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Skin barrier: Extraction and characterization of Stratum Corneum lipids

Velásquez González, Nicolas LU (2018) KEML07 20181
Department of Chemistry
Abstract
The structure and dynamics of isolated Stratum Corneum lipids in different temperatures and hydration conditions was investigated using natural abundance 13 C NMR and X-ray scattering.
In order to isolate the lipids a new extraction method was tested. The novel aspect of this method was its ability to extract more lipids from SC. This new method (referred to as Method II in-text) was further modified. The resulting method (Method III) was chosen as the method to follow during this project. These two methods were also compared (using 13 C NMR) to an extraction method used in a pre-study. The lipids obtained through Method III were characterized with polarization transfer solid-state NMR and wide/small angle x-ray scattering.
NMR studies... (More)
The structure and dynamics of isolated Stratum Corneum lipids in different temperatures and hydration conditions was investigated using natural abundance 13 C NMR and X-ray scattering.
In order to isolate the lipids a new extraction method was tested. The novel aspect of this method was its ability to extract more lipids from SC. This new method (referred to as Method II in-text) was further modified. The resulting method (Method III) was chosen as the method to follow during this project. These two methods were also compared (using 13 C NMR) to an extraction method used in a pre-study. The lipids obtained through Method III were characterized with polarization transfer solid-state NMR and wide/small angle x-ray scattering.
NMR studies showed that a greater amount of lipids in a rigid state were being extracted with the new extraction method. These studies also showed that hydration has a clear effect on lipid mobility at temperatures of 32 ˚C. In the dry state there is low mobility, while upon full
hydration, a fraction of lipids are in a mobile state coexist with solid lipids. SAXS studies showed that SC lipids form two types of lamellar phases, one with a lamellar repeat distance of ~144 Å in dry and hydrated conditions, while another with a repeat distance of ~71Å in dry
conditions and ~68 Å in hydrated conditions. In the solid fraction of SC lipids, the hydrophobic chain adopts hexagonal packing, as detected with WAXS. (Less)
Popular Abstract
The largest organ in our bodies is the skin. It forms a protective barrier against exogenous substances and dehydration. The barrier function is attributed to the Stratum Corneum (SC), which is the outermost layer of the skin epidermis. The main components of the SC are proteins
called corneocytes (dead cells containing mainly keratin and water) and lipids. These lipids form an intercellular matrix wherein the corneocytes are embedded. This lipid matrix, which is highly ordered, consists chiefly of ceramides (CERs), free fatty acids (FFAs) and cholesterol
(CHOL), in an almost equimolar ratio. Knowing how the barrier function behaves, for instance in the presence of compounds such as drugs, is extremely desirable. To do this, we studied... (More)
The largest organ in our bodies is the skin. It forms a protective barrier against exogenous substances and dehydration. The barrier function is attributed to the Stratum Corneum (SC), which is the outermost layer of the skin epidermis. The main components of the SC are proteins
called corneocytes (dead cells containing mainly keratin and water) and lipids. These lipids form an intercellular matrix wherein the corneocytes are embedded. This lipid matrix, which is highly ordered, consists chiefly of ceramides (CERs), free fatty acids (FFAs) and cholesterol
(CHOL), in an almost equimolar ratio. Knowing how the barrier function behaves, for instance in the presence of compounds such as drugs, is extremely desirable. To do this, we studied and characterized lipids extracted from porcine SC, whose properties are highly similar to those of
human SC. Their molecular mobility and structure was investigated in different conditions, such as temperature and relative humidity. Structurally, the lipids arrange themselves in periodical layers referred to as lamellae and are stacked parallel to the surface of the skin. Two
periodicity phases have been detected, long and short. The lamellar phases also possess density, which is how tight the chains are packed together. Variations in lipid composition, temperature and hydration conditions, will alter the lipid phase behavior.
Powerful techniques used to characterize extracted lipids are 13 C polarization transfer solid-state NMR (PT ss-NMR) and Small/Wide X-ray scattering (S/WAXS). Both providing high resolution and sensitivity, necessary to study the microscopic properties of the intercellular lipid
matrix and subsequently the skin barrier function. (Less)
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author
Velásquez González, Nicolas LU
supervisor
organization
course
KEML07 20181
year
type
M2 - Bachelor Degree
subject
keywords
stratum corneum, skin barrier, lipids, physical chemistry, fysikalisk kemi
language
English
id
8959325
date added to LUP
2018-11-06 13:45:55
date last changed
2018-11-06 13:45:55
@misc{8959325,
  abstract     = {The structure and dynamics of isolated Stratum Corneum lipids in different temperatures and hydration conditions was investigated using natural abundance 13 C NMR and X-ray scattering.
In order to isolate the lipids a new extraction method was tested. The novel aspect of this method was its ability to extract more lipids from SC. This new method (referred to as Method II in-text) was further modified. The resulting method (Method III) was chosen as the method to follow during this project. These two methods were also compared (using 13 C NMR) to an extraction method used in a pre-study. The lipids obtained through Method III were characterized with polarization transfer solid-state NMR and wide/small angle x-ray scattering.
NMR studies showed that a greater amount of lipids in a rigid state were being extracted with the new extraction method. These studies also showed that hydration has a clear effect on lipid mobility at temperatures of 32 ˚C. In the dry state there is low mobility, while upon full
hydration, a fraction of lipids are in a mobile state coexist with solid lipids. SAXS studies showed that SC lipids form two types of lamellar phases, one with a lamellar repeat distance of ~144 Å in dry and hydrated conditions, while another with a repeat distance of ~71Å in dry
conditions and ~68 Å in hydrated conditions. In the solid fraction of SC lipids, the hydrophobic chain adopts hexagonal packing, as detected with WAXS.},
  author       = {Velásquez González, Nicolas},
  keyword      = {stratum corneum,skin barrier,lipids,physical chemistry,fysikalisk kemi},
  language     = {eng},
  note         = {Student Paper},
  title        = {Skin barrier: Extraction and characterization of Stratum Corneum lipids},
  year         = {2018},
}