Genetically Encoded Fluorescent Proteins Enable High-Throughput Assignment of Cell Cohorts Directly from MALDI-MS Images.

Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) provides a unique in situ chemical profile that can include drugs, nucleic acids, metabolites, lipids, and proteins. MSI of individual cells (of a known cell type) affords a unique insight into normal and disease-related processes and is a prerequisite for combining the results of MSI and other single-cell modalities (e.g.

Sample Preparation and Analysis for Imaging Mass Spectrometry.

Imaging mass spectrometry (IMS) is a novel quantitative technique used to investigative diverse biomolecules in tissue sections. Specifically, IMS uses analytical separation of mass spectrometry to determine the spatial distribution of certain lipids and/or proteins located directly on biological sections from a single tissue sample. Typically, IMS is combined with histological analysis to reveal additional distribution details of characterized biomolecules including cell type and/or subcellular localization.

Tissue preparation for the in situ MALDI MS imaging of proteins, lipids, and small molecules at cellular resolution.

The resolution of MALDI MS imaging is limited by the displacement of analytes during matrix deposition or by laser focal diameter. Here we present three methods that minimize the displacement of analytes during matrix deposition, including a method where image resolution is not limited by the laser focal diameter. The first method, matrix solution fixation, simultaneously fixes tissue while depositing matrix and is optimal for analyzing proteins and for applications requiring a fast preparation time.