Ceria-zirconia Nanoparticles Research Articles

PEG-Capped Ceria–Zirconia Nanoparticles Improved Renal Fibrosis In Cellular and Animal Models of Fabry Disease

PEG-Capped Ceria–Zirconia Nanoparticles Improved Renal Fibrosis In Cellular and Animal Models of Fabry Disease

Polydopamine functionalised ceria-zirconia nanoparticles embedded water-borne epoxy nanocomposite for anti-biofouling coatings

Biofouling, the accumulation of microorganisms, plants, algae on wet surfaces is one of the major issues adversely affecting the overall hydrodynamic performance of the marine vessels. Ceria (CeO2) nanoparticles (NPs) are effectively used as anti-biofouling agent to prevent the deterioration of steel structures, due to their excellent redox capacity. Various approaches are being investigated to enhance the antifouling activity of ceria NPs. Here, we report the development of novel polydopamine (PDA) functionalised ceria-zirconia nanoparticles filled water-borne epoxy nanocomposite coating to prevent the microbial-induced corrosion of mild steel. Ceria NPs were functionalised with PDA to enhance the dispersibility and improve their ability to resist biofouling in water-borne epoxy resin coatings against microbial species. As the anti-biofouling activity of ceria depends on their oxygen storage capacity, zirconium was incorporated to create a defective crystal structure with more active oxygen storage and release sites. Ceria and ceria-zirconia NPs were synthesised by precipitation method and functionalised with PDA. The functionalisation of ceria-zirconia (CZ) NPs was confirmed by Fourier Transform Infrared (FTIR) spectroscopy, X-ray Diffraction (XRD), Confocal Raman spectroscopy and X-ray Photon spectroscopy (XPS). Thermogravimetric analysis (TGA) shows that incorporation of zirconium increases the amount of oxygen vacancies in the crystal lattice there by enhancing ceria's redox potential. Anti-biofouling and anti-biocorrosion properties of the coatings were explored against different microbial strains. The antibacterial tests show that colony-forming units (CFU) of PDA functionalized ceria-zirconia epoxy (EPCZ) nanocomposites were suppressed by 93 % and 87 % in the case of Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa) bacteria, respectively. Biofilm inhibition studies show that EPCZ nanocomposite coatings have higher biofilm inhibition efficiency against gram-negative bacteria (96.37 %) than gram-positive bacteria (62.67 %) due to the differences in their morphology. The practical applicability of the nanocomposite coatings was studied using cultured seawater consortia, and the results reveal that PCZ nanoparticles provide superior biofilm inhibition. Electrochemical impedance spectroscopy (EIS) reveals that the EPCZ coatings exhibit significant enhancement in charge transfer resistance and coating resistance. The synergistic effect of PDA functionalisation and zirconium incorporation in ceria leads to the exceptional biocorrosion resistance in corrosive bacterial environments.

Synergistic effect of ceria-zirconia nanoparticles and hBN nanosheets incorporation on the corrosion resistance of MoS2 solid lubricant coatings

Molybdenum disulphide is a conventional solid lubricant material due to their layered crystal structure enabling easy shearing resulting in low coefficient of friction. Even though MoS2 is highly lubricating, the corrosive nature of this dry solid lubricant limits its application, especially in oxidizing and humid environment. The present work focuses on the improvement of corrosion resistance properties of MoS2 nanosheets coatings, while maintaining its excellent anti-friction properties by incorporating hexagonal boron nitride (hBN) nanosheets and ceria-zirconia nanoparticles (CZ NPs). A hybrid structure consisting of MoS2, hBN and CZ NPs was prepared as a composite and multilayer coating. The coatings were characterized by FE-SEM, XRD, Raman spectroscopy and XPS. The inclusion of hBN and CZ NPs did not significantly alter the coefficient of friction (CoF) and wear for the composite and multilayer coatings, as determined by the tribological investigations conducted using high frequency reciprocating rig (HFRR). The MH30-CZ composite coatings showed higher CoF compared to MH30-CZ multilayer coatings, with only 7.75 % increase as compared to pure MoS2 coating. The composite structure and multilayer structure showed high long-term corrosion resistance while the latter had the highest resistance to corrosion and oxidation. The hybrid multilayer structure had the lowest corrosion current density and corrosion rate with 167 % enhancement in total impedance. In the hybrid coating, hBN acts as a physical and insulating barrier to the flow of corrosive ions and charge transfer while CZ NPs forms insoluble precipitates which further impedes the corrosion. The galvanic cell formation of MoS2 with steel was suppressed due to the presence of insulating CZ NPs layers. The synergic effect of hBN and CZ NPs resulted in high long-term corrosion resistance of the coating.

