Simultaneous cryo X-ray ptychographic and fluorescence microscopy of green algae
Simultaneous cryo X-ray ptychographic and fluorescence microscopy of green algae
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DOI：
10.1073/pnas.1413003112
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发表时间：
2015-02-24
影响因子：
11.1
通讯作者：
Jacobsen, Chris J.
中科院分区：
文献类型：
--
作者：
Deng, Junjing;Vine, David J.;Jacobsen, Chris J.
微量金属在正常和致病的生物功能中起着重要作用。X射线荧光显微镜揭示微量元素与结合亲和力（不像与可见光荧光团）和提高灵敏度相对于电子探针的依赖。然而，X射线荧光对于显示构成大部分细胞材料的轻元素不是非常敏感。在这里，我们表明，X射线重叠关联成像可以结合荧光成像细胞结构和微量元素分布在冷冻水化细胞在低温下，具有较高的结构和化学保真度。重叠关联重建算法以超出照明透镜或光束尺寸的分辨率提供相位和吸收对比度图像。使用5.2 keV的X射线，我们已经获得了亚30 nm分辨率的结构图像和类似于90 nm分辨率的荧光图像的几个元素在冷冻水合绿色藻类。这种结合的方法提供了一种研究微量元素在其结构背景中的作用的方法。
Trace metals play important roles in normal and in disease-causing biological functions. X-ray fluorescence microscopy reveals trace elements with no dependence on binding affinities (unlike with visible light fluorophores) and with improved sensitivity relative to electron probes. However, X-ray fluorescence is not very sensitive for showing the light elements that comprise the majority of cellular material. Here we show that X-ray ptychography can be combined with fluorescence to image both cellular structure and trace element distribution in frozen-hydrated cells at cryogenic temperatures, with high structural and chemical fidelity. Ptychographic reconstruction algorithms deliver phase and absorption contrast images at a resolution beyond that of the illuminating lens or beam size. Using 5.2-keV X-rays, we have obtained sub-30-nm resolution structural images and similar to 90-nm-resolution fluorescence images of several elements in frozen-hydrated green algae. This combined approach offers a way to study the role of trace elements in their structural context.