Year of Publication

2011

Degree Name

Doctor of Philosophy (PhD)

Document Type

Doctoral Dissertation

College

Engineering

Department

Chemical Engineering

First Advisor

Dr. Thomas D. Dziubla

Abstract

Even though the role of oxidative stress in a variety of disease states is known, strategies to alleviate this oxidative stress by antioxidants have not been able to achieve clinical success. Particularly, treatment of oxidative stress by small molecule antioxidants has not received due attention because of the challenges associated with its delivery. Antioxidant polymers, where small molecule antioxidants are incorporated into the polymer backbone, are an emerging class of materials that can address some of these challenges.

In this work, biodegradable polymers incorporating phenolic antioxidants in the polymer backbone were synthesized. Antioxidant polymers were then characterized for their in vitro degradation, antioxidant release and their effect on oxidative stress levels (redox state) in the cells. Trolox, a water-soluble analogue of vitamin E, was polymerized to synthesize poly(trolox ester) with 100% antioxidant content which undergoes biodegradation to release trolox. Nanoparticles of poly(trolox ester) were able to suppress oxidative stress injury induced by metal nanoparticles in an in vitro cell injury model.

In another study, we polymerized polyphenolic antioxidants (e.g. curcumin, quercetin) using a modified non-free-radical polymerization poly(β-amino ester) chemistry. This synthesis scheme can be extended to all polyphenolic antioxidants and allows tuning of polymer degradation rate by choosing appropriate co-monomers from a large library of monomers available for β-amino ester chemistry. Poly(antioxidant β-amino esters) (PABAE) were synthesized and characterized for their degradation, cytotoxicity and antioxidant activity. PABAE degradation products suppressed oxidative stress levels in the cells confirming antioxidant activity of degradation products.

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