Effect of liposomes on delipidized stratum corneum structure: an ‘in vitro’ study based on high resolution low temperature scanning electron microscopy

The structural modifications induced in the delipidized stratum corneum (SC) by the addition of SC lipid liposomes were investigated ‘in vitro’ using double-layer for high resolution low-temperature scanning electron microscopy technique (HRLTSEM). Liposomes were prepared from a lipid mixture extracted from the SC with organic solvents and characterized by freeze-fracture electron microscopy. After delipidization and subsequent incubation with liposomes no structural modifications were detected in the SC protein domains. However, the lipid lamellar structure detected in the native SC was lacking after delipidization. The subsequent treatment with liposomes of this delipidized tissue led to the formation of new structures in the intercellular spaces that showed similar organization to the lipid lamellae structure of the native SC. Image analyses of the desmosomes found in the delipidized SC and of the structures formed after treatment with liposomes demonstrated that these new structures did not correspond to desmosomes in spite of the similar appearance of both structures. Hence, the new structures could be associated with a restoration of the damaged lipid lamellae structure of the delipidized SC by the SC lipid liposomes. This effect would involve the interaction between the lipids of the liposomes and the remaining material after delipidization.