Ambient Mass Spectrometry Imaging by Water-Assisted Laser Desorption/Ionization for Ex Vivo and in Vivo Applications

• Published in: Methods in molecular biology (Clifton, N.J.) Vol. 2688; p. 83
• Main Authors: Ogrinc, Nina, Chaillou, Paul, Kruszewski, Alexandre, Duriez, Cristian, Salzet, Michel, Fournier, Isabelle
• Format: Journal Article
• Language: English
• Published: United States 2023
• Subjects: Imaging, Three-Dimensional; Lasers; Light; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization - methods; Water; 3D; In vivo; Ambient ionization mass spectrometry; Topography; Robotics; Mass spectrometry imaging
• ISSN: 1940-6029
• DOI: 10.1007/978-1-0716-3319-9_8

Water-assisted laser desorption/ionization mass spectrometry (WALDI-MS), also known as SpiderMass, is an emerging ambient ionization technique for in vivo and real-time analysis. It employs a remote infrared (IR) laser tuned to excite the most intense vibrational band (O-H) of water. The water molecules act as an endogenous matrix leading to the desorption/ionization of a variety of biomolecules from tissues, particularly metabolites and lipids. WALDI-MS was recently advanced into an imaging modality for ex vivo 2D sections and 3D in vivo real-time imaging. Here, we describe the methodological aspects for performing 2D and 3D imaging experiments with WALDI-MSI and the parameters for optimizing the image acquisition.