Atomic force microscopy characterization of corneocytes: effect of moisturizer on their topology, rigidity, and friction.

BACKGROUND/PURPOSE Atomic force microscopy (AFM) is a novel technique for skin characterization. OBJECTIVES To develop AFM tests for characterization of the outermost epidermis layer, corneocytes. As an example, the effect of moisturizer on the corneocyte properties is studied. METHODS AND MATERIALS Topology, rigidity, and friction (between individual corneocytes and AFM probe) of the top layer of corneocytes were measured by means of Veeco DM3100 AFM. Quench moisturizing cream was applied daily on the forearm of five volunteers for a period of 9 days. The skin flakes were collected before and after the treatment using Cuderm tape strips. No additional treatment of flakes was performed before the measurements. RESULTS A protocol for the AFM study of corneocytes is developed. After the treatment, we observed overall smoothening of the corneocyte surface, an increase of friction, and a decrease of rigidity (the Young modulus). CONCLUSION AFM can be used as a very sensitive tool for early detection of changes in corneocytes.