In September 2025, I visited ELDICO Scientific in Allschwil, Switzerland, for a Short-Term Scientific Mission (STSM) under the COST Action CA22107 – BEST-CSP.  Hosted by Dr.  Gunther Steinfeld, the Founder & Principal Scientist at ELDICO, my work focused on applying three-dimensional electron diffraction (3D-ED) to study photoswitchable organic materials at the nanocrystallographic level.

Conventional crystallographic analysis depends on large single crystals for X-ray diffraction, but many functional and drug-like molecules form only micro- or nanocrystals, which are unsuitable for XRD. Moreover, uniform photoexcitation is difficult in large crystals. In contrast, 3D-ED enables structural studies on nanoscale crystals and allows detection of light-induced transformations with high sensitivity.  

During the mission, I investigated azobenzene derivatives and Axitinib, both capable of reversible trans–cis photoisomerization. Using the ED-1 electron diffractometer, I collected datasets before and after controlled UV irradiation. Noticeable changes in diffraction patterns confirmed that 3D-ED can detect light-driven molecular rearrangements—an encouraging step toward understanding how light affects the structure of photoactive and druggable molecules.  This STSM directly supports BEST-CSP objectives by generating benchmark datasets, developing in-situ photo-irradiation protocols, and demonstrating the integration of 3D-ED into CSP workflows. The collaboration between IMC CAS, ELDICO Scientific, and ELI Beamlines will continue through data analysis and a forthcoming joint publication.

Beyond the scientific outcomes, this experience was personally enriching, thanks to STSM support. Working closely with ELDICO’s research team and operating advanced instrumentation like the ED-1 provided me with valuable technical skills and new scientific perspectives that will strongly influence my future research.