Synthesis of Ceric Oxide Nanoparticles and DOX-Loaded ZIF-8@CeO2

Ceric oxide nanoparticles (CeO₂ NPs) were synthesized following established protocols with slight modifications^{24 (link)}. Specifically, 430 mg of cerium (III) acetate hydrate and 3.2 g of oleylamine were dissolved in 15 mL of xylenes and vigorously stirred for 24 h. The mixture was then gradually heated to 90 °C, and 1 mL of deionized (DI) water was swiftly injected. The solution was maintained at 90 °C for 3 h. Ethanol was employed to precipitate the CeO₂ NPs, which were subsequently collected through centrifugation.
The synthesis of DOX@ZIF-8@ CeO₂ (ZC-DOX) followed a previously reported procedure with some adaptations^{25 (link)}. Specifically, 500 mg of 2-methylimidazole and 5 mg of doxorubicin were combined in 4 mL of methanol and stirred for 10 min at room temperature. Subsequently, 1 mL of a water solution containing 2.5 mg of Zn(NO₃)₂·6H₂O was introduced to the mixture. The reaction was vigorously stirred for 15 min, resulting in an emulsion-like suspension. The nano-cerium oxide particles and polyvinylpyrrolidone were dispersed in methanol and added to the emulsion-like suspension, followed by stirring for an additional 5 min at room temperature. The final product was obtained through centrifugation, and impurities were removed by washing with methanol. ZIF-8@CeO₂ (ZC) was synthesized using the same protocol.