Surface chemistry of cerium oxide nanocubes: Toxicity against pathogenic bacteria and their mechanistic study

The present study investigated the bacterial toxicity of cerium oxide (CeO2) nanocubes. The X-ray diffraction and Raman spectral studies revealed the formation of nanoceria with cubic fluorite structure. The minimum inhibitory concentration (MIC) of CeO2 nanocubes against pathogenic bacteria was evaluated by a microdilution method. MICs such as 16 μg/mL (against Escherichia coli) and 8 μg/mL (against Salmonella typhimurium and Enterococcus faecalis), and 4 μg/mL (against Bacillus subtilis) suggest that CeO2 nanocubes have predominant anti-bacterial activity. The evaluation of bacterial enzymatic (β-d-galactosidase) activity in the hydrolysis of o-nitrophenol-β-d-galactopyranoside suggested the disruption of bacterial cell wall mechanism, responsible for bacterial toxicity.