Spatial Mapping of Cellular Metabolites Using DESI Ion Mobility Mass Spectrometry

Spatial mapping of cellular metabolites, such as neurotransmitters and lipids, on the tissue, can increase our understanding of the biological functions of those molecules. Mass spectrometry imaging (MSI) techniques, such as desorption electrospray ionization (DESI), have not demonstrated the ability to perform metabolite analysis at mammalian single cell level yet. However, they can be a valuable tool to provide insight into cellular metabolism in a very small population (tens) of cells. DESI MSI, coupled with ion mobility separation, improves the peak capacity and signal-to-noise ratio of detected analytes by separating a molecule of interest from interfering isobaric species found in a complex biological matrix. Here we present a protocol for mapping cellular metabolites neurotransmitters, such as serotonin, adenosine, and glutamine directly in brain tissue samples using DESI MSI.