Rare Earth Nanoparticles Prevent Retinal Degeneration Induced by Intracellular Peroxides
Lajos P. Balogh in Nano-Enabled Medical Applications, 2020
Cerium is a rare earth element of the lanthanide series and cerium oxide (CeO2) is an inorganic compound that is insoluble in water, which has routinely been used in polishing glass and jewellery, and in catalytic converters for automobile exhaust systems and other commercial applications. Although most of the rare earth elements exist in the trivalent state, cerium also occurs in a 4 state and may flip-flop between the two in a redox reaction [6–8]. + Cerium oxides are excellent oxygen buffers because of their redox capacity [9]. As a result of alterations in the cerium oxidation state, CeO2 forms oxygen vacancies or defects in the lattice structure by loss of oxygen and/or its electrons. The valence and defect structure of CeO2 is dynamic and may change spontaneously or in response to physical parameters such as temperature, the presence of other ions, and oxygen partial pressure [7, 8, 10]. Earlier studies have shown that, with a decrease in particle size, nanoceria particles demonstrate the formation of more oxygen vacancies [11, 12]. The increased surface-area-to-volume ratio that exists in a nanoparticle of ∼5 nm diameter enables CeO2 to regenerate its activity and thereby act catalytically.
Novel UV Filtering Agents for Next-Generation Cosmetics: From Phytochemicals to Inorganic Nanomaterials
Madhu Gupta, Durgesh Nandini Chauhan, Vikas Sharma, Nagendra Singh Chauhan in Novel Drug Delivery Systems for Phytoconstituents, 2020
Cerium oxide is the oxide of cerium (MW-57) and element of lanthanide series, which was known for its anti-abrasive properties and used for glass cleaning agent, anti-abrasive in reactors, as a catalyst in fuel cell power generation and catalytic converters, and in fuel-borne additives. Studies demonstrating the biological application have recently begun to unravel in the present decade, leading to the exponential increase in the studies pertaining to use of nanoceria in various biological conditions and perturbations caused by environmental stress. The mechanism of radical scavenging and biological effects caused thereby are an outcome of switching between Ce3+ and Ce4+ oxidation, making nanoceria superlative to existing antioxidants. Oxygen defects in crystal lattice enables nanoceria to scavenge superoxide, hydrogen peroxide, hydroxyl, and nitric oxide radicals. Besides this, nanoceria mimics the activities of cellular antioxidant enzymes, superoxide dismutase (SOD) (Heckert et al., 2008), catalase (Pirmohamed et al., 2010), oxidase (Asati et al., 2010), catalytic amplifier for alkaline phosphatase activities (Hayat et al., 2014), and peroxynitrite scavenging activities (Dowding et al., 2012). Surface reactions underlying SOD and catalase mimetic activities have been illustrated in Figure 7.4.
Cerium oxide nanoparticles protects against acrylamide induced toxicity in HepG2 cells through modulation of oxidative stress
Published in Drug and Chemical Toxicology, 2019
Aala Azari, Mohammad Shokrzadeh, Ehsan Zamani, Nahid Amani, Fatemeh Shaki
Cerium oxide (CeO2) is a rare earth metal oxide which belongs to the lanthanide series of the periodic table. CeO2 nanoparticles (nano-ceria) have the potential to be developed as a therapeutic for oxidative stress insults. They have a strong and recyclable ROS scavengers properties via shuttling between Ce3+ and Ce4+ oxidation states (Kwon et al.2016). Furthermore, it was shown that nano-ceria have mimic activity of some antioxidant enzymes such as superoxide dismutase (Korsvik et al.2007) and catalase (Pirmohamed et al. 2010). Current research efforts have produced findings that strengthen the role of nano-ceria as an efficient antioxidant in in vitro studies. Ghaznavi et al. (2015) illustrated that CeO2 nanoparticle reduces ROS production in glucose treated cells. Previous study showed that nano-ceria treatment significantly inhibits hydrogen peroxide-induced oxidative damage and cytotoxicity in the adult spinal cord model system (Das et al. 2007). It has also been reported that the use of nano-ceria for therapeutic purposes provides multiple advantages over other novel antioxidant approaches (Estevez and Erlichman 2014).
Human macrophage responses to metal-oxide nanoparticles: a review
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2018
Camila Figueiredo Borgognoni, Joo Hyoung Kim, Valtencir Zucolotto, Harald Fuchs, Kristina Riehemann
ROS scavengers are useful to reduce the damage of oxidative stress. The body has an antioxidant defence system composed of enzymes (e.g. superoxide dismutase) and substances like glutathione and some vitamins. However, facing the abundance of ROS, several substances such as Trolox, PEG, BHA and NAPDH oxidase have been used in studies presenting efficient ROS scavenging abilities [59,73,78–80]. Interestingly, some metal oxide nanoparticles present this property, as is the case of cerium oxide nanoparticles. Cerium oxide exhibit catalytic properties since they present a reversibility of the oxidation states Ce+3 and Ce+4 that leads to oxygen vacancies [81]. Lord et al. [82] investigated the antioxidant properties of cerium oxide nanoparticles in U-937 derived macrophages (PMA-differentiated) exposing the cells for up to 72 h to the nanoparticle. The authors demonstrated the uptake of the nanoparticles by the cells leading to a continuous intracellular ROS scavenger action.
The fate of cerium oxide nanoparticles in sediments and their routes of uptake in a freshwater worm
Published in Nanotoxicology, 2019
Richard K. Cross, Charles R. Tyler, Tamara S. Galloway
Cerium oxide nanoparticles (CeO2 NPs) have been widely used in ceramics and glass polishing. In vitro, cerium is able to generate radical oxygen species through a Fenton like reaction, redox cycling between the 3+ and 4+ states (Heckert, Seal, and Self 2008). Sublethal oxidative damage in the tissues of the marine sediment dwelling amphipod Corophium volutator exposed to CeO2 NPs has been attributed to this redox cycling between CeIII and CeIV at the nanoparticles surface in vivo (Dogra et al. 2016). Predicted environmental concentrations of these particles in surface waters are in the low µgL−1 range (O’Brien and Cummins 2011), but CeO2 has been demonstrated through both empirical and modeling studies to undergo rapid sedimentation in natural river waters (Quik, van De Meent, and Koelmans 2014). This has been ascribed to heteroaggregation with natural colloids (Quik et al. 2012), and makes them a nanomaterial of potential concern in freshwater sediment systems. Being largely insoluble under most environmental conditions (Dahle, Livi, and Arai 2015) we utilized CeO2 as a model nanomaterial for understanding nanoparticle fate and behavior in the absence of dissolution products during exposures.
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