ToF-SIMS imaging of lipids in cell membranes

Secondary ion mass spectrometry (SIMS) has been in use in biomedical imaging for more than three decades and has resulted in some important biomedical discoveries. However, SIMS has not become a part of most biologists' instrumentarium, even though this method enables chemical analysis in the context of anatomical regions and even subcellular structures. Secondary ions characteristic of a range of important lipids can now be efficiently produced from cell membranes and imaged by SIMS. Recently developed ion sources producing cluster primary ions, in combination with modem, sensitive time-of-flight (ToF) mass analyzers, have enabled this new bioimaging method. This article briefly describes cell membranes and their lipids as well as the new primary ion sources, and moves on to review recent biomembrane studies by time-of-flight secondary ion mass spectrometry (ToF-SIMS) and related methods. Further refinements in equipment and other methodology that will facilitate the use of SIMS in biomembrane studies are suggested. It is concluded that ToF-SIMS mass spectrometry for membrane and other biology applications is definitely on the rise. Copyright (C) 2006 John Wiley & Sons, Ltd.