Fossilization of bone studied in-operando by fluid-cell Raman spectroscopy

通过流体细胞拉曼光谱研究骨化石

• 批准号: 396708190
• 负责人: Professor Dr. Thorsten Geisler-Wierwille
• 金额: --
• 依托单位: Institut für Geowissenschaften
• 依托单位国家: 德国
• 项目类别: Research Units
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/396708190?language=en
• 关键词: Fossilization; bone; studied; operando; fluid

Fossil bones represent an important geochemical archive for the reconstruction of the life history of vertebrates on Earth. However, the taphonomy of the bones can change this information or even destroy it completely. Experimental studies of bone taphonomy under controlled boundary conditions are necessary, in particular to understand the processes associated with early fossilization, as these appear to be critical to the preservation of bones. New insights into the mesoscopic partial reactions and transport processes of bone taphonomy can be gained with the help of confocal hyperspectral Raman spectroscopy (RS). This technique enables real-time imaging of moving reaction interfaces during fluid-driven reactions on the micrometre scale and at elevated temperatures using special fluid cells (FC) without the need to interrupt the reaction, i.e., in operando. FC-RS can provide a wealth of information, such as the phase composition, crystallinity, crystallite size, interfacial strain, and at the same time the concentrations of aqueous species in the solution, from which even the local pH value can be estimated. In addition, due to the isotope shift, the FC-RS enables the exchange of oxygen and hydrogen isotopes between solids and aqueous molecular species to be tracked in operando when isotopically enriched precursor materials are used. Intriguing evidence for the feasibility of such in-operando FC-RS studies emerges from the results of initial experiments on dentin and silicate glasses. The results of these experiments have in both cases revealed unforeseen, short-term changes in the mechanism and the overall reaction kinetics. They also show that dynamic phenomena such as re-equilibration reactions and potentially the diffusion of molecular water through bone can be studied and quantified when 18-O and 2-H are used as tracers. First measurements indicate that it will even be possible to follow the diffusion of traces of Nd3+ in bones in-operando with the help of laser-induced photoluminescence/Raman spectroscopy. The FC-RS therefore opens up completely new possibilities to get deeper insights into bone-water reactions. The main goals of the proposed project are to gain a deeper mechanistic understanding of (i) the recrystallization of bone apatite, (ii) bone mineralization, (iii) collagen degradation, and ultimately (iv) reliable, quantitative, kinetic information about the identified transport and reaction processes as a function of the pH value, the composition of the solution (containing carbonate, phosphate, and F) and the temperature. However, the main focus will initially be on room temperature experiments that simulate near-surface conditions.

化石骨骼是重建地球上脊椎动物生活史的重要地球化学档案。然而，骨骼的埋藏学可以改变这些信息，甚至完全破坏它。控制边界条件下的骨埋藏的实验研究是必要的，特别是要了解与早期骨化相关的过程，因为这些似乎是至关重要的保存骨骼。共焦高光谱拉曼光谱（RS）技术的应用为深入研究骨埋藏过程中的介观局部反应和输运过程提供了新的视角。该技术使得能够在微米尺度上和在高温下使用特殊流体单元（FC）在流体驱动反应期间对移动反应界面进行实时成像，而不需要中断反应，即，在歌剧中。FC-RS可以提供丰富的信息，如相组成、结晶度、微晶尺寸、界面张力，同时还可以提供溶液中含水物质的浓度，甚至可以从中估计局部pH值。此外，由于同位素位移，当使用同位素富集的前体材料时，FC-RS使得能够在操作中跟踪固体和水性分子物质之间的氧和氢同位素的交换。有趣的证据，这种在operando FC-RS研究的可行性出现从牙本质和硅酸盐玻璃的初步实验的结果。在这两种情况下，这些实验的结果都揭示了机制和总体反应动力学的不可预见的短期变化。他们还表明，动态现象，如再平衡反应和潜在的分子水通过骨的扩散，可以研究和量化时，18-O和2-H被用作示踪剂。第一次测量表明，它甚至将有可能遵循的扩散的痕量的Nd 3+在骨中的操作与激光诱导的光致发光/拉曼光谱的帮助。因此，FC-RS为深入了解骨水反应开辟了全新的可能性。拟议项目的主要目标是获得对（i）骨磷灰石的重结晶、（ii）骨矿化、（iii）胶原蛋白降解以及最终（iv）有关已识别的运输和反应过程的可靠、定量、动力学信息的更深入的机械理解作为pH值、溶液组成（包含碳酸盐、磷酸盐和F）和温度的函数。然而，最初的主要重点将是模拟近地表条件的室温实验。