Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States.
Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708, United States.
J Am Soc Mass Spectrom. 2023 May 3;34(5):869-877. doi: 10.1021/jasms.2c00353. Epub 2023 Mar 29.
Numerous preparatory methods have been developed to preserve the cellular and structural integrity of various biological tissues for different -omics studies. Herein, two preparatory methods for mass spectrometry imaging (MSI) were evaluated, fresh-frozen and sucrose-embedded, paraformaldehyde (PFA) fixed, in terms of ion abundance, putative lipid identifications, and preservation of analyte spatial distributions. Infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI)-MSI was utilized to compare the preparatory methods of interest with and without the use of the conventional ice matrix. There were 2.5-fold and 1.6-fold more lipid species putatively identified in positive- and negative-ion modes, respectively, for sucrose-embedded, PFA-fixed tissues without an ice matrix relative to the current IR-MALDESI-MSI gold-standard, fresh-frozen tissue preparation with an exogenous ice matrix. Furthermore, sucrose-embedded tissues demonstrated improved spatial distribution of ions resulting from the cryo-protective property of sucrose and paraformaldehyde fixation. Evidence from these investigations supports sucrose-embedding without ice matrix as an alternative preparatory technique for IR-MALDESI-MSI.
已经开发出许多预备方法来保存各种生物组织的细胞和结构完整性，以用于不同的组学研究。在此，评估了两种用于质谱成像 (MSI) 的预备方法，即新鲜冷冻和蔗糖包埋、多聚甲醛 (PFA) 固定，从离子丰度、潜在脂质鉴定以及分析物空间分布的保留方面进行了评估。利用红外基质辅助激光解吸电喷雾电离 (IR-MALDESI)-MSI 比较了感兴趣的预备方法，有无使用常规冰基质。在正离子和负离子模式下，分别有 2.5 倍和 1.6 倍的更多脂质种类被推测为蔗糖包埋、无冰基质的 PFA 固定组织，相对于当前的 IR-MALDESI-MSI 金标准，具有外源性冰基质的新鲜冷冻组织。此外，蔗糖包埋组织显示出由于蔗糖和多聚甲醛固定的冷冻保护特性而导致的离子空间分布得到改善。这些研究结果表明，无冰基质的蔗糖包埋作为 IR-MALDESI-MSI 的替代预备技术是可行的。
