X-Ray Diffraction (XRD) has been an indispensable tool in structural chemistry, structural biology and material science. Despite the evolution in laboratory X-ray and synchrotron sources that have occurred in the last decade, a significant roadblock in the determination of molecular structures is the ability to grow crystals of sufficient size and quality which can be time-consuming, complicated, requires a large amount of purified molecules, or even unfeasible for many biological macromolecules and pharmaceutical compounds. Three-Dimensional electron diffraction (3D ED), also known as Micro-crystal electron diffraction (MicroED), is an emerging and game-changing technique with the potential to overcome these challenges as it allows structure determination of crystals 1 billionth the size of those used for SCXRD.

Since 2007, 3D ED has allowed structure determination of landmark samples, mostly inorganic, that were considered impracticable for X-ray methods. Researchers from several labs have developed different experimental set-ups for data acquisitions, for example automated diffraction tomography (ADT) and rotation electron diffraction (RED, Stockholm University). In 2013, Gonen’s lab successfully developed the MicroED technique for the determination of macromolecular crystal structures. However, 3D ED/MicroED is still in its infancy. Further development is required in order to unleash the full potential of 3D ED/MicroED applications in materials science, structural chemistry and structural biology.

In this talk, I would like to present our latest development in specimen preparation, data collection and processing protocol, examples of crystal structure determination by MicroED, ongoing method developments and future perspective of 3D ED/MicroED and new electron crystallography methods.