Molecular Dynamics Simulations of DMPC/DPPC Mixed Bilayers

Poghosyan, Armen H.; Gharabekyan, Hrant H.; Shahinyan, Aram A.

doi:10.1142/s0129183107010267

Cited by 9 publications

(9 citation statements)

References 68 publications

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“…the penetration of alkyl chains located on opposite sides of the bilayer is observed. Thus, we see the full interpenetration of the SPDS alkyl chains located on opposite sides of the bilayer (fully interdigitated gel state); however, together with ordered molecules, the disordered domains or so-called “clusterized regions” are also presented; hence, we assume that the formation of the gel phase coexisted with a lamellar L α phase.…”

Section: Resultsmentioning

confidence: 96%

Molecular Dynamics Study of Intermediate Phase of Long Chain Alkyl Sulfonate/Water Systems

2012

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Using atomic level simulation we aimed to investigate various intermediate phases of the long chain alkyl sulfonate/water system. Overall, about 800 ns parallel molecular dynamics simulation study was conducted for a surfactant/water system consisting of 128 sodium pentadecyl sulfonate and 2251 water molecules. The GROMACS software code with united atom force field was applied. Despite some differences, the analysis of main structural parameters is in agreement with X-ray experimental findings. The mechanism of self-assembly of SPDS molecules was also examined. At T = 323 K we obtained both tilted fully interdigitated and liquid crystalline-like disordered hydrocarbon chains; hence, the presence of either gel phase that coexists with a lamellar phase or metastable gel phase with fraction of gauche configuration can be assumed. Further increase of temperature revealed that the system underwent a transition to a lamellar phase, which was clearly identified by the presence of fully disordered hydrocarbon chains. The transition from gel-to-fluid phase was implemented by simulated annealing treatment, and the phase transition point at T = 335 K was identified. The surfactant force field in its presented set is surely enabled to fully demonstrate the mechanism of self-assembly and the behavior of phase transition making it possible to get important information around the phase transition point.

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Section: Resultsmentioning

confidence: 96%

Molecular Dynamics Study of Intermediate Phase of Long Chain Alkyl Sulfonate/Water Systems

2012

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“…Figure 3 a shows the results obtained from ellipsometric studies for mixture DPPC:DMPC (2:1). This binary compound is denominated “ideal” because their surfactants have similar chemical structures, so it presents a high interaction between their components [ 58 ]. This bilayer displays an initial thickness of 6.9 nm at 21.2 °C, this value decay to ~6.1 nm at 55.0 °C (total differential thickness: 0.8 nm).…”

Section: Resultsmentioning

confidence: 99%

Thermal Response Analysis of Phospholipid Bilayers Using Ellipsometric Techniques

et al. 2017

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Biomimetic planar artificial membranes have been widely studied due to their multiple applications in several research fields. Their humectation and thermal response are crucial for reaching stability; these characteristics are related to the molecular organization inside the bilayer, which is affected by the aliphatic chain length, saturations, and molecule polarity, among others. Bilayer stability becomes a fundamental factor when technological devices are developed—like biosensors—based on those systems. Thermal studies were performed for different types of phosphatidylcholine (PC) molecules: two pure PC bilayers and four binary PC mixtures. These analyses were carried out through the detection of slight changes in their optical and structural parameters via Ellipsometry and Surface Plasmon Resonance (SPR) techniques. Phospholipid bilayers were prepared by Langmuir-Blodgett technique and deposited over a hydrophilic silicon wafer. Their molecular inclination degree, mobility, and stability of the different phases were detected and analyzed through bilayer thickness changes and their optical phase-amplitude response. Results show that certain binary lipid mixtures—with differences in its aliphatic chain length—present a co-existence of two thermal responses due to non-ideal mixing.

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“…32 Interestingly, these two very similar lipids have been found to mix nonideally in the liquid crystalline phase of SUVs. 36 FTIR and NMR spectroscopic characterization 37 along with molecular dynamic simulation studies 38 of the mixed DMPC/DPPC lipid systems have provided some valuable information about the conformational order as well as packing in the acyl chain regions of the DMPC/DPPC bilayer.…”

Section: Introductionmentioning

confidence: 99%

Small Mismatches in Fatty Acyl Tail Lengths Can Effect Non Steroidal Anti-Inflammatory Drug Induced Membrane Fusion

Majumdar

Sarkar

2016

J. Phys. Chem. B

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Biological membranes are made up of a variety of lipids with diverse physicochemical properties. The lipid composition modulates different lipidic parameters, such as hydration, dynamics, lipid packing, curvature strain, etc. Changes in these parameters affect various membrane-mediated processes, such as membrane fusion which is an integral step in many biological processes. Packing defects, which originate either from mismatch in the headgroup region or in the hydrophobic acyl tail region, play a major role in modulating membrane dynamics. In this study, we demonstrate how even a small mismatch in the fatty acyl chain length, achieved by incorporation of low concentrations (up to 30 mol %) of dipalmitoylphosphatidylcholine (DPPC) into dimyristoylphosphatidylcholine (DMPC) small unilamellar vesicles (SUVs), alters several lipidic parameters like packing, dynamics, and headgroup hydration. This in turn affects non steroidal anti-inflammatory drug (NSAID) induced membrane fusion. Dynamic light scattering, differential scanning calorimetry, second-derivative absorption spectrophotometry, and steady-state and time-resolved fluorescence have been used to elucidate the effect of small mismatch in the tails in DMPC/DPPC mixed vesicles and how it modulates membrane fusion induced by the oxicam NSAIDs, meloxicam (Mx), piroxicam (Px), and tenoxicam (Tx). Fusion kinetics was monitored using fluorescence based fusion assays. At low DPPC concentration of 10 mol %, additional fluidization promotes lipid mixing to some extent for Mx, but at higher mol % of DPPC, subsequent increase in rigidity of membrane interior along with increase in headgroup hydration, synergistically inhibits fusion to various extents for the three different drugs, Mx, Px, and Tx.

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Molecular Dynamics Simulations of DMPC/DPPC Mixed Bilayers

Cited by 9 publications

References 68 publications

Molecular Dynamics Study of Intermediate Phase of Long Chain Alkyl Sulfonate/Water Systems

Molecular Dynamics Study of Intermediate Phase of Long Chain Alkyl Sulfonate/Water Systems

Thermal Response Analysis of Phospholipid Bilayers Using Ellipsometric Techniques

Small Mismatches in Fatty Acyl Tail Lengths Can Effect Non Steroidal Anti-Inflammatory Drug Induced Membrane Fusion

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