Presentation Information
[P03-347]Integration of Chemical and Architectural Features Enable Crush Resistance in Soldier Termite Mandibles
○Andrew Tran Nguyen1, Patryk Wasik2, Derek Lublin1, Juan Fernando Cucuyame Morales3, Marie Kate Palau Andrade3, Atsushi Arakaki4, Nathan Lord5, Paul Bardunias6, Pablo Zavattieri3, David Kisailus1,7 (1. Materials and Manufacturing Technologies Program, University of California, Irvine (USA), 2. National Synchrotron Light Source II, Brookhaven National Laboratory (USA), 3. Lyles School of Civil and Construction Engineering, Purdue University (USA), 4. Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology (Japan), 5. Air Force Research Laboratory/RW, Eglin Air Force Base (USA), 6. Department of Biological Sciences, Florida Atlantic University (USA), 7. Department of Materials Science and Engineering, University of California, Irvine (USA))
Keywords:
Structure-function,Biological composite,Arthopod,Mechanics,Bio-inspired materials
[Purpose]
Biological materials are well recognized as lightweight, strong and tough structural materials. While mineralized systems accomplish this feat by controlling size, morphology, crystallinity, phase, and orientation of the inorganic components, organisms lacking mineral must employ different techniques. These non-mineralized biological materials represent complex hierarchical composites commonly composed of α-chitin fibers assembled by and surrounded with a proteinaceous matrix. An example is found in soldier termites; these organisms possess highly specialized mandibles adapted for colony defense under extreme mechanical loading. In Neotermes castaneus, crushing-type mandibles generate bite forces that scale among the upper range for insects of similar head width. Here, we investigate the region-specific organization of material components within these mandibles, and how its architecture enables resistance to compressive failure without mineral reinforcement.
[Method]
Multi-scale structural characterization was performed via micro-computed tomography, scanning electron microscopy, wide-angle X-ray scattering, and nanoindentation. Subsequent chemical investigation involved atomic force microscopy with spatially resolved infrared spectroscopy (AFM-IR) and elemental mapping. Finite element modeling and mechanical testing of bio-based fiber-reinforced composites were then used to validate the role of these design themes.
[Results]
We reveal a non-uniform reinforcement architecture in which α-chitin fibers are preferentially aligned parallel to the dominant compressive loading direction. Comparative analysis with a slashing-type soldier termite species shows the absence of this reinforcement motif, indicating functional association with crushing behavior. Chemical analysis demonstrates localized zinc enrichment at the crushing edge, correlating with increased hardness, while regions subjected to bending-induced tensile stresses exhibit reduced zinc concentration, but higher stiffness. Models and bioinspired mimics with controlled fiber orientation confirm that alignment parallel to compressive loading enhances load-bearing capacity.
[Consideration]
The biomolecular constituents that dictate assembly and cross-linking are not fully understood but are central to understanding how insects create lightweight and high-performance structural materials from inherently simple and weak components. Thus, future work will elucidate the proteins associated with chitin-binding, assembly and sclerotization within the mandibles.
[Conclusion]
These results demonstrate cooperative architectural and chemical reinforcement in a fully organic composite system and provide design blueprints for lightweight, damage-tolerant structural materials. Ultimately, we aim to reveal mechanistic insights towards sustainable synthetic pathways and molecular blueprints for future, lightweight bioinspired composites with tunable mechanical properties used for many applications.
Biological materials are well recognized as lightweight, strong and tough structural materials. While mineralized systems accomplish this feat by controlling size, morphology, crystallinity, phase, and orientation of the inorganic components, organisms lacking mineral must employ different techniques. These non-mineralized biological materials represent complex hierarchical composites commonly composed of α-chitin fibers assembled by and surrounded with a proteinaceous matrix. An example is found in soldier termites; these organisms possess highly specialized mandibles adapted for colony defense under extreme mechanical loading. In Neotermes castaneus, crushing-type mandibles generate bite forces that scale among the upper range for insects of similar head width. Here, we investigate the region-specific organization of material components within these mandibles, and how its architecture enables resistance to compressive failure without mineral reinforcement.
[Method]
Multi-scale structural characterization was performed via micro-computed tomography, scanning electron microscopy, wide-angle X-ray scattering, and nanoindentation. Subsequent chemical investigation involved atomic force microscopy with spatially resolved infrared spectroscopy (AFM-IR) and elemental mapping. Finite element modeling and mechanical testing of bio-based fiber-reinforced composites were then used to validate the role of these design themes.
[Results]
We reveal a non-uniform reinforcement architecture in which α-chitin fibers are preferentially aligned parallel to the dominant compressive loading direction. Comparative analysis with a slashing-type soldier termite species shows the absence of this reinforcement motif, indicating functional association with crushing behavior. Chemical analysis demonstrates localized zinc enrichment at the crushing edge, correlating with increased hardness, while regions subjected to bending-induced tensile stresses exhibit reduced zinc concentration, but higher stiffness. Models and bioinspired mimics with controlled fiber orientation confirm that alignment parallel to compressive loading enhances load-bearing capacity.
[Consideration]
The biomolecular constituents that dictate assembly and cross-linking are not fully understood but are central to understanding how insects create lightweight and high-performance structural materials from inherently simple and weak components. Thus, future work will elucidate the proteins associated with chitin-binding, assembly and sclerotization within the mandibles.
[Conclusion]
These results demonstrate cooperative architectural and chemical reinforcement in a fully organic composite system and provide design blueprints for lightweight, damage-tolerant structural materials. Ultimately, we aim to reveal mechanistic insights towards sustainable synthetic pathways and molecular blueprints for future, lightweight bioinspired composites with tunable mechanical properties used for many applications.
Comment
To browse or post comments, you must log in.Log in