Finite-size polyelectrolyte bundles at thermodynamic equilibrium

Sayar, Mehmet; Holm, Christian

doi:10.1209/0295-5075/77/16001

Cited by 39 publications

(60 citation statements)

References 33 publications

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“…It is noteworthy that there have been a large amount of studies on a collection of free polyelectrolytes in solution [57][58][59]. Yet, the geometric constraint of the brush system with one end being grafted makes substantial difference.…”

Section: Discussionmentioning

confidence: 99%

Heterogeneous Morphology and Dynamics of Polyelectrolyte Brush Condensates in Trivalent Counterion Solution

2017

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Recent experiments have shown that trivalent ion, spermidine 3+ , can provoke lateral microphase segregation in DNA brushes. Using molecular simulations and simple theoretical arguments, we explore the effects of trivalent counterions on polyelectrolyte brushes. At a proper range of grafting density, polymer size, and ion concentration, the brush polymers collapse heterogeneously into octopus-like surface micelles. Remarkably, the heterogeneity in brush morphology is maximized and the relaxation dynamics of chain and condensed ion are the slowest at the 1:3 stoichiometric concentration of trivalent ions to polyelectrolyte charge. A further increase of trivalent ion concentration conducive to a charge inversion elicits modest reswelling and homogenizes the morphology of brush condensate. Our study provides a new insight into the origin of the diversity in DNA organization in cell nuclei as well as the ion-dependent morphological variation in polyelectrolyte brush layer of biological membranes.Polyelectrolyte brushes are ubiquitous in biological systems. As the main component of outer membrane in Gram-negative bacteria, lipopolysaccharides, consisting of charged O-polysaccharides side chains, form a brush layer and mediate the interaction of bacteria with their environment [1]. For vertebrates, negatively charged polysaccharide hyaluronic acids play a vital role in the organization of pericellular matrix [2,3]. Double-stranded DNA brushes on a biochip [4] at a cell-like density (∼ 10 4 kb/µm 3 ) have been developed as a platform to study cell-free gene expression [5]. Due to the negative charges along the backbone, this synthetic system behaves like a well-defined strong polyelectrolyte brush [5], the height of which can be varied by modulating the ionic strength of monovalent salt (NaCl) solution and the grafting density [6]. Recently, it has been reported that trivalent counterions, spermidine 3+ (Spd 3+ ), can induce a collapse transition of DNA brush into fractal-like dendritic macroscopic domains [7]. The heterogeneous morphology of DNA condensate points to polyamine-mediated regulation of local DNA configuration and gene expression [8,9], underscoring the importance of understanding the effects of multivalent counterions on polyelectrolyte brush [10,11]. Compared with uncharged polymer brushes in good or poor solvent, the electrostatic interaction and osmotic pressure, which are readily controlled by the salt concentration and pH, yield additional flexibilities in manipulating polyelectrolyte brushes, and thus holding promise for its wide applications [12,13].Conventional theoretical approaches, successful in explaining the behaviors of polyelectrolytes in monovalent salt solutions [11,14,15], are of limited use, particularly, when multivalent counterions are at work. For example, the solution to the mean-field PoissonBoltzmann theory [16] fails to account for phenomena such as ion condensation, charge over-compensation, and collapse of like-charged polymers [17][18][19][20]. A prediction from a nonlocal den...

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Section: Discussionmentioning

confidence: 99%

Heterogeneous Morphology and Dynamics of Polyelectrolyte Brush Condensates in Trivalent Counterion Solution

2017

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“…An enormous body of theoretical studies that followed has been successful in characterizing the thermodynamic stability of finite-sized aggregates in various systems such as polyelectrolytes (5,7,11,(15)(16)(17)(18)(19), colloidal suspensions (20-24), and block copolymer and protein solutions (4,8,(25)(26)(27)(28)(29)(30). The optimal size of the assembled clusters is often attributed to the balance of short-ranged attraction and longer-ranged repulsion between the primary building blocks.…”

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confidence: 99%

“…The optimal size of the assembled clusters is often attributed to the balance of short-ranged attraction and longer-ranged repulsion between the primary building blocks. Nevertheless, uniform clusters are also found in systems where the repulsion is not necessarily long-ranged by nature: it can be energetic (e.g., charge accumulation due to counterions and salt ions on the cluster surfaces as aggregation progresses), entropic (e.g., steric effects due to the nonnegligible size of the counterions and the packing frustration within the aggregates, which prevents counterion penetration), or both (5,7,11,16,18). Recently, Johnston and coworkers studied the formation of gold colloids in polymeric solutions, showing that the cluster size can be tuned by varying polymer concentration.…”

