Chen Yanfeng, Liu Ying, Allegood Jeremy, Wang Elaine, Cachón-González Begoña, Cox Timothy M, Merrill Alfred H, Sullards M Cameron
School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, USA.
Methods Mol Biol. 2010;656:131-46. doi: 10.1007/978-1-60761-746-4_7.
Matrix deposition is a critical step in tissue imaging by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). It greatly affects the quality of MALDI imaging, especially for the analytes (such as lipids) that may easily dissolve in the solvent used for the matrix application. This chapter describes the use of an oscillating capillary nebulizer (OCN) to spray small droplets of matrix aerosol onto the sample surface for improved matrix homogeneity, reduced crystal size, and controlled solvent effects. This protocol allows visualization of many different lipid species and, of particular interest, sphingolipids in tissue slices of Tay-Sachs/Sandhoff disease by imaging MALDI-MS. The structures of these lipids were identified by analysis of tissue extracts using electrospray ionization in conjunction with tandem mass spectrometry (MS/MS and MS(3)). These results illustrate the usefulness of tissue imaging MALDI-MS with matrix deposition by OCN for the molecular analysis in normal physiology and pathology. In addition, the observation of numerous lipid subclasses with distinct localizations in the brain slices demonstrates that imaging MALDI-MS could be effectively used for "lipidomic" studies.
基质沉积是基质辅助激光解吸/电离质谱（MALDI-MS）进行组织成像的关键步骤。它极大地影响MALDI成像的质量，尤其是对于那些可能容易溶解在用于施加基质的溶剂中的分析物（如脂质）。本章介绍了使用振荡毛细管雾化器（OCN）将基质气溶胶小液滴喷到样品表面，以提高基质均匀性、减小晶体尺寸并控制溶剂效应。该方案通过成像MALDI-MS实现了在泰-萨克斯病/桑德霍夫病组织切片中可视化许多不同的脂质种类，尤其是鞘脂。通过使用电喷雾电离结合串联质谱（MS/MS和MS(3)）分析组织提取物，确定了这些脂质的结构。这些结果说明了通过OCN进行基质沉积的组织成像MALDI-MS在正常生理学和病理学分子分析中的实用性。此外，在脑切片中观察到众多具有不同定位的脂质亚类，表明成像MALDI-MS可有效地用于“脂质组学”研究。
