Lipid organization in pig stratum corneum

Area of Science:

• Biophysics
• Materials Science
• Dermatology

Background:

• The stratum corneum is the outermost layer of the skin, providing a vital barrier.
• Understanding its lipid and keratin structure is key to skin barrier function and drug delivery.

Purpose of the Study:

• To elucidate the lipid and keratin structure of pig stratum corneum.
• To investigate the influence of hydration and temperature on this structure.

Main Methods:

• Small- and wide-angle X-ray diffraction techniques were employed.
• Measurements were conducted across varying hydration levels and temperatures.
• Lipid recrystallization was analyzed at different temperatures.

Main Results:

• Intercellular lipids organized into at least two lamellar structures (6 nm and 13.2 nm repeat distances), with a potential third phase (9 nm).
• Wide-angle patterns showed hexagonal (0.414 nm) and liquid lateral packing (~0.46 nm).
• The 0.414 nm reflection diminished and disappeared with increasing temperature (60-95°C), indicating structural changes. Crystalline cholesterol and alpha-keratin were identified.

Conclusions:

• Pig stratum corneum exhibits complex, ordered intercellular lipid structures.
• Temperature significantly impacts keratin structure and lipid organization.
• These findings provide insights into the skin barrier's physical properties and potential for modification.