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Analysis of structural changes in bleached keratin fibers (black and white human hair) using Raman spectroscopy
Author(s) -
Kuzuhara Akio
Publication year - 2006
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.20453
Subject(s) - chemistry , cuticle (hair) , keratin , sepia , cortex (anatomy) , shampoo , biophysics , raman spectroscopy , anatomy , optics , botany , officinalis , biology , organic chemistry , paleontology , physics , neuroscience
To investigate the influence of bleaching treatments on keratin fibers, the structure of cross‐sections at various depths of bleached human hair (black and white human hair) was directly analyzed without isolating the cuticle and cortex, using Raman spectroscopy. The S–S band intensity existing from the cuticle region to the center of cortex region of virgin white human hair decreased, while the S–O band intensity at 1040 cm −1 , assigned to cysteic acid, increased by performing the bleaching treatment. Especially, the S–O band intensity of the cuticle region increased remarkably compared with that of the cortex region. Also, the amide III (unordered) band intensity in the cortex region increased, indicating that some of the proteins existing throughout the cortex region changed to the random coil form. Moreover, it has been found that the S–S band intensity existing from the cuticle region to the center of the cortex region of the virgin black human hair decreased remarkably, while the S–O band intensity increased significantly compared with that of the virgin white human hair by performing the bleaching treatment. From these experiments, we concluded that the melanin granules including metal ions act as a decomposition accelerator for the oxidizing agent, thereby leading to a higher level of disulfide (–SS–) group cleavage in the black human hair compared with that of the white human hair. © 2006 Wiley Periodicals, Inc. Biopolymers 81: 506–514, 2006 This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com