title: Reactive oxygen species scavenging properties of ZrO2-CeO2 solid solution nanoparticles.
abstract: OBJECTIVE
  The hypothesis that an increase in defects in cerium oxide (CeO(2)) nanoparticles induced by solid solutions with differences in valency and ionic radius of the solute will yield superior reactive oxygen species (ROS) scavengers at room temperature will be tested.
  
  
  METHODS
  Solid solutions of zirconium in CeO(2), that is, Ce(x)Zr(1-x)O(2) nanoparticles, were synthesized by a reverse micelle method. Their crystal structures, particle sizes and level of agglomeration were characterized. The nanoparticles' activities to scavenge ROS were tested in response to hydrogen peroxide at physiological levels and room temperature using an enzyme peroxidase-based assay.
  
  
  RESULTS
  Solid solutions of Zr in CeO(2) nanoparticles enhanced ROS scavenging fourfold. The hypothesis is confirmed that more defects are formed and that the scavenging activities of Ce(x)Zr(1-x)O(2) correlate to the nanoparticles' oxygen-storage capacity.
  
  
  CONCLUSIONS
  The antioxidant efficacy of CeO(2) nanoparticles can be enhanced by dissolving zirconium in the CeO(2) lattice. The Ce(x)Zr(1-x)O(2) nanoparticles act as an enhanced catalyst at room temperature that scavenges ROS. Increased efficacy will enable lower nanoparticle dosages to protect cells from ROS, thus increasing the therapeutic width of these compounds.
authors.affiliation: Department of Materials Science & Engineering, University of Florida, Gainesville, FL 32611, USA.
authors.forename: Yi-Yang
authors.initials: YY
authors.lastname: Tsai
authors.forename: Jose
authors.initials: J
authors.lastname: Oca-Cossio
authors.forename: Sheng-Min
authors.initials: SM
authors.lastname: Lin
authors.forename: Karran
authors.initials: K
authors.lastname: Woan
authors.forename: Pei-Ching
authors.initials: PC
authors.lastname: Yu
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Sigmund
mesh_terms: D000975:Antioxidants / Q000737:chemistry; D002384:Catalysis; D002563:Cerium / Q000737:chemistry*; D018360:Crystallography, X-Ray / Q000379:methods; D016166:Free Radical Scavengers / Q000737:chemistry / Q000494:pharmacology*; D053768:Metal Nanoparticles / Q000737:chemistry*; D008823:Micelles; D046529:Microscopy, Electron, Transmission; D008956:Models, Chemical; D053758:Nanoparticles / Q000737:chemistry; D010316:Particle Size; D017382:Reactive Oxygen Species / Q000737:chemistry*; D012834:Silver / Q000737:chemistry; D013696:Temperature; D015040:Zirconium / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D016166:Free Radical Scavengers; D008823:Micelles; D017382:Reactive Oxygen Species; D002563:Cerium; D012834:Silver; C030583:ceric oxide; D015040:Zirconium; C028541:zirconium oxide