1. Minimizing Crinkling of Soft Specimens Using Holey Gold Films on Molybdenum Grids for Cryogenic Electron Microscopy
- Author
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Jiang, Xi, Xuan, Sunting, Zuckermann, Ronald N, Glaeser, Robert M, Downing, Kenneth H, and Balsara, Nitash P
- Subjects
Engineering ,Materials Engineering ,cryo-crinkling ,cryo-EM ,crystalline polypeptoid membranes ,crystallography ,specimen flatness ,MSD-General ,MSD-Soft Matter EM ,Condensed Matter Physics ,Biochemistry and Cell Biology ,Microscopy ,Biochemistry and cell biology ,Materials engineering - Abstract
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.
- Published
- 2021