Date of Award

Fall 2019

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Biomedical Engineering

Abstract

Understanding the performance of widely applied nanoscale hydrogel biomaterials is an unmet need within the biomedical field. The objective of this master’s thesis project was to evaluate the effects size and surface area has on the in vivo behavior of nanoscale hydrogels. The hypothesis tested was that at the nanoscale, the increased surface area to volume effects of nanoscale hydrogels play and important role in the overall swelling of hydrogels, such that nanoscale hydrogels swell to a greater degree than their bulk counterparts. To investigate this, the bulk swelling behavior of a series of neutral poly (ethylene glycol) di-methacrylate (PEGDMA) hydrogels was experimentally tested. Along with experimental studies, a computational model based on the experimental findings was developed to serve as a means of predicting nanoscale swelling and subsequent drug release behavior. The computational hydrogel model was validated with the experimental densities and swelling ratios calculated. The surfaces of swollen hydrogels had a density gradient until reaching a stabilized, core density. As the size of the hydrogel decreases, the surface area to volume ratio increases, which enhances surface effects for micro- and nanoscale hydrogels. This conclusion helps to confirm the hypothesis that the increased surface area to volume ratio of nanoscale hydrogels affects the overall swelling ratio in comparison to their bulk counter parts. Particle size should be considered when characterizing nanoscale hydrogels. In this thesis, a computational hydrogel model capable of simulating hydrogel swelling for hydrogels with a dry state diameter of 40 nm was created. In the future, this model would ideally be able to simulate hydrogels with a dry state diameter ≥ 100 nm to test the full range of nanoscale size effects on hydrogel swelling.

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