Evidence for helical microstructure of aragonite fibers in pteropod shells
Abstract: Planktonic gastropods of the suborder Euthecosomata (order Pteropoda) secrete a unique microstructure made of tightly interlocked, space-filling helically coiled aragonite fibers. This material has a high degree of ordering because all fibers are in phase at a given growth plane. The recog...
| Autores: | , , , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2023 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/343590 |
| Acceso en línea: | http://hdl.handle.net/10261/343590 |
| Access Level: | acceso abierto |
| Palabra clave: | 3D modeling Biomimetic processes Carbonate minerals Functional materials Microstructure Molluscs Scanning electron microscopy All fiber Aragonite Aragonite fiber Degree of ordering Helical fiber In-phase Pteropod Scanning electron micrographs Space filling Theoretical modeling Fibers |
| Sumario: | Abstract: Planktonic gastropods of the suborder Euthecosomata (order Pteropoda) secrete a unique microstructure made of tightly interlocked, space-filling helically coiled aragonite fibers. This material has a high degree of ordering because all fibers are in phase at a given growth plane. The recognition of the helical nature from mere scanning electron micrographs is somewhat uncertain. In addition, three-dimensional (3D) reconstructions of individual helices are hindered by the small dimensions of fibers, and the virtual absence of intervening organic interphases. Here, we (1) reexamine the morphological characteristics of the fibers in fracture and find them compatible with a helical model, (2) provide direct evidence of the helical mode of coiling in the form of anaglyphs, and (3) develop a 3D model, which is fully consistent with the patterns observed in fractures and polished sections. Proposals based on motifs different from helices are not congruent with the observations. Graphical abstract: [Figure not available: see fulltext.] Impact statement: Some planktonic gastropods of the order Pteropoda secrete a unique microstructure that was originally described as made of tightly interlocked helically coiled continuous aragonite fibers. Despite this material having been described 50 years ago, there is still debate as to the helical design of such fibers. We provide additional unambiguous evidence that fibers describe true helical trajectories during growth. Establishing their true nature is essential in order to know the spectrum of calcified biomaterials produced by molluscs. This is also a prerequisite for future biomimetic studies aiming at producing bioinspired highly functional materials. |
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