scholarly journals Can Polarity-Inverted Surfactants Self-Assemble in Nonpolar Solvents?

2020 ◽  
Author(s):  
Manuel Carrer ◽  
Tatjana Skrbic ◽  
Sigbjørn Løland Bore ◽  
Giuseppe Milano ◽  
Michele Cascella ◽  
...  
Keyword(s):  
Self Assembly ◽  
Diffusion Constant ◽  
Micelle Formation ◽  
Triethylene Glycol ◽  
Coarse Grained ◽  
Hydrophobic Core ◽  
Particle Field ◽  
Nonpolar Solvents ◽  
Thermodynamic Conditions ◽  
Dynamics Simulations

We investigate the self-assembly process of a surfactant with inverted polarity in water and cyclohexane using both all-atom and coarse grained hybrid particle-field molecular<br>dynamics simulations. Unlike conventional surfactants, the molecule under study proposed in a recent experiment is<br><div>formed by a rigid and compact hydrophobic adamantane moiety, and a long and floppy triethylene glycol tail. In water, we report the formation of stable inverted micelles with the adamantane heads grouping together into a hydrophobic core, and the tails forming hydrogen bonds with water. By contrast, multi-microsecond simulations do not provide evidence of stable micelle formation in cyclohexane. Validating the computational results by comparison with experimental diffusion constant and small-angle neutron scattering intensity, we show that at laboratory thermodynamic conditions the mixture resides in the supercritical region of the phase diagram, where aggregated and free surfactant states co-exist in solution. Our simulations also provide indications about how to escape this region, to produce thermodynamically stable micellar forms.</div>

scholarly journals Can Polarity-Inverted Surfactants Self-Assemble in Nonpolar Solvents?

2020 ◽  
Author(s):  
Manuel Carrer ◽  
Tatjana Skrbic ◽  
Sigbjørn Løland Bore ◽  
Giuseppe Milano ◽  
Michele Cascella ◽  
...  
Keyword(s):  
Self Assembly ◽  
Diffusion Constant ◽  
Micelle Formation ◽  
Triethylene Glycol ◽  
Coarse Grained ◽  
Hydrophobic Core ◽  
Particle Field ◽  
Nonpolar Solvents ◽  
Thermodynamic Conditions ◽  
Dynamics Simulations

We investigate the self-assembly process of a surfactant with inverted polarity in water and cyclohexane using both all-atom and coarse grained hybrid particle-field molecular<br>dynamics simulations. Unlike conventional surfactants, the molecule under study proposed in a recent experiment (M. Facchin et al., RSC Adv. 2017, 7, 15337–15341) is<br><div>formed by a rigid and compact hydrophobic adamantane moiety, and a long and floppy triethylene glycol tail. In water, we report the formation of stable inverted micelles with the adamantane heads grouping together into a hydrophobic core, and the tails forming hydrogen bonds with water. By contrast, multi-microsecond simulations do not provide evidence of stable micelle formation in cyclohexane. Validating the computational results by comparison with experimental diffusion constant and small-angle neutron scattering intensity, we show that at laboratory thermodynamic conditions the mixture resides in the supercritical region of the phase diagram, where aggregated and free surfactant states co-exist in solution. Our simulations also provide indications about how to escape this region, to produce thermodynamically stable micellar forms.</div>

scholarly journals Can Polarity-Inverted Surfactants Self-Assemble in Nonpolar Solvents?

2020 ◽  
Author(s):  
Manuel Carrer ◽  
Tatjana Skrbic ◽  
Sigbjørn Løland Bore ◽  
Giuseppe Milano ◽  
Michele Cascella ◽  
...  
Keyword(s):  
Self Assembly ◽  
Diffusion Constant ◽  
Micelle Formation ◽  
Triethylene Glycol ◽  
Coarse Grained ◽  
Hydrophobic Core ◽  
Particle Field ◽  
Nonpolar Solvents ◽  
Thermodynamic Conditions ◽  
Dynamics Simulations

We investigate the self-assembly process of a surfactant with inverted polarity in water and cyclohexane using both all-atom and coarse grained hybrid particle-field molecular<br>dynamics simulations. Unlike conventional surfactants, the molecule under study proposed in a recent experiment is<br><div>formed by a rigid and compact hydrophobic adamantane moiety, and a long and floppy triethylene glycol tail. In water, we report the formation of stable inverted micelles with the adamantane heads grouping together into a hydrophobic core, and the tails forming hydrogen bonds with water. By contrast, multi-microsecond simulations do not provide evidence of stable micelle formation in cyclohexane. Validating the computational results by comparison with experimental diffusion constant and small-angle neutron scattering intensity, we show that at laboratory thermodynamic conditions the mixture resides in the supercritical region of the phase diagram, where aggregated and free surfactant states co-exist in solution. Our simulations also provide indications about how to escape this region, to produce thermodynamically stable micellar forms.</div>

scholarly journals DNA and lipid bilayers: self-assembly and insertion

2008 ◽  
Vol 5 (suppl_3) ◽  
pp. 241-250 ◽  
Author(s):  
Syma Khalid ◽  
Peter J Bond ◽  
John Holyoake ◽  
Robert W Hawtin ◽  
Mark S.P Sansom
Keyword(s):  
Lipid Bilayers ◽  
Self Assembly ◽  
Potential Of Mean Force ◽  
Coarse Grained ◽  
Hydrophobic Core ◽  
Dna Molecule ◽  
Dna Insertion ◽  
Dynamics Simulations ◽  
Dna Dodecamer ◽  
Insight Into

