Materials Nanoarchitecturing via Cation‐Mediated Protein Assembly: Making Limpet Teeth without Mineral |
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| Authors: | Tina Ukmar‐Godec Luca Bertinetti John W. C. Dunlop Aljaž Godec Michal A. Grabiger Admir Masic Huynh Nguyen Igor Zlotnikov Paul Zaslansky Damien Faivre |
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| Affiliation: | 1. Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany;2. Mathematical Biophysics Group, Max Planck Institute for Biophysical Chemistry, G?ttingen, Germany;3. Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA;4. B CUBE – Center for Molecular Bioengineering, Technische Universit?t Dresden, Dresden, Germany;5. Charite, Julius Wolff Institute for Biomechanics and Musculoskeletal Regeneration, Berlin, Germany |
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| Abstract: | ![]()
Teeth are designed to deliver high forces while withstanding the generated stresses. Aside from isolated mineral‐free exception (e.g., marine polychaetes and squids), minerals are thought to be indispensable for tooth‐hardening and durability. Here, the unmineralized teeth of the giant keyhole limpet (Megathura crenulata) are shown to attain a stiffness, which is twofold higher than any known organic biogenic structures. In these teeth, protein and chitin fibers establish a stiff compact outer shell enclosing a less compact core. The stiffness and its gradients emerge from a concerted interaction across multiple length‐scales: packing of hydrophobic proteins and folding into secondary structures mediated by Ca2+ and Mg2+ together with a strong spatial control in the local fiber orientation. These results integrating nanoindentation, acoustic microscopy, and finite‐element modeling for probing the tooth's mechanical properties, spatially resolved small‐ and wide‐angle X‐ray scattering for probing the material ordering on the micrometer scale, and energy‐dispersive X‐ray scattering combined with confocal Raman microscopy to study structural features on the molecular scale, reveal a nanocomposite structure hierarchically assembled to form a versatile damage‐tolerant protein‐based tooth, with a stiffness similar to mineralized mammalian bone, but without any mineral. |
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| Keywords: | limpet teeth mechanical properties nanoindentation radula structure– function relationship |
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