PhD Project by Marcus F. Hufe

Project Title: Phase-Plate Fabrication and Application for Electron Microscopy
Group: Materials at the Interface of Biology
Supervisor: Paul J. Kempen

Project Description
High resolution electron microscopy of biological samples has a huge potential. Visualizing biological structures with near atomic resolution is a key tool to understand fundamental biological processes. However, image quality and the amount of information that can be extracted from an electron microscopy image is strongly dependent on the contrast, which can be challenging when imaging biological materials. To image these weak-phase objects different techniques are necessary.

As in conventional light microscopy, phase contrast is a means to overcome this problem. This can be achieved using phase plates (PP) which are placed into the beam path of the transmission electron microscope (TEM) to increase contrast from non-uniform biological samples and thereby enabling the nano-characterization of these samples with low inherent contrast. The development of robust and reproducible phase plates is key for the continuing adoption of phase plates in cryo electron microscopy. This project is focused on the improvement of conventional phase plates, like the Zernike or Volta phase plates, and the development of novel phase plates, passive or electrostatic, with inspirations taken from Boersch or Zach phase plates for example.

Perspective
The goal of the project is to develop and fabricate phase plates to characterize biological soft-matter systems. DTU Nanolab’s state-of-the-art cleanroom will be used to develop phase plates with improved aging characteristics and reproducibility. Advanced TEM techniques will be used to investigate the effect of aging on the PP structure, and design impacts on the phase shift. There is also further space to improve PPs to increase and tune the phase contrast creation. This development and implementation of phase plates for electron microscopy, both conventional and novel, will enable improved characterization of soft materials at DTU Nanolab.