Low Energy Electron Holography
We are developing a low-energy electron holographic microscope (LEEH) capable of operating at temperatures as low as 40K and as high as 500K, enabling the imaging of single proteins, organic molecules as well as inorganic nanometer sized objects at sub-nm spatial resolution and millisecond time resolution.
The powerful combination of the contamination-free sample preparation of natively sprayed proteins using electrospray ion beam deposition with the unique characterization method of LEEH enables the imaging of single biomolecules like proteins and protein complexes, currently with 7 Ångstrom resolution without any averaging over an ensemble. The use of coherent, low energy electrons with kinetic energies of 30-250eV allows for the imaging of single biomolecules without imposing radiation damage to the molecules. Thus, in contrast to structure determination by X-ray diffraction or in cryo electron microscopy, no averaging over several different molecules is required.
Work at low temperatures in a low vibration environment is in progress to push the resolution of the microscope to the atomic scale. Moreover, the temporal resolution of the imaging is in the range of 10 - 100 ms and is therefore suitable to access dynamic properties or conformational changes in one individual bio/macromolecule allowing new insights into biomolecular processes.