Authors: J.M. Perez, A. Asati, S. Nath, C. Kaittanis
Affilation: University of Central Florida, United States
Pages: 230 - 231
Keywords: antioxidant, cancer therapeutics, radioprotection, cerium oxide
Cerium oxide nanoparticles (nanoceria) are potent free radical scavengers with neuroprotective, radioprotective, and anti-inflammatory properties. However, most synthetic procedures for nanoceria results in nanoparticles with poor water solubility or synthesized by procedures involving toxic solvents, therefore hindering their potential clinical use. To advance these studies, we have developed a facile synthetic procedure for monodisperse, water soluble and highly crystalline dextran-coated nanoceria. These nanoparticles are composed of a cerium oxide core of 4 nm surrounded by a dextran coating for a total nanoparticle size of 10nm. One of the most interesting properties of nanoceria is its autocatalytic behavior. The ability of these nanoparticles to reversibly switch from Ce+3 to Ce+4 is a key factor for their catalytic and biological applications as antioxidants. Our results show that the dextran coating does not affect the autocatalytic properties of nanoceria, as hydrogen peroxide and peroxyl radicals can diffuse through the hydrophilic dextran coating and oxidize Ce+3 to Ce+4. Most importantly, we made the surprising discovery that the antioxidant activity of dextran nanoceria is significantly reduced at acidic pH. This could have important applications in the design of improved therapeutics in the radioprotection of healthy tissue during radiation therapy of acidic tumors.