The class of PEGylated emulsifiers finds broad application in the pharmaceutical and cosmetic industry. We target on one of the categories of polyethylene glycol (PEG) alkyl ethers with different lipophilic and hydrophilic chain length and aim to examine their effects on the skin comprehensively. In this study, we employed confocal Raman spectroscopy for skin depth profiling and imaging. A unique probe of heavy water (D₂O) was incorporated, which can be tracked percutaneously and simultaneously monitor the effects caused by emulsifiers. According to the results, most of the PEGylated emulsifiers caused changes in skin lipid content/organization and induced the alteration in relative water content/hydrogen bonding structure. The results obtained from the depth profiling analysis provided the possibility to estimate the least penetration depth of emulsifiers. Among them, PEG‐20 ethers displayed the most penetration ability. Meanwhile, it is interesting to find that the treatment of emulsifiers also affected the spatial distribution of D₂O whose differences were in line with the molecular skin variations. In particular, the isotopic H/D substitution in the skin was highlighted in detail. This result supports the possibility to use D₂O as an excellent and cost‐effective probe to evaluate the skin barrier function.

中文翻译：

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跟踪重水结合共聚焦拉曼光谱法，以评估聚乙二醇化乳化剂对皮肤屏障的影响

聚乙二醇化乳化剂的种类在制药和化妆品工业中得到广泛的应用。我们针对具有不同亲脂性和亲水性链长的一类聚乙二醇（PEG）烷基醚，并旨在全面研究其对皮肤的影响。在这项研究中，我们采用共聚焦拉曼光谱进行皮肤深度分析和成像。独特的重水探头（D ₂O）被并入，可以经皮追踪并同时监测乳化剂引起的效果。根据结果​​，大多数PEG化乳化剂引起皮肤脂质含量/组织的变化，并引起相对水含量/氢键结构的改变。从深度剖析分析获得的结果为估算乳化剂的最小渗透深度提供了可能性。其中，PEG-20醚显示出最大的渗透能力。同时，有趣的是发现乳化剂的处理也影响了D ₂的空间分布。O的差异与皮肤的分子差异一致。特别是，皮肤中的同位素H / D取代得到了特别的强调。该结果支持使用D ₂ O作为评估皮肤屏障功能的极佳且具有成本效益的探针的可能性。