In Vitro Antibacterial Activity Evaluation and Mechanism of Morphology-Controlled Synthesis of Cerium Dioxide Nanoparticles

Cerium dioxide (CeO2) nanoparticles with distinct morphologies, including rods, cubes, and octahedrons, were synthesized via a straightforward hydrothermal method. The microstructure and morphology of the as-prepared samples were systematically characterized. The antibacterial activity of the samples against Escherichia coli was evaluated using the plate counting method. The antibacterial experiments revealed that the antibacterial properties of the samples were arranged in the following order: rod > cube > octahedron. Data analysis indicated that the superior antibacterial performance of the CeO2 nanorod was attributed to the higher concentration of oxygen vacancies and adsorption of reactive oxygen species (ROS) on the surface, with ROS playing a critical role in the antibacterial mechanism of CeO2. Additionally, density functional theory (DFT) calculations were employed to simulate the oxygen vacancy environments of CeO2 with different morphologies and provided indirect insights into ROS behavior. Combining experimental and computational results, a mechanistic framework was proposed to elucidate the dependence relationship between morphology and antibacterial activity of CeO2.