EAGER/Collaborative Research: Understanding How Enamel Prism Lattices Promote a Remarkable Combination of Fracture and Wear Resistance in Grazing Mammal Dentitions

EAGER/合作研究：了解牙釉质棱镜晶格如何促进放牧哺乳动物牙列的抗折性和耐磨性的显着组合

• 批准号: 1937088
• 负责人: Brandon Krick
• 金额: $ 6.65万
• 依托单位: Lehigh University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-08-01 至 2020-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1937088&HistoricalAwards=false
• 关键词: EAGER; Collaborative; Research; Understanding; How

Fracture and wear are common issues in engineering - to the extent that the terms "worn," "fractured," and "broken" are generally synonymous with the end-of-utility of devices. In many cases, traditional materials fail to meet the complex, simultaneous performance requirements that would be ideal for next generation engineering systems. The enamel of the teeth of grazing animals represents one of nature's most remarkable biological materials -- a ceramic-like composite showing exceptional strength, toughness, wear-resistance, and ability to slow crack propagation. This is an important set of properties for a structure that is key to long-term survival in these animals - as functional teeth are required for feeding. This EArly-Concept Grant for Exploratory Research (EAGER) project will study these damage-tolerant biomaterials using a combination of evolutionary biology, biomechanics, and materials science. Results and methods from this research will be of considerable interest to investigators in many disciplines, including engineering, materials science, evolutionary biology, ecology, comparative anatomy, mammalogy, and paleontology. The research will also support the development of novel, sustainable materials with improved wear and fracture behavior. Graduate students will be involved in this truly interdisciplinary project and learn how the various fields can work together to tackle challenging questions. This research will also introduce a more effective, evolutionary approach for exploring nature for biomimetic examples.The goal of this interdisciplinary research is to specifically understand the biomechanical form, function and performance of enamel lattices, known as Modified Radial Enamel (MRE), in the grinding teeth of large herbivorous mammals. Samples will be obtained from numerous species, including equines (horses), bovids (e.g. bison and cattle) and suids (e.g. warthogs). This study will specifically focus on how these animals' teeth endure tens to hundreds of millions of high stress contact loading cycles and impacts while chewing tough and abrasive plant matter, such as grasses whose roots are laden with hard, fracture-promoting sediment inclusions. The underlying hypothesis is that MRE is an evolutionarily optimized compromise for: 1) incredible fracture resistance due to prism arrangements that localize damage and strategically control crack direction; 2) unexpected strength and toughness made possible by compliant proteinaceous prism sheaths that circumvent hydroxyapatite's inherent brittleness; and 3) wear resistance conveyed through hard, hyper-mineralized, oriented enamel prisms. The project will investigate this hypothesis through two objectives. First, the study will use an evolutionary biology approach to identify the ancestral enamel fabric character states to MRE that independently evolved in horses, bovids and warthogs. From this information, it will be possible to readily identify the specific evolutionary modifications to the enamel fabrics that enabled grinding and identify living species that can be used to undertake comparative biomechanical assessment. Second, the project will investigate the structure-property relationships of the enamel across multiple length scales by comprehensively characterizing the material properties using micro-and nano-mechanical tools, spectroscopy, and advanced electron microscopy. Teeth of grinding species with MRE will be compared with close relatives that retain the ancestral enamel fabrics, thereby revealing the salient anatomical changes that enabled the optimized combination of biomechanical properties.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

骨折和磨损是工程中常见的问题 - 在某种程度上，“磨损”，“破裂”和“破碎”通常是设备终止的代名词。在许多情况下，传统材料无法满足复杂的同时性能要求，这对于下一代工程系统来说是理想的选择。放牧动物牙齿的搪瓷代表了自然界最引人注目的生物材料之一 - 一种类似陶瓷的复合材料，表现出非凡的强度，韧性，耐磨性和减慢裂纹繁殖的能力。对于这些动物的长期生存的关键，这是一组重要的特性，因为喂食需要功能性牙齿。 探索性研究（急切）项目的这项早期概念赠款将使用进化生物学，生物力学和材料科学的结合来研究这些耐受损害的生物材料。这项研究的结果和方法对许多学科的研究者将引起人们的极大兴趣，包括工程，材料科学，进化生物学，生态学，比较解剖学，哺乳动物学和古生物学。该研究还将支持开发新颖的可持续材料，并具有改善的磨损和断裂行为。研究生将参与这个真正的跨学科项目，并了解各个领域如何共同解决具有挑战性的问题。 这项研究还将引入一种更有效的进化方法，用于探索仿生示例的自然。这项跨学科研究的目的是在大型herbivoroot哺乳动物的磨牙中特别了解搪瓷晶格的生物力学形式，功能和性能。 样品将从许多物种中获得，包括马（马），牛（例如野牛和牛）和Suids（例如Warthogs）。这项研究将专门关注这些动物的牙齿如何忍受数十亿高应力接触量和影响，同时咀嚼坚硬和磨碎的植物物质，例如，其根部充满坚硬，强化裂​​缝的沉积物夹杂物的草。基本的假设是MRE是一个进化优化的折衷：1）由于棱镜安排的棱柱布置而引起的令人难以置信的断裂抗性，这些棱镜的抗性能够定位损害并在战略上控制裂纹方向； 2）符合抗氧化磷灰石固有的脆性的依从性蛋白质棱镜护套使意外的强度和韧性成为可能； 3）耐磨性通过坚硬的，超矿物化的搪瓷棱镜传达。该项目将通过两个目标调查这一假设。 首先，该研究将采用进化生物学方法来识别祖传搪瓷织物特征状态，以独立发展在马，牛和疣猪中。从这些信息中，可以轻松地对牙釉质织物进行特定的进化修饰，从而使磨碎和识别可用于进行比较生物力学评估的活物种。 其次，该项目将通过使用微力和机械工具，光谱和高级电子显微镜来全面表征材料特性，从而研究牙釉质在多个长度尺度上的结构特性关系。用MRE磨碎物种的牙齿将与保留祖先搪瓷织物的近亲进行比较，从而揭示了显着的解剖变化，从而实现了生物力学特性的优化组合。该奖项反映了NSF的法定任务，并被认为是通过基金会的知识优点和广泛的Criperia criperia的评估来通过评估来获得的。