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confidence: 99%

“…self-assembly | terminal assemblies | self-limited aggregation T he spontaneous formation of uniformly sized aggregates observed in inorganic, biological, and colloidal systems (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14) is of both fundamental and practical interest. Their formation suggests that a generic mechanism is applicable to those chemically distinct systems, whereas their ability to serve as building blocks for engineering nanostructures at larger length scales is of practical interest.…”

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confidence: 99%

“…Their formation suggests that a generic mechanism is applicable to those chemically distinct systems, whereas their ability to serve as building blocks for engineering nanostructures at larger length scales is of practical interest. Examples of uniform aggregates include filaments, bundles, and toroids with uniform diameters formed by macromolecules (6)(7)(8)(9), and regular domains by like-charged macroions on planar and cylindrical surfaces (5,11). In a recent study, we observed the assembly of positively charged polydisperse CdSe, PbS, and PbSe nanoparticles (NPs) into monodisperse supraparticles (SPs), which form colloidal crystals at sufficiently high density (12).…”

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confidence: 99%

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Generic, phenomenological, on-the-fly renormalized repulsion model for self-limited organization of terminal supraparticle assemblies

Nguyen

Schultz

Kotov

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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Self-limited, or terminal, supraparticles have long received great interest because of their abundance in biological systems (DNA bundles and virus capsids) and their potential use in a host of applications ranging from photonics and catalysis to encapsulation for drug delivery. Moreover, soft, uniform colloidal aggregates are a promising candidate for quasicrystal and other hierarchical assemblies. In this work, we present a generic coarse-grained model that captures the formation of self-limited assemblies observed in various soft-matter systems including nanoparticles, colloids, and polyelectrolytes. Using molecular dynamics simulations, we demonstrate that the assembly process is self-limited when the repulsion between the particles is renormalized to balance their attraction during aggregation. The uniform finite-sized aggregates are further shown to be thermodynamically stable and tunable with a single dimensionless parameter. We find large aggregates self-organize internally into a core-shell morphology and exhibit anomalous uniformity when the constituent nanoparticles have a polydisperse size distribution.self-assembly | terminal assemblies | self-limited aggregation T he spontaneous formation of uniformly sized aggregates observed in inorganic, biological, and colloidal systems (1-14) is of both fundamental and practical interest. Their formation suggests that a generic mechanism is applicable to those chemically distinct systems, whereas their ability to serve as building blocks for engineering nanostructures at larger length scales is of practical interest. Examples of uniform aggregates include filaments, bundles, and toroids with uniform diameters formed by macromolecules (6-9), and regular domains by like-charged macroions on planar and cylindrical surfaces (5, 11). In a recent study, we observed the assembly of positively charged polydisperse CdSe, PbS, and PbSe nanoparticles (NPs) into monodisperse supraparticles (SPs), which form colloidal crystals at sufficiently high density (12). Spherical SPs with uniform size were also obtained from the assembly of similarly charged protein molecules (cytochrome C) and CdTe nanoparticles (13). It was also demonstrated that SPs can serve as a versatile tool to make nanoscale assemblies with unusual spiky shapes and form several constitutive blocks (14). The fact that the characteristic dimensions of these assemblies is highly uniform over a wide range of monomer concentration suggests that their formation from monomer aggregation is thermodynamically selflimited rather than kinetically arrested.Seminal theoretical studies of uniformly sized aggregates date back to the 1980s, and primarily focused on developing models of aggregation in reactive systems (1-3). An enormous body of theoretical studies that followed has been successful in characterizing the thermodynamic stability of finite-sized aggregates in various systems such as polyelectrolytes (5,7,11,(15)(16)(17)(18)(19), colloidal suspensions (20-24), and block copolymer and protein solutions (4,8,(25)(...

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Bundling in semiflexible polymers: A theoretical overview

Benetatos

Jho

2016

Advances in Colloid and Interface Science

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Finite-size polyelectrolyte bundles at thermodynamic equilibrium

Cited by 39 publications

References 33 publications

Heterogeneous Morphology and Dynamics of Polyelectrolyte Brush Condensates in Trivalent Counterion Solution

Heterogeneous Morphology and Dynamics of Polyelectrolyte Brush Condensates in Trivalent Counterion Solution

Generic, phenomenological, on-the-fly renormalized repulsion model for self-limited organization of terminal supraparticle assemblies

Bundling in semiflexible polymers: A theoretical overview

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