Diffusion coefficient of solute in heterogeneous and macroporous hydrogels and its correlation with the effective crosslinking density

Tokuyama, Hideaki; Nakahata, Yu; Ban, Takahiko

doi:10.1016/j.memsci.2019.117533

Cited by 21 publications

(5 citation statements)

References 35 publications

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“…It is then kept constant, allowing the deformation to be driven by the diffusion of water molecules into the film. To accurately capture the folding, we incorporate the change in diffusion coefficient with the change in cross-link density, which is one of the main factors contributing to the concentration difference in the film. − According to the Flory–Rehner theory of swellable polymers, , it is elucidated that Young’s modulus of a swollen polymer is a function of the polymer volume fraction and as given in Sperling as E ∝ N , where N is the number of active polymer chains per unit volume calculated from Flory–Huggins equation . Therefore, the stiffness ( E ) is expressed in terms of the number of polymer chains ( N ) and the molar volume (ν).…”

Section: Experimental Methodsmentioning

confidence: 99%

Solvent-Responsive Functionally Graded Hydrogel Thin Films for Programmed Actuation

Debta,

Kumbhar,

Ghosh

et al. 2024

ACS Appl. Eng. Mater.

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Shape-shifting solvent-responsive hydrogels have emerged as a crucial material platform for the design of soft robots, sensors, and actuators. Generally, to achieve actuation under different environments, using a layered structure with heterogeneous properties is a prevalent approach. However, the nonuniform force distribution at the interface between the layers can induce material delamination, thus greatly compromising the system’s stability and applicability. Here, we present the fabrication, design, and analysis of a reversible and structurally stable single-component functionally graded (FG) hydrogel thin film. The gradation is in terms of the modulus and diffusion coefficient. The FG film exhibits a fast actuation rate and is capable of actuating in both immersed and nonimmersed aqueous environments. The fabricated FG film can eliminate the requirement for a layered structure yet retain all its functionalities. A coupled diffusion–deformation framework using the finite element (FE) method is employed to comprehend the mechanism and understand the factors governing the actuation of a FG film. The displacement profiles obtained from the simulations are successfully compared with the experiments for a FG–chitosan–water system. The rate of concentration change in different layers of the FG film is shown to play a pivotal role in steering the direction of actuation as well as the reversibility of folding under different conditions. The differential strain obtained from the length change between the different layers of the FG films is identified as a contributing factor for different actuation rates. Additionally, the simulation curvatures from different scenarios elucidate the influence of cross-linking gradation, water diffusion, and thickness on the folding of a FG film. As a prospective application, we demonstrate the design of different underwater grippers using geometrically engineered symmetric and asymmetric FG films.

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Section: Experimental Methodsmentioning

confidence: 99%

Solvent-Responsive Functionally Graded Hydrogel Thin Films for Programmed Actuation

Debta,

Kumbhar,

Ghosh

et al. 2024

ACS Appl. Eng. Mater.

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“…The particles are trapped for a time period before eventually escaping due to thermal fluctuations and either continue diffusive motion or get trapped again. The common approach to model such diffusion behavior is the continuous time random walk (CTRW) framework in which a random walker waits for a certain time (“caging” time) at any given site before jumping to a neighboring site. , While this formalism has been used to describe diffusion in different types of complex heterogeneous systems like desorption dynamics in porous activated carbon grains, electronic transport in disordered solids, and protein dynamics, its application to heterogeneous hydrogels and ECM is still in its infancy. ,,, …”

Section: Biomolecular Transport For Cell Communicationmentioning

confidence: 99%

“…116,121 While this formalism has been used to describe diffusion in different types of complex heterogeneous systems like desorption dynamics in porous activated carbon grains, 122 electronic transport in disordered solids, 123 and protein dynamics, 124 its application to heterogeneous hydrogels and ECM is still in its infancy. 116,118,125,126 An alternative approach to improve diffusion of large solute molecules is through dynamic reconfiguration of the network using reversible cross-linking. As the cross-link junctions are subject to continuous breaking and reformation, it is possible for a large solute to escape out of their trapped cages.…”

Section: Poroelasticitymentioning

confidence: 99%

Mechanics of 3D Cell–Hydrogel Interactions: Experiments, Models, and Mechanisms

et al. 2021

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Hydrogels are highly water-swollen molecular networks that are ideal platforms to create tissue mimetics owing to their vast and tunable properties. As such, hydrogels are promising cell-delivery vehicles for applications in tissue engineering and have also emerged as an important base for ex vivo models to study healthy and pathophysiological events in a carefully controlled three-dimensional environment. Cells are readily encapsulated in hydrogels resulting in a plethora of biochemical and mechanical communication mechanisms, which recapitulates the natural cell and extracellular matrix interaction in tissues. These interactions are complex, with multiple events that are invariably coupled and spanning multiple length and time scales. To study and identify the underlying mechanisms involved, an integrated experimental and computational approach is ideally needed. This review discusses the state of our knowledge on cell−hydrogel interactions, with a focus on mechanics and transport, and in this context, highlights recent advancements in experiments, mathematical and computational modeling. The review begins with a background on the thermodynamics and physics fundamentals that govern hydrogel mechanics and transport. The review focuses on two main classes of hydrogels, described as semiflexible polymer networks that represent physically cross-linked fibrous hydrogels and flexible polymer networks representing the chemically cross-linked synthetic and natural hydrogels. In this review, we highlight five main cell− hydrogel interactions that involve key cellular functions related to communication, mechanosensing, migration, growth, and tissue deposition and elaboration. For each of these cellular functions, recent experiments and the most up to date modeling strategies are discussed and then followed by a summary of how to tune hydrogel properties to achieve a desired functional cellular outcome. We conclude with a summary linking these advancements and make the case for the need to integrate experiments and modeling to advance our fundamental understanding of cell−matrix interactions that will ultimately help identify new therapeutic approaches and enable successful tissue engineering.

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“…sGiven these applications, understanding the mechanisms underlying drug motion inside the hydrogel network at the molecular level, the effects of the polymeric backbone (drug-polymer interactions) and its relationship with the macroscopic release is of fundamental importance for the design of efficient drug delivery systems. To date, several theoretical models have been reported, including the simple Fickian diffusion model (Tokuyama, Nakahata, & Ban, 2020), and more complex mechanistic models (Masaro, & Zu, 1999) essentially based on i) obstruction effects, ii) free volume theory (Fujita, 1961), and iii) hydrodynamic theories (Cukier, 1984) which consider the hydrodynamic interactions present in the whole system. Furthermore, a comprehensive multi-scale model, accounting for the effects of different diffusion mechanisms, has been proposed to describe the diffusion of dextran of different sizes in a series of poly(ethylene glycol) (PEG) and alginate-based hydrogels (Axpe et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Hyaluronic acid-based hydrogels: Drug diffusion investigated by HR-MAS NMR and release kinetics

Vanoli

Delleani²,

Casalegno³

et al. 2023

Carbohydrate Polymers

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Diffusion coefficient of solute in heterogeneous and macroporous hydrogels and its correlation with the effective crosslinking density

Cited by 21 publications

References 35 publications

Solvent-Responsive Functionally Graded Hydrogel Thin Films for Programmed Actuation

Solvent-Responsive Functionally Graded Hydrogel Thin Films for Programmed Actuation

Mechanics of 3D Cell–Hydrogel Interactions: Experiments, Models, and Mechanisms

Hyaluronic acid-based hydrogels: Drug diffusion investigated by HR-MAS NMR and release kinetics

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