Quantitative biological imaging by ptychographic x-ray diffraction microscopy
Quantitative biological imaging by ptychographic x-ray diffraction microscopy
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DOI：
10.1073/pnas.0905846107
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发表时间：
2010-01-12
影响因子：
11.1
通讯作者：
Salditt, Tim
中科院分区：
文献类型：
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作者：
Giewekemeyer, Klaus;Thibault, Pierre;Salditt, Tim
相干X射线衍射成像的最新进展为纳米尺度下非致密样品的可靠和定量成像铺平了道路。一年前推出的一种先进的重叠关联相干衍射成像技术消除了以前在样品制备和照明条件方面的许多限制。在这里，我们将这种最近的方法应用于生物显微镜在纳米尺度上的结构测定。我们表明，投影的电子密度的未染色和未切片的冻干细胞的细菌耐辐射球菌可以来自重建的阶段，在一个简单的和可重复的方式，与量化和小的误差。因此，这种方法可能有助于在未来的高度有争议的细菌细胞的类核结构的理解。在本研究中，细胞的估计分辨率为85 nm（半周期长度），而50 nm的分辨率被证明为光刻测试结构。相对于用于照射样品的针孔的直径，分别对于细胞和对于测试结构实现了约15和30的超分辨率。应根据应用的低剂量（约等于或等于1.3）评估这些值。10（5）戈伊，并显示与光子通量成比例。
Recent advances in coherent x-ray diffractive imaging have paved the way to reliable and quantitative imaging of noncompact specimens at the nanometer scale. Introduced a year ago, an advanced implementation of ptychographic coherent diffractive imaging has removed much of the previous limitations regarding sample preparation and illumination conditions. Here, we apply this recent approach toward structure determination at the nanoscale to biological microscopy. We show that the projected electron density of unstained and unsliced freeze-dried cells of the bacterium Deinococcus radiodurans can be derived from the reconstructed phase in a straightforward and reproducible way, with quantified and small errors. Thus, the approach may contribute in the future to the understanding of the highly disputed nucleoid structure of bacterial cells. In the present study, the estimated resolution for the cells was 85 nm (half-period length), whereas 50-nm resolution was demonstrated for lithographic test structures. With respect to the diameter of the pinhole used to illuminate the samples, a superresolution of about 15 was achieved for the cells and 30 for the test structures, respectively. These values should be assessed in view of the low dose applied on the order of similar or equal to 1.3 . 10(5) Gy, and were shown to scale with photon fluence.