Microwave-Assisted Synthesis of Ceria-Zirconia Nanoparticles: Characterization and their Antimicrobial Studies

Ceria-zirconia (CZAA) nanoparticles with varied molar ratio of 1:1, 0.8:0.2, 0.6:0.4, 0.4:0.6 and 0.2:0.8 labelled as CZAA-0, CZAA-1, CZAA-2, CZAA-3 and CZAA-4 were prepared using cerium nitrate, zirconium nitrate and ascorbic acid as promoter. The X-ray diffraction, scanning electron microscopy, ultraviolet-visible, Raman and Fourier transform infrared spectra were used to characterize the prepared nanoparticles. The prepared CZAA nanoparticles were tested for antibacterial activity against Escherichia coli, Klebsiella pneumonia, Staphylococcus aureus and Enterococcus faecalis bacterial strains as well as Aspergillus niger, Penicillium and Candida albicans fungal strains using the well diffusion method. They were shown to be highly antimicrobial agents to all pathogenic strains tested.

Ceria-Zirconia nanoparticles reduce intracellular globotriaosylceramide accumulation and attenuate kidney injury by enhancing the autophagy flux in cellular and animal models of Fabry disease

BackgroundFabry disease (FD) is a lysosome storage disease (LSD) characterized by significantly reduced intracellular autophagy function. This contributes to the progression of intracellular pathologic signaling and can lead to organ injury. Phospholipid–polyethyleneglycol-capped Ceria-Zirconia antioxidant nanoparticles (PEG-CZNPs) have been reported to enhance autophagy flux. We analyzed whether they suppress globotriaosylceramide (Gb3) accumulation by enhancing autophagy flux and thereby attenuate kidney injury in both cellular and animal models of FD.ResultsGb3 was significantly increased in cultured human renal proximal tubular epithelial cells (HK-2) and human podocytes following the siRNA silencing of α galactosidase A (α-GLA). PEG-CZNPs effectively reduced the intracellular accumulation of Gb3 in both cell models of FD and improved both intracellular inflammation and apoptosis in the HK-2 cell model of FD. Moreover these particles attenuated pro fibrotic cytokines in the human podocyte model of FD. This effect was revealed through an improvement of the intracellular autophagy flux function and a reduction in reactive oxygen species (ROS). An FD animal model was generated in which 4-week-old male B6;129-Glatm1Kul/J mice were treated for 8 weeks with 10 mg/kg of PEG-CZNPs (twice weekly via intraperitoneal injection). Gb3 levels were reduced in the kidney tissues of these animals, and their podocyte characteristics and autophagy flux functions were preserved.ConclusionsPEG-CZNPs alleviate FD associated kidney injury by enhancing autophagy function and thus provide a foundation for the development of new drugs to treat of storage disease.Graphical

Advanced characterization of precipitation synthesized ceria and ceria-zirconia hybrid nanoparticles

In this work, the cerium oxide (CeO2) and ceria-zirconia (Ce–Zr, hybrid) nanoparticles were synthesized using distinct chemical formulation routines. The approach chosen was the precipitation method (PM), a bottom-up methodology for the development of the various nano-compounds. Cerium (III) nitrate hexahydrate got utilized as the primary precursor. Isopropanol and zirconium oxychloride were added as reagents to synthesize CeO2 and Ce–Zr (hybrid) nanoparticles, respectively. The high-end characterization technologies were employed to investigate the comprehensive physical and chemical states of the distinct nanoparticles. It includes high-resolution transmission electron microscopy (HR-TEM), scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FT-IR), x-ray diffractogram spectroscopy (XRD), and zeta potential (ZP) analyses. Surfactant modification using polyoxyethylene sorbitan monolaurate (tween 20, C26H50O50) was also performed to evaluate their respective dispersion stabilities, in comparison to the bare forms. The Ce–Zr (hybrid) nanoparticles demonstrated superior characteristics in terms of morphology and stability, in which the hybridization using zirconia is confirmed to have contributed a significant role.

