May 2024 in “Ultramicroscopy” Atomic Force Microscopy is a more accurate way to assess hair damage and the effect of cosmetic treatments.
October 2021 in “Digital Library of Theses and Dissertations (Universidade de São Paulo)” This study utilized Atomic Force Microscopy (AFM) to evaluate the effectiveness of a cosmetic active ingredient in improving the mechanical properties of human hair fibers. The research compared virgin hair fibers with chemically damaged ones, treated with and without the active ingredient. The AFM analysis revealed that the control group showed a significant decrease in the natural logarithm of the Young's modulus (ln(E)) compared to virgin fibers, while the active ingredient group showed an increase in ln(E) compared to both the control and placebo groups. This indicated that the active ingredient effectively improved the Young's modulus of damaged fibers. Additionally, a radial decrease in ln(E) was observed in the active group, consistent with Confocal Raman Spectroscopy results, suggesting varied active ingredient permeation. The study highlighted the advantage of FV-AFM analysis over traditional Tensile Tester methods, which did not show significant differences between groups. A correlation was found between decreased ln(E) and higher adhesion forces, possibly due to distinct adhesive structures with low cystine content.
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November 2015 in “Scientific reports” Human hair has a new region with ordered filaments and the cuticle contains β-keratin sheets.
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December 2006 in “Biopolymers” Permanent waving weakens hair by altering its protein structure.
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December 2012 in “Journal of molecular structure” The study found that thioglycolic acid breaks down hair bonds more consistently than l-cysteine, which is less damaging to hair.