Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
Ministry of Education Key Laboratory of Protein Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China.
ACS Nano. 2021 Oct 26;15(10):16562-16571. doi: 10.1021/acsnano.1c06233. Epub 2021 Sep 27.
Cryo-electron microscopy (cryo-EM) has emerged as a vital tool to reveal the native structure of beam-sensitive biomolecules and materials. Yet high-resolution cryo-EM analysis is still limited by the poorly controlled specimen preparation and urgently demands a robust supporting film material to prepare desirable samples. Here, we developed a bilayer Janus graphene membrane with the top-layer graphene being functionalized to interact with target molecules on the surface, while the bottom layer being kept intact to reinforce its mechanical steadiness. The ultraclean and atomically thin bilayer Janus membrane prepared by our protocol on one hand generates almost no extra noise and on the other hand reduces the specimen motion during cryo-EM imaging, thus allowing the atomic-resolution characterization of surface functional groups. Using such Janus membranes in cryo-EM specimen preparation, we were able to directly image the lithium dendrite and reconstruct macromolecules at near-atomic resolution. Our results demonstrate the bilayer Janus design as a promising supporting material for high-resolution cryo-EM and EM imaging.
冷冻电子显微镜（cryo-EM）已经成为揭示对电子束敏感的生物分子和材料的天然结构的重要工具。然而，高分辨率的 cryo-EM 分析仍然受到样品制备控制不佳的限制，迫切需要一种稳健的支撑膜材料来制备理想的样品。在这里，我们开发了一种双层 Janus 石墨烯膜，其顶层石墨烯被功能化以与表面上的目标分子相互作用，而底层则保持完整以增强其机械稳定性。我们的方案制备的超清洁和原子级薄的双层 Janus 膜一方面几乎不会产生额外的噪声，另一方面减少了 cryo-EM 成像过程中的样品运动，从而允许对表面官能团进行原子分辨率的表征。在 cryo-EM 样品制备中使用这种 Janus 膜，我们能够直接对锂枝晶进行成像，并以近原子分辨率重构大分子。我们的结果表明，双层 Janus 设计是高分辨率 cryo-EM 和 EM 成像的有前途的支撑材料。