Highly selective microglial uptake of ceria–zirconia nanoparticles for enhanced analgesic treatment of neuropathic pain

Highly selective microglial uptake of ceria–zirconia nanoparticles for enhanced analgesic treatment of neuropathic pain

Tribological characteristic evaluation of coconut oil dispersed with surfactant modified ceria-zirconia hybrid nanoparticles

ABSTRACTThe tribological characteristics of coconut oil added with ceria-zirconia hybrid (Ce-Zr) nanoparticle additives are investigated using a sophisticated pin-on-disk tribometer. A chemical processing technique namely, precipitation method (PM) is used for the synthesis of Ce-Zr nanoparticles. High-end characterization practices using microscopy and spectroscopy analyses were utilized to determine their morphology, composition, and structure. A model was developed through the Response Surface Methodology (RSM) technique, in which the Box Behnken Design (BBD) was chosen to develop the experimental design. The extent of influence held by the various factors, viz. speed, load, temperature, and nanoparticle concentration (wt.%) were evaluated using distinct methods such as analysis of variance (ANOVA), regression analysis and normal probability distribution. The thermo-physical properties such as kinematic viscosity, flash, and fire point of the lubricant were also subject to examination for any possible improvement. The optimum concentration of Ce-Zr nanoparticles for maximum performance of the formulated fluid was determined to be 0.62 wt.%.

Highly selective microglial uptake of ceria-zirconia nanoparticles for enhanced analgesic treatment of neuropathic pain.

Neuropathic pain is a chronic and pathological pain caused by injury or dysfunction in the nervous system. Pro-inflammatory microglial activation with aberrant reactive oxygen species (ROS) generation in the spinal cord plays a critical role in the development of neuropathic pain. However, the efficacy of current therapeutic methods for neuropathic pain is limited because only neurons or neural circuits involved in pain transmission are targeted. Here, an effective strategy to treat pain hypersensitivity using microglia-targeting ceria-zirconia nanoparticles (CZ NPs) is reported. The CZ NPs are coated with microglia-specific antibodies to promote their delivery to microglia, and thus to improve their therapeutic efficacy. The targeted delivery facilitates the elimination of both pro-inflammatory cytokines and ROS in microglia, enabling the rapid and effective inhibition of microglial activation. As a result, greatly ameliorated mechanical allodynia is achieved in a spinal nerve transection (SNT)-induced neuropathic pain mouse model, proving the potent analgesic effect of the microglia-targeting CZ NPs. Given the generality of the approach used in this study, the microglia-targeting CZ NPs are expected to be useful for the treatment of not only neuropathic pain but also other neurological diseases associated with the vicious activation of microglia.

Enhanced release of palladium and platinum from catalytic converter materials exposed to ammonia and chloride bearing solutions.

The environmental levels of platinum group elements (PGEs) are steadily rising, primarily due to exhaust emissions of vehicle catalytic converter (VCC) materials containing solid PGEs. Once these VCC materials reach soil and water, the PGEs may be transported in the form of nanoparticles (dimensions 1-100 nm) or they may be mobilized by forming coordination complexes with ligands in the environment. Chloride (Cl-) and ammonia (NH3) are two ligands of particular concern due to their ubiquity as well as their potential to form the chemotherapy drug cisplatin (Pt(NH3)2Cl2) or other potentially bioactive complexes. This initial study examines the release of Pd and Pt into solutions exposed to VCC materials at pH 8 and 25 °C, using elemental analysis of metal content in post-exposure extracts. The solutions had total ammonia nitrogen concentrations (TAN, [NH4+] + [NH3]) of 0 μM, 5.56 μM, 55.6 μM and 1.13 × 105 μM (0 ppm, 0.1 ppm, 1 ppm, and 2147 ppm). The former three represent background environmental levels had a minimal effect on release. However, when combined with 1.13 × 105 μM Cl- (4000 ppm Cl-), 55.6 μM TAN induced a marked increase in metal release (∼41× for Pd). High TAN solutions induced more Pd and Pt release than equimolar NaCl solutions. Materials characterization revealed that ∼4 nm palladium-containing nanoparticles were present, spatially associated with nanoparticles of γ-Al2O3; ceria-zirconia nanoparticles were also present but did not have any metal associated with them. Platinum-containing nanoparticles were not observed.

Continuous Fabrication of Monodisperse Ceria-Zirconia-Yttria Composite Oxide Nanoparticles Using a Novel High-Shear Agitation Reactor.

Monodisperse ceria–zirconia nanoparticles have attracted much attention as potential high-performance catalysts. Acidic aqueous solutions are generally used for peptizing aggregated precipitates during the fabrication of disperse nanoparticles. However, the peptization process requires multiple hours of aging, which significantly decreases the production efficiency. Hence, various researchers have attempted to eliminate this stage altogether by performing a coprecipitation process under ambient conditions using common salts as the starting materials. In this work, we report a continuous and direct technique for the fabrication of monodisperse composite oxide nanoparticles via coprecipitation inside a novel high-shear agitation reactor without aging. Using this method, monodisperse ceria–zirconia–yttria composite oxide nanoparticles with diameters of 3 nm were successfully synthesized.

