Date of Award

12-2013

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Legacy Department

Materials Science and Engineering

Advisor

Mefford, Olin T

Committee Member

Alexis, Frank

Committee Member

Lickfield, Gary

Committee Member

Luzinov, Igor

Abstract

The future of diagnostics and therapeutic drugs in biomedicine is nanoparticles. These nanoparticles come in many different shapes, sizes, and combination of materials. Magnetic nanoparticles have been studied for many years for use in biomedicine, not only for their high surface area, but also because of its unique magnetic properties. They can magnetically interact with their environment, be guided to a specific location, and manipulated to release energy in the form of heat. To ensure that these magnetic nanoparticles survive in the circulatory system, they must be modified with materials to make them colloidally stable in water and shield them from the body's immune response to foreign objects.

The purpose of this project is to design and synthesize a ligand for the modification of iron oxide nanoparticles with three important characteristics: 1) water-dispersable, 2) biologically stable, and 3) functional surface. This was accomplished by synthesizing specialized heterobifunctional polyethylene oxide (PEO) that has a catechol on one end to bind strongly to iron oxide nanoparticles and an alkyne on the other end to provide further functionality. This design allows for easy customization of the particles surface, using "click chemistry," with targeting and fluorescent moieties for any desired application.

The work reported discusses the techniques used for synthesizing a variety of heterobifunctional PEO via anionic ring opening polymerization of ethylene oxide and subsequent end group modifications that ultimately led to the design of a universal ligand for iron oxide nanoparticles, with improved stability in biological environments, that can be used in many biomedical applications. These universal magnetic nanoparticles were modified with different fluorescent dyes for imaging biofilms, carbohydrates for targeting bacteria, and radiotracers for multifunctional diagnostic probes to demonstrate the versatility of this surface.

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