Date of Award

6-2018

Document Type

Thesis

Department

Bioengineering

First Advisor

Maryam Mobed-Miremadi

Abstract

Alginate hydrogels provide desirable biocompatibility and material properties for various biomedical applications, but are limited by the polymer's natural pore size. With the rise of nanotechnology, the desired crosslinked pore size range of 30 nm to 100 nm has not yet been achieved. This project aimed to develop a method to increase the pore size of alginate-based hydrogels in a reproducible manner without compromising their structural integrity. Experimental methods included altering alginate composition using carboxymethyl cellulose or gelatin and inducing conformational changes via Mach-1TM mechanical compression. Fluorescence microscopy was used to visualize the diffusion of FITC-dextran weight markers and fluorescent polystyrene nanoparticles into the microcapsules (d = 300 μm) and macrocapsules (d = 3 mm) for all experimental conditions. Based on pilot experiments, altered alginate composition did not significantly increase the pore size of alginate capsules for the modeled diffusivity range D = 1 x 10-14 m2/s to D = 1 x 10-15 m2/s. Mechanical compressions did not significantly affect the porosity or diffusivity of alginate macrocapsules (p > 0.05) under all conditions for Young’s moduli ranging from E = 76 kPa to E = 200 kPa. Based on image analysis results, it could be hypothesized that molecular weight cutoff cutoff may be increased to 500 kDa following 10 successive compressions. Additional work to optimize fluorescent microscopy methods and pore size manipulation methods is required for expanded use of alginate capsules with emerging nanotechnologies.

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