Stratum corneum hydration: phase transformations and mobility in stratum corneum, extracted lipids and isolated corneocytes.

摘要: The outermost layer of skin, stratum corneum (SC), functions as the major barrier to diffusion. SC has architecture dead keratin filled cells embedded in a lipid matrix. This work presents detailed study hydration process extracted lipids, isolated corneocytes and intact SC. Using isothermal sorption microcalorimetry relaxation wideline (1)H NMR, we these systems at varying degrees hydration/relative humidities (RH) 25 C. basic findings are (i) there is substantial swelling both high RH. At low RHs take up more water than lipids do, while pronounced that corneocytes. (ii) Lipids fluid state present (iii) fraction lower 1.4% content 15% but remains virtually constant further increased. (iv) Three exothermic phase transitions detected RH=91-94%, speculate re-organization responsible for hydration-induced variations permeability. (v) causes corneocytes, it does not affect mobility solid components (keratin filaments).