Nanoceria and Hybrid Silver–ceria Nanoparticles Fabricated by Liquid-Mediated Laser Ablation As Antimicrobial Agents

In this study, cerium oxide and hybrid silver–ceria nanoparticles (NPs) have been fabricated, characterized and tested for antimicrobial efficacy for applications in the fields of biotechnology and environmental object disinfection/protection. For the preparation of CeO2 and the hybrid silver–ceria NPs, two approaches based on an eco-friendly laser ablation in solution method have been developed. Ceria NPs were synthesized by pulsed laser ablation of a ceria pressed tablet in distilled water. The size distribution of the formed NPs was bimodal, with average diameters of 2.5 and 7.6 nm. The cubic crystalline structure of the NPs (space group Fm-3 m) was confirmed by X-ray diffraction data, as well as Raman and optical absorption spectroscopy. The sequential laser ablation of silver and ceria targets in water allows for the preparation of hybrid CeO2–Ag NPs having a core–shell, decorated and Janus-like structure. Laser ablation of Ag in a CeO2 colloidal solution offers new opportunities to tune the structure and morphology, and to enhance the antimicrobial properties of the resulting NPs. The interaction of ceria and silver in a composite resulted in an improved antimicrobial activity, as tested towards Escherichia coli, Staphylococcus aureus bacteria and Candida albicans fungi, demonstrating the great potential of the hybrid silver–ceria NPs in biocatalytic and antimicrobial applications.