Influence of Synthesis Conditions on the Physical Characteristics and Antibacterial Activities of Cerium Oxide Nanoparticles in Biomedical Applications
Abstract
The present work aims to describe the influence of synthesis conditions of cerium oxide nanoparticles (CeO2 NPs) by a hydrothermal method on physical properties and antibacterial activities. The structural and optical properties of the CeO2 NPs were investigated using X-ray diffraction (XRD), Raman spectroscopy, and diffuse reflectance spectroscopy. The XRD analysis revealed a cubic crystal structure. The Raman mode at approximately 463 cm-1 was identified as the F2g optical phonon mode for the stretching of the Ce-O vibration. Optical energy band gap of the CeO2 NPs were estimated to be 3.2 to 3.3 eV by UV-Vis diffuse reflectance spectroscopy. The Ce-O stretching behavior was confirmed by Fourier Transform Infrared Spectrometer (FTIR). Field emission scanning electron microscopy (FE-SEM) and energy-dispersive X-ray spectroscopy (EDX) were used to examine the morphological features and elemental analysis of the CeO2 NPs. The antibacterial activity of the CeO2 NPs was examined using the disc diffusion method. The minimum inhibitory concentration (MIC) values obtained were 500 μg/ml and 1000 μg/ml for 12 h and 24 h treated CeO2 NPs respectively, against E. coli, and 500 μg/ml for 24 h treated CeO2 NPs against S. aureus. No antibacterial activity was observed after 48 h of treatment with CeO2 NPs.