Yb, Er Codoped Cerium Oxide Upconversion Nanoparticles Enhanced the Enzymelike Catalytic Activity and Antioxidative Activity for Parkinson's Disease Treatment.

Oxidative stress plays an important role in Parkinson's disease (PD) and is considered a therapeutic target for PD. However, most therapeutic antioxidants show limitations due to their low reactive oxygen species (ROS) catalytic properties and low crossing of blood-brain barrier. Herein, the antioxidative activity of Yb and Er double-doped CeO (Yb/Er/CeO) upconversion nanoparticles (UCNPs) is obtained for PD treatment. Doping of Yb and Er ions increases oxygen vacancies, which leads to higher enzymelike catalytic activities compared to CeO nanoparticles alone. Tyrosine hydroxylase protein and glial fibrillary acidic protein expression in substantia nigra and striatum as well as the open-field activity test indicates that Yb/Er/CeO is effective for treatment of PD. The activities of glutathione peroxidase and total antioxidant capacity increase and the production of ROS decreases with Yb/Er/CeO UCNP treatment compared with MPTP-induced injury. This indicates that the mechanism of PD treatment is to catalyze ROS products. There have been no reports to date on the usage of Yb/Er/CeO as an antioxidant for PD treatment. Yb/Er/CeO UCNPs cross the blood-brain barrier and exhibit biocompatibility and antioxidant catalytic properties, which decrease the ROS and effectively help in treating PD.