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Püffel F, Meyer L, Imirzian N, Roces F, Johnston R, Labonte D. Developmental biomechanics and age polyethism in leaf-cutter ants. Proc Biol Sci 2023; 290:20230355. [PMID: 37312549 PMCID: PMC10265030 DOI: 10.1098/rspb.2023.0355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 05/05/2023] [Indexed: 06/15/2023] Open
Abstract
Many social insects display age polyethism: young workers stay inside the nest, and only older workers forage. This behavioural transition is accompanied by genetic and physiological changes, but the mechanistic origin of it remains unclear. To investigate if the mechanical demands on the musculoskeletal system effectively prevent young workers from foraging, we studied the biomechanical development of the bite apparatus in Atta vollenweideri leaf-cutter ants. Fully matured foragers generated peak in vivo bite forces of around 100 mN, more than one order of magnitude in excess of those measured for freshly eclosed callows of the same size. This change in bite force was accompanied by a sixfold increase in the volume of the mandible closer muscle, and by a substantial increase of the flexural rigidity of the head capsule, driven by a significant increase in both average thickness and indentation modulus of the head capsule cuticle. Consequently, callows lack the muscle force capacity required for leaf-cutting, and their head capsule is so compliant that large muscle forces would be likely to cause damaging deformations. On the basis of these results, we speculate that continued biomechanical development post eclosion may be a key factor underlying age polyethism, wherever foraging is associated with substantial mechanical demands.
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Affiliation(s)
- Frederik Püffel
- Department of Bioengineering, Imperial College London, London, UK
| | - Lara Meyer
- Faculty of Nature and Engineering, City University of Applied Sciences Bremen, Bremen, Germany
| | - Natalie Imirzian
- Department of Bioengineering, Imperial College London, London, UK
| | - Flavio Roces
- Department of Behavioural Physiology and Sociobiology, University of Würzburg, Würzburg, Germany
| | | | - David Labonte
- Department of Bioengineering, Imperial College London, London, UK
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Chemo-mechanical-microstructural coupling in the tarsus exoskeleton of the scorpion Scorpio palmatus. Acta Biomater 2023; 160:176-186. [PMID: 36706852 DOI: 10.1016/j.actbio.2023.01.038] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 01/07/2023] [Accepted: 01/17/2023] [Indexed: 01/26/2023]
Abstract
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. STATEMENT OF SIGNIFICANCE: The pincer exoskeleton is a fundamental part of the scorpion's body due to its multifunctionality. Precise structural and compositional analysis within the hierarchy is paramount to understand the fundamentals of the mechanical properties of the composite exoskeleton. Here, we expose the intact chitin-fiber architecture of the pincer exoskeleton using nondestructive analysis. In-situ mechanical characterization was performed at nanometer levels within the exoskeleton hierarchy, which complemented with simulations, uncovered the elastic modulus of the protein matrix. Our findings confirm the presence and distribution of metal ions and their role as reinforcements in the protein matrix via ligand coordinate bonds. In future work, these findings can be of great potential to inspire the design of composite materials.
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Spaeker O, Taylor GJ, Wilts BD, Slabý T, Abdel‐Rahman MAK, Scoppola E, Schmitt CNZ, Sztucki M, Liu J, Bertinetti L, Wagermaier W, Scholtz G, Fratzl P, Politi Y. Gradients of Orientation, Composition, and Hydration of Proteins for Efficient Light Collection by the Cornea of the Horseshoe Crab. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2203371. [PMID: 36251923 PMCID: PMC9685478 DOI: 10.1002/advs.202203371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 08/30/2022] [Indexed: 06/16/2023]
Abstract
The lateral eyes of the horseshoe crab, Limulus polyphemus, are the largest compound eyes within recent Arthropoda. The cornea of these eyes contains hundreds of inward projecting elongated cuticular cones and concentrate light onto proximal photoreceptor cells. Although this visual system has been extensively studied before, the precise mechanism allowing vision has remained controversial. Correlating high-resolution quantitative refractive index (RI) mapping and structural analysis, it is demonstrated how gradients of RI in the cornea stem from structural and compositional gradients in the cornea. In particular, these RI variations result from the chitin-protein fibers architecture, heterogeneity in protein composition, and bromine doping, as well as spatial variation in water content resulting from matrix cross-linking on the one hand and cuticle porosity on the other hand. Combining the realistic cornea structure and measured RI gradients with full-wave optical modeling and ray tracing, it is revealed that the light collection mechanism switches from refraction-based graded index (GRIN) optics at normal light incidence to combined GRIN and total internal reflection mechanism at high incident angles. The optical properties of the cornea are governed by different mechanisms at different hierarchical levels, demonstrating the remarkable versatility of arthropod cuticle.
