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.

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.

scholarly journals Effect of C60 on the phase transition behavior of a lipid bilayer under high pressure

RSC Advances ◽  
2018 ◽  
Vol 8 (2) ◽  
pp. 655-661 ◽  
Author(s):  
Haiyang Yang ◽  
Zhiheng Huang ◽  
Yong Zhang
Keyword(s):  
Phase Transition ◽  
Molecular Dynamics ◽  
High Pressure ◽  
Molecular Dynamics Simulations ◽  
Fluid Phase ◽  
Coarse Grained ◽  
Phase Transition Behavior ◽  
Gel Phase ◽  
Dynamics Simulations ◽  
Pressure Phase

By employing coarse-grained molecular dynamics simulations, we obtained the temperature–pressure phase diagrams of a dipalmitoylphosphatidylcholine bilayer, which exhibits a gel phase and a fluid phase, with variation of the C60versus lipid ratios.

Coarse-grained simulation of the self-assembly of lipid vesicles concomitantly with novel block copolymers with multiple tails

Soft Matter ◽  
2021 ◽  
Author(s):  
Alexander Kantardjiev
Keyword(s):  
Molecular Dynamics ◽  
Block Copolymers ◽  
Self Assembly ◽  
Lipid Vesicles ◽  
The Self ◽  
Coarse Grained ◽  
Copolymer Concentration ◽  
Copolymer Structure ◽  
Coarse Grained Molecular Dynamics

We carried out a series of coarse-grained molecular dynamics liposome-copolymer simulations with varying extent of copolymer concentration in an attempt to understand the effect of copolymer structure and concentration on vesicle self-assembly and stability.

scholarly journals The Impact of O-Glycosylation on Cyanidin Interaction with POPC Membranes: Structure-Activity Relationship

Molecules ◽  
2018 ◽  
Vol 23 (11) ◽  
pp. 2771
Author(s):  
Sylwia Cyboran-Mikołajczyk ◽  
Piotr Jurkiewicz ◽  
Martin Hof ◽  
Halina Kleszczyńska
Keyword(s):  
Biological Activity ◽  
Free Radicals ◽  
Lipid Bilayer ◽  
Lipid Membrane ◽  
Lipid Vesicles ◽  
Structure Activity Relationship ◽  
Activity Relationship ◽  
Beneficial Effects ◽  
Structure Activity ◽  
The Impact

Cyanidin and its O-glycosides have many important physiological functions in plants and beneficial effects on human health. Their biological activity is not entirely clear and depends on the structure of the molecule, in particular, on the number and type of sugar substituents. Therefore, in this study the detailed structure-activity relationship (SARs) of the anthocyanins/anthocyanidins in relation to their interactions with lipid bilayer was determined. On the basis of their antioxidant activity and the changes induced by them in size and Zeta potential of lipid vesicles, and mobility and order of lipid acyl chains, the impact of the number and type of sugar substituents on the biological activity of the compounds was evaluated. The obtained results have shown, that 3-O-glycosylation changes the interaction of cyanidin with lipid bilayer entirely. The 3-O-glycosides containing a monosaccharide induces greater changes in physical properties of the lipid membrane than those containing disaccharides. The presence of additional sugar significantly reduces glycoside interaction with model lipid membrane. Furthermore, O-glycosylation alters the ability of cyanidin to scavenge free radicals. This alteration depends on the type of free radicals and the sensitivity of the method used for their determination.

scholarly journals The interplay between lipids and dopamine on α-synuclein oligomerization and membrane binding

2013 ◽  
Vol 33 (5) ◽  
Author(s):  
Chi L. L. Pham ◽  
Roberto Cappai
Keyword(s):  
Lipid Membranes ◽  
Amyloid Fibrils ◽  
Lipid Membrane ◽  
Hydrophobic Interactions ◽  
Membrane Integrity ◽  
Lipid Vesicles ◽  
Helical Conformation ◽  
Unfolded Protein ◽  
Natively Unfolded Protein ◽  
Natively Unfolded

