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Abstract：
Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) has become an important tool for skin analysis, as it allows the simultaneous detection and localization of diverse molecular species within a sample. The use of in vivo and ex vivo human skin models is costly and presents ethical issues; therefore, reconstructed human epidermis (RHE) models, which mimic the upper part of native human skin, represent a suitable alternative to investigate adverse effects of chemicals applied to the skin. However, there are few publications investigating the feasibility of using MALDI MSI on RHE models. Therefore, the aim of this study was to investigate the effect of sample preparation techniques, i.e., substrate, sample thickness, washing, and matrix recrystallization, on the quality of MALDI MSI for lipids analysis of the SkinEthic RHE model. Images were generated using an atmospheric pressure MALDI source coupled to a high-resolution mass spectrometer with a pixel size of 5 μm. Masses detected in a defined region of interest were analyzed and annotated using the LipostarMSI platform. The results indicated that the combination of (1) coated metallic substrates, such as APTES-coated stainless-steel plates, (2) tissue sections of 6 μm thickness, and (3) aqueous washing before HCCA matrix spraying (without recrystallization), resulted in images with a significant signal intensity as well as numerous m/z values. This refined methodology using AP-MALDI coupled to a high-resolution mass spectrometer should improve the current sample preparation workflow to evaluate changes in skin composition after application of dermatocosmetics.
摘要：
基质辅助激光解吸/电离（MALDI）质谱成像（MSI）已成为皮肤分析的重要工具，因为它允许同时检测和定位样品中的不同分子种类。体内和离体人类皮肤模型的使用是昂贵的，并提出了伦理问题;因此，重建人类表皮（RHE）模型，模仿人体皮肤的上部，代表了一种合适的替代方法来研究应用于皮肤的化学物质的不利影响。然而,很少有出版物研究在RHE模型上使用MALDIMSI的可行性。因此,这项研究的目的是研究样品制备技术的效果，即，基材,样品厚度,washing,和基体再结晶，关于MALDIMSI用于SkinEthicRHE模型脂质分析的质量。使用与像素尺寸为5μm的高分辨率质谱仪耦合的大气压MALDI源产生图像。使用LipostarMSI平台分析和注释在定义的感兴趣区域中检测到的质量。结果表明，（1）涂层金属基材的组合，如APTES涂层不锈钢板，(2)6μm厚的组织切片,和（3）在HCCA基质喷涂之前的水洗涤（没有重结晶），导致图像具有显著的信号强度以及许多m/z值。这种使用AP-MALDI与高分辨率质谱仪耦合的改进方法应改善当前的样品制备工作流程，以评估皮肤化妆品施用后皮肤成分的变化。
