Reproductive cells are a very special kind of material for the analysis. Depending on the species, their dimensions allow for the application of mass spectrometry imaging-based techniques to receive a reasonable data for interpretation of their condition without any additional sample preparation steps, except for typical sample preparation characteristic for IMS protocols. A comparison between lipid profiles of oocytes could answer the question of the overall quality of the cells in the function of time or conditions of storage. Even tiny differences in the lipid profiles, but still detectable by bioinformatic analysis, could be crucial for the estimation of the conditions of the cells in various stages of development or aging. In our study, MALDI-TOF/TOF MSI was used to analyze and visualize the single oocytes. We deposited the cells on the transparent indium-tin-oxide (ITO) glass and marked their positions, which allowed for the fast localization of the cells and precise laser targeting in the ion source. We also optimized the usage of different MALDI matrices and different approaches. The proposed way of measurement allows analyzing quite a significant quantity of oocytes in a reasonably short time. During the analysis, the lipid composition of the single cell was successfully estimated in a conventional usage of the MALDI ion source, and the localization of lipids was confirmed by imaging mass spectrometry (IMS) analysis. The observed quantity of the lipids allowed for the application of the LIFT™ technique to obtain MS/MS spectra sufficient for lipids' unambiguous identification. We hope that our idea of the oocyte analysis will help to elucidate chemical changes that accompany different processes in which oocytes are involved. There could be such fascinating phenomena as the oocyte maturation, changes in the lipid components during their storage, and much more.

中文翻译：

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MALDI-TOF MS对脂质组学进行小鼠单卵母细胞成像。

生殖细胞是一种非常特殊的分析材料。根据物种的不同，它们的尺寸允许应用基于质谱成像的技术来接收合理的数据，以解释其状况，而无需任何额外的样品制备步骤，IMS协议的典型样品制备特性除外。卵母细胞脂质分布之间的比较可以回答时间或储存条件下细胞整体质量的问题。脂质谱中的微小差异，但仍可通过生物信息学分析检测到，对于估计发育或衰老各个阶段的细胞状况可能至关重要。在我们的研究中，MALDI-TOF / TOF MSI用于分析和可视化单个卵母细胞。我们将细胞沉积在透明的氧化铟锡（ITO）玻璃上，并标记了它们的位置，从而实现了细胞的快速定位以及离子源中的精确激光定位。我们还优化了不同MALDI矩阵和不同方法的用法。所提出的测量方式允许在相当短的时间内分析相当多的卵母细胞。在分析过程中，已按常规使用MALDI离子源成功估算了单个细胞的脂质组成，并通过成像质谱（IMS）分析确认了脂质的定位。观察到的脂质量允许应用LIFT™技术获得足以对脂质进行明确鉴定的MS / MS光谱。我们希望我们对卵母细胞分析的想法将有助于阐明伴随卵母细胞参与的不同过程的化学变化。可能会出现令人着迷的现象，如卵母细胞成熟，脂质成分在储存过程中的变化等。