X-rays Reveal the Internal Structure of Keratin Bundles in Whole Cells
X-rays Reveal the Internal Structure of Keratin Bundles in Whole Cells
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DOI：
10.1021/acsnano.5b07871
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发表时间：
2016-03-01
期刊：
影响因子：
17.1
通讯作者：
Koester, Sarah
中科院分区：
文献类型：
--
作者：
Hemonnot, Clement Y. J.;Reinhardt, Juliane;Koester, Sarah
近年来，生物细胞的X射线成像已经成为荧光和电子显微镜的补充替代品。建立了不同的技术，并成功地应用于细胞中的大分子组装和结构。然而，在分辨率达到纳米级的同时，剂量也在增加。必须制定克服或减少辐射损害的战略。在这里，我们通过结合两种不同的X射线技术，即重叠关联和纳米衍射，在一个实验中，在同一个样品上，解决这个内在的问题。我们以65 nm的分辨率获取全细胞的低剂量重叠关联成像概览图像。随后，我们从感兴趣的区域记录高分辨率的纳米衍射数据。通过比较两种模式的图像，我们可以排除辐射损伤对标本的强烈影响。从衍射数据中，我们检索定量结构信息，从细胞内束角蛋白中间丝，如5 nm的细丝半径，六边形几何排列与丝间距离为14 nm和束直径的顺序为70 nm。因此，我们提出了一个有吸引力的组合方法来回答软物质物理学，生物物理学和生物学中的广泛问题。
In recent years, X-ray imaging of biological cells has emerged as a complementary alternative to fluorescence and electron microscopy. Different techniques were established and successfully applied to macromolecular assemblies and structures in cells. However, while the resolution is reaching the nanometer scale, the dose is increasing. It is essential to develop strategies to overcome or reduce radiation damage. Here we approach this intrinsic problem by combing two different X-ray techniques, namely ptychography and nanodiffraction, in one experiment and on the same sample. We acquire low dose ptychography overview images of whole cells at a resolution of 65 nm. We subsequently record high-resolution nanodiffraction data from regions of interest. By comparing images from the two modalities, we can exclude strong effects of radiation damage on the specimen. From the diffraction data we retrieve quantitative structural information from intracellular bundles of keratin intermediate filaments such as a filament radius of 5 nm, hexagonal geometric arrangement with an interfilament distance of 14 nm and bundle diameters on the order of 70 nm. Thus, we present an appealing combined approach to answer a broad range of questions in soft matter physics, biophysics and biology.