Date of Award

8-2014

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Legacy Department

Physics

Advisor

Ding, Feng

Committee Member

He , Jian

Committee Member

Ladner, David

Committee Member

Rao, Apparao

Abstract

The last few decades have seen an explosion in the study and application of nanomaterials that continues to grow at a dizzying pace. Despite exciting applications in nano-enabled electronics, materials, medicine, and environmental remediation, an understanding of the interactions of these materials with natural materials and systems and the resulting implications lags severely behind. The purpose of this Dissertation is to illuminate these interactions as well as develop novel environmental applications from a biophysical perspective. Following an introduction and literature review in Chapter 1, Chapters 2-4 will explore the application of dendritic polymers as novel and biocompatible oil dispersants for more environmentally conscious response to catastrophic oil spills. Chapter 2 will serve as a proof-of-concept, exploring the interactions between two model dendritic polymers and two model oil hydrocarbons. Next, the biocompatibility of these nanoscale dispersing agents is addressed in Chapter 3, using a soil amoeba as the primary model organism with emphasis on the mechanisms of any observed toxicity. Finally, in an effort to minimize cationic charge-induced cytotoxicity, the cationic terminal functional groups of poly(amidoamine) (PAMAM) dendrimers are replaced with either anionic or neutral functional groups. The resulting changes in structure and oil-dispersing function of the original and modified dendrimers are then investigated. Chapter 5 details a study of the applications and implications of graphene derivatives. Specifically, the environmental persistence of graphene and graphene oxide are assessed by studying their interactions with natural amphiphiles using synergistic experiments and molecular dynamics simulations. The application of graphene oxide for the removal of polyaromatic hydrocarbons from aquatic systems is also investigated and compared to the efficacy of PAMAM dendrimers in the same application. Finally, Chapter 6 explores the interactions between silver nanoparticles and cytoskeletal proteins using a variety of biophysical techniques. In this way, we may better understand the fate of silver nanoparticles after their uptake by live cells. Chapter 7 will then provide a brief conclusion and future directions in the field. The goal of this research is to provide a deeper understanding of both promising applications and the unintended implications of emerging nanomaterials. In this way, we may both advance and secure the future of the rapidly growing and promising field of nanotechnology.

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