Excellence Strategy fundingThoughts on the “Marvelous Magnifying Glass”

2 October 2025, by Christina Krätzig

Photo: UHH/Kornowski

A high-resolution electron microscope reveals the distribution of elements in a nanoparticle: lead selenide (green) and cadmium selenide (purple).

With its 5 electron microscopes, the University of Hamburg is a major location for these large pieces of equipment. The chemist Dr. Charlotte Ruhmlieb explains how to make them as useful to as many researchers as possible and why research today is inconceivable without these microscopes.

Dr. Ruhmlieb, you head the electron microscopy section in the Department of Chemistry. What role do these instruments play in research at the University of Hamburg?

We are in the very special position of having 5 of these instruments at once. Other universities would be happy with one. These microscopes easily cost several million euros and need an absolutely vibration-free, radiation-insulated room without any temperature fluctuations, and that is also expensive.

We have these devices thanks to the former spokesman for the CUI cluster of excellence, Prof. Dr. Horst Weller. He established research on nanostructures, for which we use the instruments, at the University of Hamburg. This research continues to form the heart of the cluster, which studies the properties of matter at molecular and atomic levels. Having said that, we use the microscopes for very different concerns, for example, in the Cluster of Excellence Understanding Written Artefacts (UWA) or Earth System Sciences.

What kind of inquiries are those?

For Earth Systems Sciences, we have actually studied dinosaur bones. Using the annual rings in the bones, we could ascertain the age of a sauropod. And for the UWA researchers, we created a cross-section image of an historical parchment. We wanted to make the structure of the material visible and even discovered microscopically tiny fungi that provided new information about the artifact’s history.

Why do you need electron microscopes for these kinds of investigations? What can they do that other microscopes can’t?

They can magnify to such a degree as to render individual atoms visible. Unlike other microscopes, they don’t use light directed through optical lenses; they use a ray of very rapid, electrically charged particles. These electron rays hit the object of investigation, and the particles then interact very differently—for example, they disperse or they permeate the material. These different effects create different signals that are captured and converted into an image. The image reveals details that would remain invisible with a conventional light microscope.

What challenges are facing electron microscopy at the University of Hamburg?

In the past few years, my team and I have worked on making devises for researchers throughout the entire University available, as an electron microscopy technological platform. By now we are handling investigations for researchers from areas far beyond physics and chemistry. We take on the microscopy work and help researchers evaluate the data. We also continuously work on expanding the instruments’ possibilities. In the mid-term, however, our microscopes are nearing the end of their life cycles. So we need to procure new ones and set up a new location for them in Science City Hamburg Bahrenfeld. That is a huge project for which many people at the University will have to pull together.

Last weekend, the University of Hamburg invited a working group for electron microscopy (IGEME) to share their thoughts. Why is that important?

Many universities are facing similar upheavals. This is why it was very valuable to us that 35 researchers from more than 20 universities accepted our invitation. We benefit from others’ experiences as they do from ours. And of course, visibility and presence in the community are important.

The IGEME conference and the development of the technology platform at the University of Hamburg are being funded through the Excellence Strategy of the Federal and State Governments. Developing excellent research infrastructure is one of the 5 central goals of Universität Hamburg—University of Excellence.