今井健仁*,1,2 丹羽正直1，川村秀登2，木村 勝2，中野 隆2
Staining Mechanism of Oxidative Hair Dyes in the Cuticle Layers of Human Scalp Hair
Takehito IMAI*,1,2, Masanao NIWA1, Hideto KAWAMURA2, Masaru KIMURA2, Takashi NAKANO2
We report the staining mechanism of oxidative hair dyes (permanent hair color) in cuticle layers of human hair. In general, the staining mechanism of oxidative hair dyes is considered that the oxidative hair dye monomer penetrates into the cortex, and is polymerized and colors in there. It was, however, confirmed that the cuticle layers were not only the pathway to the cortex of oxidative hair dyes, but also were staining sites with them, by the observation with digital microscope of the cuticle fragment and the thin cross-section of the dyed hair. The metals may be distributed in the β-layer of cuticular CMC (cell membrane complex), which was suggested by transmission electron microscopy (TEM) observation. We suggest the staining mechanism of oxidative hair dyes in cuticle layers as that the dye monomer predominantly penetrates through the δ-layer of cuticular CMC and being polymerized in the β-layer / δ-layer interface, which will be catalyzed by trace metals in the β-layer.
oxidative hair dye, cuticle, CMC, β-layer , metal.
1,* ホーユー株式会社 総合研究所
General Research & Development Institute, Hoyu Co., Ltd.
School of Medicine, Aichi Medical University