Scientists Uncover New Structural Features Of Human Hair
A global team of scientists – led by Dr Vesna Stanic of the Brazilian Synchrotron Light Supply – has detected new structural options of human hair.
False-shade micrograph of human hair cross-section: the highest area exhibits the external part of the hair – cuticle region; the bottom region shows the internal macrofibrils – cortex region. extensions Picture credit score: Fabiano Emmanuel Montoro / LNNano / CNPEM.
“Human hair is primarily composed of keratin molecules organized in hierarchical construction, where the fundamental building block is called an intermediated filament,” Dr Stanic stated.
While studying materials used for hair treatments, Dr Stanic and her colleagues wondered what effect these therapies were having on the diffraction pattern of the hair.
Although diffraction patterns have been examined and reported in long hairstyles for small faces several publications in the past, they involved bundles of hair fibers or microdiffraction on single hair fibers; and, most significantly, the X-ray beam was all the time oriented perpendicular to the hair fiber axis.
So the scientists decided to take a better look at the diffraction sample of the hair by measuring it with an X-ray beam aimed parallel to the hair axis.
By utilizing a sub-micron X-ray beam and transmission electron microscopy, they have been able to spatially resolve the native structure of the three important regions of the human hair: the medulla, the cortex and the cuticle.
The researchers performed a full diffraction map from a 30 micron thick cross-section of hair, with the incident beam parallel to the hair axis and in contrast it to the diffraction map with the beam perpendicular to the hair axis.
“We found that as one moves the X-ray beam from the exterior of the hair to the medulla, the association of the keratin fibrils change into increasingly disordered. The combination of the sub-micron X-ray beam and the cross-section geometry enables us to detect a new structural options not previously observed,” Dr Stanic stated.
They found that inside the cuticle a key diffraction feature of the alpha keratin is absent – indicating the presence of beta keratin as an alternative of the alpha keratin phase.
Until now, it was believed that keratin in the whole hair had solely an alpha conformation.
“The study provides irrefutable experimental proof of the hair section variation throughout the three major regions of hair and is an important step towards gaining a greater understanding of hierarchical ordering of the intermediate filaments of keratin,” Dr Stanic stated.
“It also highlights the significance of utilizing a submicron X-ray beam to unravel the constructions of poorly ordered, multiphase systems similar to hair.”
Dr Stanic and co-authors believe the cosmetics trade will benefit from their findings, which were offered on Wednesday, July twenty ninth at the American Crystallographic Affiliation 2015 Assembly in Philadelphia.
Vesna Stanic et al. Sub-micron X-ray Beam Research of Human Hair.