Whole-Cell Imaging at Nanometer Resolutions Using Fast and Slow Focused Helium Ions
Whole-Cell Imaging at Nanometer Resolutions Using Fast and Slow Focused Helium Ions
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DOI：
10.1016/j.bpj.2011.08.028
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发表时间：
2011-10-05
影响因子：
3.4
通讯作者：
Wattt, Frank
中科院分区：
文献类型：
--
作者：
Chen, Xiao;Udalagama, Chammika N. B.;Wattt, Frank
观察细胞和亚细胞细胞器的内部结构是了解细胞器功能的重要步骤。使用氦离子的显微镜可以在表面和亚细胞成像中发挥重要作用，因为它可以在细胞表面为慢氦离子提供亚纳米分辨率，而快氦离子可以在不显著降低分辨率的情况下穿透细胞。慢速(例如，10-50keV)的氦离子束现在可以聚焦到亚纳米尺寸(类似于0.25纳米)，并且kev氦离子显微镜可以用来以高分辨率成像细胞表面。由于使用泛洪电子束很容易中和样品电荷，表面电荷影响很小，因此可以在不需要导电金属涂层的情况下对电池表面成像。快(MeV)氦离子在穿过电池时保持直线路径。沿着离子轨迹，氦离子经历了多次电子碰撞，每次碰撞都有少量能量损失给散射的电子。通过测量每个MeV氦离子通过电池时的总能量损失，我们可以构建代表电池质量分布的能量损失图像。这项工作通过结构、元素(通过核弹性后向散射)和荧光(通过离子诱导的荧光)成像，为使用离子进行纳米分辨率的全细胞研究铺平了道路。
Observations of the interior structure of cells and subcellular organelles are important steps in unraveling organelle functions. Microscopy using helium ions can play a major role in both surface and subcellular imaging because it can provide subnanometer resolutions at the cell surface for slow helium ions, and fast helium ions can penetrate cells without a significant loss of resolution. Slow (e.g., 10-50 keV) helium ion beams can now be focused to subnanometer dimensions (similar to 0.25 nm), and keV helium ion microscopy can be used to image the surfaces of cells at high resolutions. Because of the ease of neutralizing the sample charge using a flood electron beam, surface charging effects are minimal and therefore cell surfaces can be imaged without the need for a conducting metallic coating. Fast (MeV) helium ions maintain a straight path as they pass through a cell. Along the ion trajectory, the helium ion undergoes multiple electron collisions, and for each collision a small amount of energy is lost to the scattered electron. By measuring the total energy loss of each MeV helium ion as it passes through the cell, we can construct an energy-loss image that is representative of the mass distribution of the cell. This work paves the way to use ions for whole-cell investigations at nanometer resolutions through structural, elemental (via nuclear elastic backscattering), and fluorescence (via ion induced fluorescence) imaging.