Single Molecule Imaging with Liquid Phase Electron Microscopy

Abstract Few single‐molecule experiments have enabled the direct imaging of functional biomacromolecules in real‐time in their native liquid environments, resolving their conformational adaptations, transient interactions, and intermediate states. Liquid phase electron microscopy (LP‐EM), due to its unique combination of spatial and temporal resolution, has shown to be a promising tool. Recent experiments have enabled successful imaging of intact structures of organic molecules and biological systems with an ordinary electron microscope. Adapting image processing methods and quantitative data analysis from single particle experiments based on the optical microscope, quantifying motion and relaxation of these interacting molecules allows the experimental observations of pathways, to test theoretical predictions, and discovery of new mechanisms. Combining LP‐EM with tomography, fluorescence, and mass spectroscopy allows for probing multi‐dimensional structural and dynamic information. Challenges remain in obtaining high‐quality data in large quantities, which can be improved by developing new liquid cell platforms and machine learning‐based data analysis.