Molecular Dynamics Simulation Study of Skin Lipids: Effects of the Molar Ratio of Individual Components over a Wide Temperature Range

Abstract

Atomistic molecular dynamics (MD) simulations were employed to systematically investigate the effects of the molar ratio of the individual components cholesterol (CHOL), free fatty acid (FFA), and ceramides (CER) on the properties of the skin lipid bilayer over a wide temperature range (300-400 K). Several independent simulations were performed for bilayers comprised of only CER, CHOL, or FFA molecules as well as those made up of a mixture of CER:CHOL:FFA molecules in different molar ratios. It was found that CHOL increases the stability of the bilayer, since the mixed (CER:CHOL:FFA) 1:1:0, 1:1:1, and 2:2:1 bilayers remained stable until 400 K while the pure ceramide bilayer disintegrated around ∼390 K. It was also observed that CHOL reduces the volume spanned by ceramide molecules, thereby leading to a higher area per CER and FFA molecule in the mixed bilayer system. The CHOL molecule provided more rigidity to the mixed bilayer and led to a more ordered phase at elevated temperatures. The CHOL molecule provided fluidity to the bilayer below the phase transition temperature of CER and kept the bilayer rigid above the phase transition temperature. The FFA interdigitizes with CER molecules and increases the thickness of the bilayer, while rigid CHOL decreases the bilayer thickness. The presence of CHOL increases the compressibility of the bilayer which is responsible for the high barrier function of skin. The CER molecule forms inter- and intramolecular hydrogen bonds, while CHOL only forms intermolecular hydrogen bonds.

Effect of Size and Surface Charge of Gold Nanoparticles on their Skin Permeability: A Molecular Dynamics Study

“…The CG model of skin lipid bilayer was obtained from the earlier developed united atom model32. The CG models were based on the MARTINI force field3334.…”

Monolayer and Bilayer Structures of Mixtures of Ceramide IIIb and c16‐Alkyl Glucosides

“…[13][14][15][16][17][18][19][20][21][22] On the other hand, this work investigated the stability of monolayers and bilayers that are found in commercial skin care products. [13][14][15][16][17][18][19][20][21][22] On the other hand, this work investigated the stability of monolayers and bilayers that are found in commercial skin care products.…”

“…[13][14][15][16][17][18][19][20][21][22] The bilayer membranes studied previously include those composed only of ceramides and those containing a mixture of ceramides, free fatty acids, and cholesterol. It provides molecular level information that is not accessible to current experimental techniques and, therefore, it facilitates the interpretation of experimental observations and prediction of new chemistry.…”

Perspective: Computational modeling of accurate cellular membranes with molecular resolution

“…Efforts have been made to study the biophysical properties of key lipid components with a single bilayer for the CHARMM36 and GROMOS force fields. 52,[110][111][112][113][114][115][116][117][118][119][120] Many have focused on using three-lipid models of a ceramide, fatty acid, and cholesterol to mimic the SC. Moore et al 110 found that bilayer thickness depends strongly on the level of tail-length asymmetry and permeability strongly depends on tail-length variation.…”