Approche osmotique de l'hydratation du stratum corneum

Area of Science:

• Biophysics
• Dermatology
• Materials Science

Background:

• Stratum corneum hydration is crucial for skin barrier function.
• Previous studies, like Middleton's, proposed osmotic processes govern water sorption in the stratum corneum.
• Understanding water-binding mechanisms is key for developing effective moisturizers.

Purpose of the Study:

• To investigate water osmosis and diffusion in the stratum corneum.
• To create a functional osmotic model of the stratum corneum (OMSC).
• To evaluate the impact of Natural Moisturizing Factor components on water sorption.

Main Methods:

• Construction of an OMSC using sheep wool enclosed in a dialysis bag.
• Immersion of the OMSC in water to observe water diffusion and binding.
• Quantitative analysis of water sorption rate and bound water content at saturation.
• Assessment of humectants (glycerol, urea) on OMSC water-binding capacity.

Main Results:

• The OMSC demonstrated water sorption similar to the native stratum corneum.
• At saturation, the OMSC exhibited a bound water to keratin weight ratio of 13:1.
• Natural Moisturizing Factor components and glycerol accelerated water sorption and increased bound water fraction.
• Urea was identified as the most effective component in enhancing bound water content.

Conclusions:

• The OMSC serves as a viable model for studying stratum corneum hydration.
• Humectants, particularly urea, enhance keratin's water-binding capacity by increasing available sites.
• This model can facilitate preliminary testing of water-soluble skin moisturizers and humectants.