Localized in Situ Hydrogel-Mediated Protein Digestion and Extraction Technique for on-Tissue Analysis

Glenn A. Harris, Joshua J. Nicklay, Richard M. Caprioli
2013 Analytical Chemistry  
A simultaneous on-tissue proteolytic digestion and extraction method is described for the in-situ analysis of proteins from spatially distinct areas of a tissue section. The digestion occurs on-tissue within a hydrogel network, and peptides extracted from this gel are identified with liquid chromatography tandem MS (LC-MS/MS). The hydrogels are compatible with solubility agents (e.g. chaotropes and detergents) known to improve enzymatic digestion of proteins. Additionally, digestions and
more » ... ions are compatible with Imaging Mass Spectrometry (IMS) experiments. As an example application, an initial IMS experiment was conducted to profile lipid species using a traveling wave ion mobility mass spectrometer. On-tissue MS/MS was also performed on the same tissue section to identify lipid ions that showed spatial differences. Subsequently, the section underwent an on-tissue hydrogel digestion to reveal 96 proteins that co-localized to the rat brain cerebellum. Hematoxylin and Eosin (H & E) staining was then performed to provide additional histological information about the tissue structure. This technology provides a versatile workflow that can be used to correlate multiple complementary analytical approaches in the analysis of a single tissue section.
doi:10.1021/ac3031493 pmid:23402265 pmcid:PMC3595595 fatcat:wgq4cj67o5arhnqxtuhu7ckgb4