TITLE:
Reduction and Block Staining of Human Hair Shafts and Insect Cuticles by Ammonium Thioglycolate to Enhance Transmission Electron Microscopic Observations
AUTHORS:
Shigeru Sato, Yoshihiro Sasaki, Akiko Adachi, Tokuya Omi
KEYWORDS:
Reduction and Block Staining; Ammonium Thioglycolate; Human Hair; Insect Cuticle; Electron Microscopy
JOURNAL NAME:
Journal of Cosmetics, Dermatological Sciences and Applications,
Vol.3 No.2,
June
13,
2013
ABSTRACT: We have developed a method where,
after glutaraldehyde fixation, human hair shafts and insect cuticles are
treated with ammonium thioglycolate (ATG) to improve ultrastructural staining.
Conventional transmission electron microscopic (TEM) preparations do not
distinguish the A-layer and the exocuticles of hair shafts. However, after ATG
treatment, the A-layer appears in higher contrast. ATG treatment has also been
used to observe the fibrillar structure in the cortex. In the cuticle of
beetles, the epicuticle is stained by ATG. Although the human hair shaft (keratin) and insect cuticle (chitin)
are composed of different materials, both can be reduced by the ATG solution.
The ammonium in the ATG solution reacts with hair shafts and insect cuticles,
causing a reduction of swelled cuticles. Therefore, ATG not only stains, but
also reduces human hair shafts and the cuticles of beetles.