ABSTRACT
This chapter briefly summarizes the Matrix-assisted laser desorption/ionization (MALDI) imaging mass spectrometry (IMS) experiment for proteins and biomarkers, to describe seminal research illustrating the strengths and versatility of the technique, and to elaborate on current advances, examples, and challenges relating to direct protein imaging by MALDI MS. It highlights examples from the author’s laboratory. In the imaging approach, the technology is a powerful discovery tool, highlighting areas of the tissue where certain proteins are abundant or absent, where proteins may colocalize with other proteins, and where proteins may localize in histologically well-defined areas. In addition to increased availability of image-specific software packages, there are a number of tools now commercially available that are designed to automate various aspects of sample preparation. Another approach to matrix application is to robotically deposit small droplets of matrix on discrete areas of the sample surface. The evolution of protein expression during normal mouse prostate development was examined with MALDI IMS technology.
