Mapping of phospholipids by MALDI imaging (MALDI-MSI): realities and expectations

Abstract

Matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) has emerged as a novel powerful MS methodology that has the ability to generate both molecular and spatial information within a tissue section. Application of this technology as a new type of biochemical lipid microscopy may lead to new discoveries of the lipid metabolism and biomarkers associated with area-specific alterations or damage under stress/disease conditions such as traumatic brain injury or acute lung injury, among others. However there are limitations in the range of what it can detect as compared with liquid chromatography-MS (LC-MS) of a lipid extract from a tissue section. The goal of the current work was to critically consider remarkable new opportunities along with the limitations and approaches for further improvements of MALDI-MSI. Based on our experimental data and assessments, improvements of the spectral and spatial resolution, sensitivity and specificity towards low abundance species of lipids are proposed. This is followed by a review of the current literature, including methodologies that other laboratories have used to overcome these challenges.

MSI.R scripts reveal volatile and semi-volatile features in low-temperature plasma mass spectrometry imaging (LTP-MSI) of chilli (Capsicum annuum)

“…Matrixassisted laser desorption/ionisation (MALDI)-time-of-flight (ToF) MSI now is an established tool for the analysis of biological tissue. But due to the requirement of vacuum in the ion source and analyser, mainly non-volatile compounds, such as proteins, peptides and some non-volatile compounds, can be mapped [1][2][3][4]. Additionally, the addition of matrices prior to MALDI-ToF analyses may disturb the study of small molecules.…”

Oxidative Lipidomics Coming of Age: Advances in Analysis of Oxidized Phospholipids in Physiology and Pathology

“…MS imaging involves collection MS or MRM data at a number of raster points across a sample, and reconstructing an abundance map from this using ion intensities (36,84), and its potential for phospholipids has been recently reviewed (113). The most commonly used method to date is MALDI, although a range of newer methods that operate at atmospheric pressure, such as desorption ESI (24), laser ablation electrospray ionization (LAESI) (86), laserspray ionization (LSI) (44), and liquid extraction surface analysis (LESA) (10), which generally have limiting resolutions between 20 and 100 lm, and higher-resolution methods such as secondary-ion mass spectrometry (SIMS, sub-micron resolution) (6) are showing promise as alternative methods.…”

Lipidomics for Clinical Diagnosis: Dye-Assisted Laser Desorption/Ionization (DALDI) Method for Lipids Detection in MALDI Mass Spectrometry Imaging

“…Along the same lines, imaging of phospholipids and cholesterol after direct analysis was first done using TOF-SIMS in mice, which allowed for the mapping of these molecules in a tissue section (Touboul et al, 2004), then in MALDI (Benabdellah et al, 2010). MALDI-MSI was also used to generate LIPID MAPS of brain and liver tissue from primates, mice and rats, or invertebrate (Astigarraga et al, 2008;Burnum et al, 2009;Colsch and Woods, 2010;Franck et al, 2009a;Garrett and Dawson, 2009;Hayasaka et al, 2009;Landgraf et al, 2009;Meriaux et al, 2010Meriaux et al, , 2011Mikawa et al, 2009;Murphy et al, 2009;Snel and Fuller, 2010;Sparvero et al, 2012;Sugiura et al, 2008Sugiura et al, , 2009Vidova et al, 2010;Wang et al, 2012Wang et al, , 2014.…”