Atomically Thin Bilayer Janus Membranes for Cryo-electron Microscopy
Liming Zheng, Nan Liu, Ying Liu, Ning Li, Jincan Zhang, Chongzhen Wang, Wenqing Zhu, Yanan Chen, Dongchen Ying, Jie Xu, Zi Yang, Xiaoyin Gao, Jilin Tang, Xiaoge Wang, Zibin Liang, Ruqiang Zou, Yuzhang Li, Peng Gao, Xiaoding Wei, Hongwei Wang, Hailin Peng
Abstract
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.