Dissertation Defense: Synthesis of Biocompatible Polymer Coated Cerium Oxide Nanoparticles, Its Oxidase-like Behavior and Cellular Uptake Studies
TA 110 November 5, 2009
10:00 AM - 12:00 PM
Announcing the Final Examination of Mr. Atul Asati for the degree of Doctor of Philosophy.
Cerium oxide nanoparticles have been widely used in various applications such as catalytic converters for automobile exhaust, ultraviolet absorber, and electrolyte in fuel cells. Most recently, cerium oxide nanoparticles (nanoceria) have been employed as potent free-radical scavengers with neuroprotective, radioprotective, and anti-inflammatory properties. These properties of cerium oxide nanoparticles can open new vistas in medicine and biotechnology. The present study utilizes a water-based-wet-chemical method to synthesize biocompatible, stable and highly monodisperse polymer coated cerium oxide nanoparticles. The polymer coated cerium oxide nanoparticles retained the free-radical scavenging properties of the uncoated cerium oxide nanoparticles and were found to be effective as pH-dependent antioxidant giving cytoprotection to normal cell lines against hydrogen peroxide but not to cancer cells. Moreover, cerium oxide nanoparticles also exhibit unique oxidase-like activity at acidic pH, oxidizing a series of organic compound without the need of hydrogen peroxide. Based on these results, we have designed an immunoassay in which folate-conjugated cerium oxide nanoparticles provide dual functionality by binding to folate expressing cancer cells and facilitating detection by catalytic oxidation of sensitive colorimetric substrates (dyes). Finally, we have shown that the polymer coated cerium oxide nanoparticles show distinct toxicity depending upon their subcellular localization based on uptake studies using DiI loaded-cerium oxide nanoparticles. In these results, we have found that cerium oxide nanoparticles entrapped into lysosomes are more toxic as opposed to when they are localized in the cytoplasm. Overall we propose that the polymer coated cerium oxide nanoparticles displays selective antioxidant property, oxidase-like activity, and cytotoxicity to biological systems depending upon its pH environment.
Faculty and Staff 
Dissertation Defense: Synthesis of Biocompatible Polymer Coated Cerium Oxide Nanoparticles, Its Oxidase-like Behavior and Cellular Uptake Studies
