Persistent, Broad-Spectrum Antimicrobial Activity by Multi-Metal Surface Phase Modified Ceria Nanozymes

Abstract

With the growing threat of emergent microbes, such as novel viruses and drug-resistant bacteria, more robust and broad-spectrum antimicrobial technologies are of critical importance. Nanomaterials have the potential to deliver a broad-spectrum antimicrobial effect while maintaining resistance to degradation in various application environments. In the presented study, a multi-metal oxide nanoparticle formulation with substantial antimicrobial activity was developed: outperforming a previous bimetallic composition. The formulation was produced through a variation of an established method wherein the multi-metal oxide is formed through precursor ageing in a peroxide solution environment (room temperature, 8 week ageing period). Silver/zinc-modified cerium oxide nanoparticles exhibited substantial antiviral (0.05 mg/mL reduced virus titer to beyond detectable ranges for RV14 rhinovirus, ~3-log reduction for vesicular stomatitis virus on treatment with 0.15 mg/mL in TCID50) and antibacterial (MIC values of ~4, 6, and 6 μg/mL, respectively, for P. aeruginosa; S. aureus, and methicillin-resistant S. aureus (MRSA)) activities. Of further interest, this nano-formulation evidenced persistent antibacterial activity towards bacterial (P. aeruginosa, S. aureus) and viral (RV14 rhinovirus; Vesicular stomatitis virus,VSV) lab strains resistant to previously developed silver-modified cerium oxide nanoparticles. Nanomaterial character and potential antimicrobial mechanisms were also investigated, with enzyme-mimetic nanozyme generation of reactive oxygen species suggested by density functional theory calculations.