Structure of Intermediate Filament Assembly in Hair Deduced from Hydration Studies Using Small-Angle Neutron Scattering
April 2019
in “
Journal of structural biology
”
intermediate filament small-angle neutron scattering hydration quasi-hexagonal lattice d-spacing cuticle cortex hydrophobic oils heat treatment disulfide bonds coconut oil soybean oil SANS IF water absorption hair structure hair hydration hair cuticle hair cortex oil treatment disulfide bond reduction
TLDR Hair's internal fibers are arranged in a pattern that doesn't let much water in, and treatments like oils and heat change how much water hair can absorb.
In a study from June 2019, researchers used small-angle neutron scattering (SANS) to analyze the distribution of water in hair and to model the structure of intermediate filament (IF) assembly. They found that IFs in hair are arranged in a quasi-hexagonal lattice with a main diffraction peak at a d-spacing of approximately 90 Å. The study revealed that only a small fraction of water absorbed by hair penetrates between the IFs, with most water residing outside the IF assembly. The IF assembly in hair without the cuticle absorbed more water and was more ordered, suggesting the cuticle acts as a barrier and may compress the cortex. The study also observed that treatments with hydrophobic oils, heat, and reduction of disulfide bonds affected the hair's structure and water permeability, with coconut oil impeding hydration more effectively than soybean oil. The findings led to the proposal of a new, sterically more favorable model for IF assembly in hair.
