5.1 The presence of cell growth medium complicates a direct analysis of cells with SIMS. Attempts to wash out the nutrient medium results in the exposure of cells to unphysiological reagents that may also alter their chemical composition. This obstacle is overcome by using a sandwich freeze-fracture method (1). This cryogenic method has provided a unique way of sampling individual cells in their native state for SIMS analysis.

5.2 The procedure described here has been successfully used for imaging Na⁺ and K⁺ ion transport (3), calcium alterations in stimulated cells (4,5), and localization of therapeutic drugs and isotopically labeled molecules in single cells (6). The frozen freeze-dried cells prepared according to this method have been checked for SIMS matrix effects (7). Ion image quantification has also been achieved in this sample type (8).

5.3 The procedure described here is amenable to a wide variety of cell cultures and provides a way for studying the response of individual cells for chemical alterations in the state of health and disease and localization of isotopically-labeled molecules and theraputic drugs in cell culture models.

1.1 This guide provides the Secondary Ion Mass Spectrometry (SIMS) analyst with a cryogenic method for analyzing individual tissue culture cells growing in vitro. This guide is suitable for frozen-hydrated and frozen-freeze-dried sample types. Included are procedures for correlating optical, laser scanning confocal and secondary electron microscopies to complement SIMS analysis.

1.2 This guide is not suitable for cell cultures that do not attach to the substrate.

1.3 This guide is not suitable for any plastic embedded cell culture specimens.

1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.