Stratum corneum lipid bilayers (SC lipids)

The stratum corneum lipid bilayers constitute the primary permeability barrier of the human skin, located between the corneocytes of the outermost epidermal layer. These bilayers are unique in their composition, consisting primarily of ceramides, free fatty acids, and cholesterol, organized into highly ordered lamellar structures rather than the fluid mosaic models seen in living cell membranes (StatPearls, Physiology, Skin Barrier). Their main biological function is to prevent excessive transepidermal water loss and protect the body from the ingress of pathogens, allergens, and chemicals (PubMed, PMCID: PMC2847158). In various dermatological conditions such as atopic dermatitis and psoriasis, the composition and organization of these lipid bilayers are significantly altered, leading to a compromised barrier and increased inflammation. Therapeutically, these lipids are targeted in two ways: through barrier repair therapy, where exogenous lipids like ceramides are applied to restore integrity, and through the use of chemical penetration enhancers that temporarily fluidize or disrupt the lipid packing to allow the delivery of topical or transdermal drugs (Journal of Controlled Release, 'The role of stratum corneum lipids in drug delivery'). Understanding the phase behavior and molecular packing of these lipids is critical for developing effective dermatological treatments and systemic transdermal delivery systems.

Other names

Skin lipid barrierIntercellular lipid lamellaeStratum corneum intercellular lipidsEpidermal lipid barrier

Disruption of lipid packing to enhance drug permeability or lipid replacement to restore barrier integrity