Australian Synchrotron, Clayton, Australia.
Proc Natl Acad Sci U S A. 2010 Sep 7;107(36):15676-80. doi: 10.1073/pnas.1001469107. Epub 2010 Aug 18.
X-ray fluorescence tomography promises to map elemental distributions in unstained and unfixed biological specimens in three dimensions at high resolution and sensitivity, offering unparalleled insight in medical, biological, and environmental sciences. X-ray fluorescence tomography of biological specimens has been viewed as impractical-and perhaps even impossible for routine application-due to the large time required for scanning tomography and significant radiation dose delivered to the specimen during the imaging process. Here, we demonstrate submicron resolution X-ray fluorescence tomography of a whole unstained biological specimen, quantifying three-dimensional distributions of the elements Si, P, S, Cl, K, Ca, Mn, Fe, Cu, and Zn in the freshwater diatom Cyclotella meneghiniana with 400-nm resolution, improving the spatial resolution by over an order of magnitude. The resulting maps faithfully reproduce cellular structure revealing unexpected patterns that may elucidate the role of metals in diatom biology and of diatoms in global element cycles. With anticipated improvements in data acquisition and detector sensitivity, such measurements could become routine in the near future.
X 射线荧光断层成像有望以高分辨率和灵敏度对未经染色和固定的生物样本中的元素分布进行三维成像，为医学、生物学和环境科学提供无与伦比的洞察力。由于扫描断层成像所需的时间长，以及在成像过程中向样本输送的辐射剂量大，因此人们一直认为对生物样本进行 X 射线荧光断层成像是不切实际的——甚至可能不可能进行常规应用。在这里，我们展示了整个未经染色的生物样本的亚微米分辨率 X 射线荧光断层成像，以 400nm 的分辨率定量测量淡水硅藻环面 Menegheniana 中 Si、P、S、Cl、K、Ca、Mn、Fe、Cu 和 Zn 三种元素的三维分布，将空间分辨率提高了一个数量级以上。生成的图谱忠实地再现了细胞结构，揭示了意想不到的模式，这些模式可能阐明金属在硅藻生物学中的作用以及硅藻在全球元素循环中的作用。随着数据采集和探测器灵敏度的预期提高，此类测量在不久的将来可能成为常规。
