Date of Award

11-7-2022

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Biomedical and Chemical Engineering

Advisor(s)

Monroe, Mary Beth

Subject Categories

Chemical Engineering | Polymer Chemistry

Abstract

Shape memory polymers (SMPs) are a class of smart materials that can be temporarily stored in a deformed shape and can actively recover their original shape upon exposure to an external stimulus, such as heat, magnetic field, moisture, pH, light, or electric field. The ability of SMPs to change shape when required can be used for a wide range of applications, especially in the case of minimally invasive biomedical applications. In this work, polyurethane-based SMPs were explored for their use in tissue engineering, drug delivery, and wound healing applications.

In the second chapter, low density porous foams with tunable degradability were developed for their use in tissue engineering applications. In vitro degradation profiles were compared to in vivo degradation profiles to establish a correlation between the two. This work is useful to accurately develop an understanding of the degradability of materials before testing them on animals. It is vital to match the biomaterial’s degradation rate to the regeneration rate of surrounding tissues and thereby avoid any hindrance caused by the biomaterials to new tissue growth.

The third chapter explores the use of magnetically activated SMP films to achieve on-demand drug delivery. The films developed here can be remotely triggered to undergo a shape change by exposure to an alternating magnetic field and thereby provide drug release as required. The ability to control the rate of shape change based on the polymer chemistry and the magnetic particle content enables tunability of drug release rate. These materials can either be used to release a single drug at varying time points or simultaneously administer two drugs at different release rates.

In the fourth chapter, antimicrobial poly(ethylene glycol)-based polyurethane hydrogels were developed. Readily available plant-based phenolic acids were physically incorporated into the hydrogels to impart the antimicrobial properties. When applied to a topical wound site, these hydrogels could easily recover their original shape, seal the wound, and release the phenolic acids. These materials proved to inhibit bacterial growth for 20 days, which could be used to prevent an acute wound from developing into a chronic wound.

Overall, this work demonstrates the ability to alter SMP scaffold properties as required to develop a range of biomaterials for varied healing applications.

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