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Rare Earth Nanoparticles Prevent Retinal Degeneration Induced by Intracellular Peroxides
Published in Lajos P. Balogh, Nano-Enabled Medical Applications, 2020
Junping Chen, Swanand Patil, Sudipta Seal, James F. McGinnis
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
Published in Madhu Gupta, Durgesh Nandini Chauhan, Vikas Sharma, Nagendra Singh Chauhan, 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 thin films: synthesis, characterization, photocatalytic activity and influence on microbial growth
Published in Biofouling, 2022
Luminita Andronic, Damir Mamedov, Cristina Cazan, Marcela Popa, Mariana Carmen Chifiriuc, Atabek Allaniyazov, Simona Palencsar, Smagul Zh. Karazhanov
There is a need to fully understand the ecotoxicological impact of cerium oxide thin films on the aquatic environment. Conflicting reports are published (Pelletier et al. 2010; Kuang et al. 2011; Leung et al. 2015) about CeO2 nanoparticle toxicity. Several groups report toxicity toward bacteria (Pelletier et al. 2010; Kuang et al. 2011), algae (Rodea-Palomares et al. 2011), plants (Cassee et al. 2011), soil nematodes (Roh et al. 2010), and epithelial and cancer cells in human lungs (Lin et al. 2006). It is also proposed (Asati et al. 2010) the possibility of controlling of toxicity of CeO2 by modulating the surface charge with a polymer coating. Due to their high chemical activity and stability, CeO2 was an excellent catalyst for the photodegradation of ciprofloxacin, widely used fluoroquinolone antibiotics (Liu et al. 2016; Oropesa et al. 2018). However, it should be noted that the above studies related to toxicity and antimicrobial properties of CeO2 have been done for nanoparticles only. No such study related to thin films CeO2 would be important in the photovoltaic and window applications.
Nanoceria distribution and effects are mouse-strain dependent
Published in Nanotoxicology, 2020
Robert A. Yokel, Michael T. Tseng, D. Allan Butterfield, Matthew L. Hancock, Eric A. Grulke, Jason M. Unrine, Arnold J. Stromberg, Alan K. Dozier, Uschi M. Graham
Nanoceria (nanoscale cerium oxide, cerium dioxide, ceria, CeO2) is a family of metal oxide-engineered nanomaterials extensively used industrially and shown to have beneficial pharmaceutical properties. Nanoceria are auto-catalytically redox active, cycling between Ce+++ and Ce++++ (Deshpande et al. 2005). The surface has oxygen vacancies in its cubic fluorite structure that allow it to easily accept and donate oxygen, providing its catalytic properties. Nanoceria are used as catalysts in diesel fuel, abrasives in chemical mechanical planarization in integrated circuit manufacture, as structural supports for catalysts for fuel synthesis applications, in solid oxide fuel cells, and in rechargeable batteries (Feng et al. 2006; Younis, Chu, and Li 2016). Cerium oxide was selected by the Organization for Economic Co-operation and Development (OECD) Working Party on Manufactured Nanomaterials as one of the 13 representative manufactured nanomaterials for safety testing (OECD 2010).
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).