P-215 - Ceria-Zirconia nanoparticles as an enhanced multi-antioxidant attenuates apoptosis of human kidney proximal tubular epithelial cells in hypoxia

Aims Ischemia/reperfusion injury, resulting from hypoxic damage within a graft, is the leading cause of cell death and graft rejection. In this study, we investigated whether Ceria-Zirconia nanoparticles (CZ NPs) as an enhanced multi-antioxidant have a great role in ischemic injury in a cellular model in which experimental hypoxia was induced using CoCl2. Main methods The ischemic injury induced in HK-2 cells by CoCl2 was validated by reduced cell viability at different times and doses. CZ NPs with size 2–3 nm were synthesized using non-hydrolytic sol-gel reaction. Results Cellular survival was reduced in a dose-dependent manner for 24 h after CoCl2 exposure. Because approximately 70% of cells survived after treatment with 300 µM of CoCl2 for 24 h, this dose was chosen for further study. CoCl2 caused a significant increase in ROS production 2 h after CoCl2. The extent of the effect of CoCl2 on ROS levels was significantly reduced by CZ NPs treatment. CZ NPs down-regulated proinflammatory markers and reduced caspase 3/7 activity in hypoxic HK-2 cells. CZ NPs also improved the survival of HK-2 cells in response to hypoxia. Conclusions CZ NPs have the potential as a therapeutic medicine for preventing ROS-related ischemia reperfusion injury after transplantation.

Antioxidant nanoparticles could treat sepsis

Sepsis occurs when the body’s immune response to an infection spirals out of control. The inflammatory signals designed to kill bacteria and other invaders spread beyond the infection site and in the worst cases lead to organ failure and death. The only effective treatment for sepsis is antibiotics, but they target only the source of the infection, not its symptoms. To combat that inflammation, scientists at Seoul National University, led by Seung-Hoon Lee and Taeghwan Hyeon, synthesized ceria-zirconia nanoparticles to scavenge reactive oxygen species (ROS) that damage and kill cells. The cerium ion Ce3+ mimics natural catalysts that remove superoxide and hydroxyl radicals, so a high Ce3+:Ce4+ ratio in the particles is important for treating inflammation. Shifting to the +3 oxidation state is energetically unfavorable, however, so the researchers added Zr4+ ions to the nanoparticles to stabilize the Ce3+:Ce4+ ratio and improve their antioxidant capabilities over ceria-only nanoparticles (Angew. Chem.

Ceria–Zirconia Nanoparticles as an Enhanced Multi‐Antioxidant for Sepsis Treatment

AbstractThe two oxidation states of ceria nanoparticles, Ce3+ and Ce4+, play a pivotal role in scavenging reactive oxygen species (ROS). In particular, Ce3+ is largely responsible for removing O2− and .OH that are associated with inflammatory response and cell death. The synthesis is reported of 2 nm ceria–zirconia nanoparticles (CZ NPs) that possess a higher Ce3+/Ce4+ ratio and faster conversion from Ce4+ to Ce3+ than those exhibited by ceria nanoparticles. The obtained Ce0.7Zr0.3O2 (7CZ) NPs greatly improve ROS scavenging performance, thus regulating inflammatory cells in a very low dose. Moreover, 7CZ NPs are demonstrated to be effective in reducing mortality and systemic inflammation in two representative sepsis models. These findings suggest that 7CZ NPs have the potential as a therapeutic nanomedicine for treating ROS‐related inflammatory diseases.

Ceria-Zirconia Nanoparticles as an Enhanced Multi-Antioxidant for Sepsis Treatment.

The two oxidation states of ceria nanoparticles, Ce3+ and Ce4+ , play a pivotal role in scavenging reactive oxygen species (ROS). In particular, Ce3+ is largely responsible for removing O2- and . OH that are associated with inflammatory response and cell death. The synthesis is reported of 2 nm ceria-zirconia nanoparticles (CZ NPs) that possess a higher Ce3+ /Ce4+ ratio and faster conversion from Ce4+ to Ce3+ than those exhibited by ceria nanoparticles. The obtained Ce0.7 Zr0.3 O2 (7CZ) NPs greatly improve ROS scavenging performance, thus regulating inflammatory cells in a very low dose. Moreover, 7CZ NPs are demonstrated to be effective in reducing mortality and systemic inflammation in two representative sepsis models. These findings suggest that 7CZ NPs have the potential as a therapeutic nanomedicine for treating ROS-related inflammatory diseases.

