ABALONE SHELL BUFFALO PEOPLE AND ANCIENT TRAILS

Biological materials (biomaterials) have had a marked increase in interest from the material science and engineering community due to unique characteristics and properties that are typically sought after in traditional engineering materials. During the last few decades, research on biomineralized composites such as abalone shell, fish armor, turtle shell, and human bone revealed that those biological systems possess a carefully arranged multilayered composite structure. Unlike metals, ceramics, and traditional composite materials; biomineralized composites often possess enhanced characteristics such as, penetration resistance high toughness, flaw tolerance energy dissipation, damage mitigation, and delamination resistance all while achieving high strength-to-weight ratios. In this research experimentally driven finite element modeling was used to investigate the elastic response for the biocomposite structure. The Atractosteus spatula (Alligator gar) was used as the model structure for determining the elastic properties.

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Genetic Coding in Biomineralization of Microlaminate Composites

MRS Proceedings ◽

10.1557/proc-292-59 ◽

1992 ◽

Vol 292 ◽

Cited By ~ 11

Author(s):

Daniel E. Morse ◽

Marios A. Cariolou ◽

Galen D. Stucky ◽

Charlotite M. Zaremba ◽

Paul K. Hansma

Keyword(s):

Organic Matrix ◽

Nucleation And Growth ◽

Direct Crystallization ◽

Basic Principles ◽

Shell Matrix ◽

Additional Protein ◽

Flexible Deformation ◽

Abalone Shell ◽

Crystalline Domains ◽

Present Understanding

AbstractBiomineralization is precisely controlled by complex templating relationships ultimately encoded in the genes. In the formation of the molluscan shell, polyanionic pleated sheet proteins serve as templates for the nucleation and epitaxial growth of calcium carbonate crystalline domains to yield microlaminate composites of exceptional strength and crystal ordering. The strength and fracture-resistance of these composites far exceed those of the minerals themselves, as a result of both the capacity for flexible deformation of the organic matrix layers and the retardation of crack propagation at each mineral-organic interface. The basic principles controlling low temperature biosynthesis of these materials thus are of both fundamental and applied importance. The abalone shell consists of microlaminates with a remarkable regularity of lamina thickness (ca. 0.5 micron), the formation of which defies present understanding. We have found that shells of abalone larvae formed prior to metamorphosis contain only aragonite, whereas the adult shell made after metamorphosis contains both aragonite and calcite. This transition is accompanied by a switch in genetic expression of the template proteins, suggesting that the premetamorphic protein may serve as a template for aragonite nucleation and growth, while template proteins synthesized after metamorphosis may direct crystallization of calcite. These analyses are based on improvements we recently reported for the detection and purification of proteins from the demineralized shell matrix. Genetic cloning experiments now in progress are aimed at discovering additional protein sequences responsible for the programmed control of crystal phase termination, since it is the termination and reinitiation of mineralization that is responsible for the regularity of highly ordered microlaminates produced in nature.

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Low-loss Electron Energy-loss Spectroscopy and Dielectric Function of Biological and Geological Polymorphs of CaCO3

Microscopy and Microanalysis ◽

10.1017/s1431927699000197 ◽

1999 ◽

Vol 5 (5) ◽

pp. 358-364 ◽

Cited By ~ 13

Author(s):

Kalpana S. Katti ◽

Maoxu Qian ◽

Daniel W. Frech ◽

Mehmet Sarikaya

Keyword(s):

Energy Loss ◽

Electron Energy ◽

Dielectric Function ◽

Electronic Structures ◽

Microstructural Characterization ◽

Low Loss ◽

Composite Microstructure ◽

Abalone Shell ◽

Electron Energy Loss ◽

Electron Excitations

Previous work on microstructural characterization has shown variations in terms of defects and organization of nanostructures in the two polymorphs of calcium carbonate, calcite, and aragonite in mollusc shells. Large variations in mechanical properties are observed between these sections which have been attributed to variations in composite microstructure as well as intrinsic properties of the inorganic phases. Here we present local low-loss electron energy-loss spectroscopic (EELS) study of calcitic and aragonitic regions of abalone shell that were compared to geological (single-crystal) counterpart polymorphs to reveal intrinsic differences that could be related to organismal effects in biomineralization. In both sets of samples, local dielectric function is computed using Kramer-Kronig analysis. The electronic structures of biogenic and geological calcitic materials are not significantly different. On the other hand, electronic structure of biogenic aragonite is remarkably different from that of geological aragonite. This difference is attributed to the increased contribution from single electron excitations in biogenic aragonite as compared to that of geological aragonite. Implications of these changes are discussed in the context of macromolecular involvement in the making of the microstructures and properties in biogenic phases.

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Screw Dislocations and Spriral Growth in Abalone Shell Nacre

Microscopy and Microanalysis ◽

10.1017/s1431927606062210 ◽

2006 ◽

Vol 12 (S02) ◽

pp. 912-913 ◽

Cited By ~ 1

Author(s):

A Epstein ◽

A Akey ◽

N Yao

Keyword(s):

Screw Dislocations ◽

Abalone Shell

Extended abstract of a paper presented at Microscopy and Microanalysis 2006 in Chicago, Illinois, USA, July 30 – August 3, 2006

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