Soft X-ray induced radiation damage in thin freeze-dried brain samples studied by FTIR microscopy

Abstract

In order to push the spatial resolution limits to the nanoscale, synchrotron-based soft X-ray microscopy (XRM) experiments require higher radiation doses to be delivered to materials. Nevertheless, the associated radiation damage impacts onthe integrity of delicate biological samples. Herein, the extent of soft X-ray radiation damage in popular thin freeze-dried brain tissue samples mounted onto Si3N4 membranes, as highlighted by Fourier transform infrared microscopy (FTIR), is reported. The freeze-dried tissue samples were found to be affected by general degradation of the vibrational architecture, though these effects were weaker than those observed in paraffin-embedded and hydrated systems reported in the literature. In addition, weak, reversible and specific features of the tissue-Si3N4 interaction could be identified for the first time upon routine soft X-ray exposures, further highlighting the complex interplay between the biological sample, its preparation protocol and X-ray probe.