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Local structure of human hair spatially resolved by sub-micron X-ray beam.

Stanić V, Bettini J, Montoro FE, Stein A, Evans-Lutterodt K - Sci Rep (2015)

Bottom Line: We also find that in the cuticle, a key diffraction feature is absent, indicating the presence of the β-keratin rather than that of the α-keratin phase.This is direct structural evidence that the cuticle contains β-keratin sheets.This work highlights the importance of using a sub-micron x-ray beam to unravel the structures of poorly ordered, multi-phase systems.

View Article: PubMed Central - PubMed

Affiliation: Brazilian Synchrotron Light Source, CNPEM, SP 13083-970, Brazil.

ABSTRACT
Human hair has three main regions, the medulla, the cortex, and the cuticle. An existing model for the cortex suggests that the α-keratin- based intermediate filaments (IFs) align with the hair's axis, but are orientationally disordered in-plane. We found that there is a new region in the cortex near the cuticle's boundary in which the IFs are aligned with the hair's axis, but additionally, they are orientationally ordered in-plane due to the presence of the cuticle/hair boundary. Further into the cortex, the IF arrangement becomes disordered, eventually losing all in-plane orientation. We also find that in the cuticle, a key diffraction feature is absent, indicating the presence of the β-keratin rather than that of the α-keratin phase. This is direct structural evidence that the cuticle contains β-keratin sheets. This work highlights the importance of using a sub-micron x-ray beam to unravel the structures of poorly ordered, multi-phase systems.

No MeSH data available.


Related in: MedlinePlus

A detailed comparison of SAXS and WAXS diffraction patterns of the cuticle and cortex taken with the incident x-ray beam  to the hair axis.The WAXS of the cuticle is shown in (A), and the SAXS of the cuticle is shown in (B). The SAXS simply is an expanded view of the interior of (A). Similarly, (D) is the WAXS of the cortex, and (E) is the SAXS of the cortex. In (C), we project the intensity along the red line in (A). In (F), we project the intensity along the red line in (D). The well-ordered SAXS pattern of the cuticle shown in (B) is anisotropic, and is characteristic of a layered structure. The SAXS features of the cortex (E) are isotropic, with an intense first-order 94 Å, and weaker higher orders. The broad 10 Å ring is isotropic and is barely statistically significant in the cuticle (A), while the same 10 Å, ring in the cortex (D) is more intense and is also isotropic.
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f2: A detailed comparison of SAXS and WAXS diffraction patterns of the cuticle and cortex taken with the incident x-ray beam to the hair axis.The WAXS of the cuticle is shown in (A), and the SAXS of the cuticle is shown in (B). The SAXS simply is an expanded view of the interior of (A). Similarly, (D) is the WAXS of the cortex, and (E) is the SAXS of the cortex. In (C), we project the intensity along the red line in (A). In (F), we project the intensity along the red line in (D). The well-ordered SAXS pattern of the cuticle shown in (B) is anisotropic, and is characteristic of a layered structure. The SAXS features of the cortex (E) are isotropic, with an intense first-order 94 Å, and weaker higher orders. The broad 10 Å ring is isotropic and is barely statistically significant in the cuticle (A), while the same 10 Å, ring in the cortex (D) is more intense and is also isotropic.

Mentions: In Fig. 2, we show diffraction images with better counting statistics for the cuticle (Fig. 2A,B) and cortex (Fig. 2D,E). We observed that, in addition to the primary ring at 94 Å, there are weaker, broader rings at 53.5 Å, 46.2 Å and 31 Å. This is consistent with 2D fluid-like disorder of close packed aligned IFs, probably with a short-range hexagonal, para-crystal arrangement22021.


Local structure of human hair spatially resolved by sub-micron X-ray beam.

Stanić V, Bettini J, Montoro FE, Stein A, Evans-Lutterodt K - Sci Rep (2015)

A detailed comparison of SAXS and WAXS diffraction patterns of the cuticle and cortex taken with the incident x-ray beam  to the hair axis.The WAXS of the cuticle is shown in (A), and the SAXS of the cuticle is shown in (B). The SAXS simply is an expanded view of the interior of (A). Similarly, (D) is the WAXS of the cortex, and (E) is the SAXS of the cortex. In (C), we project the intensity along the red line in (A). In (F), we project the intensity along the red line in (D). The well-ordered SAXS pattern of the cuticle shown in (B) is anisotropic, and is characteristic of a layered structure. The SAXS features of the cortex (E) are isotropic, with an intense first-order 94 Å, and weaker higher orders. The broad 10 Å ring is isotropic and is barely statistically significant in the cuticle (A), while the same 10 Å, ring in the cortex (D) is more intense and is also isotropic.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4663634&req=5

f2: A detailed comparison of SAXS and WAXS diffraction patterns of the cuticle and cortex taken with the incident x-ray beam to the hair axis.The WAXS of the cuticle is shown in (A), and the SAXS of the cuticle is shown in (B). The SAXS simply is an expanded view of the interior of (A). Similarly, (D) is the WAXS of the cortex, and (E) is the SAXS of the cortex. In (C), we project the intensity along the red line in (A). In (F), we project the intensity along the red line in (D). The well-ordered SAXS pattern of the cuticle shown in (B) is anisotropic, and is characteristic of a layered structure. The SAXS features of the cortex (E) are isotropic, with an intense first-order 94 Å, and weaker higher orders. The broad 10 Å ring is isotropic and is barely statistically significant in the cuticle (A), while the same 10 Å, ring in the cortex (D) is more intense and is also isotropic.
Mentions: In Fig. 2, we show diffraction images with better counting statistics for the cuticle (Fig. 2A,B) and cortex (Fig. 2D,E). We observed that, in addition to the primary ring at 94 Å, there are weaker, broader rings at 53.5 Å, 46.2 Å and 31 Å. This is consistent with 2D fluid-like disorder of close packed aligned IFs, probably with a short-range hexagonal, para-crystal arrangement22021.

Bottom Line: We also find that in the cuticle, a key diffraction feature is absent, indicating the presence of the β-keratin rather than that of the α-keratin phase.This is direct structural evidence that the cuticle contains β-keratin sheets.This work highlights the importance of using a sub-micron x-ray beam to unravel the structures of poorly ordered, multi-phase systems.

View Article: PubMed Central - PubMed

Affiliation: Brazilian Synchrotron Light Source, CNPEM, SP 13083-970, Brazil.

ABSTRACT
Human hair has three main regions, the medulla, the cortex, and the cuticle. An existing model for the cortex suggests that the α-keratin- based intermediate filaments (IFs) align with the hair's axis, but are orientationally disordered in-plane. We found that there is a new region in the cortex near the cuticle's boundary in which the IFs are aligned with the hair's axis, but additionally, they are orientationally ordered in-plane due to the presence of the cuticle/hair boundary. Further into the cortex, the IF arrangement becomes disordered, eventually losing all in-plane orientation. We also find that in the cuticle, a key diffraction feature is absent, indicating the presence of the β-keratin rather than that of the α-keratin phase. This is direct structural evidence that the cuticle contains β-keratin sheets. This work highlights the importance of using a sub-micron x-ray beam to unravel the structures of poorly ordered, multi-phase systems.

No MeSH data available.


Related in: MedlinePlus