A facile and rapid route to synthesize ceria-zirconia nanoparticles with high performance for CH3SH decomposition

A novel and facile route was employed to rapidly synthesize ceria-zirconia nanoparticles with high-performance for CH3SH catalytic decomposition. Compared with classical surfactant-assisted method, the modified urea grind combustion (UGC) method offered advantages of easy operation and time-saving. An improvement of catalytic activity for CH3SH decomposition was observed for Ce0.8Zr0.2O2 nanoparticles prepared by this method. The synthesized materials were characterized by nitrogen adsorption-desorption, XRD, Raman, TEM, UV-vis, H2-TPR and XPS. Combined with those results, it was found that increased concentration of oxygen vacancies and surface chemisorbed oxygen species were formed in Ce0.8Zr0.2O2 nanoparticles prepared by this UGC method, thus improving reducibility and catalytic activity of the catalyst. In addition, the used catalysts have been characterized to understand the reaction processes during CH3SH catalytic decomposition.

A novel and facile method to rapidly synthesize Ce0.8Zr0.2O2 nanoparticles for CO preferential oxidation in H2-rich stream.

A novel urea grind combustion (UGC) route was reported in this paper to rapidly prepare the ceria-zirconia nanoparticles (Ce0.8Zr0.2O2). For comparison, the conventional surfactant-assisted (SA) and sol-gel (SG) methods were also employed to prepare Ce0.8Zr0.2O2 nanoparticles. CO preferential oxidation in H2-rich stream (CO-PROX) was chosen as probe reaction to investigate the catalytic performance of these Ce0.8Zr0.2O2 catalysts prepared with different methods to highlight the superiority of UGC. It was found that Ce0.8Zr0.2O2-UGC showed the better reducibility and oxygen mobility than the Ce0.8Zr0.2O2 prepared by SA and SG, because the UGC route favored the more incorporation of zirconia into CeO2, leading to more serious distortion of the structure, and more defective sites in the Ce0.8Zr0.2O2. As a result, Ce0.8Zr0.2O2-UGC exhibited the higher CO conversion, better O2 selectivity, and excellent catalytic stability without any deactivation during 72-h reaction on stream. More importantly, the UGC method, as compared to the relatively complex and time-consuming SA and SG method, is simple, facile, low-cost, time-saving (within 30 minutes) and scalable, thereby, might be very promising for the application in many fields.

Improved low-temperature reducibility in ceria zirconiananoparticles by redox treatment

It is found that optimized redox treatment can improve the low-temperature reducibility in ceria zirconia. We have studied the atomic-level structure and chemistry of individual nanoparticles for the raw and redox-treated ceria zirconia nanopowders to understand the origin of this improved performance.

Nanoscale compositional and structural evolution in ceria zirconia during cyclic redox treatments

We report changes in nanoscale composition and structure in individual ceria zirconia nanoparticles (nominal composition Ce0.7Zr0.3O2), before and after redox treatment, determined by energy dispersive X-ray (EDX) analysis using scanning transmission electron microscopy (STEM) and high resolution transmission electron microscopy (HRTEM) imaging. According to the chemical analysis of individual nanoparticles, the redox treatments promote the formation of more compositionally homogenous ceria zirconia solid solution nanoparticles, resulting in a uniform low-temperature reduction. Local pyrochlore-type cation ordering in individual nanoparticles was also observed after the high temperature reduction step. For nanoparticles with 70% ceria content, redox cycling treatment was critical to obtain material which exhibits a strong low temperature reducibility. The origin of significant X-ray diffraction line broadening and particle sintering mechanism in the solid solution nanopowders are discussed based on compositional and structural variation within and between individual nanoparticles and oxygen vacancies formed during high temperature reduction treatment.

In situ environmental TEM studies of dynamic changes in cerium-based oxides nanoparticles during redox processes

We apply in situ environmental transmission electron microscopy (ETEM) to study the dynamic changes taking place during redox reactions in ceria and ceria–zirconia nanoparticles in a hydrogen atmosphere. For pure ceria, we find that a reversible phase transformation takes place at 730 °C in which oxygen vacancies introduced during reduction order to give a cubic superstructure with a periodicity of roughly twice the basic fluorite lattice. We also observe the structural transformations taking place on the surface during reduction in hydrogen. The (1 1 0) ceria surface is initially constructed with a series of low-energy (1 1 1) nanofacets. Under strong reduction, the surface slowly transforms to a smooth (1 1 0) surface which was not observed to change upon re-oxidation. The surface transformation allows the reduced surface to accommodate a high concentration of oxygen vacancies without creating a strong perpendicular dipole moment. In the ceria–zirconia system, we are able to use ETEM to follow the redox activity of individual nanoparticles and correlate this property with structure and composition. We find considerable variation in the redox activity and interpret this in terms of structural differences between the nanoparticles.