3D elemental and structural analysis of biological specimens using electrons and ions

We demonstrate the utility of focused ion beam scanning electron microscopy combined with energy dispersive x-ray spectrometry for 3D morphological and elemental correlative analysis of subcellular features. Although recent advances in super-resolution light microscopy techniques and traditional transmission electron microscopy methods can provide cellular imaging at a wide range of length scales, simultaneous 3D morphological and elemental imaging of cellular features at nanometre scale can only be achieved with techniques such as focused ion beam scanning electron microscopy with energy dispersive x-ray spectrometry capability. We demonstrate the technique by analysing the 3D silicon cell wall structure of a marine diatom, Thalassiosira pseudonana. This study also highlights the limitations of the technique in its current state and suggests several possible improvements needed for the routine use of the technique for biological specimens.