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Document Type

Campus-Only Access for Five (5) Years

Degree Name

Doctor of Philosophy (PhD)

Degree Program

Food Science

Year Degree Awarded

2018

Month Degree Awarded

May

First Advisor

Hang Xiao

Subject Categories

Other Food Science

Abstract

Many food products contain engineered inorganic nanoparticles (NPs), such as titanium dioxide (TiO2) NPs as a part of food additive, due to both unintentional and intentional additions. There has been increasing concern about the health risks associated with foodborne inorganic NPs. However, the detailed understanding of the biological fate and potential adverse effects of foodborne TiO2 NPs is not available despite a limited number of published toxicity studies on TiO2 NPs. The purpose of this thesis was to characterize the interactions of TiO2 NPs and food components including dietary flavonoids and dietary proteins, and evaluate the adverse effects of foodborne TiO2 NPs in the obese and non-obese mice. Surface-Enhanced Raman Spectroscopy (SERS) analysis clearly demonstrated that specific flavonoids could bind TiO2 NPs with the functional groups 3ˊ-OH and 4ˊ-OH on Ring B and formed charge-transfer complexes. SERS signals, ξ-potential, turbidity, particle size, TEM images and enthalpy changes using ITC were obtained to characterize the interaction of TiO2 NPs with casein, and in vitro digestion model were used to evaluate the impact on the gastrointestinal fate. These findings suggests that interaction of ingested nanoparticles with food matrix and gastrointestinal condition should be taken into consideration in toxicology studies of the nanoparticles. Our toxicology study showed TiO2 NPs significantly altered plasma chemistry parameters related to normal liver and kidney function in mice, indicating a potential liver and kidney toxicity. TiO2 NPs also significantly increased the abundance of immune cells (e.g., macrophages and dendritic cells) and the level of pro-inflammatory cytokine in the mouse colonic mucosa, demonstrating pro-inflammatory effects of TiO2 NPs in the colon. Moreover, TiO2 NPs significantly perturbed the normal structures and composition of gut microbiota based on next generation sequencing analysis of fecal samples. Overall, our fingdings provided new perspectives on the potential adverse effects of foodborne TiO2 NPs among populations with different obese status.

Available for download on Saturday, May 11, 2019

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