Dr. Larissa Müller places a cell sample under the laser of the element microscope.

Dr. Larissa Müller places a cell sample under the laser of the element microscope.

Source: BAM/David Weyand

BAM chemist Dr. Larissa Müller is developing an element microscope. Using a tiny laser beam, she first removes organic test material, which is turned into gas by a plasma flame. She can use this to measure the mass of different atoms and molecules and thus identify them unequivocally. Together with scientists from the Charité teaching hospital in Berlin, she is working to optimise the element microscope. In the future, it could be able to significantly improve medical diagnostics. In this interview, Dr. Müller explains how the partnership works and what new discoveries the researchers have made.

Why does your research promise great innovation in the field of medical technology?

We can use the element microscope to locate and analyse individual elements in biological cells. Previously, the method was only used for inorganic trace analysis, for example to identify metals in steel. In the meantime, lasers have become finer, meaning that they can also be used to extract and investigate biological samples down to the micrometre range. The method is still too expensive for general diagnostics, but our foundational research should prepare the way for this.

Why is BAM working with Charité Berlin?

Charité radiologist Prof. Eyk Schellenberger and his team wanted to use contrast agents to make deposits in the aortas of mice visible. This standard imaging technique was unsuccessful, because there is natural iron in the animals' vessels and it was difficult to distinguish between this and the artificially introduced iron oxide nanoparticles. Then they read about our research, which sounded like it might be helpful to them. Colleagues at Charité were marking the nanoparticles with the element europium, which does not appear in biological samples. Using the element microscope we can distinguish between the artificially introduced particle and naturally occurring iron, which makes the deposits easy to see. 

How do you rate this partnership?

BAM and Charité complement each other superbly: they use our methods for their medical research and we are able to improve these because we receive well-prepared organic samples. We often exchange ideas in person too, and work together across disciplines in a structured way. This means we have also jointly proposed a project to the Deutsche Forschungsgemeinschaft [German Research Association] in order to be able to further research our methods.

Why do you use nanoparticles in your research, and what sort of insights does this provide you with?

We want to look inside the cells themselves. To do this, we first use tiny iron oxide nanoparticles marked with europium as a probe. Secondly, we can also mark antibodies with elements like europium and in this way trace the proteins that are responsible for causing diseases. Until now, commercial imaging techniques have only been able to examine seven parameters at a time, now 30 disease parameters can be investigated simultaneously. More may be possible in future. Biologists and medics would be able to use this to distinguish between mutated and healthy individual cells in biological tissue and to analyse their characteristics.

Does the method have any further advantages?

As well as locating nanoparticles for medical diagnostics, the element microscope also improves the analysis of nanoparticles themselves. They are contained in more and more products, but their effects on the human body are still not entirely clear. By showing where and to what extent the tiny particles are found in individual cells, we can help toxicologists and authorities undertake risk analysis. This also benefits the industry, who can better analyse the nanoparticles that require labelling.