Light mediated, switchable, antibacterial activity of cerium dioxide nanoparticles on gram positive and gram negative bacteria

This work emphasizes the development of cerium dioxide nanoparticles (CeO2 NPs) having switchable antibacterial property. The study gives new insights on the effects of light irradiation on the antibacterial activity of CeO2. In the present study, the CeO2 NPs are synthesized by controlled sol - gel methods. The morphological and optical properties of the nanoparticles are investigated using Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), X-ray diffractometer (XRD) and UV-Vis spectrophotometer (UV-Vis). The TEM analyzes reveals the size of the synthesized CeO2 NPs as 20±5 nm. The XRD patterns confirm the presence of cubic fluorite structure of CeO2 NPs. The antibacterial activity of CeO2 NPs is examined against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). The study discloses that the CeO2 NPs exhibit inhibitory effects against S. aureus bacteria in the presence of light, at low nanoparticle concentration (1.5g/L). But it in the absence of light irradiation, no bacterial inhibitory effects are observed. The study foresees the usage of CeO2 nanoparticles as a switchable nontoxic antibacterial agent which can be used for variety of biological applications.