Discovery of New Phenomena in Biomineral Formation

非技术：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形成的机制。这些生物矿物是由生物体形成的结晶复合材料。尽管它们是结晶的，但它们并不经常表现出地质晶体所特有的平面和锋利的边缘，而是具有圆形的表面，并且形状与它们的功能高度适应。它们通过附着无定形颗粒生长，这种情况首先在海胆生物矿物质中被发现，后来在蛋壳和其他物质中被发现，但从未直接在贝壳的形成中被发现。本提案将分析这些生物矿物，以研究它们是如何形成的。利用晶体取向测量，该奖项将以定量的方式研究蛋壳中的晶体生长。本研究的发现将极大地推进生物矿物形成机制的知识，并且结果将有助于未来这些生物矿物的仿生3D打印，在骨修复和替代以及其他有用的设备中具有潜在的用途。这些生物矿物的发现将在同行评议的出版物中广泛传播，在研究人员经常受邀演讲的会议上，在通俗科学杂志上，在物理学本科女性会议上，在参加“大学预科丰富学习机会计划”项目的少数族裔高中学生中，在参加“扩展你的视野”年度活动的小学女生中，以及在公开讲座中。技术：研究人员和团队成员将研究形成生物矿物的新现象，选择以最大限度地提高新的，意想不到的结果的可能性，因为它们从未以相同的目标进行研究。目的1利用钙离子l边的x射线吸收近边结构光谱，在20 nm空间分辨率、3 nm探测深度的组分定位图中，鉴定新鲜形成的贻贝珠层、棱柱层和蛋壳中的非晶态前体相。方解石、文石及其无定形前体具有明显的XANES谱线形状，因此可识别。如果在蛋壳、珠层和棱镜的形成过程中存在无定形前驱相，我们将其识别为原文石或原方解石。这些“多晶岩”分别具有文石和方解石的短阶，并有望转变为相应的晶相。目的2是利用氧k边缘的偏振相关成像对比度（PIC）测绘，从合成文石中获得球晶的定量定义。这一定义将用于确定珠质和蛋壳是否呈球形生长。元件映射和pic映射都是最先进的同步加速器方法，该研究人员介绍并继续改进。

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.