Abstract
The function of living systems is essentially connected to fluid biological membranes. Lipid fluctuations can readily seal defects and leaks, enable membrane remodeling, regulate the passive permeability of solutes, and facilitate protein function.
In contrast, the skin barrier lipids are primarily rigid and tightly packed. In addition, these ceramide-dominant lipid mixtures do not form the canonical bilayers but minimally hydrated stacks of the long periodicity phase (LPP, ~13 nm periodicity) in the stratum corneum extracellular spaces.
Although this unusual lipid rigidity makes sense for restricting water loss and preventing the penetration of harmful substances, it is less conceivable how such lipids attain their complex architecture. We show here that fluid lipids are anessential intermediate state in the for-mation of impermeable lamellae inhuman stratum corneum lipids in vitro.