A Study of the Chemistries, Growth Mechanisms, and Antibacterial Properties of Cerium- and Yttrium-Containing Nanoparticles

Abstract

Under the current climate, physicians prescribe antibiotics for treating bacterial infections, and such a limitation to a single class of drugs is disadvantageous since antibiotic-resistant bacteria have adapted to withstanding their stresses. Antibiotic alternatives are sought, and herein metal nanoparticles comprised of the rare earth elements cerium and yttrium were determined to invoke toxicity on methicillin-resistant Staphylococcus aureus (MRSA) and a multi-drug-resistant strain of Escherichia coli (MDR E. coli). Ceria nanoparticles, yttrium-doped ceria nanoparticles, and cerium-doped yttria nanoparticles were fabricated by a wet chemical route, homogeneous precipitation in hexamethylenetetramine (HMT). To demonstrate the drastic variations in nanoparticle structure and toxicity that occur when the synthesis method and solvent are substituted, two additional approaches involving solvothermal and hydrothermal reactions were pursued in the production of yttrium-containing nanoparticles. Intrinsic nanoparticle features of size, morphology, and composition were construed by physiochemical characterizations, which aided in the elaboration of chemical reaction and growth mechanisms. It was determined by in vitro plate count assays that ceria nanoparticles which had been doped using the yttrium metal precursor after 30 min of the HMT reaction, at 500 μg/mL, were the most effective at inhibiting MRSA growth without imposing significant cytotoxicity on human dermal fibroblast cells. A total of 500 μg/mL of cerium- and yttrium-containing nanoparticles, prepared in a 1:1 molar ratio, were similarly biocompatible and antimicrobial, in the case of MDR E. coli. Indeed, as this study showed, nanoalternatives to antibiotics are feasible, adaptable, and can be facilely produced. The possible clinical applications of the rare earth metal nanoparticles are variegated, and ceria and yttria nanoparticles are additionally credited in the literature as dynamic antioxidants, regulators of tissue regeneration, and anticancer agents.

Systematic review of the osteogenic effect of rare earth nanomaterials and the underlying mechanisms

“…Wakabayashi [ 94 ] demonstrated that RE ions exhibit antibacterial activity against Staphylococcus aureus and Escherichia coli ( E. coli ) . It has been reported that Ce- [ 95 ], La- [ 96 , 97 ], Y- [ 98 ], Tb- [ 99 ], Dy- [ 100 ], Nd- [ 101 , 102 ], Yb- [ 103 ], Sm- [ 104 ] and Ho-based [ 105 ] nanomaterials possess extensive antibacterial properties and high biocompatibility, making them promising candidates for bone regeneration [ 106 ].…”

Surfactant-Free Synthesis of Melon Seed–Like CeO2 and Ho@CeO2 Nanostructures with Enriched Oxygen Vacancies: Characterization and Their Enhanced Antibacterial Properties

“…It has been reported that the mixed valence states in ceria structures or the reversible conversion of Ce 3+ and Ce 4+ states has strongly been linked to the antioxidant properties of ceriumbased systems. 74 For the claimed antimicrobial activity of Ho@ MS-CeO 2 nanostructures, continuous reversible switching occurred on the ceria surface, which is a distinct property of CeO 2 lattices. 74 Figure 15A shows the XPS spectrum of Ho@ MS-CeO 2 after the antibacterial test, which clearly shows the conversion of ions (Ce 4+ reduced into Ce 3+ ).…”

“…74 For the claimed antimicrobial activity of Ho@ MS-CeO 2 nanostructures, continuous reversible switching occurred on the ceria surface, which is a distinct property of CeO 2 lattices. 74 Figure 15A shows the XPS spectrum of Ho@ MS-CeO 2 after the antibacterial test, which clearly shows the conversion of ions (Ce 4+ reduced into Ce 3+ ). Figure 15B shows that the oxygen peak intensities of Ho@MS-CeO 2 have a higher peak intensity (O L ), which evidently specified the presence of more oxygen vacancies.…”

In vitro antioxidant and antibacterial potential of biosynthesized yttrium oxide nanoparticles using floral extract of Illicium verum

“…Since Y 2 O 3 nanoparticles bind to the cell membrane by strong electrostatic forces, they are able to effectively suppress the growth of both Gram-positive and Gram-negative bacteria at a concentration of 100 µg/mL. According to the previous reports on the mechanism of antibacterial action of Y 2 O 3 nanoparticles, yttrium ions may penetrate the cell wall of bacteria and inhibit the growth through down-regulation of enzyme activity, which leads to bacterial cell death [5,31,32]. In contrast to antibiotics, Y 2 O 3 nanoparticles that were synthesized from the leaf extract of Lantana camara (LC) exhibited an excellent inhibitory zone.…”