Morphology- and pH-dependent peroxidase mimetic activity of nanoceria

Abstract

The peroxidase mimetic properties of nanoceria have attracted extensive attention in recent years.

Inorganic nanohybrids combat antibiotic-resistant bacteria hiding within human macrophages

“…55,56 Since the initial oxidation state is regenerated and due to their physical stability, ceria nanoparticles may stay active for prolonged times and can, therefore, express a more sustained effect. 57 Supporting these findings, a strong dependence of the antimicrobial activity on environmental variables 56,58 and nanoceria material properties (such as morphology 59,60 or the initial oxidation state 37,38,48,61 ) has been reported. Generally, catalytically active nanoceria tends to also be antimicrobial, 48,61 which holds true for the nanoparticles discussed in this work (H 2 O 2 decomposition and enzyme mimetic activity shown in Fig.…”

Prooxidant potential of CeO2 nanoparticles towards hydrogen peroxide

“…The nature of the peroxidase-like activity of nanocrystalline cerium dioxide is mainly explained by formation of HO radicals under acidic conditions, while peroxide-like intermediates play an important role along with HO at neutral and basic pH values. In comparison with CeO 2 nanocubes, nanorods demonstrated higher peroxidase activity, due to the higher Ce 3+ concentration and the concentration of oxygen vacancies [40].…”

“…According to the literature, the redox activity of nanodispersed cerium dioxide is influenced by the size and the shape of the particles, pH of the reaction medium, the presence of surface ligands, etc. Thus, in a recent study, a strong structure-sensitive peroxidase-mimetic activity of CeO 2 nanoparticles (nanocubes and nanorods) was revealed [40]. Two types of oxidants were identified in CeO 2 /H 2 O 2 systems: HO• and peroxidase-like intermediates, the formation of which strongly depends on pH and morphology of CeO 2 nanocrystals.…”

“…The formation of highly reactive hydroxyl radicals in the presence of CeO 2 nanoparticles was confirmed and studied by various methods [36][37][38]. Some researchers associate the catalytic activity of CeO 2 nanoparticles with the formation of peroxide-like intermediates [39,40]. Despite various assumptions regarding the mechanism of ceria enzyme-like activity, most researchers agree that the pro-and antioxidant properties of nanodispersed CeO 2 are closely related to each other and are determined by several factors.…”

Different adsorption-degradation behavior of methylene blue and Congo red in nanoceria/H2O2 system under alkaline conditions

“…2c ), and MB is positively charged. Under these conditions, MB adsorption on the nanoceria surface mainly takes place through electrostatic attraction, and the higher adsorption capacity of nanocubes may be owing to the higher negative charge 38 . Similar adsorption behavior has also been observed for cationic dye rhodamine B (RhB) and Orange II, which were adsorbed by CeO 2 through strong electrostatic attraction 13 , 39 .…”