National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, China.
Key Laboratory for Power Machinery and Engineering of Ministry of Education, Shanghai Jiao Tong University, Shanghai, China.
Methods Mol Biol. 2021;2306:285-298. doi: 10.1007/978-1-0716-1410-5_19.
Desorption electrospray ionization mass spectrometry imaging (DESI-MSI) can record 2D distribution of polar lipids in tissue slices at ambient condition. However, sensitivity of DESI-MSI for nonpolar lipids is restricted by low ionization efficiency and severe ion suppression. Here, a compact post-photoionization assembly combined with DESI (DESI/PI) was developed for simultaneous imaging polar and nonpolar lipids in tissue sections by switching off/on a portable krypton lamp. Compared with DESI, higher signal intensities of nonpolar compounds could be detected with DESI/PI. We describe the fabrication, optimization, implementation, and data transformation for imaging both the polar and nonpolar lipids in mouse brain tissue using an Agilent 6224 Accurate-Mass TOF mass spectrometer. More than ten nonpolar lipids including cholesterol and GalCer lipids were detected by DESI/PI in the positive ion mode, compared with that by DESI. In the negative-ion mode, ion yields of DESI/PI for lipids (HexCer, PE, and PE-P) were also increased by several folds.
解吸电喷雾电离质谱成像（DESI-MSI）可以在环境条件下记录组织切片中极性脂质的 2D 分布。然而，DESI-MSI 对非极性脂质的灵敏度受到低离化效率和严重的离子抑制的限制。在这里，我们开发了一种紧凑的后光解吸组件，该组件与 DESI（DESI/PI）相结合，通过关闭/打开便携式氪灯来实现对组织切片中极性和非极性脂质的同时成像。与 DESI 相比，DESI/PI 可以检测到更高强度的非极性化合物信号。我们描述了使用安捷伦 6224 精确质量 TOF 质谱仪在小鼠脑组织中同时成像极性和非极性脂质的制造、优化、实施和数据转换。与 DESI 相比，DESI/PI 在正离子模式下检测到了十多种非极性脂质，包括胆固醇和 GalCer 脂质。在负离子模式下，DESI/PI 对脂质（HexCer、PE 和 PE-P）的离子产率也增加了几倍。