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Affiliation(s)
- Oliver Spaeker
- Department of BiomaterialsMax Planck Institute of Colloids and Interfaces14476PotsdamGermany
| | - Gavin J. Taylor
- Institute for Globally Distributed Open Research and Education (IGDORE)Ribeirão Preto14091‐310Brazil
| | - Bodo D. Wilts
- Chemistry and Physics of MaterialsUniversity of SalzburgJakob‐Haringer‐Str. 2aSalzburg5020Austria
- Adolphe Merkle InstituteUniversity of FribourgChemin des Verdiers 4Fribourg1700Switzerland
| | - Tomáš Slabý
- TELIGHTLibušina třída 21Brno623 00Czech Republic
| | | | - Ernesto Scoppola
- Department of BiomaterialsMax Planck Institute of Colloids and Interfaces14476PotsdamGermany
| | - Clemens N. Z. Schmitt
- Department of BiomaterialsMax Planck Institute of Colloids and Interfaces14476PotsdamGermany
| | - Michael Sztucki
- European Synchrotron Radiation Facility (ESRF)71 avenue des Martyrs, CS 40220Grenoble Cedex 938043France
| | - Jiliang Liu
- European Synchrotron Radiation Facility (ESRF)71 avenue des Martyrs, CS 40220Grenoble Cedex 938043France
| | - Luca Bertinetti
- B CUBE – Center for Molecular BioengineeringTechnische Universität Dresden01307DresdenGermany
| | - Wolfgang Wagermaier
- Department of BiomaterialsMax Planck Institute of Colloids and Interfaces14476PotsdamGermany
| | - Gerhard Scholtz
- Humboldt‐University BerlinInstitute of BiologyPhilippstraße 1310115BerlinGermany
| | - Peter Fratzl
- Department of BiomaterialsMax Planck Institute of Colloids and Interfaces14476PotsdamGermany
| | - Yael Politi
- B CUBE – Center for Molecular BioengineeringTechnische Universität Dresden01307DresdenGermany
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Kamtsikakis A, Weder C. Asymmetric Mass Transport through Dense Heterogeneous Polymer Membranes: Fundamental Principles, Lessons from Nature, and Artificial Systems. Macromol Rapid Commun 2021; 43:e2100654. [PMID: 34792266 DOI: 10.1002/marc.202100654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 11/15/2021] [Indexed: 11/08/2022]
Abstract
Many organisms rely on directional water transport schemes for the purpose of water retention and collection. Directional transport of water and other fluids is also technologically relevant, for example to harvest water, in separation processes, packaging solutions, functional clothing, and many other applications. One strategy to promote mass transport along a preferential direction is to create compositionally asymmetric, multi-layered, or compositionally graded architectures. In recent years, the investigation of natural and artificial membranes based on this design has attracted growing interest and allowed researchers to develop a good understanding of how the properties of such membranes can be tailored to meet the demands of particular applications. Here a summary of theoretical works on mass transport through dense asymmetric membranes, comprehensive reviews of biological and artificial membranes featuring this design, and a discussion of applications, remaining questions, and opportunities are provided.
