Electron Paramagnetic Resonance Investigation of Stratum Corneum Lipid Structure

Abstract

Electron paramagnetic resonance (EPR) in conjunction with a slow-tumbling simulation was utilized for defining stratum corneum (SC) lipid structure. We found that ordering calculated from the simulation is an appropriate index for evaluating SC lipids structure. The SC from two sites (mid-volar forearm and lower-leg) of human volunteers was stripped consecutively from one to three times using a glass plate coated with a cyanoacrylate resin. Aliphatic spin probes, 5-doxylstearic acid (5-DSA) and 3beta-doxyl-5alpha-cholestane (CHL), were used to monitor SC ordering. EPR spectrum of 5-DSA incorporated in the SC demonstrated a characteristic peak for the first strip. However, EPR spectra of CHL in the SC did not show a clear difference for each strip, except for the peak intensity. The results imply that CHL is not incorporated into the lipid phase as easily as 5-DSA is. A slow-tumbling simulation of the EPR spectrum was performed to analyze the detailed lipid structure. The simulation results for 5-DSA show differences in values of the SC ordering as a function of depth. Thus, these results along with the simulation analysis provide a detailed SC layer structure.

Stratum Corneum Lipid Structure Investigated by EPR Spin‐Probe Method: Application of Terpenes

“…1 and Fig. 2) between the rotational diffusion symmetry axis (the lipid in SC) and the z-axis of the nitroxide axis system [21]. Figure 8 represents the schematic illustration of the bilayer distance in relation to the angle.…”

Characterization of Melanin Radicals in Paraffin-embedded Malignant Melanoma and Nevus Pigmentosus Using X-band EPR and EPR Imaging

“…The EPR spectrum may appear as an asymmetric line-shape or have multiple overlapping lines, depending on the type of biomedical sample being assessed. [2][3][4][5][6] X-band EPR imaging (EPRI) has a higher spatial resolution and greater sensitivity than L-band EPRI. Thus, non-invasive EPRI can provide detailed information regarding the location and concentration of paramagnetic species in naturally occurring biomedical samples, such as melanin radicals in MM.…”

“…[4][5][6] The EPR methods can provide insight into the characterization of the radicals. Detailed studies of EPR line intensities, line widths, and line separations with various radicals may provide information on radical moiety.…”

Interaction of Antidepressant Drug, Clomipramine, with Model and Biological Stratum Corneum Membrane as Studied by Electron Paramagnetic Resonance

“…Electron paramagnetic resonance with spin probes was also found as a sensitive method for characterization of protein and lipid fraction of SC. A spin-labeled maleimide derivative was used to evaluate SC protein mobility, 23,24 whereas for monitoring the properties of SC lipids, the stearic acid spin probes were used 14,15,[25][26][27][28][29] and was supported with the EPR spectra line shape simulation. 26,28,30 The results give information about the alkyl chain packing and mobility in the SC membranes.…”

“…A spin-labeled maleimide derivative was used to evaluate SC protein mobility, 23,24 whereas for monitoring the properties of SC lipids, the stearic acid spin probes were used 14,15,[25][26][27][28][29] and was supported with the EPR spectra line shape simulation. 26,28,30 The results give information about the alkyl chain packing and mobility in the SC membranes. The method was found to be sensitive to the changes produced due to the hydration of the skin, 14 different surfactants, 15 permeation enhancers, 30 drugs, 29 and was shown to be useful in the investigations of protein-lipid interaction in native SC, 31 as well as in different cases of skin diseases and lesions.…”