Imaging and differentiation of mouse embryo tissues by ToF-SIMS

Time-of-flight secondary ion mass spectrometry (ToF-SIMS) equipped with a gold ion gun was used to image mouse embryo sections and differentiate tissue types (brain, spinal cord, skull, rib, heart and liver). Embryos were paraffin-embedded and then deparaffinized. The robustness and repeatability of the method was determined by analyzing ten tissue slices from three different embryos over a period of several weeks. Using principal component analysis (PCA) to reduce the spectral data generated by ToF-SIMS, histopathologically identified tissue types of the mouse embryos can be differentiated based on the characteristic differences in their mass spectra. These results demonstrate the ability of ToF-SIMS to determine subtle chemical differences even in fixed histological specimens.