Abstract:The author concluded that the waved virgin human hair treated with TG adjusted to pH 9.0 with ammonia solution was less damaged as compared with the waved hair treated with TGA, despite its good waving efficiency, as not only were the GGG and GGT conformations disconnected, but they were also changed to the TGT conformation by performing the reduction process with TG.
“…The 1750-450 cm −1 wavenumber range is the fundamental region analytically as it is rich in vibrational information, showing the main bands that undergo modification resulting from the treatment procedures. As hair is a very complex matrix, attempts at characterization and interpretation of the spectral data were made based on previous studies (see Table 1) [8,22,23,29,30]. Fig.…”
Section: Resultsmentioning
confidence: 99%
“…All spectra presented below were subjected to a baseline adjustment and were normalized to the intensity of the C-H band at 1449 cm −1 , as it was shown to be a band that is not influenced by the individual treatment carried out on the hair specimens [23].…”
Section: Resultsmentioning
confidence: 99%
“…Over the years, analytical studies addressing hair structures have evolved significantly and vibrational spectroscopic techniques such as Raman and infrared have been increasingly used for such purposes [16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26]. Baddiel [16] analyzed the structure and reactions of hair keratin from infrared spectroscopy.…”
Section: Introductionmentioning
confidence: 99%
“…Akhtar et al. [22] have used Raman spectroscopy to analyze untreated and discolored human hair and Kuzuhara [23] studied virgin hair treated with thioglycerol using Raman spectroscopic analysis whereas Zhang et al. [24] studied changes in the chemical and structural composition in hair fibers by infrared and Raman spectroscopic imaging.…”
Human hair fibre is subjected to various structural modifications due to the application of chemicals such as dyes, shampoos and bleaches and/or physical procedures such as heating, and often more than one procedure is performed on the same hair. The present work aims to analyze the changes incurred in hair samples of two ethnic groups, namely Caucasian and Afro, before and after different treatments such as thermal, bleaching and straightening. In addition to observing the damage caused by each treatment separately, the study of samples that received all three treatments was carried out. For molecular structural characterization, the Raman vibrational spectroscopic technique was used and scanning electron microscopy (SEM) was used for morphological analysis of the hair fibres. This investigation has shown, through vibrational spectroscopy, that several important bonds have been modified, such as the S-S, C-S, C-C and S-O bonds as well as the secondary structures of proteins that have indergone changes in their conformation as a result of the treatment. Hair from the two ethnic groups showed small differences in relation to each applied treatment. Excessive heat generated a higher rate of Raman spectral band intensity changes when compared to the other treatments and it was observed that the action of several treatments on the same hair fibres resulted in even more pronounced structural changes. Finally, scanning electron microscopy showed that each treatment caused a different morphological deformation pattern on the capillary surface of the human hair.
“…The 1750-450 cm −1 wavenumber range is the fundamental region analytically as it is rich in vibrational information, showing the main bands that undergo modification resulting from the treatment procedures. As hair is a very complex matrix, attempts at characterization and interpretation of the spectral data were made based on previous studies (see Table 1) [8,22,23,29,30]. Fig.…”
Section: Resultsmentioning
confidence: 99%
“…All spectra presented below were subjected to a baseline adjustment and were normalized to the intensity of the C-H band at 1449 cm −1 , as it was shown to be a band that is not influenced by the individual treatment carried out on the hair specimens [23].…”
Section: Resultsmentioning
confidence: 99%
“…Over the years, analytical studies addressing hair structures have evolved significantly and vibrational spectroscopic techniques such as Raman and infrared have been increasingly used for such purposes [16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26]. Baddiel [16] analyzed the structure and reactions of hair keratin from infrared spectroscopy.…”
Section: Introductionmentioning
confidence: 99%
“…Akhtar et al. [22] have used Raman spectroscopy to analyze untreated and discolored human hair and Kuzuhara [23] studied virgin hair treated with thioglycerol using Raman spectroscopic analysis whereas Zhang et al. [24] studied changes in the chemical and structural composition in hair fibers by infrared and Raman spectroscopic imaging.…”
Human hair fibre is subjected to various structural modifications due to the application of chemicals such as dyes, shampoos and bleaches and/or physical procedures such as heating, and often more than one procedure is performed on the same hair. The present work aims to analyze the changes incurred in hair samples of two ethnic groups, namely Caucasian and Afro, before and after different treatments such as thermal, bleaching and straightening. In addition to observing the damage caused by each treatment separately, the study of samples that received all three treatments was carried out. For molecular structural characterization, the Raman vibrational spectroscopic technique was used and scanning electron microscopy (SEM) was used for morphological analysis of the hair fibres. This investigation has shown, through vibrational spectroscopy, that several important bonds have been modified, such as the S-S, C-S, C-C and S-O bonds as well as the secondary structures of proteins that have indergone changes in their conformation as a result of the treatment. Hair from the two ethnic groups showed small differences in relation to each applied treatment. Excessive heat generated a higher rate of Raman spectral band intensity changes when compared to the other treatments and it was observed that the action of several treatments on the same hair fibres resulted in even more pronounced structural changes. Finally, scanning electron microscopy showed that each treatment caused a different morphological deformation pattern on the capillary surface of the human hair.
“…Raman spectroscopy has been used to analyse structural change in keratin fibres after chemical treatments and to investigate the mechanism of thioglycerol in straightening hair. Such studies have shown that structural keratin changes to hair fibres at various depths can be characterised directly through Raman spectroscopy .…”
ObjectiveIn hair care cosmetic products’ evaluation, one commonly used method is to evaluate the hair appearance as a gold standard in order to determine the effect of an active ingredient on the final state of the hair via visual appreciation. Although other techniques have been proposed for a direct analysis of the hair fibres, they give only surface or structural information, without any accurate molecular information. A different approach based on confocal Raman spectroscopy has been proposed for tracking in situ the molecular change in the keratin directly in the human hair fibres. It presents a high molecular specificity to detect chemical interactions between molecules and can provide molecular information at various depths at the cortex and cuticle levels.MethodsTo evaluate the potential of confocal Raman spectroscopy in testing the efficiency of cosmetic ingredients on keratin structure, we undertook a pilot study on the effectiveness of a smoothing shampoo on natural human hair, by analysing α‐helix and β‐sheet spectral markers in the Amide I band and spectral markers specific to the cystin sulfur content.ResultsWe confirmed that an active proved to be effective on a gold standard decreases α‐helix keratin conformation and promotes β‐sheet keratin conformation in the hair fibres. We also showed that treatment with the effective active decreases the intensity of covalent disulfide (S–S at 510 cm‐1) cross‐linking bands of cysteine. These data confirm that the effective active also acts on the tertiary structure of keratin.ConclusionFrom these experiments, we concluded that the effective active has a smoothing effect on the human hair fibres by acting on α‐helix and β‐sheet keratin conformation and on the tertiary structure of keratin. Based on these results, confocal Raman spectroscopy can be considered a powerful technique for investigating the influence of hair cosmetic ingredients on keratin structure in human hair fibres. Moreover, this analytical technique has the advantage of being non‐destructive and label free; in addition, it does not require sample extraction or purification and it can be applied routinely in cosmetic laboratories.
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