Date of Award

5-2026

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Materials Science and Engineering

Committee Chair/Advisor

Olin Thompson Mefford

Committee Member

Suvra Santa Laha

Committee Member

Igor Luzinov

Committee Member

Philip J. Brown

Abstract

Ocular melanoma is commonly treated using plaque brachytherapy; however, radiation-induced damage to healthy ocular tissues frequently results in partial or complete vision loss. This work investigates the development of an injectable, magnetically responsive silicone magnetic fluid designed to localize adjacent to the tumor and attenuate low-energy gamma radiation during treatment.

The material system consists of iron oxide nanoparticles surface-functionalized with a siloxane polymer, in which the nanoparticles provide magnetic responsiveness and radiation attenuation, while the polymer coating ensures colloidal stability, injectability, and biocompatibility. A one-pot synthetic approach was developed wherein a functionalized siloxane polymer containing iron-affinitive groups was reacted with an iron precursor in a high-boiling solvent under elevated temperature and pressure, enabling simultaneous nanoparticle formation and in situ polymer attachment.

The synthesis was shown to be highly reproducible, and systematic evaluation of structure–property–processing relationships was performed with respect to nanoparticle size, polymer brush length, and polymer brush thickness. These parameters were found to strongly influence magnetic response, rheological behavior, colloidal stability, and radiation attenuation performance.

Using insights from these relationships, the formulation was optimized to maximize radiation attenuation while remaining within relevant physical, biomedical, and practical constraints. The resulting fluid exhibits favorable injectability, magnetic responsiveness, biocompatibility, and enhanced attenuation of low-energy gamma radiation, demonstrating its suitability for use as an adjunct material in ocular melanoma brachytherapy.

Author ORCID Identifier

0000-0002-6985-6929

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