• human hair;
  • keratin;
  • cortex;
  • cuticle;
  • macrofibril;
  • intermediate;
  • α-helix;
  • protein


An attempt has been made to obtain intact individual keratin filaments of various levels from micron cortical, micron macrofibril to nano intermediate filament and polypeptide α-helix from the human hair shaft. The feasibility of this initiative has been largely demonstrated by finding that there is a longitudinal seam/zipper on the cuticle of the human hair shaft, which can be unzipped by certain solvents such as performic acid and urea, allowing one to use an anatomical approach to separate intact individual micron/nano filaments. Micron cortical and macrofibril filaments have been obtained. It is also found that the cortical filaments are twisted together to form a yarn, giving rise to the strength for the hair shaft; and that individual cortical filaments are often 2-2 paired in a similar structure to the double helix. © 2006 Wiley Periodicals, Inc. Biopolymers 83: 614–618, 2006

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