Coarse-grained molecular simulations of the melting kinetics of small unilamellar vesicles

Soft Matter ◽  
2016 ◽  
Vol 12 (6) ◽  
pp. 1765-1777 ◽  
Author(s):  
Lara A. Patel ◽  
James T. Kindt
Keyword(s):  
Dominant Role ◽  
Molecular Simulations ◽  
Lipid Vesicles ◽  
Melting Rate ◽  
Coarse Grained ◽  
Unilamellar Vesicles ◽  
Melting Kinetics ◽  
Temperature Jumps ◽  
Small Unilamellar Vesicles ◽  
Kinetics Of

Frozen lipid vesicles simulated using a coarse-grained potential and subject to temperature jumps respond by melting on timescales similar to those observed experimentally; changes in curvature stress appear to play a dominant role in controlling the melting rate.

Effective interaction between small unilamellar vesicles as probed by coarse-grained molecular dynamics simulations

2014 ◽  
Vol 86 (2) ◽  
pp. 215-222 ◽  
Author(s):  
Wataru Shinoda ◽  
Michael L. Klein
Keyword(s):  
Molecular Dynamics ◽  
Free Energy ◽  
Effective Interaction ◽  
Md Simulations ◽  
Coarse Grained ◽  
Repulsive Interaction ◽  
Spontaneous Curvature ◽  
Unilamellar Vesicles ◽  
Small Unilamellar Vesicles ◽  
Dynamics Simulations

Abstract A series of molecular dynamics (MD) simulations has been undertaken to investigate the effective interaction between vesicles including PC (phosphatidylcholine) and PE (phosphatidylethanolamine) lipids using the Shinoda–DeVane–Klein coarse-grained force field. No signatures of fusion were detected during MD simulations employing two apposed unilamellar vesicles, each composed of 1512 lipid molecules. Association free energy of the two stable vesicles depends on the lipid composition. The two PC vesicles exhibit a purely repulsive interaction with each other, whereas two PE vesicles show a free energy gain at the contact. A mixed PC/PE (1:1) vesicle shows a higher flexibility having a lower energy barrier on the deformation, which is caused by lipid sorting within each leaflet of the membranes. With a preformed channel or stalk between proximal membranes, PE molecules contribute to stabilize the stalk. The results suggest that the lipid components forming the membrane with a negative spontaneous curvature contribute to stabilize the stalk between two vesicles in contact.

Vesicle deformation and division induced by flip-flop of lipid molecules

Soft Matter ◽  
2021 ◽  
Author(s):  
Naohito Urakami ◽  
Yuka Sakuma ◽  
Toshikaze Chiba ◽  
Masayuki Imai
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Single Component ◽  
Coarse Grained ◽  
Spontaneous Curvature ◽  
Unilamellar Vesicles ◽  
Flip Flop ◽  
Small Unilamellar Vesicles ◽  
Dynamics Simulations ◽  
Coarse Grained Molecular Dynamics

We investigated the deformation of small unilamellar vesicles (SUVs) induced by flip-flops of lipids using coarse-grained molecular dynamics simulations. In case of single-component SUVs composed of zero spontaneous curvature lipids...

Kinetics of fatty acid-mediated proton movement across small unilamellar vesicles

Biochemistry ◽  
1993 ◽  
Vol 32 (41) ◽  
pp. 11085-11086
Author(s):  
Frits Kamp ◽  
Hans V. Westerhoff ◽  
James A. Hamilton
Keyword(s):  
Fatty Acid ◽  
Unilamellar Vesicles ◽  
Small Unilamellar Vesicles ◽  
Proton Movement ◽  
Kinetics Of

scholarly journals Stiffness of fluid and gel phase lipid nanovesicles: weighting the contributions of membrane bending modulus and luminal pressurization

2021 ◽  
Author(s):  
Andrea Ridolfi ◽  
Lucrezia Caselli ◽  
Matteo Baldoni ◽  
Costanza Montis ◽  
Francesco Mercuri ◽  
...  
Keyword(s):  
Mechanical Response ◽  
Lipid Membrane ◽  
Dominant Role ◽  
Fluid Phase ◽  
Lipid Vesicles ◽  
Unified Model ◽  
Coarse Grained ◽  
Bending Modulus ◽  
Membrane Rigidity ◽  
Gel Phase

