%0 Journal Article
%T A Coarse-Grained Molecular Dynamics Study of DLPC, DMPC, DPPC, and DSPC Mixtures in Aqueous Solution
%A Roghayeh Abedi Karjiban
%A Nurul Syahidah Shaari
%A Uma Villashini Gunasakaran
%A Mahiran Basri
%J Journal of Chemistry
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/931051
%X The structural and dynamics properties of the bilayer comprising 128 molecules of dipalmitoylphosphatidylcholine (DPPC), dilauroylphosphatidylcholine (DLPC), dimyristoylphosphatidylcholine (DMPC), and distearoylphosphatidylcholine (DSPC) in water were investigated using a coarse-grained molecular dynamics (CG-MD) simulation technique. The model mixture system was simulated at 298£¿K under semi-isotropic pressure conditions. The aggregation was initiated from the random configurations followed by the formation of a bilayer over a period of 500£¿ns. The calculated values of the area per lipid, thickness, and lateral diffusion for the mixed model were different from when a single lipid was used. Our results confirmed that the chain length of the lipid molecules strongly affects the phospholipid bilayer¡¯s physical properties. 1. Introduction Phospholipid bilayers are vital components of life and play a crucial role in membrane-mediated cell signaling [1]. A typical class of lipids is the phosphatidylcholines (PCs), which contains a family of saturated and symmetric phospholipids with the same molecular structures and different alkyl chain lengths. The alkyl chain lengths of PCs range from 12 carbon atoms in DLPC (1,2-dilauroyl-sn-glycero-3-phosphocholine) to 14 carbon atoms in DMPC (1,2-dimyristoyl-sn-glycero-3-phosphocholine), 16 carbon atoms in DPPC (1,2-dipalmitoyl-sn-glycero-3-phosphocholine), and 18 carbon atoms in DSPC (1,2-distearoyl-sn-glycero-3-phosphocholine) [2]. Phosphatidylcholines are considered as zwitterionic surfactant molecules due to the existence of two charged groups with different sizes. The anionic part involves phosphates, whereas the positive charge is located on the ammonium group [3]. Lipid molecules can exhibit micellar shapes, rod-like structures, and bilayers in aqueous solution due to their surfactant-like properties. The shape of the structure is usually dependent on the solution¡¯s concentration, temperature, and physicochemical properties [4]. The self-assembly of PC molecules is important for nanoemulsion formulations [5, 6]. Both theoretical and experimental studies have demonstrated that nanoemulsions have great potential for application as drug carriers for transdermal drug delivery [7]. Phosphatidylcholines can spontaneously organize into bilayers due to their cylindrical shapes [8]. Figure 1 shows the molecular structures of DLPC (a), DMPC (b), DPPC (c), and DSPC (d). Figure 1: The structures of DLPC, DMPC, DPPC, and DSPC molecules. Traditional molecular dynamics (MD), which applies all-atom level or united-atom level
%U http://www.hindawi.com/journals/jchem/2013/931051/