Diffusivities of macromolecules in composite hydrogels

Kosto, Kimberly B.; Deen, William M.

doi:10.1002/aic.10216

Cited by 62 publications

(46 citation statements)

References 47 publications

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“…However, this assumes that the transport of the 69 kDa protein with a hydraulic radius of 7.2 nm is comparable to polymeric nanoparticles with much lager radii. Theories of hindered transport in porous media suggest that the mobility of a freely suspended particle decreases as the ratio of particle size to effective pore size increases [37,16,18]. The present results for nanoparticles and previous results for liposomes indicate that the ECM significantly hinders transport of these particles, and that particle transport can be enhanced by osmotic dilation of the ECM.…”

Section: Discussionsupporting

confidence: 61%

Dilation and degradation of the brain extracellular matrix enhances penetration of infused polymer nanoparticles

et al. 2007

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This study investigates methods of manipulating the brain extracellular matrix (ECM) to enhance the penetration of nanoparticle drug carriers in convection-enhanced delivery (CED). A probe was fabricated with two independent microfluidic channels to infuse, either simultaneously or sequentially, nanoparticles and ECM-modifying agents. Infusions were performed in the striatum of the normal rat brain. Monodisperse polystyrene particles with a diameter of 54 nm were used as a model nanoparticle system. Because the size of these particles is comparable to the effective pore size of the ECM, their transport may be significantly hindered compared with the transport of low molecular weight molecules. To enhance the transport of the infused nanoparticles, we attempted to increase the effective pore size of the ECM by two methods: dilating the extracellular space and degrading selected constituents of the ECM. Two methods of dilating the extracellular space were investigated: co-infusion of nanoparticles and a hyperosmolar solution of mannitol, and pre-infusion of an isotonic buffer solution followed by infusion of nanoparticles. These treatments resulted in an increase in the nanoparticle distribution volume of 50% and 123%, respectively. To degrade hyaluronan, a primary structural component of the brain ECM, a pre-infusion of hyaluronidase (20,000 U/mL) was followed after 30 min by infusion of nanoparticles. This treatment resulted in an increase in the nanoparticle distribution of 64%. Our results suggest that both dilation and enzymatic digestion can be incorporated into CED protocols to enhance nanoparticle penetration.

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Section: Discussionsupporting

confidence: 61%

Dilation and degradation of the brain extracellular matrix enhances penetration of infused polymer nanoparticles

et al. 2007

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“…In addition, the diffusion of ions in gels is assumed to be the same as that in pure electrolytes, and the influence of geometrical obstructions due to the presence of polymer chains on the diffusion is ignored [28][29][30][31]. Nevertheless, such influences can be accounted for with models or experimental measurements of the diffusion of ions in a specific polymer charge and architecture.…”

Section: Electric Current Density Of Droplet-hydrogel Compositesmentioning

confidence: 99%

Transport in droplet-hydrogel composites: response to external stimuli

Mohammadi

2014

Colloid Polym Sci

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Determination of effective transport properties of droplet-hydrogel composites is essential for various applications. The transport of ions through a droplet-hydrogel composite subjected to an electric field is theoretically studied as an initial step toward quantifying the effective transport properties of droplet-hydrogel composites. A three-phase electrokinetic model is used to derive the microscale characteristics of the polyelectrolyte hydrogel, and the droplet is considered an incompressible Newtonian fluid. The droplethydrogel interface is modeled as a surface, which encloses the interior fluid. The surface has the thickness of zero and the electrostatic potential ζ . Standard averaging procedures are used to derive the effective governing equation for the current density that captures the macroscopic behavior. The results show that the polymer boundary condition has a modulating impact on the electrical conductivity, and the influence of the boundary condition decreases as the interior fluid viscosity increases. At the limit of the polymer's no-slip boundary condition, the interior and exterior fluids' viscosities, Brinkman screening length, and ionic strength have a significant impact on the conductivity. Interestingly, it should be possible to determine the ζ -potential for a droplet-hydrogel composite from measurements of the electrical conductivity with the aid of the formula derived for the conductivity. Finally, the theoretical study for determining the response of droplet-hydrogel composites to an imposed pressure gradient is undertaken, and it is found that the polymer boundary condition has a modulating impact on the response.A. Mohammadi ( )

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“…Composite hydrogel systems have also been of interest, such as agarose-dextran composite gels (50). FRAP was used to measure diffusion of proteins and polysaccharides in these hydrogels and in aqueous solution, indicating an increase in hindered diffusion with hydrodynamic diameter.…”

Section: Diffusion Inside Hydrogelsmentioning

confidence: 99%

FRAP in Pharmaceutical Research: Practical Guidelines and Applications in Drug Delivery

et al. 2013

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Fluorescence recovery after photobleaching (FRAP) is a fluorescence microscopy technique that has attracted a lot of interest in pharmaceutical research during the last decades. The main purpose of FRAP is to measure diffusion on a micrometer scale in a non-invasive and highly specific way, making it capable of measurements in complicated biomaterials, even in vivo. This has proven to be very useful in the investigation of drug diffusion inside different tissues of the body and in materials for controlled drug delivery. FRAP has even found applications for the improvement of several medical therapies and for the field of diagnostics. In this review, an overview is given of the different applications of FRAP in pharmaceutical research, together with essential guidelines on how to perform and analyse FRAP experiments.

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Diffusivities of macromolecules in composite hydrogels

Abstract: Diffusivities of fluorescein-labeled macromolecules were measured in dilute aqueous solution (D ϱ)

Cited by 62 publications

References 47 publications

Dilation and degradation of the brain extracellular matrix enhances penetration of infused polymer nanoparticles

Dilation and degradation of the brain extracellular matrix enhances penetration of infused polymer nanoparticles

Transport in droplet-hydrogel composites: response to external stimuli

FRAP in Pharmaceutical Research: Practical Guidelines and Applications in Drug Delivery

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