Biomarker Discovery with Mass Spectrometry Imaging and Profiling

Mass spectrometry imaging (MSI) and mass spectrometry (MS) profiling are two especially suitable methods for recording and visualizing microscopic molecular details. Mass spectrometry imaging of larger molecules, such as proteins and intact peptides, was demonstrated using a gentler imaging technique, termed matrix‐assisted laser/desorption ionization (MALDI). This chapter presents an overview of MSI and MS profiling instrumentation, sample preparation, and data analysis, with a focus on peptide and protein detection. It provides specific examples of MSI and MS profiling in biomarker discovery. Biomarkers are commonly considered to be indicators of a disease state or a therapeutic response. They have proven useful in many fields of research, including fundamental neuroscience, microbiology, and plant biology. Matrix‐assisted laser/desorption ionization‐MSI and MS profiling are valuable tools for characterizing chemical signaling in animal nervous systems, particularly for signaling peptides, which can be both detected and sequenced on tissue.