Tsai Yi-Yang, Oca-Cossio Jose, Lin Sheng-Min, Woan Karran, Yu Pei-Ching, Sigmund Wolfgang
Department of Materials Science & Engineering, University of Florida, Gainesville, FL 32611, USA.
Nanomedicine (Lond). 2008 Oct;3(5):637-45. doi: 10.2217/17435889.3.5.637.
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.
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.
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.
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.
验证溶质的化合价和离子半径不同所形成的固溶体会增加氧化铈（CeO₂）纳米颗粒中的缺陷，进而在室温下产生更优异的活性氧（ROS）清除剂这一假设。
采用反相微乳液法合成了Zr在CeO₂中的固溶体，即Ce(x)Zr(1 - x)O₂纳米颗粒。对其晶体结构、粒径和团聚程度进行了表征。在生理水平和室温下，使用基于酶过氧化物酶的检测方法，测试了纳米颗粒清除过氧化氢中ROS的活性。
Zr在CeO₂纳米颗粒中的固溶体使ROS清除能力提高了四倍。证实了该假设，即形成了更多缺陷，且Ce(x)Zr(1 - x)O₂的清除活性与纳米颗粒的储氧能力相关。
通过将锆溶解在CeO₂晶格中可提高CeO₂纳米颗粒的抗氧化功效。Ce(x)Zr(1 - x)O₂纳米颗粒在室温下作为增强型催化剂清除ROS。功效的提高将使纳米颗粒剂量降低就能保护细胞免受ROS侵害，从而增加这些化合物的治疗宽度。
