Entity

Time filter

Source Type

Taitō-ku, Japan

Objective The objective of our research was to investigate the influence of chemical treatments (reduction, stress relaxation and oxidation) on hair keratin fibres. Methods The structure of cross-sections at various depths of virgin white human hair resulting from permanent waving treatments with stress relaxation process was directly analysed at a molecular level using Raman spectroscopy. In particular, the three disulphide (-SS-) conformations in human hair were compared by S-S band analysis. Results The gauche-gauche-gauche (GGG) and gauche-gauche-trans (GGT) contents of -SS- groups remarkably decreased, while the trans-gauche-trans (TGT) content was not changed by performing the reduction process with thioglycolic acid. In addition, the high-temperature stress relaxation process after reduction accelerated the disconnection of -SS- (GGG and GGT) groups in the human hair, while the low-temperature stress relaxation process after reduction accelerated the reconnection of -SS- (GGG and GGT) groups. Moreover, the S-O band intensity at 1042 cm-1, assigned to cysteic acid, existing in the cuticle region and the surface of the cortex region increased, while the GGG content significantly decreased by performing the oxidation process after the reduction and the high-temperature stress relaxation processes. Conclusion The author concluded that the high-temperature relaxation process after reduction accelerated the disconnection of -SS- (GGG and GGT) groups, thereby leading to the remarkable local molecular disorganization (an increase in the cysteic acid content and a decrease in the GGG content) on the cuticle and cortex cells during the oxidation process. © 2015 Society of Cosmetic Scientists and the Société Française de Cosmétologie. Source


In order to investigate in detail the influence of chemical treatments (reduction, hydrolyzed eggwhite protein (HEWP) treatment, and oxidation) on damaged hair keratin fibers, the structure of cross-sections at various depths of excessively bleached (damaged) black human hair resulting from a permanent waving process was directly analyzed using Raman spectroscopy. It was found that l-cysteine (CYS) largely reacted with the gauche-gauche-gauche (GGG) conformation of disulfide (-SS-) groups (while CYS did not react with the trans-gauche-trans (TGT) conformation). In particular, not only the GGG content, but also the cysteic acid content existing throughout the cortex region of the excessively bleached human hair remarkably decreased by performing the oxidation process after reduction. On the other hand, the GGG content of the excessively bleached black human hair increased, while the TGT content decreased by performing the oxidation process after reduction and then HEWP treatment processes. From these experiments, the authors concluded that some of the keratin associated protein (KAP), which has a rich -SS- content and cysteic acid content was eluted from the cortex region along with the disconnection of -SS- groups, thereby leading to the remarkable reduction in the reconnection of -SS- groups of the excessively bleached black human hair after the permanent waving process (the reduction and oxidation processes). Also, the authors concluded that the HEWP treatment process in the permanent waving process caused the reconstruction of the KAP, thereby contributing to the acceleration of the reconnection of -SS- groups during the oxidation process. © 2014 Elsevier B.V. All rights reserved. Source


Kuzuhara A.,Sunny Place Co.
Kobunshi Ronbunshu | Year: 2012

In order to investigate m detail the influence of chemical modification on the internal structure of keratin fibers, which have a hierarchical structure, we have developed a novel method using Raman spectroscopy for directly characterizing the structure of cross-sections at various depths of keratin fibers without isolating the cuticle and cortical cells. Using this analytical technique, we have been successful in recording the Raman spectra of virgin black human hair, which had been impossible due to high melanin granule content. Moreover, the results revealed that the heterogeneous reaction between reducing agents (thioglycolic acid and L-cysteine) and keratin fibers at the molecular level could be analyzed. In particular, we found that not only the disulfide (-SS-) content, cysteic acid content, and random coil content, but also the secondary structure (α-helix content, β-sheet and/ or random coil) of cross-sections at various depths of the above hair fibers could be directly characterized by amide I band analysis. ©2012, The Society of Polymer Science, Japan. Source


In order to investigate in detail the internal structure changes in virgin black human hair keratin fibers resulting from bleaching treatments, the structure of cross-sections at various depths of black human hair, which had been impossible due to high melanin grande content, was directly analyzed using Raman spectroscopy. The gauche-gauche-gauche (GGG) content of the -SS- groups existing from the cuticle region to the center of cortex region of the virgin black human hair remarkably decreased, while the gauche-gauche-trans and trans-gauche-trans contents were not changed by performing the excessive bleaching treatment. In particular, it was found that not only the b-sheet and/or random coil content, but also the a-helix content existing throughout the cortex region of virgin black human hair decreased. In addition, the transmission electron microscope observation shows that the proteins in the cell membrane complex, the cuticle and cortex of the virgin black human hair were remarkably eluted by performing the excessive bleaching treatment. From these experiments, the author concluded that the -SS- groups, which have a GGG conformation were decomposed and finally converted to cysteic acid, and the a-helix structure of some of the proteins existing in the keratin was changed to the random coil structure, or eluted from the cortex region, thereby leading to the reduction in the protein density of the virgin human hair after the excessive bleaching treatment. © 2013 Elsevier B.V. All rights reserved. Source


Kuzuhara A.,Sunny Place Co.
Journal of Applied Polymer Science | Year: 2011

To investigate the penetration of amino acids and hydrolyzed protein derived from eggwhites (HEWP) into keratin fibers, the structure of cross-sectional samples at various depths of virgin white human hair treated with L-phenylalanine (Phe) and bleached black human hair treated with HEWP was directly analyzed without isolating the cuticle and cortex using Raman spectroscopy. The hydrophobic amino acids clearly penetrated into the virgin white human hair, while hydrophilic amino acids did not penetrate at all. The Phe hydrophobic amino acid content at various depths of the virgin white hair increased by performing the Phe treatment (at 50°C for 16 h), indicating that Phe deeply penetrated into the virgin human hair. Also, the disulfide (-SS-) and random coil contents at various depths of the bleached human hair increased by performing the HEWP treatment, indicating that HEWP also deeply penetrated into the bleached human hair. © 2011 Wiley Periodicals, Inc. Source

Discover hidden collaborations