Polyelectrolyte condensation in bulk, at surfaces, and under confinement

Dias, Rita S.; Pais, Alberto A. C. C.

doi:10.1016/j.cis.2010.02.007

Cited by 28 publications

(23 citation statements)

References 95 publications

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“…Our work is restricted to slightly charged gels, whose f ‐values are also similar to those employed in experiments with poly(NIPAM)‐based networks . Consecutive beads of a chain are connected by harmonic bonds, whose interaction potential is:

u_{bond} true(r true) = \frac{1}{2} k_{bond} {(r - r_{0})}^{2}

where

r

is the center‐to‐center distance between a given pair of particles, r 0 is its value at equilibrium and

k_{bond}

is the elastic constant (

k_{bond} = 0.4 N / m

). Polyelectrolyte chain ends are connected through tetrafunctional cross‐linkers (the same harmonic bonds are considered).…”

Section: Model and Simulationsmentioning

confidence: 99%

“…12 In the last decade, some researchers [13][14][15][16][17][18][19][20] have also contributed to a better understanding of the swelling of charged gels through computer simulations within diverse beadspring models of polyelectrolyte, in which a single bead represents a small group of atoms (coarse graining). 20,21 This powerful tool has been also employed in studies on adsorption and collapse of polyelectrolytes, [22][23][24][25][26] being particularly helpful for the analysis of certain nonspecific aspects on gels and nanogels, such as charge and size effects, since electrostatic and excluded-volume interactions can be explicit and directly considered. The effect of salt on the swelling of polyelectrolyte gels has also been explicitly investigated through coarse-grained simulations in a few preceding works.…”

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confidence: 99%

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Thermo‐responsive gels in the presence of monovalent salt at physiological concentrations: A Monte Carlo simulation study

Quesada‐Pérez

Ahualli

2014

J Polym Sci B Polym Phys

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In this work, slightly charged thermo-responsive gels in the presence of salt at concentrations close to physiological conditions have been simulated within a coarse-grained model widely used in the last decade. These simulations allow differentiate charge and salt effects, which are antagonist and coupled in many real systems because the degree of ionization might depend on the electrolyte concentration. An analysis in terms of the different contributions to osmotic pressure is also presented, which highlights the role played by excluded volume effects. In addition, our results also permit us to test some predictions based on the ideal Donnan equilibrium, a common assumption made to justify the swelling behavior of gels and microgels in the presence of salt. More specifically, simulations show that, for the slightly charged gels simulated here, such an assumption overestimates the concentration of salt inside collapsed gels and underestimates the excess of osmotic pressure associated to the additional electrolyte. KEYWORDS: computer modeling; drug delivery systems; gels; hydrogels; microgels; Monte Carlo simulations INTRODUCTION Thermo-responsive gels and microgels have gained considerable attention in different fields of biotechnology due to the ability of these materials to swell or shrink in response to temperature changes. Many researchers 1-3 have studied diverse applications of these gels, such as the controlled drug release. As potential therapeutic carriers, temperature-sensitive microgels should work at physiological conditions, that is, at ionic strengths of about 150 mM. Consequently, it should be desirable to explore how such ionic strengths can modify their thermal response.

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u_{bond} true(r true) = \frac{1}{2} k_{bond} {(r - r_{0})}^{2}

where

r

is the center‐to‐center distance between a given pair of particles, r 0 is its value at equilibrium and

k_{bond}

is the elastic constant (

k_{bond} = 0.4 N / m

). Polyelectrolyte chain ends are connected through tetrafunctional cross‐linkers (the same harmonic bonds are considered).…”

Section: Model and Simulationsmentioning

confidence: 99%

mentioning

confidence: 99%

Thermo‐responsive gels in the presence of monovalent salt at physiological concentrations: A Monte Carlo simulation study

Quesada‐Pérez

Ahualli

2014

J Polym Sci B Polym Phys

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“…Moreover, RMs have many other applications being employed in significant processes including drug delivery [20], synthesis of artificial light-harvesting systems [21] or NPs [22,23], etc. In RMs, the surfactant molecules cluster with the polar head groups toward the nano-sized water droplets and the hydrocarbon tails delimit the organic phase [24]. For RMs with spherical morphology, the size of aqueous core depends on the molar ratio of water molecules per surfactant molecule or the hydration degree (w 0 ) [25][26][27].…”

Section: Introductionmentioning

confidence: 99%

Self-aggregation of the pyrene labeled poly(acrylic acid) in nanoscopically crowded environments

Stîngă

Băran

Iovescu

et al. 2016

Journal of Photochemistry and Photobiology A: Chemistry

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“…Unfortunately, while the complexation of cationic lipids and DNA has been well studied, molecular mechanisms behind the formation of anionic lipoplexes still remain unclear. In general, the interactions and procedures that govern the adsorption of polyelectrolytes onto like‐charged surfaces is a current theme that has been scarcely studied (de Carvalho et al, ; Dias and Pais, ; Faraudo and Martín‐Molina, ; Luque‐Caballero et al, ; Tiraferri et al, ; Turesson et al, ; Yigit et al, ). As in the case of mica surfaces previously discussed, the case of adsorption of DNA onto likely charged lipid surfaces require the presence of multivalent cations.…”

Section: Introductionmentioning

confidence: 99%

Atomic force microscopy as a tool to study the adsorption of DNA onto lipid interfaces

Luque-Caballero

Maldonado-Valderrama

Quesada‐Pérez

2016

Microscopy Res & Technique

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The Atomic Force Microscopy (AFM) technique appears as a central tool for the characterization of DNA adsorption onto lipid interfaces. Regardless of the huge number of surveys devoted to this issue, there are still fascinating phenomena in this field that have not been explored in detail by AFM. For instance, adsorption of DNA onto like-charged lipid surfaces mediated by cations is still not fully understood even though it is gaining popularity nowadays in gene therapy and nanotechnology. Studies related to the complexation of DNA with anionic lipids as a non-viral gene delivery vehicle as well as the formation of self-assembled nanoscale DNA constructs (DNA origami) are two of the most attractive systems. Unfortunately, molecular mechanisms underlying the adsorption of DNA onto anionic lipid interfaces remain unclear so far. In view of that, AFM becomes an appropriate technique to provide valuable information to understand the adsorption of DNA to anionic lipid surfaces. As a second part of this review we provide an illustrative example of application of the AFM technique to probe the DNA adsorption onto a model lipid monolayer negatively charged. Microsc. Res. Tech. 80:11-17, 2017. © 2016 Wiley Periodicals, Inc.

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Polyelectrolyte condensation in bulk, at surfaces, and under confinement

Cited by 28 publications

References 95 publications

Thermo‐responsive gels in the presence of monovalent salt at physiological concentrations: A Monte Carlo simulation study

Thermo‐responsive gels in the presence of monovalent salt at physiological concentrations: A Monte Carlo simulation study

Self-aggregation of the pyrene labeled poly(acrylic acid) in nanoscopically crowded environments

Atomic force microscopy as a tool to study the adsorption of DNA onto lipid interfaces

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