Latent damage in keratin fibres

Gabriele Wortmann, Jennifer Marsh, Franz J Wortmann

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    Latent Damage of Keratin fibres

    G.Wortmann, J.Marsh, F.J.Wortmann

    The investigation of archaeological keratin fibers by means of polarization microscopy shows a discrepancy in the results for the degree of damage when applied in non-swelling and swelling agents.
    On the basis of these observations, the concept of latent damage was developed.
    Latent damage is specified as a subliminal, hidden damage in the protein framework, which cannot or only to a limited extent be demonstrated by using nondestructive analytical tools. This essentially relates to the helical proportions of the intermediate filaments.

    When storing keratin fibers under different, e.g. strongly influencing environmental conditions, both peptide bond breakage and oxidation and thus cleavage of cystine bridges occur.
    In dry state peptide bond breakages do not affect the arrangement of helical proteins in the intermediate filaments. The helical protein fragments are still undisturbed in their morphological position in the fiber. A damage of the helix by peptide bond breakage can thus not clearly be demonstrated with many analytical methods or only in case of a very high degree of damage.
    Swelling agents lead to a disturbance in the arrangement of the helical protein fragments and decrease the signal for helical proteins.
    In the case of multiple bleaching, this can also be illustrated. By means of Differential Scanning Calorimetry (DSC), with the number of bleaches a constant increasing damage of the intermediate filaments is observed, as wide-angle x-ray scattering (WAXS) only shows a decrease in intact helical proteins after a high numbers of bleaches.
    Cu2 + can catalyze the formation of hydroxyl radicals (HO ●) from H2O2. In the presence of oxygen these radicals lead to a fragmentation of proteins. In the presence of Cu2 +, in highly bleached hair hydroxyl radicals (HO ●) and peroxy radicals (HOO ●) are formed from residual H2O2 which result in peptide bonds breakage. Resulting damage of the intermediate filaments can be proven by means of DSC, but not by WAXS.
    Original languageEnglish
    Publication statusPublished - Sept 2017
    Event20th International Hair-Science Symposium - Dresden, Germany
    Duration: 6 Sept 20178 Sept 2017


    Conference20th International Hair-Science Symposium
    Abbreviated titleHairS'17


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