The mechanical properties of biogenic membranous compartments are thought to be relevant in numerous biological processes; however, their quantitative measurement remains challenging for most of the already available Force Spectroscopy (FS)-based techniques. In particular, the debate on the mechanics of lipid nanovesicles and on the interpretation of their mechanical response to an applied force is still open. This is mostly due to the current lack of a unified model being able to describe the mechanical response of gel and fluid phase lipid vesicles and to disentangle the contributions of membrane rigidity and luminal pressure. In this framework, we herein propose a simple model in which the contributions of membrane rigidity and luminal pressure to the overall vesicle stiffness are described as a series of springs; this approach allows estimating the two contributions for both gel and fluid phase liposomes. Atomic Force Microscopy-based FS (AFM-FS), performed on both vesicles and Supported Lipid Bilayers (SLBs), is exploited for obtaining all the parameters involved in the model. Moreover, the use of coarse-grained full-scale molecular dynamics simulations allowed for better understanding the differences in the mechanical responses of gel and fluid phase bilayers and supported the experimental findings. Results suggest that the pressure contribution is similar among all the probed vesicle types; however, it plays a dominant role in the mechanical response of lipid nanovesicles presenting a fluid phase membrane, while its contribution becomes comparable to the one of membrane rigidity in nanovesicles with a gel phase lipid membrane. The herein presented results offer a simple way to quantify two of the most important parameters in vesicular nanomechanics, and as such represent a first step towards a currently unavailable, unified model for the mechanical response of gel and fluid phase lipid nanovesicles.

Kinetics of melittin binding to phospholipid small unilamellar vesicles

1991 ◽  
Vol 1063 (1) ◽  
pp. 171-174 ◽  
Author(s):  
K. Madhavi Sekharam ◽  
Thomas D. Bradrick ◽  
S. Georghiou
Keyword(s):  
Unilamellar Vesicles ◽  
Small Unilamellar Vesicles ◽  
Kinetics Of

scholarly journals A Study of Electric Field Effect on Melting of Octadecane

2016 ◽  
Vol 17 (2) ◽  
pp. 256-261
Author(s):  
S.G. Orlovskaya ◽  
F.F. Karimova ◽  
M.S. Shkoropado
Keyword(s):  
Electric Field ◽  
Melting Rate ◽  
Melting Time ◽  
Electric Field Effect ◽  
Shape Evolution ◽  
Solid Core ◽  
Droplet Shape ◽  
Melting Kinetics ◽  
Calculation Results ◽  
Kinetics Of

A new approach is developed to study melting kinetics of n-Octadecane. Modelling of heat transfer during the melting of solid particle is described. The calculation results are in good agreement with experimental data on melting duration. The effect of applied electric field on melting kinetics is studied. Almost twofold increase of melting time is found in an electric field of strength E = 82 kv/m. In addition a rotation of a solid core inside a melt is observed, which is a manifestation of Quinke effect. A droplet shape evolution during phase transition is described. It is shown that initially elongated particle is almost spherical near the melting point and elongates again with the temperature rise. This shape evolution is explained by non-monotonous change of surface tension and is connected with rotational phase. Thus a possibility is shown to control a melting rate of normal alkanes using electric field.

scholarly journals Numerical Simulation of Melting Kinetics of Metal Particles during Tapping with Argon-Bottom Stirring

Crystals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 901
Author(s):  
Kinnor Chattopadhyay ◽  
Rodolfo Morales-Davila ◽  
Alfonso Nájera-Bastida ◽  
Jafeth Rodríguez-Ávila ◽  
Carlos Rodrigo Muñiz-Valdés
Keyword(s):  
Room Temperature ◽  
Melting Furnace ◽  
Melting Process ◽  
Melting Rate ◽  
Metal Particles ◽  
Melting Kinetics ◽  
Nickel Particles ◽  
Filling Time ◽  
The Impact ◽  
Kinetics Of

Molten steel is alloyed during tapping from the melting furnace to the argon-bottom stirred ladle. The metallic additions thrown to the ladle during the ladle filling time are at room temperature. The melting rates or kinetics of sinking-metals, like nickel, are simulated through a multiphase Euler–Lagrangian mathematical model during this operation. The melting rate of a metallic particle depends on its trajectory within regions of the melt with high or low turbulence levels, delaying or speeding up their melting process. At low steel levels in the ladle, the melting rates are higher on the opposite side of the plume zone induced by the bottom gas stirring. This effect is due to its deviation after the impact of the impinging jet on the ladle bottom. The higher melting kinetics are located on both sides at high steel levels due to the more extensive recirculation flows formed in taller baths. Making the additions above the eye of the argon plume spout increases the melting rate of nickel particles. The increase of the superheat makes the heat flux more significant from the melt to the particle, increasing its melting rate. At higher superheats, the melting kinetics become less dependent on the fluid dynamics of the melt.

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