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Lindgren EB, Stamm B, Maday Y, Besley E, Stace AJ. Dynamic simulations of many-body electrostatic self-assembly. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2018; 376:20170143. [PMID: 29431686 PMCID: PMC5805913 DOI: 10.1098/rsta.2017.0143] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 11/21/2017] [Indexed: 06/08/2023]
Abstract
Two experimental studies relating to electrostatic self-assembly have been the subject of dynamic computer simulations, where the consequences of changing the charge and the dielectric constant of the materials concerned have been explored. One series of calculations relates to experiments on the assembly of polymer particles that have been subjected to tribocharging and the simulations successfully reproduce many of the observed patterns of behaviour. A second study explores events observed following collisions between single particles and small clusters composed of charged particles derived from a metal oxide composite. As before, observations recorded during the course of the experiments are reproduced by the calculations. One study in particular reveals how particle polarizability can influence the assembly process.This article is part of the theme issue 'Modern theoretical chemistry'.
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Affiliation(s)
- Eric B Lindgren
- Department of Physical and Theoretical Chemistry, School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Benjamin Stamm
- Centre for Computational Engineering, Mathematics Department, RWTH Aachen University, Schinkelstrasse 2, 52062 Aachen, Germany
| | - Yvon Maday
- Laboratoire Jacques-Louis Lions, Sorbonne Universités, UPMC Univ Paris 06, UMR 7598, 75005 Paris, France
- Laboratoire Jacques-Louis Lions, CNRS, UMR 7598, 75005 Paris, France
- Division of Applied Mathematics, Brown University, Providence, RI, USA
| | - Elena Besley
- Department of Physical and Theoretical Chemistry, School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - A J Stace
- Department of Physical and Theoretical Chemistry, School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, UK
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Antila HS, Van Tassel PR, Sammalkorpi M. Repulsion between oppositely charged rod-shaped macromolecules: Role of overcharging and ionic confinement. J Chem Phys 2017; 147:124901. [PMID: 28964034 DOI: 10.1063/1.4993492] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
The interaction between two oppositely charged rod-shaped macro-ions in a micro-ion solution is investigated via Monte Carlo simulations of the primitive model. The focus is on the asymmetry in rod and/or ion charge, i.e., conditions where oppositely charged objects can repel one another. For equally and oppositely charged rods with asymmetric z:1 micro-ions, repulsion may be induced by overcharging one of the rods with the z valent ions. For asymmetrically charged rods in a symmetric z:z micro-ion solution, a repulsive interaction-at separation of the order of one ion diameter-can arise via an unbalanced osmotic pressure contribution from the ionic atmosphere in the inter-rod space, and an attractive interaction-at a smaller separation-may occur due to a "squeezing out" of the micro-ions from the space between the rods (with a consequent gain in entropy). The thermodynamics of each mechanism is investigated in terms of rod charge and size and micro-ion valence, size, and concentration. Our findings contribute to the understanding of the complex role of charge asymmetry on the interaction of, for example, oppositely charged polyelectrolytes, functionalized nanotubes, and rod-like biomolecules, e.g., viruses.
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Affiliation(s)
- Hanne S Antila
- Department of Chemistry and Materials Science, School of Chemical Engineering, Aalto University, 00076 Aalto, Finland
| | - Paul R Van Tassel
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06520-8286, USA
| | - Maria Sammalkorpi
- Department of Chemistry and Materials Science, School of Chemical Engineering, Aalto University, 00076 Aalto, Finland
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Antila HS, Van Tassel PR, Sammalkorpi M. Interaction modes between asymmetrically and oppositely charged rods. Phys Rev E 2016; 93:022602. [PMID: 26986372 DOI: 10.1103/physreve.93.022602] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Indexed: 06/05/2023]
Abstract
The interaction of oppositely and asymmetrically charged rods in salt-a simple model of (bio)macromolecular assembly-is observed via simulation to exhibit two free energy minima, separated by a repulsive barrier. In contrast to similar minima in the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, the governing mechanism includes electrostatic attraction at large separation, osmotic repulsion at close range, and depletion attraction near contact. A model accounting for ion condensation and excluded volume is shown to be superior to a mean-field treatment in predicting the effect of charge asymmetry on the free-energy profile.
