Illuminating interactions

In the Middle Ages, it was an alchemist's dream to produce gold from non-noble metals. Today, equipped with the knowledge of modern natural sciences, we smile at these attempts. However, the creation of new, valuable materials is as relevant now as it was then. Today, people who dedicate themselves to this task call themselves material scientists.

One of them is Antonia Neels. This modern alchemist, so to speak, works at Empa in Dübendorf. There she has headed the Centre for X-ray Analysis with ten female scientists and just as many male scientists since 2014. The lab uses X-rays to study the molecular structure of materials. "Chemistry is the science that creates new materials," says Antonia Neels. "Our investigations based on modern X-ray analytical methods, especially crystallography, make an important contribution to this."

Biomedical materials research

Materials science has a wide range of applications, from microchips to space travel. One focus of the work of Antonia Neels and her team is biomedicine. For example, the scientists are investigating materials that consist of crystalline and amorphous components. One example of such semi-crystalline materials are textile fibres, such as those woven into medical protective masks. Antonia Neels' research aims to better understand such materials. This enables to improve the mechanical stability and effectiveness of masks.

Neels' research approach is also represented by a doctoral thesis she supervised in recent years. Here, a junior scientist investigated how nanoparticles of medical active substances behave in a biological environment (proteins). The findings provide insights to the effectiveness of medicines. Also, the research related to implants and the question how they are integrated and accepted by the patient's body is of great medical importance.

Use of X-rays

For these and other scientific questions, Empa scientist Neels uses crystallography and imaging based X-ray methods. These methods are related and have in common that they use X-rays, which have a shorter wavelength than light waves and are therefore suitable for making the smallest structures on the order of nanometres (billionths of a metre) visible. In crystallography, X-rays strike crystalline material samples and produce diffractograms (diffraction patterns or images). Their evaluation provides valuable information about the 3-dimensional structure of molecules. Knowledge of these structures is indispensable for countless applications. X-ray imaging follows a different approach: also non-crystalline material such as body tissue and polymers, are characterised here via X-ray tomography revealing smallest morphological features, as it is known from medical applications.

"When I started working with these methods 30 years ago, it was very time-consuming and involved a lot of manual work. Thanks to technological advances in X-ray detectors, X-ray sources and software solutions, we have now greatly developed these analytical methods," says Antonia Neels, whose research group works at Empa's sites in Dübendorf and St. Gallen. "We are specifically developing X-ray methods for applications in the biomedical field. For nano-materials (nano-particles, body tissue) and semi-crystalline materials (polymers), we have built up an expertise in St. Gallen that allows us to engage in exciting collaborations with Swiss colleagues in science and industry," says Neels. For fifteen years, the scientist has been passing on her knowledge to the next generation of researchers with lectures at the University of Fribourg, since 2018 as a titular professor.

From East Berlin to Neuchâtel

Antonia Neels commutes by train between her places of work in Dübendorf, St. Gallen and Fribourg and her place of residence not far from Neuchâtel, where she lives with her husband and their grown-up sons Sébastien and Niklas. The fact that the native of East Berlin found a second home close to Neuchâtel is thanks to a coincidence: inspired by her father, who worked as a chemist at the Academy of Sciences in the GDR, Antonia Neels had studied chemistry in East Berlin. After graduation - the Berlin Wall had fallen shortly before - her professor received a visit from a colleague in Neuenburg. He told her about a vacant doctoral position in the field of crystallography in the French-speaking part of Switzerland. An interesting offer, thought Antonia Neels, who had learned French as a second foreign language at school.

From 1991 to 1995, Antonia Neels did her doctorate at the University of Neuchâtel. One source of inspiration during this time was Helen Stoeckli-Evans, who had previously worked as a postdoc with the British Nobel Prize winner Dorothy Hodgkin, a co-founder of X-ray crystallography. Antonia Neels dedicated her doctoral thesis to the structural analysis of coordination polymers with magnetic properties. After a year as a postdoc at Texas A&M University (1995-96), Neels returned to the University of Neuchâtel as a senior assistant (1998-2006) and from 2008 set up an X-ray laboratory at the CSEM research centre in Neuchâtel, together with a passionate crystallographer, Prof. Alex Dommann. There they investigated, among other things, defects and stresses in semiconductor materials that can affect the manufacturing quality of pressure sensors and other semiconductor products.

Sharing experience

Despite an impressive career with over 200 scientific publications to date, Antonia Neels sees herself as a family person. "Family means a lot to me, we hike, travel and do camping together. If you ask me about the most important event in my life, it was the birth of my sons." The personal experiences with the family feed back into the professional life. For example, when Antonia Neels supports junior researchers as a mentor. "I like to talk about my personal experiences with family and childcare in these conversations. I sometimes also encourage the women not to want to master everything on their own, but to accept support as well."

Author: Benedikt Vogel

Portrait #11 of Women in science in the fields of MAP (2021/22)