X-ray microscopy with synchrotron radiation: applications to cellular biology.

X-ray microscopy using synchrotron radiation is a novel and promising approach to the ultrastructural investigation of the cell. In terms of resolution it lies between light and transmission electron microscopy, having a practical resolving power of 30-50 nm. Specimen preparation is minimal, a thickness of up to 10 microm can easily be accommodated and there is no need to fix, stain, dry or put the sample into vacuum. High contrast projection images of fully-hydrated whole cells in physiological medium can be obtained. The application and significance of the soft X-ray microscope to cellular biology will be discussed along with recent methodologies developed to optimise imaging, such as, cryo-preservation, immuno-labelling and elemental mapping.