title: Prospective ultramorphological characterization of human hair by optical coherence tomography.
abstract: OBJECTIVE
  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 microm and the hair diameter was 122+/-16 microm 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 microm at eight frames per second, and the entire 3D image was constructed in 60 s.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Laboratory of Cosmetology, Department of Pharmacy, School of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil.
authors.forename: Maria Valéria Robles
authors.initials: MV
authors.lastname: Velasco
authors.forename: André Rolim
authors.initials: AR
authors.lastname: Baby
authors.forename: Fernanda Daud
authors.initials: FD
authors.lastname: Sarruf
authors.forename: Telma Mary
authors.initials: TM
authors.lastname: Kaneko
authors.forename: Ricardo Elgul
authors.initials: RE
authors.lastname: Samad
authors.forename: Nilson Dias
authors.initials: ND
authors.lastname: Vieira Júnior
authors.forename: Anderson Zanardi
authors.initials: AZ
authors.lastname: de Freitas
mesh_terms: D044383:Black People; D006197:Hair / Q000187:drug effects* / Q000648:ultrastructure*; D006203:Hair Preparations / Q000494:pharmacology*; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000295:instrumentation / Q000379:methods; D066298:In Vitro Techniques; D013864:Thioglycolates / Q000494:pharmacology; D041623:Tomography, Optical Coherence / Q000295:instrumentation / Q000379:methods*
chemical_list: D006203:Hair Preparations; D013864:Thioglycolates; C017487:2-mercaptoacetate