Nanoceria-Based Artificial Nanozymes: Review of Materials and Applications

Abstract

Nanozymes are nanomaterial-based enzyme mimics that have dominated recent research because of their remarkable catalytic activity, stability, and low cost. Among them, CeO2 nanomaterials (CeO2 NMs) possess distinct physicochemical properties and inherent catalytic properties mimicking oxidase (OXD), peroxidase (POD), catalase (CAT), superoxide dismutase (SOD), phosphatase, nuclease, and photolyases. The surface valence state, Ce4+/Ce3+ conversion, and oxygen vacancies (OVs) on the surface of CeO2 NMs are closely associated with enzyme-like activities. Surface modification (ions, small molecules, and macromolecular capping) can strongly promote or inhibit their catalytic activities. CeO2 NMs have emerged as attractive materials for biochemical applications including biocatalytic conversion, pollutant destruction, antimicrobial therapies, biosensors, and disease therapies. We summarize here the development history, catalytic mechanisms, and surface modification methods of CeO2 mimetic enzymes and the exploration of their applications as alternatives to natural enzymes in biochemical fields. Further, we outline potential challenges and prospects and hope to provide better guidance for the design and application of these promising artificial enzymes.

Targeted treatment of gouty arthritis by biomineralized metallic nanozyme-mediated oxidative stress-mitigating nanotherapy

“…36,37 It has been reported that CNZs can mitigate ROS production in the inflammatory macrophages and supply enough oxygen to reverse the hypoxic conditions during inflammation. By scavenging the ROS and reducing angiogenesis, the CNZs tend to repolarize the M1 macrophages to M2 type, thereby downregulating the signals from inflammatory cytokines (TNFa, IL6, and IFN gamma) and expression of inflammatory proteins like iNOS, IL-1b, COX2, and others 38 . Thus, CNZs are efficient as therapeutic candidates for treating gouty arthritis.…”

Reversible CeO2–x and CeO2–x:Eu3+ Luminescent Hydrogen Peroxide Sensors with Recovery Rates Controlled by Temperature and UV Irradiation

“…Cerium oxide nanoparticles (nanoceria) are well known for their enzyme-mimicking antioxidant activity. , The catalase- and peroxidase-like activities of ceria NPs enable them to decompose HP effectively to water and oxygen, or use HP as a substrate for further chemical reactions . These activities can be monitored either by using various fluorescent ROS sensors or (preferably) by measuring the change in luminescent properties of nanoceria itself.…”

“…13,14 The catalaseand peroxidase-like activities of ceria NPs enable them to decompose HP effectively to water and oxygen, or use HP as a substrate for further chemical reactions. 15 These activities can be monitored either by using various fluorescent ROS sensors or (preferably) by measuring the change in luminescent properties of nanoceria itself. In our previous papers, 16,17 we have revealed that Ce 3+ ions form a separate luminescent band in nanoceria, whose intensity decreases upon HP addition due to the partial transition of Ce 3+ ions to Ce 4+ ones.…”

Photoelectrochemical immunoassay of alpha-fetoprotein based on a SnO2/In2S3 heterojunction and an enzyme-catalyzed precipitation strategy

“…CeO 2 has received extensive attention in the fields of photocatalysis and biosensor due to its favorable electrical, optical and peroxidase-like properties. 23 Here, CeO 2 of a uniform nanocube structure is employed as a secondary antibody (Ab 2 ) label, because it can act as both an excellent carrier for loading biomolecules and a peroxidase-like nanozyme to catalyze precipitation together with the natural enzyme HRP. As far as we know, Ab 2 labeling with a CeO 2 nanozyme and HRP natural enzyme to catalyze the production of an insoluble precipitate on the photoelectrode surface for signaling in a PEC AFP immunoassay has not been reported to date.…”