Damage-free imaging of human chromosomes

Microscopy methods have provided most of our knowledge to date on the structural organisation of chromosomes. Even after decades of research, the high order structure of human chromosomes is still under investigation. The new generation of X-ray sources, X-ray Free Electron Lasers (XFELs) have opened an opportunity for imaging these complex structures with higher than optical resolution but without the radiation damage that usually accompanies X-ray imaging. Here we report our first experimental steps towards imaging micron-sized human chromosomes using the SACLA XFEL facility in Japan using the MAXIC chamber. The paper highlights the sample preparation of chromosomes, staining and drying conditions used, as well as the imaging optimisations and shows our fi rst results.