Investigation of Molecular Transport and Distributions in Poly(ethylene glycol) Hydrogels with Confocal Laser Scanning Microscopy

Watkins, Andrew W.; Anseth, Kristi S.

doi:10.1021/ma0475232

Cited by 62 publications

(70 citation statements)

References 46 publications

(69 reference statements)

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“…It is well known that permeability as well as mechanical properties of radically cross-linked PEG hydrogels depend not only on the size of PEG-DA polymers, but also on the polymer concentration in the reaction mixture [26,27]. Well defined fluorescent molecules employed in partition ratio analysis are ideally suited to determine the long time permeability properties of hydrogels.…”

Section: Discussionmentioning

confidence: 99%

Diffusion and interaction in PEG-DA hydrogels

2013

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Polyethylenglycol (PEG) hydrogels are widely used as tuneable substrates for biological and technical applications due to their good biocompatibility and their high hydrophilicity. Here we compare the mesh size and diffusion characteristics of PEG hydrogels by analyzing the diffusion of solutes with different, well-defined sizes over long and short time scales. Interestingly, one can tune the mesh size and the density of the gel simply by changing the inital concentrations of the PEG-diacrylate (PEG-DA) polymer, which also enhances the solute uptake in equilibrium through the interaction with the PEG chains. This increased uptake can be characterized by an enhancement factor determined by partition ratio analysis. It increases linearly with the polymer volume fraction, but is not caused by immobilization inside the hydrogel as evident from FRAP measurements, thus rendering these hydrogels ideal materials for i.e. drug delivery applications

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Section: Discussionmentioning

confidence: 99%

Diffusion and interaction in PEG-DA hydrogels

2013

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“…Deeper insight into dynamic processes occurring within hydrogels have become possible by techniques such as high-flux neutron sources and X-ray synchrotrons [6,7,8]. Diffusion in hydrogel has been studied extensively using Quasi-Elastic Neutron Scattering (QENS) [9,10], Nuclear Magnetic Resonance (NMR) [11,12,13], side-by-side diffusion cells [14], fluorescence correlation spectroscopy [15,16], refractive index method [17], etc.…”

Section: Review Of Experimental and Theoretical Studies Of Hydrogelsmentioning

confidence: 99%

“…D-glucose has a hydrodynamic radius of 3.61 − 3.8Å [97,98], that is comparable to 0.53 ± 0.03 nm of rhodamine 6G [99]. Using fluorescence correlation spectroscopy, Watkins et al [15] …”

Section: Diffusion Of Rhodamine In Hydrogelsmentioning

confidence: 99%

Effect of Cross-Linking on the Diffusion of Water, Ions, and Small Molecules in Hydrogels

2009

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Understanding the diffusion of small molecules in hydrogel system is of major importance in a variety of applications including drug delivery systems, tissue engineering and contact lens. Cross-linking density of hydrogels has been commonly used to tune key parameters like mesh size and molecular weight between cross-linkers, in order to change macroscopic properties of hydrogels. In this thesis, molecular dynamics investigations of chemically-cross-linked poly(ethylene glycol) (PEG) hydrogels are reported with the aim of exploring the diffusion properties of water, ions, and rhodamine within the polymer at the molecular level.The water structure and diffusion properties were studied at various cross-linking densities with molecular weights of the chains ranging from 572 to 3400. As the cross-linking density is increased, the water diffusion decreases and the slowdown in diffusion is more severe at the polymer-water interface. The water diffusion at various cross-linking densities is correlated with the water hydrogen bonding dynamics. The diffusion of ions and rhodamine also decreased as the cross-linking density is increased. The variation of diffusion coefficient with cross-linking density is related to the variation of water content at different cross-linking densities.Comparison of simulation results and obstruction scaling theory for hydrogels showed similar trends.ii To Father and Mother.iii

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“…Thus, in this study, hydrogel mesh size was characterized via a series of dextran diffusion experiments based on an adaptation of the methodology of Watkins et al [38].…”

Section: 32mentioning

confidence: 99%

Influence of hydrogel mechanical properties and mesh size on vocal fold fibroblast extracellular matrix production and phenotype

et al. 2008

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Current clinical management of vocal fold (VF) scarring produces inconsistent and often suboptimal results. Researchers are investigating a number of alternative treatments for VF lamina propria (LP) scarring, including designer implant materials for functional LP regeneration. In the present study, we investigate the effects of the initial scaffold elastic modulus and mesh size on encapsulated VF fibroblast (VFF) extracellular matrix (ECM) production toward rational scaffold design. Polyethylene glycol diacrylate (PEGDA) hydrogels were selected for this study since their material properties, including mechanical properties, mesh size, degradation rate and bioactivity, can be tightly controlled and systematically modified. Porcine VFF were encapsulated in four PEGDA hydrogels with degradation half lives of ~25 days and initial elastic compressive moduli ranging from ~30 to 100 kPa and initial mesh sizes ranging from ~9 to 27 nm. After 30 days of static culture, VFF ECM production and phenotype in each formulation was assessed biochemically and histologically. Sulfated glycosaminoglycan synthesis increased in similar degree with both increasing initial modulus and decreasing initial mesh size. In contrast, elastin production decreased with increasing initial modulus but increased with decreasing initial mesh size. Both collagen deposition and the induction of a myofibroblastic phenotype depended strongly on initial mesh size but appeared largely unaffected by variations in initial modulus. The present results indicate that scaffold mesh size warrants further investigation as a critical regulator of VFF ECM synthesis. Furthermore, this study validates a systematic and controlled approach for analyzing VFF response to scaffold properties, which should aid in rational scaffold selection/design.

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Investigation of Molecular Transport and Distributions in Poly(ethylene glycol) Hydrogels with Confocal Laser Scanning Microscopy

Cited by 62 publications

References 46 publications

Diffusion and interaction in PEG-DA hydrogels

Diffusion and interaction in PEG-DA hydrogels

Effect of Cross-Linking on the Diffusion of Water, Ions, and Small Molecules in Hydrogels

Influence of hydrogel mechanical properties and mesh size on vocal fold fibroblast extracellular matrix production and phenotype

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