Graphene Liquid Cells Assembled through Loop‐Assisted Transfer Method and Located with Correlated Light‐Electron Microscopy

Abstract

Graphene liquid cells (GLCs) for transmission electron microscopy (TEM) enable high‐resolution, real‐time imaging of dynamic processes in water. Large‐scale implementation, however, is prevented by major difficulties in reproducing GLC fabrication. Here, a high‐yield method is presented to fabricate GLCs under millimeter areas of continuous graphene, facilitating efficient GLC formation on a TEM grid. Additionally, GLCs are located on the grid using correlated light‐electron microscopy (CLEM), which reduces beam damage by limiting electron exposure time. CLEM allows the acquisition of reliable statistics and the investigation of the most common shapes of GLCs. In particular, a novel type of liquid cell is found, formed from only a single graphene sheet, greatly simplifying the fabrication process. The methods presented in this work—particularly the reproducibility and simplicity of fabrication—will enable future application of GLCs for high‐resolution dynamic imaging of biomolecular systems.

Graphene Oxide‐Supported Microwell Grids for Preparing Cryo‐EM Samples with Controlled Ice Thickness

“…In addition, the thickness of GO window can be regulated by a type of GO transfer method (Supporting Information) and the concentration of GO solution (Figure S2, Supporting Information). Moreover, mono‐ or bilayer of graphene can be transferred to micropatterned chip with loop‐assisted transfer [ 18 ] to produce graphene‐supported microwell grid (Figure S3, Supporting Information). We also conduct Raman spectroscopy to validate the existence of GO.…”

Graphene Liquid Cell Electron Microscopy: Progress, Applications, and Perspectives

“…As formation of liquid cell depends on random collapse between graphene sheets during a spontaneous solvent-drying process, the number, size, position, and concentration of the liquid pocket is hardly controllable. Since the introduction of first-generation GLCs, several experimental protocols, such as direct or loop-scooping transfer, and fabrication of apparatuses, have been suggested to enhance fabrication yields. − However, the inhomogeneities in position and shape make searching liquid pockets difficult, accompanied by undesirable exposure of electrons. Moreover, the condensation of encapsulated liquids potentially alters the steady state of liquid cells, affecting the chemical reaction pathways. , The enriched amounts of precursor accelerate the rate of chemical reactions following the kinetic reaction path instead of equilibrium .…”

Correlative imaging for polymer science

“…Of high societal importance are at present, nano‐ and subμ‐plastic for which a methodological gap exists 28 which we believe can be filled by correlative imaging and spectroscopic analysis. For instance, by using closed graphene liquid cells in combination with fluorescent dyes 29 that can detect the release of specific components, efficient screening of (rare) events, first utilizing FM followed by EM of the prior identified positions, has come into reach. Furthermore, it is our ambition that such analysis approaches may also lead to methods for the controlled break down of polymeric materials by chemical and physical triggers into primary building blocks to facilitate the transition towards a circular economy.…”