Evidence for a liquid-crystal precursor involved in the formation of the crossed-lamellar microstructure of the mollusc shell

Almagro, Io; Cartwright, Julyan H. E.; Checa, António; Macías‐Sánchez, Elena; Sainz‐Díaz, C. Ignacio

doi:10.1016/j.actbio.2020.06.018

Cited by 12 publications

(6 citation statements)

References 20 publications

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“… 39 , 145 Biological systems often use liquid crystals based on chitin as a template. 146 It is hypothesized 39 , 40 , 145 in this case that self-organization of the liquid crystal phase leads to the formation of a helical organic scaffold, which serves as a template for the mineralized structures of the same configuration. This mechanism of scaffold formation may be analogous to the formation of helical structures in Liesegang systems, 147 , 148 which raises the possibility of using the phase-field inventory developed for such systems.…”

Section: Results and Discussionmentioning

confidence: 99%

“…Simultaneous formation of alternating organic and mineral layers in the vicinity of topological defects predicted by our simulations is a working hypothesis. Previous work suggests that the formation of spiraling organic membranes precedes mineral deposition. , Biological systems often use liquid crystals based on chitin as a template . It is hypothesized ,, in this case that self-organization of the liquid crystal phase leads to the formation of a helical organic scaffold, which serves as a template for the mineralized structures of the same configuration.…”

Section: Results and Discussionmentioning

confidence: 99%

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Phase-Field Modeling of Biomineralization in Mollusks and Corals: Microstructure vs Formation Mechanism

Gránásy

Rátkai

Tóth

et al. 2021

JACS Au

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While biological crystallization processes have been studied on the microscale extensively, there is a general lack of models addressing the mesoscale aspects of such phenomena. In this work, we investigate whether the phase-field theory developed in materials’ science for describing complex polycrystalline structures on the mesoscale can be meaningfully adapted to model crystallization in biological systems. We demonstrate the abilities of the phase-field technique by modeling a range of microstructures observed in mollusk shells and coral skeletons, including granular, prismatic, sheet/columnar nacre, and sprinkled spherulitic structures. We also compare two possible micromechanisms of calcification: the classical route, via ion-by-ion addition from a fluid state, and a nonclassical route, crystallization of an amorphous precursor deposited at the solidification front. We show that with an appropriate choice of the model parameters, microstructures similar to those found in biomineralized systems can be obtained along both routes, though the time-scale of the nonclassical route appears to be more realistic. The resemblance of the simulated and natural biominerals suggests that, underneath the immense biological complexity observed in living organisms, the underlying design principles for biological structures may be understood with simple math and simulated by phase-field theory.

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Section: Results and Discussionmentioning

confidence: 99%

Section: Results and Discussionmentioning

confidence: 99%

Phase-Field Modeling of Biomineralization in Mollusks and Corals: Microstructure vs Formation Mechanism

Gránásy

Rátkai

Tóth

et al. 2021

JACS Au

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show abstract

“…One possibility is liquid crystallization. Almagro and co-workers 40 explained the organization of the different order lamellae of the (aragonitic) crossed-lamellar microstructure, resembling the crossed-foliated, by means of liquid crystallization of chitin rods. According to them, each first OL organizes as a nematic liquid crystal domain characterized by organic rods oriented in a unique direction.…”

Section: Discussionmentioning

confidence: 99%

Organization and Formation of the Crossed-Foliated Biomineral Microstructure of Limpet Shells

Berent,

Gajewska,

Checa

2023

ACS Biomater. Sci. Eng.

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To construct their shells, molluscs are able to produce a large array of calcified materials including granular, prismatic, lamellar, fibrous, foliated, and plywood-like microstructures. The latter includes an aragonitic (the crossed-lamellar) and a calcitic (the crossed-foliated) variety, whose modes of formation are particularly enigmatic. We studied the crossed-foliated calcitic layers secreted solely by members of the limpet family Patellidae using scanning and transmission electron microscopy and electron backscatter diffraction. From the exterior to the interior, the material becomes progressively organized into commarginal first-order lamellae, with second and third order lamellae dipping in opposite directions in alternating lamellae. At the same time, the crystallographic texture becomes stronger because each set of the first order lamellae develops a particular orientation for the c -axis, while both sets maintain common orientations for one {104} face (parallel to the growth surface) and one a -axis (perpendicular to the planes of the first order lamellae). Each first order lamella shows a progressive migration of its crystallographic axes with growth in order to adapt to the orientation of the set of first order lamellae to which it belongs. To explain the progressive organization of the material, we hypothesize that a secretional zebra pattern, mirrored by the first order lamellae on the shell growth surface, is developed on the shell-secreting mantle surface. Cells belonging to alternating stripes behave differently to determine the growth orientation of the laths composing the first order lamellae. In this way, we provide an explanation as to how plywood-like materials can be fabricated, which is based mainly on the activity of mantle cells.

