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Chemo-mechanical-microstructural coupling in the tarsus exoskeleton of the scorpion Scorpio palmatus

Zhang, Haolu and Kellersztein, Israel and Freychet, Guillaume and Zhernenkov, Mikhail and Wagner, H. Daniel and Greer, Julia R. (2023) Chemo-mechanical-microstructural coupling in the tarsus exoskeleton of the scorpion Scorpio palmatus. Acta Biomaterialia, 160 . pp. 176-186. ISSN 1742-7061. doi:10.1016/j.actbio.2023.01.038.

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The multiscale structure of biomaterials enables their exceptional mechanical robustness, yet the impact of each constituent at their relevant length scale remains elusive. We used SAXD analysis to expose the intact chitin-fiber architecture within the exoskeleton on a scorpion's claw, revealing varying orientations, including Bouligand and unidirectional regions different from other arthropod species. We uncovered the contribution of individual components’ constituent behavior to its mechanical properties from the micro- to the nanoscale. At the microscale, in-situ micromechanical experiments were used to determine site-specific stiffness, strength, and failure of the biocomposite due to fiber orientation, while metal-crosslinking of proteins is characterized via fluorescence maps. At the constituent level, combined with FEA simulations, we uncovered the behavior of fiber-matrix deformation with fiber diameter <53.7 nm and protein modulus in the range 1.4-11 MPa. The unveiled microstructure-mechanics relationship sheds light on the evolved structural functionalities and constituents' interactions within the scorpion cuticle.

Item Type:Article
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URLURL TypeDescription
Zhang, Haolu0000-0002-2871-5169
Kellersztein, Israel0000-0002-8838-818X
Freychet, Guillaume0000-0001-8406-798X
Zhernenkov, Mikhail0000-0003-3604-0672
Greer, Julia R.0000-0002-9675-1508
Additional Information:© 2023 Acta Materialia Inc. Published by Elsevier. We would like to acknowledge Dr. Nili Dezorella for assisting in sample preparation. This research used the SMI beamline (12-ID) of the National Synchrotron Light Source II, a U.S. Department of energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under contract No. DE-SC0012704. JRG gratefully acknowledges the financial support of DOE BES through award DE-SC0016945. HDW, the recipient of the Livio Norzi Professorial Chair in Materials Science, thankfully acknowledges partial support from the GMJ Schmidt Minerva Centre of Supramolecular Architectures at the Weizmann Institute. This research was also made possible in part by the generosity of the Harold Perlman family. Ethics statement. Experiments on scorpions were conducted in Israel and the United States. The Israeli law “Animal suffering (experiments on animals), 1994”, and the American law “United States Animal Welfare Act and Animal Welfare Regulations” exclude invertebrate animals (including scorpions), and therefore no formal ethical approval was required to conduct the experiments. Nevertheless, the use of animals in this research was ethical and humane while using the minimum number of animals without compromising the scientific integrity of the research. Data and materials availability. All data is available in the main text or the supplementary materials. Authors declare no competing interests.
Funding AgencyGrant Number
Department of Energy (DOE)DE-SC0012704
Department of Energy (DOE)DE-SC0016945
Weizmann Institute of ScienceUNSPECIFIED
Record Number:CaltechAUTHORS:20230207-904098000.2
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:119074
Deposited By: George Porter
Deposited On:09 Feb 2023 00:20
Last Modified:27 Apr 2023 17:26

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