Date of Award

1-1-2015

Language

English

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

College/School/Department

Department of Nanoscale Science and Engineering

Program

Nanoscale Sciences

Content Description

1 online resource (xvii, 164 pages) : color illustrations

Dissertation/Thesis Chair

Sara A Brenner

Committee Members

Alison Elder, Thomas Begley, Robert Geer, J. A. Melendez

Keywords

chemical mechanical planarization, electron microscopy, human lung cells, murine inhalation model, nanoparticles, particle inhalation, Nanostructured materials, Sewage

Subject Categories

Analytical Chemistry | Nanoscience and Nanotechnology | Toxicology

Abstract

Engineered nanomaterials (ENMs) play an increasing role in manufacturing and consumer products. Currently, there is no standard approach to studying ENM toxicity, and a growing body of literature suggests that ENMs may have toxicity differing from similar compounds in bulk or dissolved form. I examined ENMs used in the semiconductor manufacturing process called chemical-mechanical planarization (CMP) for their properties, removal in the wastewater treatment system (WWT), in-vitro toxicity, and location post-inhalation in-vivo. It was found that ENMs in CMP slurries have morphology determined by their elemental composition, but assessment of size and concentration can differ substantially between accepted techniques. Particles in the WWT system are primarily silicon-oxide particles, and conventional wastewater treatment does not affect particle size . Slurries were also found to have concentration-dependent toxicity in two human-derived cell lines in-vitro. Exposure to CMP slurries was shown to increase transcript levels of pro-apoptotic proteins, despite having no significant effect on cellular redox state after 24 hours of exposure. In-vivo, following slurry inhalation, particles were found in alveoli, pulmonary blood vessels, the liver, and other organs. Changes in macrophage appearance may indicate phagocytosis of slurry particles, which may suggest a method of translocation to other organs. I thus conclude that inhaled slurry is potentially toxic to humans.

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