Single-Cell Level Mass Spectrometric Imaging

Secondary ion mass spectrometry (SIMS) is capable of imaging biological molecules across single cells with several hundred nanometer lateral resolution, and has the potential to examine the functional segregation of lipids in cell membranes. Lipids are believed to play a crucial role in fundamental biological functions, such as intercellular communication. For example, high curvature lipids may be concentrated in regions of the lipid bilayer where membrane fusion preferentially occurs, because these lipids allow the bilayer to bend into the high curvature structures that form throughout the membrane fusion process. Additionally, abnormalities in lipid composition may be involved in a wide range of diseases including Parkinson’s disease, Alzheimer’s disease, HIV, and atherosclerosis. Research to better understand the biological role of lipids could help in the development of disease therapies, thus improving the quality and longevity of life. This article will review SIMS as it pertains to biological samples and will address relevant progress in SIMS including fundamental ionization studies of lipids, instrumental developments, and novel applications of SIMS imaging to single-cell analyses.