Stratum corneum lipid phase transitions and water barrier properties.

摘要: In mammals, the outer skin layer, stratum corneum, is ultimate barrier to water loss. order relate function corneum structure, samples from porcine were investigated by using differential scanning calorimetry (DSC), infrared (IR) spectroscopy, and permeability techniques. Results of DSC IR studies show that lipids undergo thermal transitions between 60 80 degrees C similar lipid thermotropic seen in a variety synthetic biological membranes. flux experiments performed under conditions those an abrupt change at about 70 C. At low temperatures, values are obtained for human vivo, yielding activation energy 17 kcal/mol, excellent agreement with through biomembranes. contrast, temperatures above C, characterized only slightly higher than free diffusion, suggesting offers little diffusional resistance these conditions. These combined results suggest increased disorder brought transitions, dramatically altered this tissue flux. Thus, as found numerous membranes, inversely related.