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Affiliation(s)
- Aristotelis Kamtsikakis
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, Fribourg, 1700, Switzerland
| | - Christoph Weder
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, Fribourg, 1700, Switzerland
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Ma Y, Guo C, Dai N, Shen J, Guan J. Structural characterization and regulation of the mechanical properties of the carapace cuticle in tri-spine horseshoe crab (Tachypleus tridentatus). J Mech Behav Biomed Mater 2021; 125:104954. [PMID: 34741983 DOI: 10.1016/j.jmbbm.2021.104954] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 10/24/2021] [Accepted: 10/27/2021] [Indexed: 11/24/2022]
Abstract
Horseshoe crab (order Xiphosura) has a large and thick carapace that has evolved as a protective tool to defend against predators and resist impacts from surf-zone turbulence. The naturally occurring spatial variation in the mechanical properties of the carapace cuticle need to be investigated to understand their regulatory mechanism and the underlying design strategies. In this work, we used a combination of high-resolution optical microscopy, scanning electron microscopy, (SEM) and energy-dispersive X-ray spectroscopy (EDS) to evaluate the multiscale microstructure and elemental composition of the cuticle of tri-spine horseshoe crab (Tachypleus tridentatus). The moduli, ultimate strengths, and failure strains of the three individual layers and the entire cuticle were systematically characterized in both the dry and hydrated states. The failure behaviors and energy absorption of the cuticle involved stress stiffening, toughness mechanism and environmental adaptation were analyzed qualitatively and quantitatively and then correlated with the morphological features in different cuticle regions. The mechanical properties are primarily influenced by the endocuticle thickness ratio; a higher thickness ratio corresponds to more stacking of the vertical lamellae, leading to a lower modulus, weaker strength, and greater elongation of the endocuticle. Radial energy is absorbed primarily by the endocuticle, with the energy absorbed in the radial direction being nearly twice that absorbed in the circumferential direction. This is attributed to the larger failure strain and relatively small decrease in the stress plateau in the radial direction. The findings provide a deeper understanding of how nature modulates the cuticle's mechanical properties and inspiration for developing high-performance synthetic composites.
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Affiliation(s)
- Yaopeng Ma
- College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China; Institute of Bio-inspired Structure and Surface Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China
| | - Ce Guo
- College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China; Institute of Bio-inspired Structure and Surface Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China.
| | - Ning Dai
- College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China
| | - Jingyu Shen
- College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China; Institute of Bio-inspired Structure and Surface Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China
| | - Jigang Guan
- College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China; Institute of Bio-inspired Structure and Surface Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China
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Persistent polyamorphism in the chiton tooth: From a new biomineral to inks for additive manufacturing. Proc Natl Acad Sci U S A 2021; 118:2020160118. [PMID: 34088834 DOI: 10.1073/pnas.2020160118] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Engineering structures that bridge between elements with disparate mechanical properties are a significant challenge. Organisms reap synergy by creating complex shapes that are intricately graded. For instance, the wear-resistant cusp of the chiton radula tooth works in concert with progressively softer microarchitectural units as the mollusk grazes on and erodes rock. Herein, we focus on the stylus that connects the ultrahard and stiff tooth head to the flexible radula membrane. Using techniques that are especially suited to probe the rich chemistry of iron at high spatial resolution, in particular synchrotron Mössbauer and X-ray absorption spectroscopy, we find that the upper stylus of Cryptochiton stelleri is in fact a mineralized tissue. Remarkably, the inorganic phase is nano disperse santabarbaraite, an amorphous ferric hydroxyphosphate that has not been observed as a biomineral. The presence of two persistent polyamorphic phases, amorphous ferric phosphate and santabarbaraite, in close proximity, is a unique aspect that demonstrates the level of control over phase transformations in C. stelleri dentition. The stylus is a highly graded material in that its mineral content and mechanical properties vary by a factor of 3 to 8 over distances of a few hundred micrometers, seamlessly bridging between the soft radula and the hard tooth head. The use of amorphous phases that are low in iron and high in water content may be key to increasing the specific strength of the stylus. Finally, we show that we can distill these insights into design criteria for inks for additive manufacturing of highly tunable chitosan-based composites.
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