Why don’t biologists use SIMS? A critical evaluation of imaging MS

Secondary ion mass spectrometry is commonly used to study many different types of complex surfaces. Yet, compared with MALDI and ESI– MS, SIMS has not made a significant impact in biological or biomedical research. The key features of the technique, namely high spatial resolution, high detection efficiency of ions spanning a wide m/z range, surface sensitivity and the high scan rates seem to match ideally with several questions posed at the cellular level. To this date, SIMS has had only limited success in the biological arena. Why is this and what is needed to change this? This discussion paper will critically review the advances and the usefulness of SIMS in biomedical research and compare it to other approaches that offer spatially resolved molecular information available to a researcher with a biological interest.We will demonstrate that the type of information generated by the various incarnations of SIMS is strongly dependent on sample preparation and surface condition and these phenomena are only poorly understood. Modern approaches such as the cluster gun developments, ME-SIMS, gold coating and MALDI stigmatic imaging on a SIMS instrument might change the perception of SIMS being a tool for semiconductor manufacturers and physicists, and might persuade biologists to use these innovative mass spectrometric imaging tools.