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Updated: Jun 5, 2026

Resolving Water, Proteins, and Lipids from In Vivo Confocal Raman Spectra of Stratum Corneum through a Chemometric Approach
Published on: September 26, 2019
Elucidated lipid structures of various human stratum corneum investigated by electron paramagnetic resonance
1Department of Radiological Life Sciences, Graduate School of Health Sciences, Hirosaki University, Hirosaki, Japan. nakagawa@cc.hirosaki-u.ac.jp
Background:
Electron paramagnetic resonance (EPR) in conjunction with a slow-tumbling simulation is useful for defining stratum corneum (SC) lipid structure. The objectives of this investigation were to evaluate and elucidate the lipid structure of various human SC as a function of the depth.
Methods:
The SC from mid-volar forearms of human volunteers and a cadaver was stripped consecutively from one to three times using a glass plate coated with a cyanoacrylate resin. Spin probes were used to monitor SC ordering. EPR spectra were analyzed by an EPR slow-tumbling simulation. Keratin solution from human epidermis was mixed with 5-doxylstearic acid (5-DSA) aqueous solution.
Results:
EPR analyses of 5-DSA and CHL probes showed immobilized and mobile spectra, respectively. The simulation for 5-DSA spectra showed differences in ordering values of the SC as a function of depth. EPR of keratin/5-DSA showed mobile spectral pattern. In addition, EPR of CHL showed a weak and a broad signal.
Conclusions:
The keratin/5-DSA results imply that the most likely location of 5-DSA probe is in SC lipid. CHL probe may not easily permeate the SC. The EPR results along with the simulation analysis provide elucidated SC lipid structure.
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