Kinetic pathways of sheared block copolymer systems derived from Minkowski functionals

The solubilization mechanism of lipid membranes in the presence of Triton X-100 (TX-100) is investigated at molecular resolution using molecular dynamics (MD) simulations. Thanks to the large time and length scales accessible by the hybrid particle-field formulation of the models employed here, the complex process of membrane solubilization has been studied, with the goal of verifying the three stage model reported in the literature. DPPC lipid bilayers and vesicles have been studied at different concentrations of the TX-100 detergent employing coarse grained (CG) models. Systems up to ∼600.000 beads, corresponding to more than 2 millions heavy atoms, have been simulated. Moreover, in order to clarify several experimental pieces of evidence, both slow and fast detergent partition scenarios have been investigated. Flat and curved (vesicles) lipid bilayer surfaces, interacting with TX-100, have been considered to study the curvature effects on the detergent partition rate in the membrane. Shape and conformational changes of mixed DPPC/TX-100 vesicles, as a function of TX-100 content, have also been studied. In particular, high curvature surfaces, corresponding to a higher local TX-100 content, promote a membrane rupture. In flat lipid surfaces, on the time scale simulated the detergent partition is almost absent, following a different pathway of the solubilization membrane mechanism.

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“…To better quantify these findings, we have performed Minkowski Functional (MF) analysis of the solvent field 96,97 (see Fig. 11).…”

Section: Vesicles With An Intermediate Radius Of Curvaturementioning

confidence: 99%

Biomembrane solubilization mechanism by Triton X-100: a computational study of the three stage model

Pizzirusso

Sevink

Correa

et al. 2017

Phys. Chem. Chem. Phys.

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“…More recently, their possible application as descriptors of biomechanical strength in bone and as new parameters for the topological analysis of mineral distribution in hip fractures have been investigated (31–33). MFs have also been considered for their discriminative potential in the polymer industry to determine the morphology of block polymers (34). MFs allow the characterization of multidimensional objects by considering shape, structure, and connectivity, which in 2D space corresponds to the MFs: area, perimeter, and genus.…”

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confidence: 99%

Characterization of image heterogeneity using 2D Minkowski functionals increases the sensitivity of detection of a targeted MRI contrast agent

Canuto

McLachlan²,

Kettunen

et al. 2009

Magnetic Resonance in Med

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A targeted Gd 3؉ -based contrast agent has been developed that detects tumor cell death by binding to the phosphatidylserine (PS) exposed on the plasma membrane of dying cells. Although this agent has been used to detect tumor cell death in vivo, the differences in signal intensity between treated and untreated tumors was relatively small. As cell death is often spatially heterogeneous within tumors, we investigated whether an image analysis technique that parameterizes heterogeneity could be used to increase the sensitivity of detection of this targeted contrast agent. Two-dimensional (2D) Minkowski functionals (MFs) provided an automated and reliable method for parameterization of image heterogeneity, which does not require prior assumptions about the number of regions or features in the image, and were shown to increase the sensitivity of detection of the contrast agent as compared to simple signal intensity analysis. Magn Reson Med 61:1218 -1224, 2009.

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“…Integral geometry has been successfully used to analyze polymeric systems both in computer simulation and experiment. [43][44][45] Since we have two bead species, and our copolymers are symmetric, we have used only the A component to calculate Minkowski functionals using the marching squares algorithm. 46 Minkowski measures evaluated for M A = M B = 3, 4, 6, and 8 computed along paths of constant chemical potential but with decreasing temperature.…”

Section: Resultsmentioning

confidence: 99%

Adsorption of block copolymers on solid surfaces: A Monte Carlo study

Słyk

Rżysko

Bryk

2014

The Journal of Chemical Physics

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Using hyper-parallel tempering Monte Carlo simulation, multiple histogram reweighting method, and finite size scaling, we investigate the adsorption of fully flexible and rod-coil chains on the square lattice. We find that the phase behaviour changes with the chain length and flexibility. For homonuclear rod-coil chains, the phase diagram consists of only gas-disorder liquid critical point. Weakening of the interaction energy between the segments belonging to two different subunits gives rise to an order-disorder transition. The topology of the resulting phase diagram depends on the chain length and flexibility. For short chains, both fully flexible and rod-coil diblock copolymers form lamellar ordered phase with fully stretched chains, and the order-disorder transition is of the first order. The phase diagrams are similar for both chain architectures and consist of two binodals meeting in the triple point. When the chain length increases the order-disorder transition becomes second-order and the difference in the phase behaviour between the fully flexible and the rod-coil diblock copolymers becomes more pronounced. While for the former chain architecture the topology of the phase diagram involves a λ-line which meets the gas-disordered liquid binodal in the critical end-point, in the latter case the λ-line meets the gas-disordered liquid critical point and forms the tricritical point. We trace back these changes to the change in the morphology of the ordered phase. The mechanism of the order-disorder transition involves the formation of domains resembling those observed during the spinodal decomposition process. The domains subsequently merge and arrange into lamellae. These observations are supported by integral geometry analysis.

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Kinetic pathways of sheared block copolymer systems derived from Minkowski functionals

Cited by 24 publications

References 30 publications

Biomembrane solubilization mechanism by Triton X-100: a computational study of the three stage model

Biomembrane solubilization mechanism by Triton X-100: a computational study of the three stage model

Characterization of image heterogeneity using 2D Minkowski functionals increases the sensitivity of detection of a targeted MRI contrast agent

Adsorption of block copolymers on solid surfaces: A Monte Carlo study

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