The Animal Safety Of Nano Carbon Dioxide Cerium

With the widespread application of cerium oxide nanoparticles （nano-ceria）, the risks ofpublic exposure to nano-ceria are increasing. It demands urgent assessment on theenvironmental and biological safety of nano-ceria. Especially, in recent years, more studiesprove nano CeO₂has potential application value in medical and medical treatment. Thegrowing use and mass production of nano CeO₂have stimulated research on their potentialimpact on human health and environment. Nano CeO₂exits not only in the air and waterenvironment and other conventional environment, when used in medical treatment, will enterinto body through the medical approach. In the present work, we evaluated the animal safetyof7nm CeO₂and25nm CeO₂. In order to accurate determine the nano CeO₂content of tissuesand organs after different exposures, radioactive tracer method was adopted. In the presentwork, we study the dispersity of nano CeO₂in different solution. Our results suggest that nanoCeO₂dispersed well when the solution contains albumin or blood serum. In order to evaluatethe influence of ions, the cerium levitation liquid was vibrate wave for72h. The resultsshowed that only little ion exists, and will not affect the result. In the present work, weadopted three ways to study the animal safety of nano CeO₂. The results showed that, afterintraperitoneal injection, about30%of the injected nano CeO₂stuck in organs, only less than1%of the injected nano CeO₂can be eliminated from the body. We researched thetranslocation of nano-ceria to olfactory bulb after the particles were instilled to the left nostrilof mice. The results revealed a time-dependent increase of nano-ceria in the left olfactory bulbof mice and the increase was predominantly caused by the translocation of nano-ceria fromthe olfactory mucosa along the olfactory nerve. The result suggests that more efforts areneeded to investigate the long-term neural responses to inhaled nano-ceria. The study oftransplacental transport of Ceria nanoparticles demonstrated an inversely size-dependenttransplacental transport of NPs in vivo:6.6nm ceria NPs was detected in fetuses, while thetransport of25nm ceria was almost or totally blocked by the placental barrier. These resultsalso suggested that transcytosis or endocytosis of NPs contributed little to the transplacentaltransport of25nm ceria NPs. Quantitative data from the present work will promote ourunderstanding of transplacental transport of NPs.