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Affiliation(s)
- Hanne S Antila
- Department of Chemistry, Aalto University, FI-00076 Aalto, Finland
| | - Paul R Van Tassel
- Department of Chemical & Environmental Engineering, Yale University, New Haven, Connecticut 06520, USA
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Yigit C, Heyda J, Dzubiella J. Charged patchy particle models in explicit salt: Ion distributions, electrostatic potentials, and effective interactions. J Chem Phys 2015; 143:064904. [DOI: 10.1063/1.4928077] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Affiliation(s)
- Cemil Yigit
- Soft Matter and Functional Materials, Helmholtz-Zentrum Berlin, 14109 Berlin, Germany
- Helmholtz Virtual Institute “Multifunctional Biomaterials for Medicine,” 14513 Teltow, Germany
- Institut für Physik, Humboldt-Universität zu Berlin, 12489 Berlin, Germany
| | - Jan Heyda
- Department of Physical Chemistry, University of Chemistry and Technology, Prague, 166 28 Praha 6, Czech Republic
| | - Joachim Dzubiella
- Soft Matter and Functional Materials, Helmholtz-Zentrum Berlin, 14109 Berlin, Germany
- Helmholtz Virtual Institute “Multifunctional Biomaterials for Medicine,” 14513 Teltow, Germany
- Institut für Physik, Humboldt-Universität zu Berlin, 12489 Berlin, Germany
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Marcovitz A, Naftaly A, Levy Y. Water organization between oppositely charged surfaces: Implications for protein sliding along DNA. J Chem Phys 2015; 142:085102. [DOI: 10.1063/1.4913370] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
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Villarreal OD, Chen LY, Whetten RL, Yacaman MJ. Ligand-modulated interactions between charged monolayer-protected Au144(SR)60 gold nanoparticles in physiological saline. Phys Chem Chem Phys 2015; 17:3680-8. [PMID: 25556346 PMCID: PMC4303505 DOI: 10.1039/c4cp05137h] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In order to determine how functionalized gold nanoparticles (AuNPs) interact in a near-physiological environment, we performed all-atom molecular dynamics simulations on the icosahedral Au144 nanoparticles each coated with a homogeneous set of 60 thiolates selected from one of these five (5) types: 11-mercapto-1-undecanesulfonate -SC11H22(SO3(-)), 5-mercapto-1-pentanesulfonate -SC5H10(SO3(-)), 5-mercapto-1-pentaneamine -SC5H10(NH3(+)), 4-mercapto-benzoate -SPh(COO(-)), or 4-mercapto-benzamide -SPh(CONH3(+)). These thiolates were selected to elucidate how the aggregation behavior of AuNPs depends on ligand parameters, including the charge of the terminal group (anionic vs. cationic), and its length and conformational flexibility. For this purpose, each functionalized AuNP was paired with a copy of itself, placed in an aqueous cell, neutralized by 120 Na(+)/Cl(-) counter-ions and salinated with a 150 mM concentration of NaCl, to form five (5) systems of like-charged AuNPs pairs in a saline. We computed the potential of mean force (the reversible work of separation) as a function of the intra-pair distance and, based on which, the aggregation affinities. We found that the AuNPs coated with negatively charged, short ligands have very high affinities. Structurally, a significant number of Na(+) counter-ions reside on a plane between the AuNPs, mediating the interaction. Each such ion forms a "salt bridge" (or "ionic bonds") to both of the AuNPs when they are separated by its diameter plus 0.2-0.3 nm. The positively charged AuNPs have much weaker affinities, as Cl(-) counter-ions form fewer and weaker salt bridges between the AuNPs. In the case of Au144(SC11H22(SO3(-)))60 pair, the flexible ligands fluctuate much more than the other four cases. The large fluctuations disfavor the forming of salt bridges between two AuNPs, but enable hydrophobic contact between the exposed hydrocarbon chains of the two AuNPs, which are subject to an effective attraction at a separation much greater than the AuNP diameter and involve a higher concentration of counter ions in the inter-pair space.
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Affiliation(s)
- Oscar D Villarreal
- Department of Physics and Astronomy, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249, USA.
