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X-ray linear dichroic ptychography [Biophysics and Computational Biology]
Proceedings of the National Academy of Sciences of the United States of America ( IF 9.4 ) Pub Date : 2021-01-19 , DOI: 10.1073/pnas.2019068118
Yuan Hung Lo 1, 2, 3, 4 , Jihan Zhou 1, 2, 3 , Arjun Rana 1, 2, 3 , Drew Morrill 2, 5, 6 , Christian Gentry 2, 5, 6 , Bjoern Enders 7 , Young-Sang Yu 8 , Chang-Yu Sun 9 , David A Shapiro 8 , Roger W Falcone 2, 8, 10 , Henry C Kapteyn 2, 5, 6 , Margaret M Murnane 2, 5, 6 , Pupa U P A Gilbert 9, 11, 12, 13, 14 , Jianwei Miao 2, 3, 15
Affiliation  

Biominerals such as seashells, coral skeletons, bone, and tooth enamel are optically anisotropic crystalline materials with unique nanoscale and microscale organization that translates into exceptional macroscopic mechanical properties, providing inspiration for engineering new and superior biomimetic structures. Using Seriatopora aculeata coral skeleton as a model, here, we experimentally demonstrate X-ray linear dichroic ptychography and map the c-axis orientations of the aragonite (CaCO3) crystals. Linear dichroic phase imaging at the oxygen K-edge energy shows strong polarization-dependent contrast and reveals the presence of both narrow (<35°) and wide (>35°) c-axis angular spread in the coral samples. These X-ray ptychography results are corroborated by four-dimensional (4D) scanning transmission electron microscopy (STEM) on the same samples. Evidence of co-oriented, but disconnected, corallite subdomains indicates jagged crystal boundaries consistent with formation by amorphous nanoparticle attachment. We expect that the combination of X-ray linear dichroic ptychography and 4D STEM could be an important multimodal tool to study nano-crystallites, interfaces, nucleation, and mineral growth of optically anisotropic materials at multiple length scales.



中文翻译:

X射线线性二向色性谱图[生物物理学与计算生物学]

贝壳,珊瑚骨骼,骨骼和牙釉质等生物矿物是光学各向异性的晶体材料,具有独特的纳米级和微米级组织,可转化为出色的宏观机械性能,为工程学新型卓越的仿生结构提供了灵感。在这里,我们使用小球藻珊瑚骨架作为模型,通过实验证明了X射线线性二向色谱图,并绘制了文石(CaCO 3)晶体的c轴方向。氧气K边缘能量处的线性二向色相成像显示出与偏振有关的强对比度,并揭示了窄(<35°)和宽(> 35°)c的存在轴角在珊瑚样本中扩散。这些X射线刻印技术的结果在相同的样品上得到了二维(4D)扫描透射电子显微镜(STEM)的证实。共取向但不连续的珊瑚岩亚域的证据表明,锯齿状晶体边界与无定形纳米粒子的附着形成一致。我们期望X射线线性二向色性谱图技术和4D STEM的组合可能是研究多长度尺度上的光学各向异性材料的纳米微晶,界面,成核和矿物生长的重要多峰工具。

更新日期:2021-01-12
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