Masayuki Okamoto oral presentation (OA3-Tue2-3-2)
Applications of SIMS in the field of cosmetics and toiletries
Kao corporation, 1334 Minato, 641-0045 Wakayama-shi, Japan
Secondary ion mass spectrometry (SIMS) is one of the most powerful analytical tools for the detection of surface components and molecular imaging. In our laboratory, SIMS techniques have been used for the analysis of surface contaminants, imaging of surface adsorbates, penetration of agents, and investigation of surface degradation and damage of both material and biological samples. As an example, SIMS application of skin research is described.
The human skin consists of tissue layers, and the outermost layer is a stratum corneum which works as a barrier against both external stimuli and transepidermal water loss. The stratum corneum consists of corneocytes and intercellular lipids . The intercellular lipids, the ordinality of the multilamellar structure of the lipids, are responsible for maintaining the barrier function [2,3]. It was found that the synthetic pseudo-ceramides (sphingolipid E; SLE)  is effective to improve the barrier function of stratum corneum, however, verification of the existence of the SLE in the stratum corneum has been lacking. In this study, TOF-SIMS and Nano-SIMS studies were carried out to clarify the penetration of pseudo-ceramides into the stratum corneum. TOF-SIMS analysis of the cross-section of the skin was performed to examine the penetration of SLE in the stratum corneum . The results revealed that the SLE penetrated into the stratum corneum. The penetration pathway of the SLE in the stratum corneum was studied using Nano-SIMS . The SLE was detected from the inter-cellular spaces between corneocytes. These results suggest that the SLE penetrates into the stratum corneum via an inter-cellular pathway, and that the barrier function is improved by replenishing intercellular lipids at damaged sites on the stratum corneum.
In the presentation, investigation of the damage on the outermost hair surface, and the other applications of TOF-SIMS will be explained.
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