Investigation of the 3D modulation of light elements in the skeleton of the red algae

In this proposal we aim to investigate the 3D modulation of Mg in calcitic biomineralized tissues of the red algae. We have found via aberration corrected HRTEM that varying concentrations of Mg exists within these biominerals in an alternating manner. However EDS in TEM is not near as sensitive as XRF and cannot pick up small varientions. Moreover, TEM cannot reveal 3D modulations but mainly only 2D small slices. We would like for the first time to study these modulations in 3D. These modulations have implications in understanding the process of biomineralization (transformation of a Mg-rich amorphous precursor to a crystalline phase) as well as have strong affects on the mechanical properties. Such unprecedented 3D structural information due to nanotomography imaging coupled with Mg XRF will make it possible, for the first time, to localize the elemental distributions within the sample in 3D.

本研究旨在探究镁（Mg）在红藻钙化生物矿化组织中的三维调控机制。通过像差校正高分辨透射电子显微镜（aberration corrected HRTEM）观察，我们发现这些生物矿物中镁的浓度呈交替变化分布。然而，透射电子显微镜（TEM）中的能量色散X射线光谱（EDS）灵敏度远不及X射线荧光光谱（XRF），无法检测到微小的浓度变化。此外，TEM仅能揭示二维薄片结构，无法呈现三维调控特征。我们拟首次对这些三维调控特征展开研究。这些调控特征对于理解生物矿化（biomineralization）过程（即富镁非晶前驱体向结晶相的转变）以及其对力学性能的显著影响具有重要意义。通过纳米断层扫描成像（nanotomography imaging）结合镁X射线荧光光谱（Mg XRF）技术获取的这种前所未有的三维结构信息，将首次实现对样品中元素分布的三维定位。