Figure 1.

Lipid organization in human SC.

Notes: (1) The outermost layer of the epidermis, the SC, consists of dead cells (corneocytes) embedded in a lipid matrix, also referred to as the brick (corneocytes) and mortar (lipids) structure (2). The intercellular lipids are arranged in layers (lamellae; 3), with either a long or short repeat distance (d) with LPP (z=13 nm) or SPP (z=6 nm), respectively. The lateral organization is the plane perpendicular to the direction of the lamellar organization. There are three possible arrangements of the lipids: a very dense, ordered orthorhombic organization; a less dense, ordered hexagonal organization; or a disordered liquid organization. Reproduced from Biochimica et Biophysica Acta (BBA)-Molecular and Cell Biology of Lipids, 1841(3), Van Smeden J, Janssens M, Gooris GS, Bouwstra JA. The important role of stratum corneum lipids for the cutaneous barrier function, 295–313. Copyright (2014), with permission from Elsevier.⁶⁶

Abbreviations: LPP, long periodicity phase; SC, stratum corneum; SPP, short periodicity phase.