Interrelationships between the structural, spectroscopic, and antibacterial properties of nanoscale (< 50 nm) cerium oxides

Abstract

Bone healing is a complex process, and if not managed successfully, it can lead to non-union, metal-work failure, bacterial infections, physical and psychological patient impairment. Due to the growing urgency to minimise antibiotic dependency, alternative treatment strategies, including the use of nanoparticles, have attracted significant attention. In the present study, cerium oxide nanoparticles (Ce4+, Ce3+) have been selected due to their unique antibacterial redox capability. We found the processing routes affected the agglomeration tendency, particle size distribution, antibacterial potential, and ratio of Ce3+:Ce4+ valence states of the cerium oxide nanoparticles. The antibacterial efficacy of the nanoparticles in the concentration range of 50–200 µg/ml is demonstrated against Escherichia coli, Staphylococcus epidermis, and Pseudomonas aeruginosa by determining the half-maximal inhibitory concentration (IC50). Cerium oxide nanoparticles containing a more significant amount of Ce3+ ions, i.e., FRNP, exhibited 8.5 ± 1.2%, 10.5 ± 4.4%, and 13.8 ± 5.8% increased antibacterial efficacy compared with nanoparticles consisting mainly of Ce4+ ions, i.e., nanoparticles calcined at 815 °C.

Development and Characterization of Electrospun Composites Built on Polycaprolactone and Cerium-Containing Phases

“…These findings can be explained based on Ce incorporation within the developed materials, either as a CeO 2 crystalline phase or as a Ce 4+ dopant ion, occupying the sites of Ca in the crystal lattice of calcium phosphates. Most likely, the switch between Ce 4+ and Ce 3+ , the transition that is the essential part of the antibacterial mechanism and reactive oxygen species generation, happens more easily when Ce is individually localized, not as long-range ordered domains [ 56 ].…”

Acid-Base and Photocatalytic Properties of the CeO2-Ag Nanocomposites

“…Schematically, the process of formation of the CeO 2 -Ag nanocomposite is shown in Figure 7 . Since the composite was obtained by calcining cerium hydroxide with silver nanoparticles at a sufficiently high temperature—650 °C, silver can exist in the composite in an oxidized form, as well as in the form of substitutional defects Ag Ce [ 25 ].…”

Antimicrobial Properties of Metal Nanoparticles and Their Oxide Materials and Their Applications in Oral Biology

“…The redox dual nature of CeO 2 -NPs is closely related to the reversible combination of oxygen atoms and the existence of oxygen vacancies, and the valence Journal of Nanomaterials states of Ce 4+ and Ce 3+ are continuously cyclically switched. This property protects cells from oxidative stress, inflammation, and potential radiation damage [85]. Many studies have shown that CeO 2 -NPs exhibit good antibacterial activity against gram-positive and gram-negative bacteria due to the generation of reactive oxygen species (ROS) [86].…”