Prospective ultramorphological characterization of human hair by optical coherence tomography
The continuous advancement in cosmetic science has led to an increasing demand for the development of non-invasive, reliable scientific techniques directed toward claim substantiation, which is of utmost relevance, to obtain data regarding the efficacy and safety of cosmetic products. Methods:
In this work, we used the optical coherence tomography (OCT) technique to produce in vitro transversal section-images of human hair. We also compared the OCT signal before and after chemical treatment with an 18% w/w ammonium thioglycolate solution. Results:
The mean diameter of the medulla was 29±7 m and the hair diameter was 122±16 m in our samples of standard Afro-ethnic hair. A three-dimensional (3D) image was constructed starting from 601 cross-sectional images (slices). Each slice was taken in steps of 6.0 m at eight frames per second, and the entire 3D image was constructed in 60 s. Conclusion:
It was possible to identify, using the A-scan protocol, the principal structures: the cuticle, cortex and medulla. After chemical treatment, it was not possible to identify the main structures of hair fiber due to index matching promoted by deleterious action of the chemical agent.
Document Type: Research Article
Affiliations: 1: Laboratory of Cosmetology, Department of Pharmacy, School of Pharmaceutical Sciences, University of São Paulo, São Paulo, SP, Brazil 2: Centro de Lasers e Aplicações, Instituto de Pesquisas Energéticas e Nucleares, São Paulo, SP, Brazil
Publication date: November 1, 2009