PREPARATION OF BIOLOGICAL SAMPLES FOR ION MICROSCOPY

Ion Microscopy is a powerful technique for intracellular elemental localization in biological specimens. The effective use of this technique depends on the reliability of sample preparation. An ideal sample preparation should preserve the chemical and structural integrity of a living cell, and it should also satisfy the instrumental requirements for analysis. This article critically reviews different methods of sample preparation for diffusible element analysis in soft biological tissues and cultured cells. Frozen freeze-dried tissue cryosections mounted on a smooth conducting substrate provide reliable specimens for ion microscopic analysis. For tissue culture cells, a cryo freeze-fracture freeze-dry method can be used for diffusible element localization and ion transport studies. Ion images of physiologically important diffusible elements such as Ca, K, and Na are included to show their intracellular distribution in tissue sections and cultured cells. Typical sample preparation artifacts are also discussed.