Jiang Xi, Xuan Sunting, Zuckermann Ronald N, Glaeser Robert M, Downing Kenneth H, Balsara Nitash P
Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA94720, USA.
Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA94720, USA.
Microsc Microanal. 2021 Aug;27(4):767-775. doi: 10.1017/S1431927621000520.
We introduce a novel composite holey gold support that prevents cryo-crinkling and reduces beam-induced motion of soft specimens, building on the previously introduced all-gold support. The composite holey gold support for high-resolution cryogenic electron microscopy of soft crystalline membranes was fabricated in two steps. In the first step, a holey gold film was transferred on top of a molybdenum grid. In the second step, a continuous thin carbon film was transferred onto the holey gold film. This support (Au/Mo grid) was used to image crystalline synthetic polymer membranes. The low thermal expansion of Mo is not only expected to avoid cryo-crinkling of the membrane when the grids are cooled to cryogenic temperatures, but it may also act to reduce whatever crinkling existed even before cooling. The Au/Mo grid exhibits excellent performance with specimens tilted to 45°. This is demonstrated by quantifying beam-induced motion and differences in local defocus values. In addition, images of specimens on the Au/Mo grids that are tilted at 45° show high-resolution information of the crystalline membranes that, after lattice-unbending, extends beyond 1.5 Å in the direction perpendicular to the tilt axis.
我们在之前推出的全金支撑体的基础上，引入了一种新型复合多孔金支撑体，该支撑体可防止低温起皱并减少软质标本的束流诱导运动。用于软质晶体膜高分辨率低温电子显微镜的复合多孔金支撑体分两步制作。第一步，将多孔金膜转移到钼网上。第二步，将连续的薄碳膜转移到多孔金膜上。这种支撑体（金/钼网）用于对晶体合成聚合物膜进行成像。钼的低热膨胀不仅有望避免在将网冷却至低温时膜出现低温起皱，而且还可能起到减少甚至在冷却之前就已存在的任何起皱的作用。金/钼网在标本倾斜至45°时表现出优异性能。这通过量化束流诱导运动和局部散焦值的差异得以证明。此外，倾斜45°的金/钼网上标本的图像显示了晶体膜的高分辨率信息，在晶格展开后，该信息在垂直于倾斜轴的方向上延伸超过1.5埃。
