Hindered transport in composite hydrogels
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 2004.
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| Format: | Thesis |
| Language: | en_US |
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Massachusetts Institute of Technology
2005
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| Online Access: | http://hdl.handle.net/1721.1/28358 |
| _version_ | 1826202693158305792 |
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| author | Kosto, Kimberly Bryan, 1977- |
| author2 | William M. Deen. |
| author_facet | William M. Deen. Kosto, Kimberly Bryan, 1977- |
| author_sort | Kosto, Kimberly Bryan, 1977- |
| collection | MIT |
| description | Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 2004. |
| first_indexed | 2024-09-23T12:14:43Z |
| format | Thesis |
| id | mit-1721.1/28358 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T12:14:43Z |
| publishDate | 2005 |
| publisher | Massachusetts Institute of Technology |
| record_format | dspace |
| spelling | mit-1721.1/283582019-04-11T06:49:56Z Hindered transport in composite hydrogels Kosto, Kimberly Bryan, 1977- William M. Deen. Massachusetts Institute of Technology. Dept. of Chemical Engineering. Massachusetts Institute of Technology. Dept. of Chemical Engineering. Chemical Engineering. Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 2004. Includes bibliographical references (leaves 143-152). The ultimate goal of this research was to develop a greater understanding of the structural components needed to describe transport within the glomerular basement membrane (GBM). Specifically, dimensionless diffusive and convective hindrance factors were investigated by measuring macromolecular permeability through synthetic, two-fiber, agarose-dextran hydrogels at very small or very high Pe, respectively. By comparing diffusion and convection in the synthetic hydrogel with corresponding measurements in isolated rat GBM, further insight regarding the structure responsible for transport through the GBM was gained. In order to compare diffusive hindrances in the synthetic gels with those in isolated GBM, partitioning in agarose-dextran hydrogels was also examined. Additionally, hindered transport theories were tested. In studying diffusion, partitioning, and convection, macromolecules with Stokes-Einstein radii (r) ranging from 2.7 to 5.9 nm were used. Gels with agarose volume fractions of 0.040 and 0.080 were studied with dextran volume fractions (assuming dextran acts as a fiber) ranging from 0 to 0.0076 and 0 to 0.011, respectively. For the diffusion studies, two globular proteins (ovalbumin and bovine serum albumin) and three narrow fractions of Ficoll, a spherical polysaccharide, were used. For the partitioning and convection studies, four narrow fractions of Ficoll were used. Diffusivities of fluorescein-labeled macromolecules were measured in dilute aqueous solution (D[infinity]), agarose gels (D[alpha]), and agarose-dextran composite gels (D) using fluorescence recovery after photobleaching. (cont.) For both agarose concentrations, the Darcy permeability (K) decreased by an order of magnitude as the dextran concentration in the gel was increased from zero to its maximum value. For a given gel composition, the relative diffusivity (D/D[infinity]) decreased as r increased, a hallmark of hindered diffusion. For a given test molecule, D/D[infinity] was lowest in the most concentrated gels, as expected. As the dextran concentration was increased to its maximum value, 2-3 fold decreases in relative diffusivity resulted for both agarose gel concentrations. The reductions in macromolecular diffusivities caused by incorporating various amounts of dextran into agarose gels could be predicted fairly accurately from the measured decreases in K, using an effective medium model. This suggests that one might be able to predict diffusivity variations in complex, multicomponent hydrogels (e.g. those in body tissue) in the same manner, provided that values of K can be obtained. Equilibrium partition coefficients ([Phi],the concentration in the gel divided by that in free solution) of fluorescein-labeled Ficolls in pure agarose and agarose-dextran composite gels were measured as a function of gel composition and Ficoll size. As expected, [Phi] generally decreased as the Ficoll size increased (for a given gel composition) or as the amount of dextran incorporated into the gel increased (for a given agarose concentration and Ficoll size). The decrease in [Phi] that accompanied dextran addition was predicted well by an excluded volume theory in which agarose and dextran were both treated as rigid, straight, randomly positioned and oriented fibers ... by Kimberly Bryan Kosto. Ph.D. 2005-09-26T20:01:14Z 2005-09-26T20:01:14Z 2004 2004 Thesis http://hdl.handle.net/1721.1/28358 56052235 en_US M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. http://dspace.mit.edu/handle/1721.1/7582 152 leaves 5812186 bytes 5811984 bytes application/pdf application/pdf application/pdf Massachusetts Institute of Technology |
| spellingShingle | Chemical Engineering. Kosto, Kimberly Bryan, 1977- Hindered transport in composite hydrogels |
| title | Hindered transport in composite hydrogels |
| title_full | Hindered transport in composite hydrogels |
| title_fullStr | Hindered transport in composite hydrogels |
| title_full_unstemmed | Hindered transport in composite hydrogels |
| title_short | Hindered transport in composite hydrogels |
| title_sort | hindered transport in composite hydrogels |
| topic | Chemical Engineering. |
| url | http://hdl.handle.net/1721.1/28358 |
| work_keys_str_mv | AT kostokimberlybryan1977 hinderedtransportincompositehydrogels |