Kuzuhara Akio, Fujiwara Nobuki, Hori Teruo
Central Research Laboratories, Mandom Corporation, Osaka, Japan.
Biopolymers. 2007;87(2-3):134-40. doi: 10.1002/bip.20805.
To investigate the internal structure changes in virgin black human hair keratin fibers due to aging, the structure of cross-sections at various depths of virgin black human hair (sections of new growth hair: 2 mm from the scalp) from a group of eight Japanese females in their twenties and another group of eight Japanese females in their fifties were analyzed using Raman spectroscopy. For the first time, we have succeeded in recording the Raman spectra of virgin black human hair, which had been impossible due to high melanin granule content. The key points of this method are to cross-section hair samples to a thickness of 1.50-microm, to select points at various depths of the cortex with the fewest possible melanin granules, and to optimize laser power, cross slit width as well as total acquisition time. The reproducibility of the Raman bands, namely the alpha-helix (alpha) content, the beta-sheet and/or random coil (beta/R) content, the disulfide (--SS--) content, and random coil content of two adjoining cross-sections of a single hair keratin fiber was clearly good. The --SS-- content of virgin black human hair from the Japanese females in their fifties for the cortex region decreased compared with that of the Japanese females in their twenties. On the other hand, the beta/R and alpha contents of the cortex region did not change.
为了研究未处理的黑色人发角蛋白纤维因老化而发生的内部结构变化，使用拉曼光谱法分析了一组8名二十多岁的日本女性和另一组8名五十多岁的日本女性的未处理黑色人发（新生长头发：距头皮2毫米处的切片）不同深度横截面的结构。我们首次成功记录了未处理的黑色人发的拉曼光谱，由于黑色素颗粒含量高，此前这一直是不可能的。该方法的关键要点是将头发样本切成1.50微米厚的横截面，在皮质的不同深度选择黑色素颗粒尽可能少的点，并优化激光功率、交叉狭缝宽度以及总采集时间。单根头发角蛋白纤维两个相邻横截面的拉曼谱带的重现性，即α-螺旋（α）含量、β-折叠和/或无规卷曲（β/R）含量、二硫键（--SS--）含量和无规卷曲含量，明显良好。五十多岁日本女性的未处理黑色人发皮质区域的--SS--含量与二十多岁日本女性相比有所下降。另一方面，皮质区域的β/R和α含量没有变化。
