Abstract

Colloidal materials are highly diverse and present complex physicochemical properties which define their utilities in applications spanning diverse industries. In particular, nano-scale colloids have received tremendous attention due to their unique, specific activities as compared to larger-sized preparations. Within the biomedical sciences, nano-colloids are routinely used as inert carriers of therapeutics and/or diagnostic agents. Beyond this, researchers have developed functional colloids which demonstrate bio-active or diagnostic properties themselves: often related to an optimized, or tuned, surface character. Among these, nanoscale cerium oxide (nanoceria) has shown great promise as a bi-functional, therapeutic material: producing pro- or anti- oxidative chemical response in bio-systems via unique redox reactions mediated by the material surface. Studies investigating these reactions have highlighted details of material synthesis and, in particular, of the physicochemical environment interfacing with the material. Attention has been especially focused on the impacts of surface hydration/hydroxylation; ligand and co-/counter- ion adsorption/complexation; and re-structuring/micro-structuring on redox chemistry. This work seeks to address the complex surface character of several nanoceria formulations and to engineer novel formulations with potentiated redox activity. In particular, the influence of synthesis/processing conditions on colloidal stability, and surface properties are examined. The first section provides an introduction/overview of related colloid science and implications to nanoceria. Sections 2 and 3 highlight specific physicochemical properties relating to colloid formation and the effects of ageing on a peroxide-based nanoceria synthesis. Further, the developed understanding of these properties is used to produce surface-modified formulations with optimized redox properties for material use in biomedical applications. Section 4 details a study into the preparation of novel silver-modified nanoceria formulations, as well as highlights the variation in material surface character with unique synthesis conditions/processing. Further, syntheses of doped cerium oxide formulations are performed to produce particles of varying oxygen vacancy densities. Electroanalytical techniques (voltammetric techniques) are used to provide detailed characterization of fundamental material character related to surface activity. Assays for enzyme-mimetic activities are used throughout to compare and optimize formulations.

Notes

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Graduation Date

2021

Semester

Spring

Advisor

Seal, Sudipta

Degree

Doctor of Philosophy (Ph.D.)

College

College of Engineering and Computer Science

Department

Materials Science and Engineering

Degree Program

Materials Science and Engineering

Format

application/pdf

Identifier

CFE0008932

Language

English

Release Date

November 2021

Length of Campus-only Access

None

Access Status

Doctoral Dissertation (Campus-only Access)

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