DNA–lipid complexes are of biomedical importance as delivery vectors for gene therapy. To gain insight into the interactions of DNA with zwitterionic and cationic (dimyristoyltrimethylammonium propane (DMTAP)) lipids, we have used coarse-grained molecular dynamics simulations to study the self-assembly of DPPC and DPPC/DMTAP lipid bilayers in the presence of a DNA dodecamer. We observed the spontaneous formation of lipid bilayers from initial systems containing randomly placed lipids, water–counterions and DNA. In both the DPPC and DPPC/DMTAP simulations, the DNA molecule is located at the water–lipid headgroup interface, lying approximately parallel to the plane of the bilayer. We have also calculated the potential of mean force for transferring a DNA dodecamer through a DPPC/DMTAP bilayer. A high energetic barrier to DNA insertion into the hydrophobic core of the bilayer is observed. The DNA adopts a transmembrane orientation only in this region. Local bilayer deformation in the vicinity of the DNA molecule is observed, largely as a result of the DNA–DMTAP headgroup attraction.

scholarly journals Variation of Interaction Zone Size For The Target Design of 2D Supramolecular Networks

2021 ◽  
Author(s):  
Łukasz Piotr Baran ◽  
Wojciech Rżysko ◽  
Dariusz Tarasewicz
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Self Assembly ◽  
The Self ◽  
Coarse Grained ◽  
Zone Size ◽  
Interaction Zone ◽  
Supramolecular Networks ◽  
Dynamics Simulations ◽  
Target Design

In this study we have performed extensive coarse-grained molecular dynamics simulations of the self-assembly of tetra-substituted molecules. We have found that such molecules are able to form a variety of...

scholarly journals Inverse design of cholesterol attracting transmembrane helices reveals a paradoxical role of hydrophobic length

2021 ◽  
Author(s):  
Jeroen Methorst ◽  
Niek van Hilten ◽  
Herre Jelger Risselada
Keyword(s):  
Molecular Dynamics ◽  
Lipid Membranes ◽  
Transmembrane Domain ◽  
Optimal Solution ◽  
Molecular Shape ◽  
Global Optimum ◽  
Coarse Grained ◽  
Hydrophobic Core ◽  
Recognition Motifs ◽  
Dynamics Simulations

The occurrence of linear cholesterol-recognition motifs in alpha-helical transmembrane domains has long been debated. Here, we demonstrate the ability of a genetic algorithm guided by coarse-grained molecular dynamics simulations---a method coined evolutionary molecular dynamics (evo-MD)---to directly resolve the sequence which maximally attracts/sorts cholesterol within a single-pass alpha-helical transmembrane domain (TMDs). We illustrate that the evolutionary landscape of cholesterol attraction in membrane proteins is characterized by a sharp, well-defined global optimum. Surprisingly, this optimal solution features an unusual short hydrophobic block, consisting of typically only eight short chain hydrophobic amino acids, surrounded by three successive lysines. Owing to the membrane thickening effect of cholesterol, cholesterol-enriched ordered phases favor TMDs characterized by a long rather than a short hydrophobic length. However, this short hydrophobic pattern evidently offers a pronounced net advantage for the binding of free cholesterol in both coarse-grained and atomistic simulations. Attraction is mediated by the unique ability of cholesterol to snorkel within the hydrophobic core of the membrane and thereby shield deeply located lysines from the unfavorable hydrophobic surrounding. Since this mechanism of attraction is of a thermodynamic nature and is not based on molecular shape specificity, a large diversity of sub-optimal cholesterol attracting sequences can exist. The puzzling sequence variability of proposed linear cholesterol-recognition motifs is thus consistent with sub-optimal, unspecific binding of cholesterol. Importantly, since evo-MD uniquely enables the targeted design of recognition motifs for distinct fluid lipid membranes, we foresee wide applications for evo-MD in the biological and biomedical fields.

scholarly journals Dual responsive PMEEECL–PAE block copolymers: a computational self-assembly and doxorubicin uptake study

RSC Advances ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 3233-3245 ◽  
Author(s):  
Amin Koochaki ◽  
Mohammad Reza Moghbeli ◽  
Sousa Javan Nikkhah ◽  
Alessandro Ianiro ◽  
Remco Tuinier
Keyword(s):  
Block Copolymers ◽  
Self Assembly ◽  
The Self ◽  
Coarse Grained ◽  
Dual Responsive ◽  
Consistent Field ◽  
Self Consistent ◽  
Self Consistent Field ◽  
Self Consistent Field Theory ◽  
Dynamics Simulations

The self-assembly behaviour of dual-responsive block copolymers and their ability to solubilize the drug doxorubicin is demonstrated using molecular dynamics simulations, coarse-grained force field simulations and self-consistent field theory.

Self-assembly of amphiphilic polymers of varying architectures near attractive surfaces

Soft Matter ◽  
2020 ◽  
Vol 16 (3) ◽  
pp. 623-633 ◽  
Author(s):  
Michiel G. Wessels ◽  
Arthi Jayaraman
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Self Assembly ◽  
Amphiphilic Polymers ◽  
Coarse Grained ◽  
Polymer Architecture ◽  
Dynamics Simulations ◽  
Coarse Grained Molecular Dynamics

We use coarse-grained molecular dynamics simulations to investigate the assembly of A–B amphiphilic polymers near/on surfaces as a function of polymer architecture and surface attraction to the solvophobic B-block in the polymer.

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