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Alsharif SA, Chen LY, Tlahuice-Flores A, Whetten RL, Yacaman MJ. Interaction between functionalized gold nanoparticles in physiological saline. Phys Chem Chem Phys 2014; 16:3909-13. [PMID: 24441708 PMCID: PMC3947887 DOI: 10.1039/c3cp54503b] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The interactions between functionalized noble-metal particles in an aqueous solution are central to applications relying on controlled equilibrium association. Herein, we obtain the potentials of mean force (PMF) for pair-interactions between functionalized gold nanoparticles (AuNPs) in physiological saline. These results are based upon >1000 ns experiments in silico of all-atom model systems under equilibrium and non-equilibrium conditions. Four types of functionalization are built by coating each globular Au144 cluster with 60 thiolate groups: GS-AuNP (glutathionate), PhS-AuNP (thiophenol), CyS-AuNP (cysteinyl), and p-APhS-AuNP (para-amino-thiophenol), which are, respectively, negatively charged, hydrophobic (neutral-nonpolar), hydrophilic (neutral-polar), and positively charged at neutral pH. The results confirm the behavior expected of neutral (hydrophilic or hydrophobic) particles in a dilute aqueous environment, however the PMF curves demonstrate that the charged AuNPs interact with one another in a unique way-mediated by H2O molecules and an electrolyte (Na(+), Cl(-))-in a physiological environment. In the case of two GS-AuNPs, the excess, neutralizing Na(+) ions form a mobile (or 'dynamic') cloud of enhanced concentration between the like-charged GS-AuNPs, inducing a moderate attraction (∼25 kT) between them. Furthermore, to a lesser degree, for a pair of p-APhS-AuNPs, the excess, neutralizing Cl(-) ions (less mobile than Na(+)) also form a cloud of higher concentration between the two like-charged p-APhS-AuNPs, inducing weaker yet significant attractions (∼12 kT). On combining one GS- with one p-APhS-AuNP, the direct, attractive Coulombic force is completely screened out while the solvation effects give rise to moderate repulsion between the two unlike-charged AuNPs.
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Affiliation(s)
- Shada A Alsharif
- Department of Physics and Astronomy, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249, USA.
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Paillusson F, Dahirel V, Jardat M, Victor JM, Barbi M. Effective interaction between charged nanoparticles and DNA. Phys Chem Chem Phys 2011; 13:12603-13. [DOI: 10.1039/c1cp20324j] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Effective interactions between charged nanoparticles in water: What is left from the DLVO theory? Curr Opin Colloid Interface Sci 2010. [DOI: 10.1016/j.cocis.2009.05.006] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Dahirel V, Hansen JP. Ion-mediated interactions in suspensions of oppositely charged nanoparticles. J Chem Phys 2009; 131:084902. [PMID: 19725632 DOI: 10.1063/1.3193556] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The structure of oppositely charged spherical nanoparticles (polyions), dispersed in ionic solutions with continuous solvent (primitive model), is investigated by Monte Carlo (MC) simulations, within explicit and implicit microion representations, over a range of polyion valences and densities, and microion concentrations. Systems with explicit microions are explored by semigrand canonical MC simulations, and allow density-dependent effective polyion pair potentials v(alphabeta) (eff)(r) to be extracted from measured partial pair distribution functions. Implicit microion MC simulations are based on pair potentials of mean force v(alphabeta) ((2))(r) computed by explicit microion simulations of two charged polyions, in the low density limit. In the vicinity of the liquid-gas separation expected for oppositely charged polyions, the implicit microion representation leads to an instability against density fluctuations for polyion valences mid R:Zmid R: significantly below those at which the instability sets in within the exact explicit microion representation. Far from this instability region, the v(alphabeta) ((2))(r) are found to be fairly close to but consistently more repulsive than the effective pair potentials v(alphabeta) (eff)(r). This is corroborated by additional calculations of three-body forces between polyion triplets, which are repulsive when one polyion is of opposite charge to the other two. The explicit microion MC data were exploited to determine the ratio of salt concentrations c and c(o) within the dispersion and the reservoir (Donnan effect). c/c(o) is found to first increase before finally decreasing as a function of the polyion packing fraction.
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Dahirel V, Paillusson F, Jardat M, Barbi M, Victor JM. Nonspecific DNA-protein interaction: why proteins can diffuse along DNA. PHYSICAL REVIEW LETTERS 2009; 102:228101. [PMID: 19658903 DOI: 10.1103/physrevlett.102.228101] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2009] [Indexed: 05/28/2023]
Abstract
Recent single molecule experiments have reported that DNA binding proteins (DNA-BPs) can diffuse along DNA. This suggests that interactions between proteins and DNA play a role during the target search even far from their specific site on DNA. Here we show by means of Monte Carlo simulations and analytical calculations that there is a counterintuitive repulsion between the two oppositely charged macromolecules at a nanometer range. For the concave shape of DNA-BPs, and for realistic protein charge densities, we find that the DNA-protein interaction free energy has a minimum at a finite surface-to-surface separation, in which proteins can easily slide. When a protein encounters its target, the free energy barrier is completely counterbalanced by the H-bond interaction, thus enabling the sequence recognition.
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Affiliation(s)
- Vincent Dahirel
- UPMC Université Paris 06, UMR 7195, PECSA, F-75005 Paris, France.
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