

Willinger

et al. 2013

J. R. Soc. Interface.

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The calcitic prismatic units forming the outer shell of the bivalve Pinctada margaritifera have been analysed using scanning electron microscopyelectron back-scatter diffraction, transmission electron microscopy and atomic force microscopy. In the initial stages of growth, the individual prismatic units are single crystals. Their crystalline orientation is not consistent but rather changes gradually during growth. The gradients in crystallographic orientation occur mainly in a direction parallel to the long axis of the prism, i.e. perpendicular to the shell surface and do not show preferential tilting along any of the calcite lattice axes. At a certain growth stage, gradients begin to spread and diverge, implying that the prismatic units split into several crystalline domains. In this way, a branched crystal, in which the ends of the branches are independent crystalline domains, is formed. At the nanometre scale, the material is composed of slightly misoriented domains, which are separated by planes approximately perpendicular to the c-axis. Orientational gradients and splitting processes are described in biocrystals for the first time and are undoubtedly related to the high content of intracrystalline organic molecules, although the way in which these act to induce the observed crystalline patterns is a matter of future research.

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Section: Introductionsupporting

confidence: 89%

“…Up to now, no data on the misorientation between adjacent nanodomains have been provided, although values less than 28 can be inferred from fig. 2 in Okumura et al [8].…”

Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Crystallographic orientation inhomogeneity and crystal splitting in biogenic calcite

Checa

Bonarski

Willinger

et al. 2013

J. R. Soc. Interface.

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show abstract

“…Electron microscopic observations have shown that the calcite crystals in the prismatic layer are made of a rounded "cortex" less than 200 nm in size surrounded by organic material. There are several degrees of misorientation between subunits of the calcite crystal (Okumura et al 2010). The misorientation is mainly rotated around the c-axis and separates sub-grains of a few hundred nanometers divided by small-angle grain boundaries, which are probably the origin of the gradual change in crystal orientation inside the domains.…”

Section: -1 Microstructurementioning

confidence: 99%

Studies on the Chemical Structures of Organic Matrices and Their Functions in the Biomineralization Processes of Molluscan Shells

Suzuki¹,

Kogure²,

Nagasawa³

2017

AGri-Biosci. Monogr. (AGBM)

Self Cite

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Keywordscalcium carbonate and an organic matrix. In the course of shell formation, the periostracum, which is not mineralized and covers the external surface of the shell, is formed first; subsequently, the prismatic layer is formed on the periostracum. Finally, the nacreous layer is formed on the prismatic layer (Checa 2000). The nacreous layer is made of tablets of aragonite single crystals. The aragonite crystal compartment in the nacreous layer is sandwiched between sheets of organic matrix. In contrast, the prismatic layer is composed of columnar calcite surrounded by the organic matrix. The calcite crystals, surrounded by the organic framework, are oriented on the c-axis perpendicular to the shell surface.The microstructure of the shell of the limpet, Lottia kogamogai, consists of five distinct layers stacked in Studies on the Chemical Structures of Organic Matrices and Their Functions in the Biomineralization Processes of Molluscan Shells AbstractMolluscan shells protect the soft body from predators and the external environment and consist of calcium carbonate in an organic matrix. The interaction between calcium carbonate and the organic matrix forms the microstructure of the molluscan shell. In this review, we discuss several organic molecules that may be important in the formation of the shell microstructure. The iridescent color of pearls is attributed to the characteristic nacreous microstructure of molluscan shells. The Japanese pearl oyster, Pinctada fucata, is used in pearl aquaculture in Japan. The shell of P. fucata consists of two layers, prismatic and nacreous. Prismalin-14 in the prismatic layer interacts with calcium carbonate and binds to chitin. Pif in the nacreous layer interacts with aragonite crystals and plays important roles in forming the organic framework in a compartment-like structure. In contrast, limpets have a crossed lamellar microstructure in their shells. The organic matrices of limpet shells induce the formation of spindle-like aragonite crystals. Recent studies have increased our understanding of the calcification process of molluscan shells, and the findings can be applied to increase yields of high-quality pearls, lowering the cost and energy of pearl aquaculture.

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Biomineralized Materials as Model Systems for Structural Composites: Intracrystalline Structural Features and Their Strengthening and Toughening Mechanisms

Deng

Jia

2022

Advanced Science

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Biomineralized composites, which are usually composed of microscopic mineral building blocks organized in 3D intercrystalline organic matrices, have evolved unique structural designs to fulfill mechanical and other biological functionalities. While it has been well recognized that the intricate architectural designs of biomineralized composites contribute to their remarkable mechanical performance, the structural features within and corresponding mechanical properties of individual mineral building blocks are often less appreciated in the context of bio-inspired structural composites. The mineral building blocks in biomineralized composites exhibit a variety of salient intracrystalline structural features, such as, organic inclusions, inorganic impurities (or trace elements), crystalline features (e.g., amorphous phases, single crystals, splitting crystals, polycrystals, and nanograins), residual stress/strain, and twinning, which significantly modify the mechanical properties of biogenic minerals. In this review, recent progress in elucidating the intracrystalline structural features of three most common biomineral systems (calcite, aragonite, and hydroxyapatite) and their corresponding mechanical significance are discussed. Future research directions and corresponding challenges are proposed and discussed, such as the advanced structural characterizations and formation mechanisms of intracrystalline structures in biominerals, amorphous biominerals, and bio-inspired synthesis.

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Characteristics of biogenic calcite in the prismatic layer of a pearl oyster, Pinctada fucata

Cited by 51 publications

References 36 publications

Crystallographic orientation inhomogeneity and crystal splitting in biogenic calcite

Crystallographic orientation inhomogeneity and crystal splitting in biogenic calcite

Studies on the Chemical Structures of Organic Matrices and Their Functions in the Biomineralization Processes of Molluscan Shells

Biomineralized Materials as Model Systems for Structural Composites: Intracrystalline Structural Features and Their Strengthening and Toughening Mechanisms

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