Discovery of New Phenomena in Biomineral Formation

生物矿物形成新现象的发现

• 批准号: 1603192
• 负责人: Pupa Gilbert
• 金额: $ 45万
• 依托单位: University of Wisconsin-Madison
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-09-15 至 2019-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1603192&HistoricalAwards=false
• 关键词: Discovery; New; Phenomena; Biomineral; Formation

Non-technical: This award by the Biomaterials program in the Division of Materials Research to University of Wisconsin Madison is to investigate the mechanisms for the formation of natural biominerals. These biominerals are crystalline composite materials formed by living organisms. Despite being crystalline, they do not frequently exhibit the flat faces and sharp edges characteristic of geologic crystals, but have rounded surfaces, and shapes highly adapted to their functions. They grow by attachment of amorphous particles, as was first discovered in sea urchin biominerals, and later in eggshells and others, but never directly in the formation of seashells. This proposal will analyze these biominerals to study how they are formed. Using crystal orientation measurements, this award will study crystal growth in egg shells in a quantitative manner. The discoveries coming out of this study will greatly advance knowledge of biomineral formation mechanisms, and the results will be helpful for future biomimetic 3D printing of these biominerals, with potential use in bone repair and replacement, and other useful devices. The discoveries in these biominerals will be broadly disseminated in peer-reviewed publications, at conferences where the researcher gives frequent invited lectures, in popular science magazines, at the Conference for Undergraduate Women in Physics, to under-represented minority high-school students attending the "Pre-college EnrichmentOpportunity Program for Learning Excellence" program, to grade school women attending the Expanding Your Horizon yearly events, and in public lectures.Technical: The researcher and the team members will study new phenomena in forming biominerals, selected to maximize the likelihood of new, unexpected results because they have never been studied with the same objectives as planned here: Objective 1 is to identify amorphous precursor phases in fresh, forming mussel nacre and prismatic layers, and eggshells using x-ray absorption near-edge structure spectroscopy at the calcium L-edge, and localization in component-mapping with 20 nm spatial resolution, and 3 nm probing depth. Calcite, aragonite, and their amorphous precursors have distinct XANES spectral lineshape and are therefore identifiable. If there are amorphous precursor phases in forming eggshell, nacre and prisms, we will identify them as proto-aragonite or proto-calcite. These "polyamorphs" have the short-range order of aragonite and calcite, respectively, and are expected to transform into the corresponding crystalline phases. Objective 2 is to obtain a quantitative definition of spherulite from synthetic aragonite using polarization-dependent imaging contrast (PIC)-mapping at the oxygen K-edge. This definition will then be used to determine if nacre and eggshells do or do not grow spherulitically. Both component- and PIC-mapping are state-of-the-art synchrotron methods, which this researcher introduced and continues to improve.

非技术性：该奖项由威斯康星大学麦迪逊分校材料研究部生物材料项目颁发，旨在研究天然生物矿物质的形成机制。这些生物矿物质是由生物体形成的晶体复合材料。尽管是晶体，但它们并不经常表现出地质晶体的平坦表面和锋利边缘特征，而是具有圆形表面和高度适合其功能的形状。它们通过附着无定形颗粒生长，首先在海胆生物矿物质中发现，后来在蛋壳和其他物质中发现，但从未直接在贝壳的形成中发现。该提案将分析这些生物矿物质以研究它们是如何形成的。该奖项将利用晶体取向测量，定量研究蛋壳中的晶体生长。这项研究的发现将极大地推进对生物矿物形成机制的了解，其结果将有助于未来这些生物矿物的仿生 3D 打印，并有可能用于骨修复和替换以及其他有用的设备。这些生物矿物的发现将在同行评审的出版物、研究人员经常受邀演讲的会议、流行科学杂志、物理学本科女性会议上向参加该项目的少数族裔高中生广泛传播。 “大学预科学习卓越机会计划”计划，面向小学女性参加“扩展你的视野”年度活动和公开讲座。技术：研究人员和团队成员将研究形成生物矿物的新现象，选择这些现象是为了最大限度地提高新的、意想不到的结果的可能性，因为它们从未以与此处计划相同的目标进行研究：目标 1 是识别新鲜的、形成的贻贝珍珠层和棱柱体中的无定形前体相使用钙 L 边缘处的 X 射线吸收近边缘结构光谱分析层和蛋壳，并以 20 nm 空间分辨率和 3 nm 探测深度进行成分映射定位。方解石、霰石及其无定形前体具有独特的 XANES 谱线形状，因此可以识别。如果在形成蛋壳、珍珠质和棱柱时存在非晶态前体相，我们将它们鉴定为原文石或原方解石。这些“多无定形物”分别具有文石和方解石的短程有序，并且预计会转变为相应的结晶相。目标 2 是使用氧 K 边缘的偏振相关成像衬度 (PIC) 映射，从合成文石中获得球晶的定量定义。然后，该定义将用于确定珍珠质和蛋壳是否以球状生长。组件映射和 PIC 映射都是最先进的同步加速器方法，该研究人员引入并不断改进。