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“…The angle between the long axes of the 1D nanostructures of the two kinds of lamellar structures is 120°, which is significantly larger than the angles of cross-lamellar structures of other species such as Tridacna derasa (70−90°), 28 Circe rivularis (90°), Conus litteratus (78−90°), and Donax deltoides (80−90°) reported in the literature. 27,44 And the angle of the secondaryorder structure (lamellar) and the outer surface is about 30 °(Figure 2d). As far as we know, this is the first time to report on the angle of cross-lamellar structure in the Tridacna genus.…”

Section: Microstructures Of Thementioning

confidence: 98%

Investigation on the Microstructures and Mechanical Properties of the Shells of Tridacna crocea

Song

et al. 2022

Crystal Growth & Design

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Researchers have discovered that the aragonite nanofibers are packed as highly ordered cross-lamellar structures in the shells of Giant clam Tridacna gigas and have excellent mechanical properties. However, differences in the microstructures and mechanical properties between different locations of the shells of Giant clams have not been reported. The microstructures of the shells and the relationship of the micro- and nanostructures and the mechanical properties of the different parts of the shells (main part and rib part) of another kind of Giant clam Tridacna crocea have not been reported yet. In this work, the multilevel ordered micro- and nanostructures in the main part and rib part of the shells of T. crocea were investigated in detail. It shows that both the main part and the rib part are composed of cross-lamellar structures, and the third-order structure (building units) are aragonite nanoribbons, which are densely packed as a self-locking mosaic. This is the first time to report that the building units for the aragonite cross-lamellar structures are nanoribbons instead of nanofibers, while the nanoribbons have particular structural features such as self-locking mosaic packing and dense packing phenomenon on the fractured section. Furthermore, we find that the angles between the long axes of the nanoribbons of the two sets of lamellar structures of the main part and the outer layer of the rib part vary from 120 to 100°, a novel structural feature for cross-lamellar structures. In addition, the mechanical properties such as flexural strength, compressive strength, hardness, and elastic modulus for the different cross sections of different parts of T. crocea were found to be different, and their relationship with the microstructures was studied and discussed. The flexural strength values of the horizontal planes of the main part and the outer layer rib part of the shells of T. crocea are 114.3 ± 2.49 and 118.0 ± 3.74 MPa, respectively, much higher than that of the longitudinal cross sections (79.0 ± 4.55 and 58.7 ± 1.25 MPa, respectively). The compressive strength tests show that the transverse cross sections of the main part and outer layer of the rib part have the highest compressive strength values (221.7 ± 4.82 and 153.3 ± 5.91 MPa, respectively), medium values for the longitudinal cross section (189.0 ± 7.87 and 126.3 ± 9.50 MPa, respectively), and the lowest values for the horizontal plane. The average hardness and elastic modulus values of the transverse and longitudinal cross sections of the rib part gradually increase from the outer to the inner layers. In this work, we show that the mechanical properties are strongly related to the different multilevel ordered assembly modes of micro- and nanostructures.

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Evidence for a liquid-crystal precursor involved in the formation of the crossed-lamellar microstructure of the mollusc shell

Cited by 12 publications

References 20 publications

Phase-Field Modeling of Biomineralization in Mollusks and Corals: Microstructure vs Formation Mechanism

Phase-Field Modeling of Biomineralization in Mollusks and Corals: Microstructure vs Formation Mechanism

Organization and Formation of the Crossed-Foliated Biomineral Microstructure of Limpet Shells

Investigation on the Microstructures and Mechanical Properties of the Shells of Tridacna crocea

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