Characterization of cell cultures with ToF-SIMS and laser-SNMS

We have applied time-of-flight secondary ion mass spectrometry (ToF-SIMS) and non-resonant laser secondary neutral mass spectrometry (NR-laser-SNMS) for examining freeze-fractured, freeze-dried primary osteoblast and cancer cells. Both techniques can simultaneously detect all masses with very high sensitivity and subcellular resolution. Because most of the sputtered particles are neutrals, laser-SNMS has the additional advantage of being more quantitative. With both techniques, high-resolution elemental and molecular images were obtained from cell cultures. Ion-induced electron images were used to identify individual cells. Measurement of the Na/K ratio clearly demonstrated that the preparation techniques used are appropriate for preserving the chemical and structural integrity of living cells. Presputtering the samples with different primary ion dose densities makes it possible to take three-dimensional images and to monitor the elemental distributions inside the cells. From the efficiency achieved, it can be concluded that ToF-SIMS and laser-SNMS are well suited for imaging trace element and molecule concentrations in biological samples. Copyright (C) 2002 John Wiley Sons, Ltd.