Insights into Stratum Corneum Structure Post Tape Stripping via Confocal Raman Spectroscopy

Abstract

Skincare products and topical pharmaceuticals are designed to exert their effects by enabling active ingredients to penetrate the skin’s barrier and reach the intended target site. The stratum corneum, the outermost layer of the skin, is characterized by a structure often described as a “brick-and-mortar model.” In this model, the intercellular lipids, representing the mortar, play a critical role in regulating the permeability of substances. Maintaining the well-ordered structure of these lipids is essential for the skin’s barrier function. In this study, we employed confocal Raman spectroscopy as a novel approach to evaluate the structural alignment of intercellular lipids in the stratum corneum. The impact of tape stripping, a procedure that partially removes the stratum corneum, on skin barrier functions assessed by confocal Raman spectroscopy, can be compared with the results of transepidermal water loss (TEWL). The data demonstrated that this method can be an effective tool for evaluating the state of intercellular lipids and their structural organization. Interestingly, while confocal Raman spectroscopy provided valuable insights, its results did not always align with TEWL, a conventional marker of skin barrier function. This discrepancy suggests that the rapid recovery of barrier function in damaged skin involves complex biological processes beyond the maturation of intercellular lipid structures. These findings highlight the need for further investigation into the mechanisms underlying skin barrier recovery.