Nanoscale Examination of Biological Tissues Using X-ray Spectromicroscopy
Nanoscale Examination of Biological Tissues Using X-ray Spectromicroscopy
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使用 X 射线光谱显微镜对生物组织进行纳米级检查
DOI：
10.1017/s143192761801468x
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发表时间：
2018
影响因子：
2.8
通讯作者：
Everett J
中科院分区：
文献类型：
--
作者：
Everett J
确定生物材料中化合物的组成和分布是理解驱动生命的化学的基础。此外，化学稳态的特定区域变化与疾病状态有关[1]。用于探索这些关系的传统技术依赖于固定剂和染料的使用，这可以显着改变样品材料的天然化学性质 [2]。在这里，我们描述了使用 X 射线光谱显微镜技术扫描透射 X 射线显微镜 (STXM) 制备和检查生物样品材料（包括人体组织）的方法。通过 STXM，我们以纳米级分辨率显示生物样品中有机和无机材料的分布和形态。重要的是，这种方法不需要使用染料、醛固定剂或造影剂，因此为生物样品的天然化学提供了前所未有的洞察力。人脑组织经过乙醇脱水并嵌入由等摩尔三羟甲基丙烷三缩水甘油醚：4, 4'-亚甲基双（2-甲基环己胺）组成的树脂中。使用非金属刀片切割嵌入样品的半薄（通常为 200-500 nm）切片，然后安装到支架上。在碳K-边缘、氧K-边缘、钙L-边缘和铁L-边缘进行STXM。为了绘制化学物质的分布图，在与感兴趣的峰值特征相对应的能量和距该特征几个电子伏特的非峰值能量处拍摄了配对图像。然后从峰值图像中减去非峰值图像以给出差异图。图 1 展示了在碳 K 边缘成像的 200 nm 厚的人体黑质组织切片的这一过程。这里，峰图像（288.3 eV；左）对应于酰胺基团（蛋白质）的 1s 到 π* 跃迁，而非峰图像（290 eV；中）对应于树脂的主要碳 K 边缘吸收特征（另请参见 [1]）。这种图像处理可以去除伪影和背景树脂吸收特征，从而揭示真实的组织结构。从这些差异图可以看出，组织结构在所呈现的 160 µm2 区域内保存完好。高分辨率地图拍摄于约。 40 nm 分辨率（右图；插图）显示细胞结构，还显示亚细胞器。
Establishing the composition and distribution of chemical compounds within biological materials is fundamental to understanding the chemistry that drives life. Additionally, region-specific changes in chemical homeostasis have been linked to disease states [1]. Traditional techniques used to explore these relationships rely on the use of fixatives and dyes, which can significantly alter the native chemistry of the sample material [2]. Here we describe methodology for the preparation and examination of biological sample materials, including human tissues, using the X-ray Spectromicroscopy technique Scanning Transmission X-ray Microscopy (STXM). Through STXM we show the distribution and speciation of organic and inorganic materials within biological samples at a nanoscale resolution. Importantly this approach does not require the use of dyes, aldehyde fixatives or contrast agents and therefore offers an unprecedented insight into the native chemistry of biological samples.Human brain tissues were ethanol dehydrated and embedded in a resin comprised of equimolar trimethylolpropane triglycidyl ether: 4, 4’-methylenebis (2-methylcyclohexylamine). Semi-thin (typically 200-500 nm) sections from embedded samples were cut using a non-metallic blade, before being mounted onto a support. STXM was performed at the carbon K-edge, oxygen K-edge, calcium L-edge and iron L-edge. To map distributions of chemical species, paired images were taken at the energy corresponding to a peak feature of interest and an off-peak energy a few eV away from this feature. The off-peak image is then subtracted from the peak image to give a difference map. This process is demonstrated in Figure 1, for a 200 nm thick section of human substantia nigra tissue imaged at the carbon K-edge. Here the peak image (288.3 eV; left) corresponds to the 1s to π* transition for amide groups (proteins), whereas the offpeak image (290 eV; middle) corresponds to the principal carbon K-edge absorption feature for the resin (see also [1]). This image processing allows artifacts and background resin absorption features to be removed, revealing the true tissue structure. From these difference maps, tissue structure is shown to be well preserved over the 160 µm2 area presented. The high resolution map taken at ca. 40 nm resolution (right; inset) shows cellular structures, also displaying subcellular organelles.
影响因子：
8.6
作者：
N. Telling;James Everett;J. Collingwood;J. Dobson;G. van der Laan;Joseph J. Gallagher;Jian Wang
通讯作者：
N. Telling;James Everett;J. Collingwood;J. Dobson;G. van der Laan;Joseph J. Gallagher;Jian Wang