3D-Analysis of Biological Cells

Solids can be characterized with Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) 3D micro domain analysis. With this technique a sample undergoes intermittent bombardment by primary ions for the analysis and primary ions for sputtering of the sample. In general, this continuous bombardment leads to a destruction of (organic) bonds in the sample, such that usually only information about the element distribution can be acquired. With the C60 and Ar GCIB sputter sources, two technical innovations of recent years, the drawback of destruction of organic information is now partially overcome. To illustrate this point, ToF-SIMS images were acquired from rat kidney epithelial cells which were fixed using glutaraldehyde, a fixation protocol that preserves the internal cell structure. The epithelial cell surface is dominated by phospholipids; however, after sputtering with C60 intense phospholipid signal is found to surround a central area, rich in amino acids. Signals due to amino acids are represented in red whereas lipid signals and substrate signals are represented in green and blue, respectively. These results can be represented in virtual cross sections (large image: xy cross section, small image: xz cross section). Further details can be obtained from the corresponding publication.
Amino acids