Netsu Sokutei, 34 (4), p. 159, (2007)



Structure and Phase Transitions of Intercellular Lipid Assembly in Stratum Corneum

Stratum corneum which is composed of corneocytes and intercellular lipid matrix plays an important role in barrier function and maintenance of water in skin. The intercellular lipid matrix bears the main part in the function. Therefore, it is important to make clear the structure formed by the intercellular lipids. It is well-known from X-ray diffraction, electron diffraction, neutron scattering, etc. that the structure consists of long and short lamellar structures and in the orthogonal direction hexagonal and orthorhombic hydrocarbon-chain packings. However, until now the relation between each lamellar structure and each hydrocarbon-chain packing has been unresolved. From the thermal analysis and the temperature scanning small- and wide-angle X-ray diffraction analysis in stratum corneum, we revealed that there are two domains: One is the long lamellar structure with the hexagonal hydrocarbon-chain packing and the other the short lamellar structure with the orthorhombic hydrocarbon-chain packing. Based upon the structural evidence we can further study the functional mechanism of cosmetics, the drug penetration mechanism, etc.