Black Drum Fish Teeth: Built for Crushing Mollusk Shells
Black Drum Fish Teeth: Built for Crushing Mollusk Shells
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DOI：
10.1016/j.actbio.2021.10.023
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发表时间：
2021-12-11
影响因子：
9.7
通讯作者：
Li, Ling
中科院分区：
文献类型：
--
作者：
Deng, Zhifei;Loh, Hyun-Chae;Li, Ling
黑鼓鱼(Pogonias Cromis)以硬壳软体动物为唯一食物，是现存动物中咬合力最强的鱼之一。在这里，我们对黑色鼓齿进行了系统的显微结构、化学、结晶学和力学分析，以了解达到软体动物要求的结构基础。在材料水平上，最外层的釉质具有较高的弹性系数(E-r=126.9+/-16.3 Gpa，H=5.0+/-1.4 Gpa)，这归因于锌和氟掺杂在磷灰石晶体中的硬化效应以及晶体c轴和釉质棒沿咬合方向的择优共排。外层釉质的高断裂韧性(K-c=1.12MPAm(1/2))在与软体动物贝壳的挤压接触中也促进了局部屈服而不是断裂。在单个牙齿尺度上，磨牙样牙齿、高密度的牙本质小管、扩大的牙髓室和特殊的牙本质-骨连接，都有助于满足功能要求，包括限制刚性牙釉质中的接触压应力，增强顺应性牙本质中的能量吸收，以及在过高载荷下控制牙-骨复合材料的破坏。这些结果表明，黑鼓鱼的多鳞结构适合以硬壳软体动物为食。意义陈述黑鼓鱼以硬壳软体动物为食，这需要坚固、坚韧和耐磨的牙齿。本研究对黑鼓牙实现如此显著的生物学功能进行了全面、多尺度的材料和力学分析。在微观上，外层釉质区域的氟和锌掺杂磷灰石微晶垂直于咀嚼表面排列，代表了自然界中发现的最坚硬的生物矿化材料之一。在内釉质区，磷灰石晶体排列成相互缠绕的棒状，结晶方向错误，以增加抗裂性和韧性。在宏观层面上，磨牙状的几何形状、基于外牙釉质和内牙本质的双层设计、扩大的牙髓室和底层坚固的骨质牙板协同工作，有助于提高牙齿的抗磨性。(C)2021由Elsevier Ltd.出版。保留所有权利。
With an exclusive diet of hard-shelled mollusks, the black drum fish (Pogonias cromis) exhibits one of the highest bite forces among extant animals. Here we present a systematic microstructural, chemical, crystallographic, and mechanical analysis of the black drum teeth to understand the structural basis for achieving the molluscivorous requirements. At the material level, the outermost enameloid shows higher modulus (E-r = 126.9 +/- 16.3 GPa, H = 5.0 +/- 1.4 GPa) than other reported fish teeth, which is attributed to the stiffening effect of Zn and F doping in apatite crystals and the preferential co-alignment of crystallographic c-axes and enameloid rods along the biting direction. The high fracture toughness (K-c = 1.12 MPa.m(1/2)) of the outer enameloid also promotes local yielding instead of fracture during crushing contact with mollusk shells. At the individual-tooth scale, the molar-like teeth, high density of dentin tubules, enlarged pulp chamber, and specialized dentin-bone connection, all contribute to the functional requirements, including confinement of contact compressive stress in the stiff enameloid, enhanced energy absorption in the compliant dentin, and controlled failure of tooth-bone composite under excessive loads. These results show that the multi-scale structures of black drum teeth are adapted to feed on hard shelled mollusks.Statement of significanceThe black drum fish feeds on hard-shelled mollusks, which requires strong, tough, and wear-resistant teeth. This study presents a comprehensive multiscale material and mechanical analysis of the black drum teeth in achieving such remarkable biological function. At microscale, the fluoride- and zinc-doped apatite crystallites in the outer enameloid region are aligned perpendicular to the chewing surface, representing one of the stiffest biomineralized materials found in nature. In the inner enameloid region, the apatite crystals are arranged into intertwisted rods with crystallographic misorientation for increased crack resistance and toughness. At the macroscale, the molariform geometry, the two-layer design based on the outer enameloid and inner dentin, enlarged pulp chamber and the underlying strong bony toothplate work synergistically to contribute to the teeth's crushing resistance.(C) 2021 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.