SAMPLE PREPARATION OF ANIMAL-TISSUES AND CELL-CULTURES FOR SECONDARY ION MASS-SPECTROMETRY (SIMS) MICROSCOPY

Sample preparation is a critical step in the elemental analysis of ani mal tissues and cell cultures with ion microscopy. Since live cells ca nnot be analyzed with ion microscopy, a careful sample fixation is nec essary which preserves the native structural and chemical integrity of a specimen. The evaluation of morphological and chemical integrity of a fixed specimen is necessary before any physiological explanation of ion fluxes is interpreted based on ion microscopy. For diffusible ion localization studies, strict cryogenic procedures are recommended. Ex amples are shown for diffusible ion microanalysis in frozen-freeze-dri ed tissues and cell cultures. Ion microscopy studies of tightly bound elements/molecules may be conducted in chemically fixed and/or plastic embedded specimens. Since it is not generally known which elements/mo lecules are tightly bound to the tissue matrix, a confirmation of elem ental distribution with cryogenic procedures is desirable. A recent ap proach of combining laser scanning confocal fluorescence microscopy an d ion microscopy on the same frozen freeze-dried cell is also discusse d for recognizing smaller cytoplasmic structures in ion microscopy ima ges.