The mechanical consequences of the interplay of mineral distribution and organic matrix orientation in the claws of the sea slater Ligia pallasii

Vittori, Miloš (author), Šrot, Vesna (author), Korat, Lidija (author), Rejec, Matjaž (author), Sedmak, Pavel (author), Bussmann, Birgit (author), Predel, Felicitas (author), Aken, Peter A. van (author), Štrus, Jasna (author)

Exposed regions of the arthropod exoskeleton have specialized structure and mineral composition. Their study can provide insights into the evolutionary optimization of the cuticle as a material. We determined the structural and compositional features of claws in the crustacean Ligia pallasii using X-ray micro-computed tomography, scanning electron microscopy (SEM), and analytical scanning transmission electron microscopy (STEM). In addition, we used nanoindentation to determine how these features fine-tune the mechanical properties of the claw cuticle. We found that the inner layer of the claw cuticle—the endocuticle—contains amorphous calcium phosphate, while the outer layer—the exocuticle—is not mineralized and contains elevated amounts of bromine. While the chitin–protein fibers in crustacean exoskeletons generally shift their orientation, they are aligned axially in the claws of L. pallasii. As a consequence, the claw cuticle has larger elastic modulus and hardness in the axial direction. We show that amorphous calcium phosphate mineralization and the brominated cuticle are widespread in isopod crustaceans inhabiting terrestrial habitats. We discuss how the features of the claw cuticle may aid in minimizing the likelihood of fracture. Ultimately, our study points out the features that increase the durability of thin skeletal elements.

• Language: English
• Keywords: cuticle, biomaterial, biomineralization, arthropod, chitin, halogen, exoskeleton, calcium phosphate
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: BF - Biotechnical Faculty
• Publication status: Published
• Publication version: Version of Record
• Year: 2021
• Number of pages: 15 str.
• Numbering: Vol. 11, iss. 12, art. 1373
• PID: 20.500.12556/RUL-136690
• UDC: 595.2/.7
• ISSN on article: 2075-163X
• DOI: 10.3390/min11121373
• COBISS.SI-ID: 89748995
• Publication date in RUL: 16.05.2022

Record is a part of a journal

• Title: Minerals
• Shortened title: Minerals
• Publisher: MDPI AG
• ISSN: 2075-163X
• COBISS.SI-ID: 519985177

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.
• Licensing start date: 06.12.2021

Secondary language

• Language: Slovenian
• Keywords: kutikula, biomateriali, biomineralizacija, členonožci, hitin, eksoskelet, kalcijev fosfat