Coarse-grained Monte Carlo simulations of nanogel–polyelectrolyte complexes: electrostatic effects

Pérez-Mas, Luis; Quesada‐Pérez, Manuel

doi:10.1039/d0sm00173b

Cited by 8 publications

(9 citation statements)

References 54 publications

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“…As can be seen, there are three pairs of hydrogels with the same polymer volume fractions (0.06, 0.09, and 0.13, gels 7 and 11, 8 and 12, and 5 and 9, respectively) but different values of N mu and mesh size. Other parameters used in these simulations were k e = 0.4 N/m, R s = 0.633 nm, T = 298 K, η = 0.000891 Pa·s, and ε WCA = 4.11 × 10 –21 J (the value of this parameter was used in previous works − ). None of them was adjustable.…”

Section: Resultsmentioning

confidence: 99%

Coarse-Grained Simulations of Solute Diffusion in Crosslinked Flexible Hydrogels

2022

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In this work, the longtime diffusion of a solute in a chemically crosslinked and flexible hydrogel is computed from a coarse-grained model of a polymeric network. The effects of different key parameters of this model on diffusion are assessed. The relevance of chain flexibility becomes important by increasing the polymer volume fraction and the solute size. In fact, the solute particle can moderately diffuse in flexible hydrogels even when its diameter is comparable to the mesh size. The diffusion coefficients obtained here are tested by comparing with the previously reported experimental data. A reasonably good agreement between the experiment and simulation is found without requiring any adjustable parameter.

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Section: Resultsmentioning

confidence: 99%

Coarse-Grained Simulations of Solute Diffusion in Crosslinked Flexible Hydrogels

2022

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“…More recently, Sennato et al have shown that when PNIPAM microgels are collapsed, they strongly interact with oppositely charged polyelectrolytes and a large charge inversion is observed [ 56 ]. In this sense, coarse-grained Monte Carlo simulations have recently been applied to predict the charge inversion previously detected through µ e for nanogel-polyelectrolyte complexes [ 57 ]. Therein, it is demonstrated that charge inversion occurs only if the polyelectrolyte charge is large enough [ 57 ].…”

Section: Resultsmentioning

confidence: 99%

“…In this sense, coarse-grained Monte Carlo simulations have recently been applied to predict the charge inversion previously detected through µ e for nanogel-polyelectrolyte complexes [ 57 ]. Therein, it is demonstrated that charge inversion occurs only if the polyelectrolyte charge is large enough [ 57 ]. Apart from the reversal observed in the sign of the µ e shown in Figure 3 , we can also observe that the isoelectric point of DNA/mGel+ complexes does not depend on the temperature, i.e., the swelling state of the mGel+.…”

Section: Resultsmentioning

confidence: 99%

Complexation of DNA with Thermoresponsive Charged Microgels: Role of Swelling State and Electrostatics

Maldonado-Valderrama

Yang

Jimenez-Guerra

et al. 2022

Gels

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Micro- and nanogels are being increasingly used to encapsulate bioactive compounds. Their soft structure allows large loading capacity while their stimuli responsiveness makes them extremely versatile. In this work, the complexation of DNA with thermoresponsive microgels is presented. To this end, PEGylated charged microgels based on poly-N-isopropylacrylamide have been synthesized, allowing one to explore the electrostatics of the complexation. Cationic microgels complexate spontaneously by electrostatic attraction to oppositely charged DNA as demonstrated by electrophoretic mobility of the complexes. Then, Langmuir monolayers reveal an increased interaction of DNA with swollen microgels (20 °C). Anionic microgels require the presence of multivalent cations (Ca2+) to promote the complexation, overcoming the electrostatic repulsion with negatively charged DNA. Then again, Langmuir monolayers evidence their complexation at the surface. However, the presence of Ca2+ seems to induce profound changes in the interaction and surface conformation of anionic microgels. These alterations are further explored by measuring adsorbed films with the pendant drop technique. Conformational changes induced by Ca2+ on the structure of the microgel can ultimately affect the complexation with DNA and should be considered in the design. The combination of microstructural and surface properties for microgels offers a new perspective into complexation of DNA with soft particles with biomedical applications.

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“…In these simulations, elastic forces satisfy Hooke’s law:

where

is the force that particle

exerts on particle

is the elastic constant,

is the distance between particles

and

is the bond length at equilibrium and

is the unit vector pointing from particle

to particle

. As in previous works [ 43 ],

N/m and

nm (the diameter of monomeric units).…”

Section: Model and Simulationsmentioning

confidence: 99%

Coarse-Grained Simulations of Release of Drugs Housed in Flexible Nanogels: New Insights into Kinetic Parameters

et al. 2022

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The diffusion-controlled release of drugs housed in flexible nanogels has been simulated with the help of a coarse-grained model that explicitly considers polymer chains. In these in silico experiments, the effect of its flexibility is assessed by comparing it with data obtained for a rigid nanogel with the same volume fraction and topology. Our results show that the initial distribution of the drug can exert a great influence on the release kinetics. This work also reveals that certain surface phenomena driven by steric interactions can lead to apparently counterintuitive behaviors. Such phenomena are not usually included in many theoretical treatments used for the analysis of experimental release kinetics. Therefore, one should be very careful in drawing conclusions from these formalisms. In fact, our results suggest that the interpretation of drug release curves in terms of kinetic exponents (obtained from the Ritger–Peppas Equation) is a tricky question. However, such curves can provide a first estimate of the drug diffusion coefficient.

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Coarse-grained Monte Carlo simulations of nanogel–polyelectrolyte complexes: electrostatic effects

Abstract: Coarse-grained model of nanogel–polyelectrolyte complex.

Cited by 8 publications

References 54 publications

Coarse-Grained Simulations of Solute Diffusion in Crosslinked Flexible Hydrogels

Coarse-Grained Simulations of Solute Diffusion in Crosslinked Flexible Hydrogels

Complexation of DNA with Thermoresponsive Charged Microgels: Role of Swelling State and Electrostatics

Coarse-Grained Simulations of Release of Drugs Housed in Flexible Nanogels: New Insights into Kinetic Parameters

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