Shanghai Cancer Center and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, P. R. China.
Department of Chemistry, Fudan University, Shanghai, 200433, P. R. China.
Sci Rep. 2017 Mar 15;7:44466. doi: 10.1038/srep44466.
Matrix assisted laser desorption/ionization (MALDI) imaging mass spectrometry (IMS) is an increasingly important technique for detection and spatial localization of phospholipids on tissue. Due to the high abundance and being easy-to-ionize of phosphatidylcholine (PC), therefore, selecting matrix to yield signals of other lipids has become the most crucial factor for a successful MALDI-IMS analysis of phospholipids. Herein, graphene oxide (GO) was proposed as a new matrix to selectively enhance the detection of other types of phospholipids that are frequently suppressed by the presence of PC in positive mode. Compared to the commonly used matrix DHB, GO matrix significantly improved signal-to-noise ratios of phospholipids as a result of its high desorption/ionization efficiency for nonpolar compounds. Also, GO afforded homogeneous crystallizations with analytes due to its monolayer structure and good dispersion, resulting in better reproducibility of shot-to-shot (CV < 13%) and spot-to-spot (CV < 14%) analysis. Finally, GO matrix was successfully applied to simultaneous imaging of PC, PE, PS and glycosphingolipid in the mouse brain, with a total of 65 phospholipids identified.
基质辅助激光解吸/电离（MALDI）成像质谱（IMS）是一种用于检测和定位组织中磷脂的重要技术。由于磷脂酰胆碱（PC）含量丰富且易于离子化，因此，选择能够产生其他脂质信号的基质成为成功分析磷脂的 MALDI-IMS 的最关键因素。在此，我们提出氧化石墨烯（GO）作为一种新的基质，用于选择性增强正模式下因 PC 存在而经常受到抑制的其他类型磷脂的检测。与常用的基质 DHB 相比，GO 基质由于对非极性化合物具有高的解吸/电离效率，因此显著提高了磷脂的信噪比。此外，由于其单层结构和良好的分散性，GO 与分析物形成均匀的结晶，从而使 shot-to-shot（CV<13%）和 spot-to-spot（CV<14%）分析具有更好的重现性。最后，GO 基质成功应用于小鼠脑内 PC、PE、PS 和糖脂的同时成像，共鉴定出 65 种磷脂。