The deposition of α-syn (α-synuclein) as amyloid fibrils and the selective loss of DA (dopamine) containing neurons in the substantia nigra are two key features of PD (Parkinson's disease). α-syn is a natively unfolded protein and adopts an α-helical conformation upon binding to lipid membrane. Oligomeric species of α-syn have been proposed to be the pathogenic species associated with PD because they can bind lipid membranes and disrupt membrane integrity. DA is readily oxidized to generate reactive intermediates and ROS (reactive oxygen species) and in the presence of DA, α-syn form of SDS-resistant soluble oligomers. It is postulated that the formation of the α-syn:DA oligomers involves the cross-linking of DA-melanin with α-syn, via covalent linkage, hydrogen and hydrophobic interactions. We investigate the effect of lipids on DA-induced α-syn oligomerization and studied the ability of α-syn:DA oligomers to interact with lipids vesicles. Our results show that the interaction of α-syn with lipids inhibits the formation of DA-induced α-syn oligomers. Moreover, the α-syn:DA oligomer cannot interact with lipid vesicles or cause membrane permeability. Thus, the formation of α-syn:DA oligomers may alter the actions of α-syn which require membrane association, leading to disruption of its normal cellular function.

scholarly journals Long-Term Behavior of Coarse-Grained Rockfill Material and Their Constitutive Modeling

2021 ◽  
Author(s):  
Erich Bauer
Keyword(s):  
Mechanical Response ◽  
Coarse Grained ◽  
Geological Condition ◽  
Dam Foundation ◽  
Solid Hardness ◽  
Rockfill Materials ◽  
Materials Used ◽  
Creep And Stress Relaxation ◽  
Long Term Behavior

For the long-term behavior and safety assessment of rockfill dams, not only the shape of the dam body, the loading history, the geological condition of the dam foundation and abutments, the assessment of possible seismic hazards and seepage events caused by defects of the sealing are important, but also the time dependent mechanical behavior of the dam materials used can be of significant influence. In this paper a novel hypoplastic constitutive model for moisture sensitive, coarse-grained rockfill materials is presented. In the constitutive equations, the so-called solid hardness is a key parameter to reflect the influence of the state of weathering on the mechanical response. With respect to the evolution equation for the solid hardness, creep and stress relaxation can be modeled for dry and wet states of the material in a unified manner. The performance of the model is demonstrated by comparing the numerical simulation with experimental data.

Simulation of fluid/gel phase equilibrium in lipid vesicles

Soft Matter ◽  
2019 ◽  
Vol 15 (40) ◽  
pp. 8102-8112 ◽  
Author(s):  
David Stelter ◽  
Tom Keyes
Keyword(s):  
Molecular Dynamics ◽  
Phase Equilibrium ◽  
Size Effects ◽  
Finite Size ◽  
Lipid Vesicles ◽  
Finite Size Effects ◽  
Gel Phase ◽  
20 Nm

Simulation of DPPC lipid vesicles of diameter 10 nm (1350 lipids), 20 nm (5100 lipids) and 40 nm (17 600 lipids) is performed using statistical temperature molecular dynamics (STMD), to study finite size effects upon the gel/fluid transition.

A Finite Element-Based Coarse-Grained Model for Cell–Nanomaterial Interactions by Combining Absolute Nodal Coordinate Formula and Brownian Dynamics

2020 ◽  
Vol 88 (4) ◽  
Author(s):  
Teng Ma ◽  
Yuanpeng Liu ◽  
Guochang Lin ◽  
Changguo Wang ◽  
Huifeng Tan
Keyword(s):  
Finite Element ◽  
Brownian Dynamics ◽  
Lipid Membrane ◽  
Contact Region ◽  
Detection Algorithm ◽  
Polymer Chains ◽  
Coarse Grained ◽  
Absolute Nodal Coordinate ◽  
Coarse Grained Model ◽  
Dynamics Simulations

Abstract A fundamental understanding of the interactions between one-dimensional nanomaterials and the cell membrane is of great importance for assessing the hazardous effects of viruses and improving the performance of drug delivery. Here, we propose a finite element-based coarse-grained model to describe the cell entry of nanomaterials based on an absolute nodal coordinate formula and Brownian dynamics. The interactions between nanoparticles and lipid membrane are described by the Lennard–Jones potential, and a contact detection algorithm is used to determine the contact region. Compared with the theoretical and published experimental results, the correctness of the model has been verified. We take two examples to test the robustness of the model: the endocytosis of nanorods grafted with polymer chains and simultaneous entry of multiple nanorods into a lipid membrane. It shows that the model can not only capture the effect of ligand–receptor binding on the penetration but also accurately characterize the cooperative or separate entry of multiple nanorods. This coarse-grained model is computationally highly efficient and will be powerful in combination with molecular dynamics simulations to provide an understanding of cell–nanomaterial interactions.

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