Coarse-Grained Simulations of Solute Diffusion in Crosslinked Flexible Hydrogels

Quesada‐Pérez, Manuel; Maroto-Centeno, José Alberto; Ramos-Tejada, María del Mar

doi:10.1021/acs.macromol.1c02178

Cited by 9 publications

(9 citation statements)

References 57 publications

(134 reference statements)

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“…The transport of active tracers in a polymer network is a paramount subject that requires better understanding. The effects of polymer topology disorderness and near-field hydrodynamics − on this system are not well understood, proposing a future direction based on our current study. Many studies of various active particles in free spaces have been carried out, and some studies considered the active tracers in polymer solutions − or a confining trap as well as passive tracers in active polymer networks .…”

Section: Discussionmentioning

confidence: 92%

Active Diffusion of Self-Propelled Particles in Flexible Polymer Networks

2022

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Biopolymer networks having a meshwork topology, e.g., extracellular matrices and mucus gels, are ubiquitous. Understanding the diffusion mechanism of self-propelled agents, including Janus colloidal particles, through such biopolymer networks is thus of paramount importance. Here, for the first time, we computationally explore this issue in depth by explicitly modeling three-dimensional biopolymer networks and performing Langevin dynamics simulations of the active diffusion of the self-propelled tracers therein. We demonstrate that the diffusion dynamics of the active tracers feature rich, distinct physics depending on the mesh-to-particle size and Péclet number (Pe). When the particle is smaller than the mesh size ratio, it moves as if in free space with decreased mobility depending on the polymer-occupation density and Pe. However, when the particle size is increased to be comparable to the mesh size, the active particles explore the polymer network via the trapping-and-hopping mechanism. If the particle is larger than the mesh, it captures the collective viscoelastic dynamics from the polymer network at short times and the simple diffusion of the total system at large times. We study the trapped time distribution, flight-length distribution, mean-squared displacement, and long-time diffusivity on varying the Pe number and the tracer size. Finally, we discuss the scaling behavior of the long-time diffusivity with Pe, where we find a Pe range that yields a nontrivial power law. The latter turns out to originate from a large fluctuation of the trapped, activated tracers in conjugation with responsive polymer networks.

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Section: Discussionmentioning

confidence: 92%

Active Diffusion of Self-Propelled Particles in Flexible Polymer Networks

2022

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“…However, one should keep in mind that

depends on

and, in turn, this exponent depends on surface phenomena and the initial drug distribution. Previous CG simulations of solute diffusion in flexible gels concluded that the effects of the degree of crosslinking on diffusion are negligible if the solute size is smaller than the mesh size [ 29 ], which is quite common, but the role of the degree of crosslinking in drug delivery might be important for tightly meshed networks.…”

Section: Discussionmentioning

confidence: 99%

“…A high crosslinker-to-monomer ratio was deliberately chosen to generate a nanogel with a polymer volume fraction (φ) close to 0.08. According to a previous work, the diffusion coefficients in rigid and flexible gels significantly differ precisely from volume fractions of this order [ 29 ]. We would like to find out to what extent such differences affect the release kinetics.…”

Section: Model and Simulationsmentioning

confidence: 99%

“…We also want to find out to what extent chain flexibility facilitates the release of drug molecules loaded inside nanogels and modifies the corresponding kinetics. According to some recently published results, the diffusion coefficient in flexible polymer networks can be significantly greater than the value corresponding to rigid networks for moderate polymer volume fractions and solute diameters [ 29 ]. Thus, we wonder if the effect of flexibility on the release kinetics can be so significant.…”

Section: Introductionmentioning

confidence: 99%

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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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“…The potential energy (u(r)) of these forces is given by u(r) = −B mi /r 6 , where B mi is the dispersion constant for monomeric units and species i, which can be nanoparticle (B mn ) or dye (B md ), and r is the center-to-center distance between two given interacting particles, as described in previous works. 21,22 Hereafter, the values of B mn /k B T and B md /k B T (where k B is Boltzmann's constant and T is the absolute temperature) are expressed in nm −6 .…”

Section: Coarse-grained Simulations Of the Mechanismsmentioning

confidence: 99%

Synergic Thermo- and pH-Sensitive Hybrid Microgels Loaded with Fluorescent Dyes and Ultrasmall Gold Nanoparticles for Photoacoustic Imaging and Photothermal Therapy

Xiao

Pandey

Nicolas‐Boluda

et al. 2022

ACS Appl. Mater. Interfaces

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Smart microgels (μGels) made of polymeric particles doped with inorganic nanoparticles have emerged recently as promising multifunctional materials for nanomedicine applications. However, the synthesis of these hybrid materials is still a challenging task with the necessity to control several features, such as particle sizes and doping levels, in order to tailor their final properties in relation to the targeted application. We report herein an innovative modular strategy to achieve the rational design of well-defined and densely filled hybrid particles. It is based on the assembly of the different building blocks, i.e., μGels, dyes, and small gold nanoparticles (<4 nm), and the tuning of nanoparticle loading within the polymer matrix through successive incubation steps. The characterization of the final hybrid networks using UV−vis absorption, fluorescence, transmission electron microscopy, dynamic light scattering, and small-angle X-ray scattering revealed that they uniquely combine the properties of hydrogel particles, including high loading capacity and stimuli-responsive behavior, the photoluminescent properties of dyes (rhodamine 6G, methylene blue and cyanine 7.5), and the features of gold nanoparticle assembly. Interestingly, in response to pH and temperature stimuli, the smart hybrid μGels can shrink, leading to the aggregation of the gold nanoparticles trapped inside the polymer matrix. This stimuliresponsive behavior results in plasmon band broadening and red shift toward the near-infrared region (NIR), opening promising prospects in biomedical science. Particularly, the potential of these smart hybrid nanoplatforms for photoactivated hyperthermia, photoacoustic imaging, cellular internalization, intracellular imaging, and photothermal therapy was assessed, demonstrating well controlled multimodal opportunities for theranostics.

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Coarse-Grained Simulations of Solute Diffusion in Crosslinked Flexible Hydrogels

Cited by 9 publications

References 57 publications

Active Diffusion of Self-Propelled Particles in Flexible Polymer Networks

Active Diffusion of Self-Propelled Particles in Flexible Polymer Networks

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

Synergic Thermo- and pH-Sensitive Hybrid Microgels Loaded with Fluorescent Dyes and Ultrasmall Gold Nanoparticles for Photoacoustic Imaging and Photothermal Therapy

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