Hydration is a key aspect that affects the physical and mechanical properties of the skin.
Here, we examine the interaction between the molecular and macroscopic properties of the outer layer of the skin-the corneal layer (SC)
What's the difference between this and water cooperation.
The results show that the hydration leads to the molecular arrangement of peptides in the horny silk and C-
The H-bond of the terminal amino acid of the horn in SC is reoriented.
Changes in molecular structure and dynamics occur under critical hydration corresponding to ca.
Relative humidity is 85% (RH).
Mutations in the molecular properties of SC are consistent with changes in the macroscopic expansion properties and mechanical properties of SC.
The flexible terminals on the solid horny wire can be compared with the flexible polymer brush in the colloidal system, resulting in a long
The range of water repels and expands widely.
We further show that at a reduced RH, urea addition to SC results in a molecular and macroscopic reaction similar to RH increase in SC without urea.
These findings provide new molecular insights to deepen understanding of how intermediate filament organizations respond to changes in the surrounding environment.
The skin is a large interface membrane that separates the human body from the external environment.
The outermost layer of the skin-the corneal layer (SC)
Responsible for skin barrier function.
The health SC is a multi-functional material that combines the functional properties of an effective transport barrier, as well as the material properties of softness, firmness and softness to withstand the deformation of physical strain and stress.
SC is also a responsive material whose properties can be changed through changes in the skin's environment.
To sum up, SC meets several essentially different requirements, and its special material properties can be related to the organization and dynamics of its molecular composition. The SC is ca.
10-15 μm thick, consisting of nuclear death cells-corneal cells, filled with a filament of collagen, wrapped in a nuclear cladding.
The horny wire has a rigid core that highlights the terminal and is composed of the original Silk bundle (Fig. ).
Since their size range is 10-15 µnm, they are classified as "intermediate filament", which is intermediate compared to the skeletal actin filament (6u2009nm)
And microtubes (24u2009nm).
Intermediate filaments are common in the skin, hair and nails, where it acts as a mechanical support.
A similar size filament structure was also found in nerve filaments of nerve cells.
Corneal cells are embedded in multiple cells.
A plate-layer lipid matrix often described as a "brick structure.
In environmental conditions, the vast majority of SC lipid and protein components are present in solid state, unlike most other biofilm.
Nevertheless, the presence of a small number of fluid components may have a huge impact on the performance of SC macro materials. The keratin-
The filled corneal cells form ca.
85% of the total weight of the dry SC and they are related to the mechanical properties of the SC.
In general, corneal cells have a polar interior, and they may be an obstacle to the diffusion and transportation of hydrophobic molecules, while they may provide additional transport routes for more polar compounds, such as water.
When the skin is exposed to a humid environment, the corneal cells absorb a lot of water, such as swelling of the skin after bathing.
When the water is full, the corneal cells expand about 50%.
The swelling of corneal cells is not uniform in all directions, and they expand more in the vertical direction compared to the parallel direction of the skin surface.
SC lipids are also affected by hydration due to the melting of a small part of the lipid hydrocarbon chain.
Hydration can also lead to an increase in SC permeability at high relative humidity (RH)
, This may be related to the presence of more flow/flow SC lipids and protein components.
This is used in skin and skin administration and then called "occlusion ".
In occlusion, for example, skin penetration of chemicals under a skin patch or cream film can be enhanced.
In terms of strength and elasticity, the mechanical properties of the skin may be affected by hydration.
Previous studies have reported that water content in SC is indeed a major factor in determining SC flexibility.
When the moisture content rises to a higher RH, a soft transition is observed in the SC sample.
When hydrated with SC, water is absorbed mainly by corneal cells.
It has been assumed that the corneal cells control the SC adhesion properties through the plasticization of the water diagonal protein filament large molecule.
At a low RH value, the horny wire is present in a rigid state, while recent studies have shown that the molecular mobility of certain amino acids in the horny wire has changed under hydration.
It is very likely that these molecular changes in the horny filaments strongly affect their expansion and mechanical properties, and this interaction has been studied in this study.
The molecular properties of the protein can also be changed by adding other polar small molecules, E. G. g.
Urea and glycerin
These molecules naturally exist in the skin as part of so-
Called "natural moisturizing factor "(NMF)
They are often used as "moisturizers" in skin care products ".
While the term is a bit misleading, the main role of these compounds in SC is not to increase water content, but to replace water in dehydrated conditions, thus maintaining the fluidity of SC lipids and protein components.
In this study, we aim to deepen understanding of the nature of hydration
Induced changes in the inner corner of the corneal cells, and how these molecular changes lead to changes in the properties of macro materials.
The effect of hydration on molecular tissue and dynamics is also related to the addition of so-
It is called the moisturizing agent molecule commonly used in moisturizing skin care formula.
We present here data on homogeneous samples that can be used to predict the effects of water and moisturizer at different depths in SC.
The samples studied consist of extracted isolated corneal cells or complete SC under different hydration conditions determined by RH in the surrounding air.
We used more than one.
Technical methods including Wide Angle X-
Ray diffraction (WAXD)
Fourier transform infrared spectrum (FTIR)
, Polarization transfer solid state NMR (PT ssNMR)
And adsorption micro balance.
Based on the combination of the results obtained by these technologies, we can correlate the observed changes in the macroscopic properties of SC with the molecular effects from the perspective of dynamics, structure and conformations, thus deepening our hydration of SC