Nested helicoids in biological microstructures

Helicoidal formations often appear in natural microstructures such as bones and arthropods exoskeletons. Named Bouligands after their discoverer, these structures are angle-ply laminates that assemble from laminae of chitin or collagen fibers embedded in a proteinaceous matrix. High resolution elect...

Full description

Saved in:
Bibliographic Details
Published inNature communications Vol. 11; no. 1; pp. 224 - 12
Main Authors Greenfeld, Israel, Kellersztein, Israel, Wagner, H Daniel
Format Journal Article
LanguageEnglish
Published England Nature Publishing Group 13.01.2020
Nature Publishing Group UK
Nature Portfolio
Subjects
Animal Shells - anatomy & histology
Animal Shells - physiology
Animal Shells - ultrastructure
Animals
Anisotropy
Arthropods
Biological materials
Bones
Chitin
Chitin - ultrastructure
Claws
Collagen
Crack propagation
Elasticity
Exoskeleton
Exoskeletons
Extremities - anatomy & histology
Fracture toughness
Hardness
Image resolution
Laminates
Microscopy, Electron
Models, Biological
Models, Structural
Proteins - ultrastructure
Scorpions - anatomy & histology
Scorpions - ultrastructure
Stiffness
Twisting
Online AccessGet full text

Cover

More Information
Summary:Helicoidal formations often appear in natural microstructures such as bones and arthropods exoskeletons. Named Bouligands after their discoverer, these structures are angle-ply laminates that assemble from laminae of chitin or collagen fibers embedded in a proteinaceous matrix. High resolution electron microscope images of cross-sections through scorpion claws are presented here, uncovering structural features that are different than so-far assumed. These include in-plane twisting of laminae around their corners rather than through their centers, and a second orthogonal rotation angle which gradually tilts the laminae out-of-plane. The resulting Bouligand laminate unit (BLU) is highly warped, such that neighboring BLUs are intricately intertwined, tightly nested and mechanically interlocked. Using classical laminate analysis extended to laminae tilting, it is shown that tilting significantly enhances the laminate flexural stiffness and strength, and may improve toughness by diverting crack propagation. These observations may be extended to diverse biological species and potentially applied to synthetic structures.
Bibliography:ObjectType-Article-1
SourceType-Scholarly Journals-1
ObjectType-Feature-2
content type line 23
ISSN:2041-1723
2041-1723
DOI:10.1038/s41467-019-13978-6