Stratum corneum drying drives vertical compression and lipid organization and improves barrier function in vitro

Area of Science:

• Dermatology
• Materials Science
• Biophysics

Background:

• The stratum corneum (SC) is the outermost layer of the skin, crucial for barrier function.
• Exogenous hydration from skincare or bathing can alter SC structure and hydration levels.

Purpose of the Study:

• To investigate the structural and barrier function changes in the stratum corneum during the drying process after hydration.
• To elucidate the mechanisms by which drying impacts SC organization and barrier properties.

Main Methods:

• Isolation of stratum corneum sheets from reconstructed human epidermis.
• Assessment of barrier function and structural changes during dehydration.
• Utilized Electron Paramagnetic Resonance (EPR) spectroscopy.
• Employed X-ray diffraction (XRD) analysis.

Main Results:

• Water diffusion through SC sheets decreased with drying.
• SC thickness decreased, while visible light transmission increased.
• Lipid order parameter values increased, indicating greater lipid organization.
• X-ray diffraction showed increased lamellar structure intensity with 11-12 nm periodicity and 0.42 nm spacing.

Conclusions:

• The drying process significantly improves the barrier function of the stratum corneum.
• Improved barrier function is attributed to the vertical compression and enhanced organization of intercellular lipids.
• Findings provide insights into the biophysical mechanisms underlying skin barrier regulation post-hydration.