Matrix-Assisted Laser Desorption/Ionization Imaging Mass Spectrometry: Technology and Applications

Abstract

Biological imaging modalities are commonly used for characterization of health and disease, but each have trade-offs in the areas of spatial resolution, molecular coverage and specificity, and targeted or untargeted approaches. Stained tissue microscopy allows high spatial resolution to visualize tissue morphologies and cellular structure but provides little molecular information. Immunohistochemistry allows high spatial resolution similar to that of organic stains with the benefit of specific molecular information with the use of antibodies. However, molecular targets must be known in advance and antibodies may select for multiple molecular species. Matrix-assisted laser desorption/ionization (MALDI) imaging mass spectrometry (IMS) allows for the untargeted detection of hundreds to thousands of molecular species within a single experiment. Although it has somewhat lower spatial resolution than microscopy, IMS enables the detection of a wide range of biological species at increased molecular coverage with high spatial resolution and sensitivity using advanced data processing techniques. Herein, we present up-to-date examples of the current technologies of MALDI IMS.