Selective solubilization of the stratum corneum components using surfactants

Abstract

The selective solubilization of pig stratum corneum (SC) by the nonionic surfactant octyl glucoside (OG) was investigated. The solubilized components (lipids and proteins) were free of surfactant by dialysis. The lipid composition was obtained by thin-layer chromatography (TLC) coupled to an automated flame ionization detection (FID) system and the proteinic analysis was carried out using an amino acid autoanalyzer. The TEM technique was used to visualize the type of structures formed. The use of OG concentrations lower than its critical micelle concentration (CMC) led to a progressive solubilization of SC membranes, whereas when using OG concentrations slightly higher than the CMC a clear increase in its solubilizing power was obtained. In these conditions, some amino acids building the SC keratinocyte envelopes and bound to the lipids (predominantly ceramides) by covalent bounds were extracted. TEM revealed during and after surfactant incubation the formation of open multilayered structures and concentric conformations which may be correlated with the previous steps of mixed micelle formation between SC components and OG. The OG may be considered as a more suitable solubilizing agent with respect to the conventional solvents in order to obtain more specific and selective solubilization of SC components without denaturing effect on protein structures.